Caribbean - Central America Weather

U.S. & Caribbean Weather Discussions and Severe Weather Events

Moderator: S2k Moderators

Forum rules

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K.

Help Support Storm2K
Message
Author
User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19841 Postby cycloneye » Fri May 10, 2019 5:07 am

Area Forecast Discussion
National Weather Service San Juan PR
413 AM AST Fri May 10 2019

.SYNOPSIS...An unstable weather pattern is expected through the
weekend as the combination of a mid to upper-level trough and
deeper moisture will result in an increase in the coverage and
intensity of showers and thunderstorms. Conditions will improve by
early next week as a ridge builds aloft, resulting in less shower
activity across the area.

&&

.SHORT TERM...Today through Sunday...

A light to moderate east to southeast low-level winds will prevail
today becoming more southeasterly Saturday through Sunday due to the
passage of weakly induced low level trough and a tropical wave
moving westward across the eastern Caribbean. An amplifying mid to
upper-level trough and the associated subtropical jet will also move
across the southwestern Atlantic today through the weekend and
continue to erode the upper level ridge. This will weaken the trade
wind cap inversion while increasing layered moisture content/cloud
cover.

The combination of these features during the period will favor
strong low level moisture convergence/pooling across the region
along with increasing upper level divergence and instability. This
will therefore increase potential for shower development across the
islands and regional waters during the entire period. Early morning
showers will continue to stream westward while affecting portions of
the north and east coastal areas of the islands. Afternoon shower
development will follow mainly over the central interior, and
northwestern sections of Puerto Rico; as well as over the eastern
interior and parts of the San Juan metro where isolated to scattered
showers will be likely in the form of streamers steered by the east
southeast wind flow. Isolated afternoon showers can also be expected
to develop on the west end and downwind of the U.S. Virgin Islands
each day.

The anticipated periods of locally heavy rains during the afternoons
will cause ponding of water on roadways at times and may lead to
urban and small stream flooding in some areas today and over the
weekend. Current model guidance still maintain high precipitable
water values up to near 2.0 inches through the period. However, The
best potential for increased and enhanced convective development
still looks like late Saturday through Sunday but overall a moist
and unstable weather pattern is in store for the entire period.


.LONG TERM...Monday through Friday...

Conditions will improve by early next week as the upper-level
trough pulls away and a ridge aloft builds overhead. This will
result in a decrease in shower activity across the area. However,
enough moisture will still be present to result in some passing
showers across eastern portions of PR and the USVI during the
overnight and morning hours followed by more enhanced showers
across interior and western portions of Puerto Rico during the
afternoon hours due to daytime heating and local effects.
Isolated thunderstorms are also possible with the afternoon
activity given that there will be sufficient moisture in the mid-
levels and 500 mb temperatures will range between -7 and
-8 degrees Celsius, allowing for enough instability aloft to be
present. This ridging pattern is expected to hold through the end
of the work week.

&&

.AVIATION...Prevailing VFR cond durg prd. SHRA en route btw local
islands and ovr the coastal waters...SCT ocnly BKN lyrs nr FL022...
FL050...FL090...FL250. Mtn top obscr ovr Ern PR low cld lyrs/-SHRA
til 10/14Z. SHRA psbl nr TJSJ/TJMZ/TJBQ with brief MVFR low cigs
and SHRA btw 10/17Z-10/22Z. Sfc wnds bcmg fm E 10-15 kt with ocnl
higher gusts and sea breeze variations aft 10/14z. L/lvl wnds fm E-
SE 10-20 kt blo FL100. FEW tops btw FL100-FL150.


&&

.MARINE...Fairly tranquil seas between 3 and 5 feet will prevail
across the regional waters today and through the upcoming
weekend. Seas will become choppy by early next week as a larger
northerly swell arrives and spreads across the regional waters.

For beachgoers, a small northerly swell currently affecting the
area will result in a high risk of rip currents for the beaches
located along the north-central coast of Puerto Rico as well as
the San Juan and Vicinity coast. A low to moderate risk of rip
currents is expected elsewhere.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 77 88 76 / 50 30 50 50
STT 86 77 85 77 / 30 50 60 60
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19842 Postby cycloneye » Sat May 11, 2019 5:37 am

Area Forecast Discussion
National Weather Service San Juan PR
427 AM AST Sat May 11 2019

.SYNOPSIS...Unsettled weather is on tap throughout the weekend as
the combination of a mid to upper-level trough and deeper
moisture will result in periods of showers and thunderstorms
across the area. As the trough pulls away and a mid to upper-
level ridge builds overhead by early next week, more stable
weather conditions are expected with locally and diurnally induced
showers and isolated thunderstorms over interior and western
portions of Puerto Rico each afternoon.

&&

.SHORT TERM...Today through Monday...

Trofiness aloft - which is associated with short wave troughs moving
across the forecast area - will continue to prevail through at least
early Monday. At lower levels, building high pressure north of the
area will yield east southeast winds while an easterly disturbance
moves over the Caribbean waters. In terms of moisture, continue to
expect advection with precipitable water peaking near 2.0 inches
Saturday night into Sunday Morning. Precipitable water, however,
will decrease near normal values (1.75 inches) on Monday.

Under trofiness and moisture advection, an unsettled weather pattern
is expected to prevail Saturday and Sunday with periods of showers
and thunderstorms. The highest chance for showers and thunderstorms
is expected Saturday afternoon across central, north central, west
and northwest Puerto Rico as well as portions of the San Juan
Metropolitan Area. Although, the shower and thunder activity will
diminish across these areas during the evening hours, the potential
for showers and thunderstorms continues overnight. The chance for
showers and thunderstorms will be focused over east and southeast
Puerto Rico as well as the outlying islands Saturday night into
Sunday morning. There is a caveat for this afternoon, if high clouds
continue to stream across the northeast Caribbean, showers and
thunderstorms may be delayed or somewhat inhibited.

As moisture returns to normal values, the chance for showers and
thunderstorms will be focused once again over the northwest
quadrant of Puerto Rico Sunday afternoon and Monday afternoon.
Elsewhere, isolated showers will remain possible.

Periods of heavy rainfall could trigger flooding but also landslides
in areas of steep terrain, particularly the eastern third and the
northwest quadrant of Puerto Rico.

.LONG TERM...Tuesday through Saturday...

A mid to upper-level ridge will build and hold across the area
through the end of the work week. This will keep the upper-level
forcing weak and thus limit the areal coverage of showers across
the area. However, as it is typically the case during this time of
the year, there will be sufficient moisture available to result in
some passing showers across portions eastern Puerto Rico and the
USVI during the overnight and early morning hours followed by the
development of more enhanced showers across interior and western
portions of Puerto Rico during the afternoon hours due to daytime
heating and local effects. Isolated thunderstorms are also likely
with the afternoon activity given that there will be sufficient
mid-level moisture present and 500 mb temperatures will range
between -7 and -8 degrees Celsius, which will enhance the
instability aloft.

By later Friday into Saturday, model guidance is indicating a
weakening of the ridge aloft as a mid to upper-level trough
amplifies over the southwest Atlantic. If the current model
solution holds, then an increase in upper-level forcing and more
widespread shower and thunderstorm activity can be expected by
next weekend.

&&

.AVIATION...Mostly VFR conds are expected to prevail at all TAF
sites with brief periods of MVFR conds in SHRA/TSRA at JMZ/JBQ and
JSJ between 11/16z and 11/22z. East southeast winds near 12 knots
with higher gusts and sea breeze variations.

&&

.MARINE...Seas between 2 to 5 feet and winds up to 15 knots are
expected to prevail across the regional waters for today. A 4 to
5 foot northeasterly swell is expected to arrive and spread across
the Atlantic waters and local passages. This will promote choppy
seas of up to 6 feet.

For beachgoers, there is a moderate risk of rip currents for today
across the north-facing beaches of Puerto Rico, Culebra, Vieques
and Saint Thomas and the eastern beaches of Saint Croix. The rip
current risk is expected to become high by Sunday night for the
northern beaches of Puerto Rico and Culebra with the arrival of
the northeasterly swell.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 77 88 77 90 / 50 60 40 30
STT 78 85 79 86 / 60 60 30 30
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19843 Postby cycloneye » Sun May 12, 2019 5:07 am

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
433 AM AST Sun May 12 2019

.SYNOPSIS...Unsettled weather conditions will continue through
today as the combination of a mid to upper-level trough and deep
moisture will result in periods of showers and thunderstorms
across portions of the local area. A more benign weather pattern
is expected by Monday and continue through Thursday as a mid to
upper-level ridge builds overhead. However, locally and diurnally
induced showers and isolated thunderstorms can be expected across
interior and western PR each afternoon. Unsettled weather
conditions may return once again on Friday and Saturday as a mid
to upper-level trough amplifies across the southwest Atlantic.

&&

.SHORT TERM...Today through Tuesday...

Trofiness aloft will continue to prevail through at least early
Monday. As trofiness moves away and a ridge pattern builds from the
west early next workweek, the 250 and 500 MB heights will begin to
rise. Under raising heights, a sharp decrease in precipitable water
is expected on Monday. At lower levels, high pressure across the
central Atlantic will continue to yield east southeast winds while
an easterly disturbance moves well south of the area over the
Caribbean waters.

Under trofiness and precipitable water values near 2.0 inches, the
chance for periods of showers and thunderstorms continues today. The
highest chance for showers and thunderstorms is expected across
central, north central, west and northwest Puerto Rico as well as
portions of the San Juan Metropolitan Area in the afternoon. As
moisture decreases and the ridge aloft builds, the intensity and
areal coverage of showers will decrease Monday and Tuesday, being
Tuesday the driest day. Showers and isolated thunderstorms, however,
are still expected both days but mainly focused across northwest
Puerto Rico.

Periods of heavy rainfall could trigger flooding but also landslides
in areas of steep terrain this afternoon across northwest Puerto
Rico.

.LONG TERM...Wednesday through Sunday...

The mid to upper-level ridge is expected to hold through at
least Thursday. As a result, shower activity is expected to be
limited across the region due to the lack of mid to upper-level
forcing. However, locally and diurnally induced showers and
isolated thunderstorms can still be expected across interior and
western portions of Puerto Rico during the afternoon hours.

Model guidance continues to indicate a more unsettled weather
pattern for Friday and Saturday as the ridge aloft erodes due to
an amplifying mid to upper-level trough across the southwest
Atlantic. Meanwhile, at low-levels, a frontal boundary will be
located north of the region and will induce a southeasterly low-
level flow that will aid in moisture pooling across the area.
Therefore, with the combination of better moisture and better mid
to upper-level forcing, more widespread showers and thunderstorms
can be expected.

&&

.AVIATION...Mostly VFR conds are expected to prevail at all TAF
sites through the forecast cycle with brief periods of MVFR conds in
SHRA/TSRA at JMZ/JBQ and possibly JSJ between 12/16z and 12/22z.
East southeast winds at around 15 knots with higher gusts and sea
breeze variations to continue.


&&

.MARINE...Seas are expected to range between 3 to 5 feet across
most of the regional waters for most of the day. However, by this
afternoon, seas will increase up to 6 feet across the offshore
Atlantic waters with the 6 foot seas extending across the rest of
the Atlantic waters and local passages late tonight into the day
on Monday as a northeasterly swell arrives. Seas will remain
choppy through Tuesday.

For beachgoers, there is a moderate risk of rip currents across
the north-facing and some of the east-facing beaches of the
islands. The rip current risk is expected to increase to high by
this evening across the northern beaches of Puerto Rico and
Culebra with the arrival of the northeasterly swell.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 77 88 77 / 30 20 20 20
STT 86 78 86 78 / 50 30 20 30
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19844 Postby cycloneye » Mon May 13, 2019 4:51 am

Area Forecast Discussion
National Weather Service San Juan PR
418 AM AST Mon May 13 2019

.SYNOPSIS...A mid-upper level ridge is forecast to build from the
east over Puerto Rico and the U.S. Virgin Islands later today. At
the surface, Bermuda High pressure will promote a southeast wind
flow through the end of the upcoming work-week.


&&

.SHORT TERM...Today through Wednesday...

A surface high pressure across the central Atlantic, and a surface
low pressure across the eastern seaboard of the US, will cause
southeasterly winds across the local area for the next several days.
The upper level though over the local islands will continue to
slowly move east, and it is forecast for the axis of the trough to
be just east of the local islands by this afternoon, which would put
the local islands on the subsident side of the trough with
northwesterly winds in the upper levels. That said, showers are
still expected this afternoon across northern and northwestern
Puerto Rico since there may still be enough moisture--around 1.7
inches of precipitable water for 13/18Z according to the GFS model--
to combine with the diurnal heating and local effects. The USVI is
expected to observe mainly fair weather today with a slight chance
of brief showers.

For Tuesday and Wednesday, mainly fair weather is expected as drier
air starts to filter in and the upper trough is expected to be
replaced by an upper ridge. Only locally induced showers in the
afternoons across western PR are expected. The USVI is expected to
observe mainly fair weather, only a slight chance of brief showers
for the USVI.

.LONG TERM...Thursday through Monday...

Models continue to suggest a more unstable pattern for Friday
and Saturday as the ridge aloft erodes due to an amplifying mid to
upper-level trough across the southwest Atlantic. Meanwhile, at
low-levels, a frontal boundary will be located north of the region
and will induce a southeasterly low- level flow that will aid in
moisture pooling across the area. Therefore, with the combination
of better moisture and better mid to upper-level forcing, more
widespread showers and thunderstorms can be expected.


&&

.AVIATION...Prevailing VFR cond expected for the next 24 hours.
Cloudiness may cause CIGS at around FL030 the USVI terminals through
10Z for TIST and TISX, higher CIGS possible at TISX through 13/20Z.
Winds will be from the East to ESE today, between 10-15 KT, sea
breeze variations developing after 13/13Z. SHRA expected across
North and NW-PR, which could cause VCSH at TJBQ and TJSJ after
13/17Z.


&&

.MARINE...A northeast swell will rapidly build across the local
Atlantic waters and all local passages. The 41043 Bouy has been
reporting 5 to 6 feet swell with 13 second periods since midnight
therefore the NE will be reaching the northern coast of Puerto
Rico before mid morning today. There is a High Rip Current Risk
in effect through Tuesday afternoon. Winds will be mainly East at
10 to 15 knots with higher gusts.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 77 90 78 / 20 10 10 20
STT 86 78 86 78 / 20 20 10 20
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19845 Postby cycloneye » Tue May 14, 2019 5:14 am

Area Forecast Discussion
National Weather Service San Juan PR
441 AM AST Tue May 14 2019

.SYNOPSIS...A ridge pattern will promote dry air at mid-levels
through the short- term period. Bermuda High pressure will result
in a southeast wind flow through the end of the work-week. This ridge
aloft is forecast to erodes between late Thursday and Friday as
an amplifying mid to upper- level trough moves across the
southwest Atlantic.

&&

.SHORT TERM...Today through Thursday...

A surface high pressure across the central Atlantic, and a surface
low pressure across the northeastern coast of the US, will continue
to cause east-southeasterly winds across the local area for the next
few days. The upper level though that affected the local area this
past weekend is now to the east of the local islands, which puts the
local islands under the upper ridge that is expected to remain over
the local area for the next few days. There is drier air moving in
with some Saharan dust across the area today, which will cause haze
across the area and would limit shower development in the afternoon.
That said, there is still a chance of showers across NW-PR this
afternoon, but the coverage area affected is expected to be very
limited and the rainfall amounts are not expected to be high enough
to cause significant flooding. The temperatures across the lower
elevations are expected to reach the low 90s once again today with a
east-southeast to southeast wind flow.

For Wednesday, mainly fair weather is expected in the morning as the
drier air with Saharan dust is still expected to be present.
However, the latest guidance is showing a patch of moisture for
western PR on Wednesday afternoon, and the high-res guidance
continues to insist on good shower development across portions of
northern PR, central PR and western PR in the afternoons of both
Wednesday and Thursday. But this shower development would be mainly
locally induced due to local effects and increase in moisture
expected. The Saharan dust concentrations should diminish for
Thursday afternoon. The USVI is expected to observe mainly fair
weather, only a slight chance of brief showers over the next few
days. We may have to wait until the upper level dynamics become
favorable in order to have good shower activity over the USVI,
which is not expected to happen at least over the next few days.

.LONG TERM...Friday through Tuesday...

Models continue to suggest a more unstable pattern for Friday
and Saturday as the ridge aloft erodes due to an amplifying mid to
upper-level trough across the southwest Atlantic. Meanwhile, at
low-levels, a frontal boundary will be located north of the region
and will induce a southeasterly low-level flow that will aid in
moisture pooling across the area through at least mid week,
increasing the shower coverage across the local forecast area.


&&

.AVIATION...Haze is expected due to Saharan dust but
visibilities are expected to remain P6SM. Prevailing VFR cond
expected for the next 24 hours. Winds will be from the ESE today,
between 10-15 KT, sea breeze variations developing after 14/13Z.
SHRA possible across NW-PR, which could cause VCSH at TJBQ.


&&

.MARINE...Northern swells will continue to subside today through
tonight therefore the high rip current risk will continue through
late tonight. At this moment the rincon and the San Juan buoys are
reporting 4 to 5 feet waves. Another pulse of NE swells will
arrive our local waters on Thursday night.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 79 91 78 / 20 20 20 10
STT 86 79 86 77 / 10 20 20 20
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19846 Postby cycloneye » Wed May 15, 2019 4:56 am

Area Forecast Discussion
National Weather Service San Juan PR
450 AM AST Wed May 15 2019

.SYNOPSIS...The combination of a ridge pattern aloft and a low-level
southeasterly wind flow will continue to promote warm temperatures
across the local islands. Stable weather conditions will persist
through at least Thursday. Localized induced showers should not be
ruled out each afternoon across the interior and western sections
of Puerto Rico.


&&

.SHORT TERM...Today through Friday...

A mid to upper level ridge pattern should inhibit thunderstorm
development today over mainland PR. Drier air with suspended Saharan
dust is forecast to gradually diminish during the next few days. A
broad surface high pressure spread across the central-eastern
Atlantic will continue to promote a light to moderate southeasterly
wind flow across the forecast area today. This will continue to
cause above normal temperatures along the coastal areas of the
islands. A frontal boundary is expected to remain west and north of
the region through the short term period. As the front approaches,
winds will relax and are forecast to remain under 10 kt.

A small surge in low level moisture, currently moving across the
Leeward islands should reach the region during the afternoon hours
and aid in the development of locally induced afternoon showers
along the Cordillera Central and western sections of PR.
Precipitable water content will gradually increase and peak on
Thursday afternoon/evening into Friday morning as an upper level
trough press against the upper ridge and as Saharan dust diminish
across the area. This will enhance once again diurnal convection
over the interior and western sections of PR as well result in
passing showers across the USVI and eastern sections of PR during
the overnight/early morning hours. Decided to remove thunderstorms
from the forecast for now due to lacking any significant mid to
upper level forcing and as the forecast 500mb temps are warmer than
previous model runs.

.LONG TERM...Saturday through Wednesday...

The unstable pattern will prevail through at least Sunday as the
ridge aloft erodes due to an amplifying mid to upper-level trough
across the southwest Atlantic. Meanwhile, at low-levels, a frontal
boundary will be located north of the region and will induce a
southeasterly low- level flow that will aid in moisture influx across
the area through at least mid week, increasing the shower
coverage across the local forecast area.


&&

.AVIATION...HZ due to Saharan dust expected early in the fcst period
but visibilities are expected to remain P6SM. Otherwise, mainly VFR
conditions are expected to prevail across all terminals for the next
24 hours. ESE winds between 10-15 KT with sea breeze variations
developing after 15/13Z. SHRA expected this afternoon over west-
interior PR may cause tempo MVFR at TJBQ/TJMZ.


&&

.MARINE...The northern swell have subside and local near shore
buoys are reporting 3 feet or less. Tranquil marine conditions are
expected to continue through at least Thursday night as another
pulse of energy is forecast. Swells will be at around 3 feet at 12
seconds. Today expect 2 to 4 feet and winds at around 10 mph with
higher gusts.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 78 90 78 / 10 10 20 10
STT 86 78 85 76 / 20 30 30 20

&&
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19847 Postby cycloneye » Thu May 16, 2019 5:13 am

Area Forecast Discussion
National Weather Service San Juan PR
453 AM AST Thu May 16 2019

.SYNOPSIS...The combination of a ridge pattern aloft and a low-level
southeasterly wind flow will promote warm temperatures across the
local islands. Stable weather conditions will persist through at
least Today. However, localized induced showers will develop across
the interior portions of Puerto Rico each afternoon. An amplifying
upper- level trough, which is expected to move across the western
Atlantic, will weaken the ridge pattern aloft Friday into the
weekend.


&&

.SHORT TERM...Today through Saturday...

Upper level ridge across the central Caribbean is expected to
collapse later today as a polar trough over the western Atlantic
press against it. At the lower levels, moisture is expected to
gradually increase and peak on Friday with precipitable water
values near 1.80 inches. Light steering winds will continue for the
next few days as the surface high pressure over the central Atlantic
shifts further east and a surface front lingers over the western
Atlantic to the north/northwest of the islands. Therefore, afternoon
showers and thunderstorms will be induced by the combination of the
available low level moisture, daytime heating, sea breeze
convergence and orographic effects. Due to light steering winds, the
potential for flooding rains will increase due to slow moving storms
each afternoon mainly over the interior and western sections of PR.
Southerly winds will continue to promote above normal temperatures
today and highs should reach the low 90s along coastal areas.

A surface high pressure is forecast to build behind the front over
the southwestern Atlantic by Friday morning, this will promote a
northeasterly steering wind flow and the focus of showers should
shift over the west/southwest quadrant of PR on Friday and Saturday
with light passing showers across the USVI and northeastern sections
of PR during the overnight/early morning hours.

.LONG TERM...Sunday through Thursday...

The old frontal boundary will continue to be situated to the north
of the local area through at least mid week. This feature will
maintain moisture influx toward the local region increasing the
chances of showers and thunderstorms every afternoon mainly across
the interior and western portions of Puerto Rico. A low to mid low
pressure will develop early Sunday over the western Atlantic just
east of the northern Bahamas. This feature will help shift the
wind pattern more from the southeast across the local region
between Monday and Tuesday.


&&

.AVIATION...Aviation...Mainly VFR conditions are expected prevail during the
next 24 hours across all terminals. However, TSRA/SHRA btw 17-21z
over the interior sections of PR could result in tempo MVFR conds at
TJMZ/TJBQ/TJPS. Surface winds will continue from the SE between 5-10
kts with sea breeze variations aft 14z.


&&

.MARINE...Tranquil marine conditions will prevail through at
least the incoming weekend. Seas will be 4 feet or less and winds
will continue at around 10 knots with highers gust along the
coastal regions.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 78 90 77 / 20 10 10 10
STT 86 76 86 76 / 30 20 20 20
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19848 Postby cycloneye » Fri May 17, 2019 5:00 am

Area Forecast Discussion
National Weather Service San Juan PR
358 AM AST Fri May 17 2019

.SYNOPSIS...The combination of a surface high pressure across the
north-central Atlantic and a frontal boundary north of the area
will continue to induce a southeasterly flow into the upcoming
weekend. Meanwhile, in the mid to upper-levels, a ridge will
continue to gradually weaken during the next couple of days as a
trough amplifies across the southwest Atlantic. Showers and
isolated thunderstorms are expected to develop and affect mainly
interior and western portions of Puerto Rico during the afternoon
hours.

&&

.SHORT TERM...Today through Sunday...

Upper level ridge will continue to weaken across the eastern
Caribbean as an amplifying upper level trough over the southwestern
Atlantic continues to build during the next several days. At the
surface, a front extends from the Bahamas into the north central
Atlantic. Behind the front a weak surface high will build across the
western Atlantic through the short term period, while a broad
surface high over the central Atlantic shifts further east. This
will continue to promote a light to moderate east to southeast
steering wind flow for the next couple of days.

Showers with isolated thunderstorms are expected to develop each
afternoon over the interior/western sections of Puerto Rico due to
the combination of the available low level moisture, daytime
heating, sea breeze convergence and orographic effects. Urban and
small stream flooding can be expected with the heaviest showers.
Across the rest of Puerto Rico and the U.S. Virgin Islands, isolated
to brief scattered showers are possible in diurnal shallow
convection and with passing showers. Maximum temperatures are
expected to range from the mid 80s to low 90s in general across the
islands.

.LONG TERM...Monday through Friday...the low to mid level low
will continue to meander just east of the northern Bahamas between
Monday and Tuesday maintaining the core of moisture to the north
of the region. A weak frontal boundary is forecast exit the
eastern coast of U.S. on Tuesday Morning. As this boundary dig SE,
it will push the moisture core of the old boundary across the
local islands increasing the shower and cloud coverage between
Wednesday and Friday.

Models are suggesting a weak tropical wave moving across the
Atlantic waters through mid week through the labor day weekend.
This wave is forecast to remain south of our regions as it moves
across the Caribbean waters.

&&

.AVIATION...Mainly VFR conditions are expected prevail during the
next 24 hours across all terminals. However, TSRA/SHRA btw 18-22z
over the western interior sections of PR could result in tempo MVFR
conds at TJMZ. East to southeast winds between 5-10 kts with sea
breeze variations and higher gusts expected after 14z.


&&

.MARINE...Marine conditions will remain relatively tranquil for
the next several days although winds will slowly increase in the
next 24 to 36 hours. This could generate a slight chop mainly
along the coastal sections due to the local sea breeze effect. At
this moment models are showing a small ground swell reaching the
at the local Atlantic waters. This long period swell will slowly
dissipate through Saturday night. A moderate risk of rip currents
is expected for the northern beaches of Puerto Rico and Culebra
through Friday, with a low risk expected elsewhere.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 89 78 / 10 10 20 20
STT 86 77 86 77 / 20 20 40 40
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19849 Postby cycloneye » Sat May 18, 2019 5:07 am

Area Forecast Discussion
National Weather Service San Juan PR
543 AM AST Sat May 18 2019

.SYNOPSIS...A broad surface high pressure across the east-central
Atlantic and a frontal boundary north of the region will continue
to promote a light to moderate east to southeast wind flow
through early next week. A mid to upper level ridge will continue
to erode as an upper level low builds over the southwest
Atlantic. Showers and isolated thunderstorms are expected to
develop across the interior and western sections of PR each
afternoon.

&&

.SHORT TERM...Today through Monday...

A weak upper-level ridge will hold over the region through the
weekend, then a deepening upper-level trough over the western
Atlantic waters will cause the upper-level ridge to retreat east of
Puerto Rico on Monday. As the upper-level ridge weakens mid to upper-
level moisture is expected to increase over the Atlantic waters just
north of Puerto Rico. The mid to upper-level moisture increase is
depicted by the GFS 500 and 250 relative humidity images. Also,
shallow patches of low-level moisture will move across the island
periodically through Monday. In addition, the sub-tropical jet will
increase upper-level level winds over the region. At this time Upper-
level winds are expected to be near 40 to 50 kts.

Over the next several days urban and small stream flooding is
possible due to heavy rainfall caused by afternoon convection mainly
over portions of interior and western areas of Puerto Rico. However,
can not rule out flooding in other areas too.

Today, showers are forecast to develop across western, northwestern
and interior areas of Puerto Rico this afternoon. In addition,
isolated showers are possible across portions of eastern Puerto Rico
and the U.S. Virgin Islands during the afternoon. Showers and
isolated thunderstorms will develop as a result of significant
surface heating combined with local and diurnal effects. TJSJ skew-T
shows a convective temperature of 87 degrees today, the forecast
calls for a daytime high temperature of 88 to 90 degrees. The
convective temperature is the temperature the surface of the the
earth must warm to in order for thunderstorms to occur. Therefore,
with significant surface heating expected today, and daytime
temperatures above the convective temperature isolated thunderstorms
are possible. Showers and isolated thunderstorms that develop should
diminish by sunset as surface heating decreases.

Sunday and Monday, low-level moisture is forecast to filter into the
region from the east. The increases in moisture combined with weak
upper-level instability provided by the deepening upper-level trough
and sub-tropical jet should help showers to mature to thunderstorms
across the interior and western areas of Puerto Rico during the
afternoon. Furthermore, abundant surface heating combined with local
and diurnal effects will aid in shower and thunderstorm development
during the afternoon.


.LONG TERM...Tuesday through Saturday...

An upper level low over the southwest Atlantic is forecast to
merge with a deep polar trough by mid week. At lower levels, an
associated low and weak frontal boundary over the western Atlantic
are expected to promote a moist east to southeast wind flow over
the region. These features will provide sufficient moisture and
instability for the development of showers and thunderstorms
across portions of the interior and north/northwest sections of PR
as well enhance diurnal convection between the USVI and eastern
sections of PR each afternoon through at least Thursday.
Thereafter, weak perturbations on the trade winds will bring
sufficient low level moisture to aid in the development of
diurnally induced showers mainly over western PR and from
streamers developing off the USVI.


&&

.AVIATION...VFR conds expected for most of the forecast period.
SHRA/TSRA near TJBQ, and TJMZ by 18/18Z, while SHRA is possible near
TJSJ. MVRF conds are possible across terminal sites TJBQ AND TJMZ
due to SHRA/TSRA. Winds will be out of the east at 15 to 20 kts
with higher gusts possible. Sea breeze variations and occasional
gusts, especially near SHRA or TSRA.


&&

.MARINE...The combination of a small long period northerly swell
and onshore winds due to the sea breeze later today will cause a
high risk of rip currents along the north central coast of Puerto
Rico. Seas are expected to continue between 2-4 feet in general
across the regional waters with the exception of the Atlantic
coastal waters were seas up to 5 feet are expected. Also, small
crafts should exercise caution across these waters due to winds up
to 20 knots later today. Elsewhere, a light to moderate east to
southeast wind flow will prevail.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 89 77 / 20 20 30 40
STT 87 78 86 77 / 20 40 40 30
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19850 Postby cycloneye » Sun May 19, 2019 4:58 am

Area Forecast Discussion
National Weather Service San Juan PR
515 AM AST Sun May 19 2019

.SYNOPSIS...A surge in low level moisture will increase showers
across the USVI and eastern PR later today and through the
overnight hours. Showers and thunderstorms are expected each afternoon
mainly across the northwest quadrant of Puerto Rico for the next
several days. Elsewhere, scattered showers are possible and
isolated thunderstorms can not be ruled out. An upper level
trough will continue to approach the forecast area from the
northwest and move just north of the region by Thursday. Light to
moderate southeasterly trades will continue across the region
through next week.


&&

.SHORT TERM...Sunday through Tuesday...

A mid to upper-level trough currently northwest of Puerto Rico will
continue to move to the east over the next several days. As the mid
to upper-level trough moves closer it will weaken the mid to upper-
level ridge, and cause the ridges to gradually move to the east. At
the low-levels a surface high over the eastern Atlantic and trough
350 miles north of Puerto Rico will induce an east to southeast
winds over the region. Also, an increase low-level moisture over the
next several days across Puerto Rico and the local waters.

An increase in showers and isolated thunderstorms are forecast to
develop across northwestern areas of Puerto Rico. As a result of
significant surface heating combined with local and diurnal effects.
In addition, due to proximity of the mid to upper-level trough and
sub-tropical jet a slight increase in upper-level divergence is
expected mainly across northwestern areas of Puerto Rico during the
afternoon.

Therefore, during the rest of of the short-term period
showers will mature to thunderstorms across interior and western
areas of Puerto Rico. These showers could cause urban and small
stream flooding and ponding of water on roadways. Elsewhere,
isolated to scattered showers are possible across the U.S. Virgin
Islands, interior, and eastern areas of Puerto Rico during the early
morning and afternoon.

.LONG TERM...Wednesday through Sunday...

A mid to upper level trough is forecast to move from the western
Atlantic and over the northeastern Caribbean between Wednesday and
Thursday. This will provide upper level support for the
development of showers and thunderstorms across PR and portions of
the USVI. Precipitable water content is forecast to peak during
this period between 1.75-2.00 inches, therefore the potential for
flooding rains will be high.

Another short wave trough is forecast to move just northeast of
the region during the weekend. This will continue to provide
divergence aloft to support afternoon convection. At lower levels,
the absence of the trade wind cap and light southerly steering
winds will allow for tropical moisture to pool over the region.
Induced perturbations across the eastern Caribbean in combination
with trough pattern aloft will increase the potential for shower
activity with possible thunderstorms across the Caribbean waters
and across the USVI/eastern sections of PR late in the weekend.


&&

.AVIATION...VFR conds expected through the forecast period with
VCSH/VCTS at TJMZ and TJBQ by 19/18Z. then SHRA/VCTS should end by
20/01Z with SCT to BKN skies. Winds will be out of the east to
southeast at 10 to 15 kts with higher gusts possible.


&&

.MARINE...Seas are expected to range between 3-5 feet in general
with the highest seas expected across the Atlantic waters. East to
southeast winds will prevail between 5-15 kts with sea breeze
influences after 10 am each day. A moderate risk of rip currents
will continue for the northern beaches of Puerto Rico and St.
Thomas.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 89 77 / 30 40 30 30
STT 86 77 86 77 / 40 30 30 50
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19851 Postby cycloneye » Mon May 20, 2019 4:58 am

Area Forecast Discussion
National Weather Service San Juan PR
444 AM AST Mon May 20 2019

.SYNOPSIS...
An unstable weather pattern is forecast to persist today through
the end of the week. The unsettled weather is due to a mid to
upper-level trough north of Puerto Rico and low-level moisture
that will pool over the region. The factors above will increase
the likelihood for the development of deep convection, and
isolated thunderstorms across northern, interior and western areas
of Puerto Rico during the afternoon. Wednesday current guidance
shows a week sub- tropical jet with winds of 50 to 80 kts near the
area through Monday of next week. The sub-tropical jet combining
with a mid to upper-level trough that develops during the middle
of the week will increase the divergence aloft across Puerto Rico
and the U.S. Virgin Islands. The divergence aloft will aid in the
development of deep convection and thunderstorms across the
western, interior and northern areas of Puerto Rico during the
afternoon. The thunderstorms and deep convection could cause urban
and small stream flooding with ponding of water on roadways.

&&

.SHORT TERM...

The proximity of a mid to upper level trough will continue to weaken
the ridge aloft. This trough is forecast to move close to the
northeastern Caribbean through the next few days providing upper
level support for the development of showers and thunderstorms
across the islands of Puerto Rico and the U.S. Virgin Islands. A
trough of low pressure located off to the north-northwest of the
islands will induce a moist southeast wind flow across the region
through the short term period. Model guidance are suggesting
precipitable water values between 1.75-2.10 inches, which are near
or above normal values for this time of the year. In addition, a sub-
tropical jet will reach it maximum around Wednesday increasing upper
level divergence. Under this weather pattern, the development of
showers and thunderstorms is likely, especially along and north of
the Cordillera Central each afternoon.

Soils are already saturated across portions of the interior,
northwest and northeast Puerto Rico. Therefore, as the potential for
showers and thunderstorms increase, the risk for flooding will
increase. Under a southeast wind flow, the potential for urban and
small stream flooding is high across the San Juan Metro Area.

High temperatures will reach the low 90s along coastal areas each
afternoon.

&&

.LONG TERM...Thursday through Monday...

A mid to upper-level trough in the Western Atlantic will increase
upper-level instability across Puerto Rico and the local waters
through the end of the workweek. As a result, an increase in
upper-level divergence aloft for portions of northern, central,
and western areas of Puerto Rico. Analysis of the 500 mb
temperature showers values ranging from 8 to 9.5 degrees celsius.
In addition, precipitable water values will range from 1.7 to 2.00
inches through most of the long-term period. Also, the sub-
tropical jet will provide added instability and increase
divergence aloft with winds ranging from 50 to 80 kts across the
region through the long-term period.

The combination of significant low-level moisture combining with
mid to upper-level instability with local and diurnal effects will
increase the likelihood for the development of deep convection.
The deep convection will be in the form of thunderstorms over the
interior, eastern, western areas of Puerto Rico during the
afternoon. Also, showers and isolated thunderstorms are possible
across the U.S. Virgin Islands and other areas of the region
during the afternoon.

This weekend another mid to upper-level trough is forecast to
develop in move north of Puerto Rico. However, the mid to upper-
level trough will provide upper-level instability and aid in the
development of deep convection across the Puerto Rico and the U.S.
Virgin Islands.

Current model guidance shows steep lapse rates, veering winds,
and deep tropical moisture across most of the area. For the
reasons above an increase in deep convection and thunderstorms are
forecast during the afternoon across the Caribbean waters, U.S.
Virgin Island, and eastern sections of Puerto Rico Saturday
through early next week. Showers and isolated thunderstorms that
develop could cause urban and small stream flooding with ponding
of water on roadways.

&&

.AVIATION...

VFR conds expected through the morning hours. But, VCSH
will move from time to time across the terminals of E-PR/USVI/Lesser
Islands. SHRA/TSRA will develop along and north of the Central
Mountain Range of Puerto Rico between 20/16-23. This activity will
create MVFR or even IFR conds at TJBQ and possibly at TJMZ/TJSJ.
Winds will continue calm to light and VRB, becoming from the ESE at
10-15 KT with sea breeze variations and occasional gusts after
20/13Z.

&&

.MARINE...
Tranquil marine conditions will continue over the next several
days. Seas will range from 3 to 5 feet across all local and region
waters. Winds will be out of the east to southeast at 10 to 15
kts. A moderate risk of rip currents across portions of the north
facing beaches of Puerto Rico today.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 89 78 / 50 30 30 40
STT 86 77 86 77 / 40 20 20 30
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19852 Postby cycloneye » Wed May 22, 2019 5:01 am

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST Wed May 22 2019

.SYNOPSIS...
Unstable weather conditions will persist through at least Thursday
due to the proximity of a mid- to upper-level trough. This feature
along with plenty of moisture will result in rounds of showers
and thunderstorm each day, especially during the afternoon hours.
A slight improvement is expected Friday and Saturday. Once again,
a trof pattern combined with abundant tropical moisture will
enhance the potential for showers and thunderstorms across the
islands by the next week.

&&

.SHORT TERM...Today through Friday...

A light to moderate east to southeast wind flow will prevail across
the region supported by a surface ridge extending southwestward over
the central Atlantic. At mid to upper levels, a southeastward
propagating trough will continue to sink into the northeastern
Caribbean. As this feature approaches the forecast area, favorable
conditions aloft will persist under a divergence pattern and
increased instability. These conditions along with plenty tropical
moisture--model precipitable water estimates between 1.5 and 2.0
inches--will result in enhanced shower and thunderstorm development
with peak intensity and areal coverage expected on Thursday.
Overnight and morning showers are expected to stream over the waters
into portions of eastern and southern Puerto Rico, as well as over
the U.S. Virgin Islands. As the day progresses, the bulk of this
activity is forecast to shift and cluster along the interior and
western sectors of Puerto Rico. Showers and isolated thunderstorm
are also expected to move over the San Juan metropolitan area and
the U.S. Virgin Islands. Rainfall accumulations are forecast to peak
around an inch and a half with isolated higher amounts today, but
the potential for widespread activity will result in rainfall totals
up to 2 inches with isolated higher amounts on Thursday. As a
result, there is an increasing potential for urban and small streams
flooding, as well as mudslides in areas near steep terrain,
particularly on Thursday.

A slight improvement is expected on Friday, but afternoon convection
will once again affect the northwestern quadrant of Puerto Rico.

.LONG TERM...Saturday through Wednesday...

Although weather conditions should improve somewhat on Saturday,
early morning showers across eastern PR and the US Virgin Islands
followed by afternoon convection along and west of the Cordillera
Central should not be ruled out.

Global models continues to suggest an amplifying trough
interacting with deep tropical moisture early next week, Sunday
through Tuesday. Precipitable water values could range between 1.8
and 2.2 inches through this period. GFS Chiclets look reasonable
consistent during the last few runs. Therefore, if these
solutions are correct, unsettle weather conditions could be
expected the first part of the upcoming week. Confidence is
increasing somewhat but continues low-moderate, because still
far in the forecast time. Please continue to monitor the latest
forecast updates during the next several days.

Model guidances continues to suggest a tropical wave moving across
the local Caribbean waters by Wednesday.

&&

.Aviation...Mainly VFR conds expected through 22/16Z. However, brief
SHRA will result in VCSH across the Leeward and USVI terminals.
Enhanced afternoon convection will result in VCSH/VCTS with BKN at
FL030-050 at TJMZ/TJBQ between 22/17Z and 23/02Z, where MVFR
conditions are possible. Light and variable winds will continue,
turning from the ESE at 10-15 KT with sea breeze variations and
occasional gusts after 22/14Z.

&&

.MARINE...Across the regional waters and local passages, seas are
expected to remain at 5 feet or less. East to southeast winds
will continue between 10 to 15 knots. There is a low risk of rip
currents, except for the north-central beaches of Puerto Rico
where the risk is moderate.

Mariners can expect isolated thunderstorms each afternoon mainly
across the western coastal waters of Puerto Rico. Shower and
thunderstorm activity could increase across the region between
Sunday and Tuesday of the upcoming week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 88 77 / 40 40 40 40
STT 88 78 86 77 / 40 40 40 40
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19853 Postby cycloneye » Thu May 23, 2019 5:26 am

Area Forecast Discussion
National Weather Service San Juan PR
508 AM AST Thu May 23 2019

.SYNOPSIS...
A mid- to upper-level low northwest of the islands will dominate
the local weather conditions through the upcoming weekend. This
feature along with plenty of tropical moisture will enhance the
formation of showers and thunderstorms throughout the day. As this
feature moves eastward, weather conditions should improve
somewhat Friday and Saturday. However, locally induced showers
and thunderstorms are expected each afternoon.

&&

.SHORT TERM...Today through Saturday...

A light to moderate east to southeast wind flow will prevail across
the region. A mid to upper level southeastward propagating trough
will continue to sink across the western Atlantic and remain north
of the region through the short term forecast period. As this
feature approaches the forecast area, favorable conditions with a
divergence pattern aloft will persist today. These conditions
combined with plenty tropical moisture--model precipitable water
estimates between 1.7 and 2.0 inches--will result in enhanced shower
and thunderstorm development. However, a layer of mid to upper level
clouds could significantly reduce the impact of these conditions
and limit the intensity and areal coverage of this activity.

Overall, overnight and morning showers are expected to stream over
the waters into portions of eastern and southern Puerto Rico, as
well as over the U.S. Virgin Islands. As the day progresses, the
bulk of this activity is forecast to shift and cluster along the
interior and western sectors of Puerto Rico. Showers and isolated
thunderstorm are possible over the San Juan metropolitan area, the
U.S. Virgin Islands and local waters. Rainfall accumulations are
forecast to peak between 1-2 inches with isolated higher amounts. As
a result, there is a potential for urban and small streams flooding,
as well as mudslides in areas near steep terrain.

Conditions aloft are to gradually turn unfavorable as the mid to
upper level trough continues to drift eastward and away from the
region on Friday into the weekend. Although conditions are expected
to improve during this period, afternoon convection is still
expected to develop and affect the interior and western sectors of
Puerto Rico each day. Rainfall accumulations are forecast to peak
at around an inch on Friday and half an inch on Saturday with
isolated higher amounts. Given that soils are saturated, the
potential for urban and small stream flooding will continue,
particularly across the northwestern quadrant of Puerto rico.

.LONG TERM...SUNDAY THROUGH THURSDAY...
Model guidances continue to show plenty of tropical moisture next
week. However, model guidance is now backing-up about the final
position of the amplifying trough aloft. Although PW values could
peak between 1.7 and 2.2 inches, the upper-level dynamic could
fade-away during that period. Confidence is low to moderate due to
inconsistencies in the previous solutions. But, if model guidance
is correct, shower and thunderstorm activity will be associated
to low level convergence, and local and diurnal effects through
at least Tuesday.

A tropical wave is forecast to move off to the south of the
islands by Wednesday. Then, another mid- to upper-level trough is
forecast to amplify from the northwest near the islands by
Thursday, which could interact with the lingering tropical
moisture.

&&

.AVIATION...Mainly VFR conds expected through at least 23/16Z.
However, brief SHRA will result in VCSH at TJSJ/TIST/TISX/TNCM/TKPK.
Enhanced afternoon convection will result in VCSH/VCTS with BKN
to OVC at FL025-030 at TJMZ/TJBQ/TJPS between 23/16Z and 03/06Z,
where MVFR conditions are possible. Light and variable winds will
continue, turning from the ESE at 10-15 KT with sea breeze
variations and occasional gusts after 23/14Z.

&&

.MARINE...
Mariners can expect seas of 5 feet or less across the regional
waters. East to southeast winds will prevail at 10 to 15 knots,
although local effects will promote higher winds up to 20 knots
each afternoon. A northerly swell will move across the Atlantic
Waters next week. There is a moderate risk of rip currents for
the north facing beaches of Puerto Rico.

Thunderstorm formation are expected across the western coastal
waters of Puerto Rico this afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 88 78 / 40 40 40 40
STT 87 78 86 77 / 40 40 20 30
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19854 Postby cycloneye » Fri May 24, 2019 5:42 am

Area Forecast Discussion
National Weather Service San Juan PR
508 AM AST Fri May 24 2019

.SYNOPSIS...
A mid- to upper-level low will dominate local weather conditions
through early this weekend. Plenty of tropical moisture will
continue across the islands through at least next week. Shower and
thunderstorm development is likely each day across portions of the
islands.

&&

.SHORT TERM...Today through Sunday...

A mid to upper level trough continues to be the dominant feature
during the short term forecast period. Model guidance suggests that
this system will cross the forecast area today, maintaining somewhat
favorable conditions aloft. These conditions combined with
sufficient moisture content--model PW estimates of 1.90 inches--will
support the development of showers and thunderstorms. This activity
is forecast to cluster over the waters during the morning hours and
along the interior and northwestern quadrant of Puerto Rico in the
afternoon. Showers and thunderstorms affecting the San Juan
metropolitan area cannot be ruled out. Rainfall accumulations
between 1-2 inches with isolated higher amounts are expected with
this activity. That said, the potential for urban and small stream
flooding, as well as mudslides near areas of steep remains remains
elevated today.

Conditions aloft are to gradually turn unfavorable as the mid to
upper level trough continues to drift eastward and away from the
region tonight and continuing into the weekend. Although the
intensity and areas coverage of showers and thunderstorms are
expected to diminish during the weekend, sufficient moisture content
supported by diurnal heating and local effects will enhance the
development of localized afternoon convection across the interior
and western sectors of Puerto Rico each day. Rainfall accumulations
are forecast to peak at 1.0-1.5 inches on Saturday and 0.5-1.0
inches on Sunday with isolated higher amounts. Although with a lower
potential, the threat for urban and small stream flooding will
continue during the weekend.

.LONG TERM...Monday through Friday...
Although a mid- to upper-level ridge is forecast to build across
northeast Caribbean, plenty of tropical moisture will move from
the Caribbean Sea into the local region increasing the potential
for showers and locally induced thunderstorms Monday and Tuesday.
Model guidance continues to indicate a weak tropical wave moving
off to the south across the Caribbean Sea by Wednesday or
Thursday. Another mid- to upper-level trough is forecast to
amplify near the region Thursday and Friday. If models are
correct, a wet pattern with favorable conditions for shower and
thunderstorm development may be possible next week.

&&

.AVIATION...SHRA/TSRA will result in VCSH/VCTS conds and brief MVFR
conditions at TJPS, USVI and Leeward terminals through 24/14Z.
Similar conditions with brief MVFR conds possible are expected at
TJSJ between 24/14-18Z and TJMZ/TJBQ after 24/18Z. BKN to OVC
between FL020-040 expected with this activity. Light and variable
winds through 24/14Z, turning from the ESE at 10-15 KT with sea
breeze variations and occasional gusts after 23/14Z, particularly
near SHRA/TSRA.

&&

.MARINE...
Mariners can expect seas around 4 feet across most of the local
waters. A small northerly swell will persist across the Atlantic
Waters through at least Saturday. Trade winds will continue from
the east to southeast between 10 and 15 knots, although local
effects will promote higher winds up to 20 knots each afternoon. A
northerly swell will move across the Atlantic Waters early next
week. There is a moderate risk of rip currents for some north
facing beaches of Puerto Rico.

Thunderstorm formation are expected across portions of the
coastal waters of Puerto Rico and the U.S. Virgin Islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 77 89 77 / 50 40 40 40
STT 86 77 88 77 / 40 40 20 30
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19855 Postby cycloneye » Sat May 25, 2019 5:16 am

Area Forecast Discussion
National Weather Service San Juan PR
431 AM AST Sat May 25 2019

.SYNOPSIS...A moderate east to southeast wind flow will prevail
across the region. The presence of above normal moisture content
will support shower and thunderstorms development, particularly
along the interior and western Puerto Rico each afternoon.
Enhanced shower and thunderstorms activity is expected on
Monday/Tuesday and Thursday under favorable conditions aloft.
That said, the potential for urban and small stream flooding
remains elevated.


&&

.SHORT TERM...Today through Monday...

A relatively rainy next couple of days are expected. The latest
guidance and observations indicate that the available moisture will
be above normal and the mid and upper levels will have some weak
divergence which provides some instability. Also, there will be the
diurnal heating and local effects to consider. For that reason,
there are numerous showers and isolated thunderstorms in the
forecast every day this weekend and early next week. Today, looks to
be the driest day, and by that I mean less rainfall coverage
expected, because it will still be rainy in the afternoon across the
northwestern quadrant of PR as well as portions of the San Juan
metro, central PR and north central PR.

The precipitable water today at 12Z will be above normal, but
decreasing to normal values by this afternoon, which may be why the
rainfall is not expected to be more widespread. However, the
precipitable water for Sunday at 18Z is forecast to be above 1.8
inches and on Monday above 2.1 inches. This increase in moisture
will combine with relatively weak but the persistence divergence in
the mid and upper levels and local effects to cause a larger
coverage of showers and thunderstorms during the daytime hours,
especially starting in the late morning to early afternoon hours.

At this time, the more significant showers and thunderstorms are
expected over Puerto Rico, especially interior to western PR, but
the other areas of PR can also expect occasional significant showers
and isolated thunderstorms. The USVI however may be limited to
scattered showers with the possibility of an occasional but brief
heavy shower on Sunday and Monday. That said, the moisture will
increase significantly on Monday and the official forecast is drier
than the model guidance since it seemed like the guidance was rather
bullish on the rainfall forecast, but, given the amount of moisture
that may be moving in, it is not surprising for the models to
forecast that much rain. We will make adjustments in the forecast if
necessary. Bottom line though, is that there may be a wet start to
the week with good coverage of rainfall across Puerto Rico, but
today we expect mainly locally induced showers, while the USVI may
be limited to scattered showers with some heavier showers possible,
but relatively brief.

.LONG TERM...Tuesday through Saturday...

Recent model guidance, which has been fairly consistent, suggests
that a wet pattern will dominate through most of the long-term
forecast period. This is the result of high tropical moisture
advection into the region with PW model estimated values ranging
from 2.12 inches on Tuesday morning to 1.70 inches on Friday
afternoon. In addition, two independent southeasterly propagating
mid to upper level short-wave troughs will approach the region,
resulting in favorable upper level conditions. The peak of this
activity is expected on Tuesday into Wednesday and then on
Thursday when each trough is forecast to move across Hispanola,
which places the associated divergence pattern over the forecast
area. If models are correct, these conditions will support
enhanced shower and thunderstorms development across the local
islands and waters through the end of the workweek. Conditions are
to improve on Saturday, but afternoon convection remains
possible.


&&

.AVIATION...VFR conds expected in the morning, through
25/16Z. SHRA/TSRA will result in VCSH/VCTS conds and brief MVFR
conditions at TJMZ/TJBQ after 25/17Z. BKN to OVC between FL020-040
expected with this activity. Light and variable winds through
25/14Z, turning from the East at 10-15 KT with sea breeze variations
and occasional gusts.


&&

.MARINE...Tranquil marine conditions with seas up to 5 feet are
expected to prevail across the regional waters through at least
Monday, when a northerly swell is forecast to spread across the
Atlantic waters and local passages. A moderate east to southeast
surface wind flow peaking at 10-15 knots will hold across the
region. There is a moderate risk for rip currents for beaches
along the north coast of Puerto Rico, Vieques, Culebra, and Saint
Thomas. Elsewhere, a low risk will continue.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 89 77 / 40 40 40 40
STT 88 79 87 77 / 20 30 30 30
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19856 Postby cycloneye » Sun May 26, 2019 4:49 am

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
419 AM AST Sun May 26 2019

.SYNOPSIS...A moderate east to southeast wind flow will prevail
across the region. Enhanced shower and thunderstorm development is
expected, particularly along the interior and western Puerto Rico
during the afternoon hours. This activity is forecast to peak on
Tuesday through Thursday. That said, there will be a potential for
urban and small stream flooding each day. A seasonal and
relatively drier weather pattern is expected to return by the end
of the workweek.

&&

.SHORT TERM...Today through Tuesday...

Models still insist in a wet pattern for the next few days. The
satellite derived Precipitable Water (PW) indicates that there is
already an area with over 2 inches of PW around PR and over the
USVI. The latest guidance indicates that this plume of moisture will
linger for the next few days, causing the available moisture to be
above normal through at least the first part of the week. The mid
and upper levels will have some weak divergence which provides some
instability. Even though there is some cloudiness in the upper
levels, they are mostly south of Puerto Rico, so there could be some
diurnal heating and local effects to consider today. For that
reason, there are numerous showers and isolated thunderstorms in the
forecast today, even though we stayed a bit drier than the very
bullish WRF model, some of the other hi-res models are less
aggressive with the rainfall today. That said, the truth is that all
of the guidance and observations indicate that we should expect a
rainy pattern today through Tuesday with variably to mostly cloudy
skies. Even considering some discrepancies among the different model
guidance, the discrepancies are generally slight but essentially
indicate the same message. The areas with the heaviest rainfall are
expected to be across the interior to western and northwestern PR in
the afternoon hours each day. The USVI is expected to have mainly
scattered and passing showers, at times the showers may be
moderate to heavy but the duration of any one showers is expected
to be brief. So, variably to mostly cloudy skies could also be
expected for the USVI with a few showers from time to time.

Across the western Atlantic we have a surface high pressure, which
will slowly move east and pass to the north of the local area,
mainly causing moderate East to ESE winds for the next few days.
There will also be an upper trough digging across the western
Caribbean, which will technically keep the local islands under a
ridge. That said, the pressure gradient in the upper levels will
tighten just to the NE of the local islands, likely causing some
speed divergence and contributing some instability over the local
area. The GFS forecast soundings seem to be in agreement and they
also show the column of moisture increasing at all levels with each
passing day. Also, the instability and energy parameters seem to
support enough instability for thunderstorms to develop. One thing
to note though is that the GFS model initialized a bit drier than it
was actually observed at 26/00Z, causing the precipitable water
currently being observed at 06Z to be higher than what the model is
suggesting, which puts a question mark on the PW forecast in the
short term.

.LONG TERM...Wednesday through Sunday...

A wetter and unsettled weather pattern is expected during the
long-term forecast period, but recent model guidance suggests
that this pattern will hold only on Wednesday and Thursday. This
will be the result of high moisture content across the region with
PW model estimated values ranging between 2.15 inches on
Wednesday morning to 1.93 inches on Thursday afternoon. In
addition, a series of southeasterly propagating mid to upper level
short-wave troughs will promote favorable upper level conditions--
a divergence pattern and increased instability aloft--during this
period. If models forecast unfolds, which so far they have been
fairly consistent, these conditions will support enhanced shower
and thunderstorms development while maintaining an elevated
potential for urban and small stream flooding across the local
islands.

A more seasonal weather pattern with overnight and morning
showers streaming over the waters into eastern Puerto Rico and the
U.S. Virgin Islands, followed by locally induced afternoon
convection along the interior and western Puerto Rico is expected
to return on Friday and continue through the weekend.


&&

.AVIATION...SHRA gradually increasing, which will cause VCSH for
TIST, TISX and TJSJ in the morning. VFR conds expected through
26/16Z. SHRA/TSRA will result in VCSH/VCTS conds and brief MVFR
conditions at TJMZ/TJBQ after 26/17Z. BKN to OVC between FL020-040
expected with this activity, bkn050-060 expected elsewhere. Light
and variable winds through 26/13Z, turning from the East to ESE at
10-15 KT with sea breeze variations and occasional gusts.


&&

.MARINE...Tranquil marine conditions with seas up to 5 feet are
expected to prevail across the regional waters through at least
Monday afternoon, before a northerly swell arrives and spreads
across the Atlantic waters and local passages. The latter will
result in choppy seas up to 6 feet and caution from small craft
operators. A moderate east to southeast surface wind flow peaking
at 10-15 knots will hold across the region. There is a moderate
risk for rip currents for beaches along the north coast of Puerto
Rico, Vieques, Culebra, and Saint Thomas. Elsewhere, a low risk
will continue.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 88 76 / 40 40 40 20
STT 87 78 86 77 / 30 30 20 40
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19857 Postby cycloneye » Mon May 27, 2019 5:49 am

Area Forecast Discussion
National Weather Service San Juan PR
455 AM AST Mon May 27 2019

.SYNOPSIS...Surface high pressure across the western Atlantic is
slowly moving east, to the north of the local islands. There is a
stronger surface high pressure across the northeastern Atlantic.
This setup is causing a light to moderate southeasterly winds.
Higher than normal available moisture is expected to move in
today, and linger through most of the workweek. Upper trough will
cause an increase in instability mid to late this week. A rainy
weather pattern is expected this week.

&&

.SHORT TERM...Today through Wednesday....

A wetter pattern is forecast to persist through the short-term
period, as a result of deep layered tropical moisture out of the
Caribbean pooling across Puerto Rico and the U.S. Virgin Islands.
During this time precipitable water values will range from 1.9 to
2.2 inches across the region. Also, scattered to numerous showers
are forecast to develop each day during the afternoon. Rainfall
amounts each day will range from 0.50 to 1.00 inches with higher
amounts in isolated areas. Additionally, soils are saturated from
previous days rainfall and any additional rainfall could lead to
urban and small stream flooding, as well as, ponding of water on
roadways.

This morning moderate to heavy rainfall fell across portions of
northwestern, eastern, interior of Puerto Rico. Elsewhere, light to
moderate showers were observed across the U.S. Virgin Islands and
other parts of Puerto Rico. Later this morning light to moderate
showers are possible across portions of eastern Puerto Rico and the
U.S. Virgin Islands through mid morning. Then scattered to numerous
showers and isolated thunderstorms are forecast to develop over the
interior, and western areas of Puerto Rico this afternoon. These
showers will develop as a result of significant surface heating,
abundant low-level moisture and local effects. Also, a weak jet to
the north of Puerto Rico will provided modest upper-level
instability today which will aid in showers and isolated
thunderstorm development.

Tuesday, weak troughiness develops to the northwest of Puerto Rico
and is expected to continue to deepen north of the area through
Wednesday. Tuesday and Wednesday scattered showers and isolated
thunderstorms are forecast to develop during the afternoon across
most areas of Puerto Rico. The combination of deep layered tropical
moisture through the entire atmospheric column, increasing
instability as a result of a developing low-level jet and deepening
upper-level trough will induce showers and isolated thunderstorms.
In addition, local and diurnal effects will help aid in showers and
isolated thunderstorm develop. Therefore, moderate to heavy rainfall
is likely during the afternoon for most of the island.

However, current guidance shows that mid to upper-level clouds might
linger during the early mornings through mid afternoon across
eastern, interior and western areas of Puerto Rico. If these clouds
develop they will limit surface heating and delay shower and
thunderstorm development.

.LONG TERM...Thursday through Tuesday...

The deep moisture is expected to linger into Thursday, so at least
some widely scattered to numerous showers and isolated
thunderstorms are expected during the day. However, slightly drier
air is expected to move in for Friday, which could cause a
decrease in shower activity over the local area. That said, there
is an upper trough with axis just to our west for Friday, which
will increase instability, but the models have been somewhat
inconsistent on the exact location to the jury is still out on
this. Next weekend looks like it will be rainy, the available
moisture will be near or slightly above normal and we may have the
upper tough still over the general area, so enhanced shower and
thunderstorm activity is possible in the afternoons over Puerto
Rico with scattered showers elsewhere.

&&

.AVIATION...VFR conds are forecast to continue across all terminal
sites through 27/16Z with an occasional iso/sct SHRA. This afternoon
SHRA/Isold TSRA mainly ovr ctrl and W PR and vcty
TJSJ/TJMZ/TJBQ/TJNR til 28/03. Sfc winds out of the east at 10 to 15
kts with sea breeze variations.

&&

.MARINE...Seas will be up to 5 feet today with winds up to 15
knots, but a northerly swell is expected to move in tonight,
causing the local seas to increase up to 6 feet across the
Atlantic waters. There is a moderate risk of rip currents today,
but a high risk is expected starting this evening across the
northwest to northeast beaches of Puerto Rico, north beaches of
Culebra and Saint Thomas.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 77 87 75 / 40 40 50 60
STT 86 77 85 76 / 30 30 40 60
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19858 Postby cycloneye » Tue May 28, 2019 4:33 am

Area Forecast Discussion
National Weather Service San Juan PR
442 AM AST Tue May 28 2019

.SYNOPSIS...Upper level trough across the western Caribbean will
prevail today with an upper ridge over the local islands. This
upper trough will gradually weaken on Wednesday and Thursday while
a broad trough starts strengthening with its axis just west of
Hispaniola. Instability will increase over the local area on
Wednesday and Thursday. Available moisture will remain above
normal for the next several days. Weak surface high pressure will
cause light to moderate east to southeast wind flow for the next
few days. Rainy days are expected through Thursday with the more
significant showers and thunderstorms expected for Wednesday and
Thursday for Puerto Rico, and mainly on Thursday for the U.S.
Virgin Islands.

&&

.SHORT TERM...Today through Thursday...

The main concern during the short-term period is flash flooding and
mudslides across the northwest, western, and interior areas of
Puerto Rico over the next several days. Also, flooding is possible
over the eastern, northern, and southern areas of the island too.

The wettest days at this time will be Wednesday and Thursday. Soils
are saturated from previous week rainfall, and with additional
moderate to heavy rainfall over the next several days will cause
rapid river rises and flooding along tributaries. Also, there is
potential that roadways become washed away, and mudslides in higher
terrain. It is important to stay abreast of the evolving situation
and listen to local emergency managers and local government
officials.

The short-term period will be wet and unsettled as a result of deep
layered tropical moisture, significant surface heating, and local
effects. The combined factors above will lead to moderate to heavy
rainfall during the afternoon for most of Puerto Rico and adjacent
islands. Rainfall amounts will range from 1.00 to 2.00 inches with
the possibility for higher amounts in isolated areas. Current
guidance shows precipitable water values ranging from 2.0 to 2.34
inches this ranks in the 99th percentile for the month of May. The
SJU-GFS shows the entire atmospheric column becoming saturated this
afternoon through Thursday. Additionally, light 0 to 3 km winds of 5
kts will cause showers and thunderstorms to move slowly, and
increase the likelihood of flooding.

Wednesday a mid to upper-level trough begins to develop across the
western Atlantic. The mid to upper-level trough is forecast to
continue to deep north of Puerto Rico over the next several days. As
a result it will causes troughiness over Puerto Rico and the adjunct
islands. The combination of troughiness aloft and a weak jet will
increase upper-level instability and divergence aloft over Puerto
Rico during the afternoon. An inhibiting factor that could delay
the onset of showers and thunderstorms and decrease rainfall amounts
are the mid to upper-level clouds. These clouds are from a weak mid
to upper-level trough currently east of the Yucatan Peninsula. This
trough is expected to weaken over the next 12 to 24 hours, however,
if the trough lingers it could cause a slight change to the short
term forecast.

.LONG TERM...Friday through Wednesday.

The available moisture is expected to diminish slightly for Friday
and for the days thereafter. However, it will still be near or
slightly above normal. The upper trough that is expected to affect
the local islands on Wednesday and Thursday will continue moving
east and probably have its axis over PR on Friday, which will
cause enhanced instability for areas near and around the USVI.
That said, showers and thunderstorms will still be possible over
PR, but if the models are to verify, the instability and chances
of thunderstorms will be better east and near the USVI. This upper
trough will continue to slowly move east but then stalling over
the area and weakening. For that reason the global models still
have some rain over the local islands but the area of enhanced
rainfall just east of the local islands. Seeing how dependent the
activity seems to be in this upper trough, the confidence on the
exact location this far out in the forecast is low. That said, it
looks like the unsettled weather with some showers and
thunderstorms could linger into early next week.

&&

.AVIATION...VFR conds are forecast to continue all across all
terminal sites through 28/16Z with an occasional iso/sct SHRA.
This afternoon SHRA/TSRA are expected to develop over ctrl, W PR
and VCTY TJSJ,TJMZ,TJBQ/TJNR til 29/03Z. Brief MVRF /IFR conds are
possible due to SHRA/TSRA near the local terminal sites. SFC
winds out of the east to southeast at 5 to 10 kts.

&&

.MARINE...Northerly swell is causing the local seas to become
choppy and up to 6 feet. Small craft operators are urged to
exercise caution. The local winds will be mainly from the east
to southeast at 10 to 15 knots. There is a high risk of rip
currents today and tonight. Seas are expected to gradually improve
on Wednesday.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 76 85 76 / 60 60 60 60
STT 86 77 85 76 / 50 60 60 60
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19859 Postby cycloneye » Wed May 29, 2019 4:36 am

Area Forecast Discussion
National Weather Service San Juan PR
425 AM AST Wed May 29 2019

.SYNOPSIS...A Flash Flood Watch is in effect through Thursday
evening. A weakening upper level trough across the western
Caribbean will prevail through most of today with an upper ridge
over the local islands. By Thursday, an upper level trough
develops to the northwest of the local islands, with its axis
just west of Puerto Rico. The available moisture will remain
above normal for the next several days today and Thursday. Weak
surface high pressure will continue to cause light to moderate
east to southeast wind flow for the next few days. Unsettled
weather is expected today and Thursday across Puerto Rico, and
also for the U.S. Virgin Islands, especially on Thursday.

&&

.SHORT TERM...Today through Friday...

The main concern with this forecast continues to be the potential
for flooding, rapid rivers rises and mudslides in high terrain
areas.

Deep layered tropical moisture and southeasterly winds will remain
entrenched across the region over the next several days. A mid to
upper-level trough will continue to deepen across the northwestern
Caribbean today through Thursday. This feature will increase upper-
level instability over the region. Also, a weak upper-level jet with
winds of 30 to 50 kts will develop near Puerto Rico today through
Friday. The aforementioned factors above will support development of
deep convection and thunderstorms across Puerto Rico and the U.S.
Virgin Islands mainly during the afternoon.

Furthermore, soils remain saturated from the previous days`
rainfall. Over the last several day`s rainfall amounts have ranged
from 1.00 to 3.00 inches across most areas of Puerto Rico. Over the
last couple of days there as been reports of rivers flooding out of
their banks and mudslides in higher terrain.

Therefore, a high flood potential is expected today and Thursday as
a result of the deep tropical moisture and instability aiding in
the development of showers and thunderstorms across most of Puerto
Rico and the U.S. Virgin Islands today and Thursday.

Friday, low-level moisture is expected to diminish slightly with
weak troughiness remaining over the region. Local and diurnal
effects will cause showers and isolated thunderstorms to develop
during the afternoon.


.LONG TERM...Saturday through Thursday...

The available moisture is expected to be a bit lower
on Saturday and for the next several days after, but still above
normal. The upper trough that is expected to affect the local
islands today and Thursday will continue moving east and probably
have its axis east of PR by Saturday, but enhanced instability is
still possible for the USVI. That said, showers and thunderstorms
will still be possible over PR, but if the models are to verify,
the instability and chances of thunderstorms will be better east
and near the USVI. This upper trough will continue to slowly move
east but then stalling over the area while weakening, yet still
causing a diffluent pattern in the upper levels. For that reason
the global models still have some rain over the local islands but
the area of enhanced rainfall just east of the local islands.
The confidence on the exact location this far out in the forecast
is low. That said, it still looks like the unsettled weather with
some showers and thunderstorms could linger into next week.


&&

.AVIATION...Mainly VFR conditions should prevail across the local terminals
through 29/16z. SHRA and TS are expected across interior and western
PR between 29/16z and 29/23z, affecting TJMZ, TJBQ, TJSJ and
likely other terminal sites. MVFR to possibly IFR conditions are
possible, especially if the activity moves over the terminals.
Winds out of the east to southeast at 10 to 15 kts with higher
gusts likely due to TSRA.

&&

.MARINE...The northerly swell is subsiding and seas are now
expected to be at 5 feet or less. The coastal winds will be mainly
from the east to southeast at 10 to 15 knots. There is a moderate
risk of rip currents for many of the local beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 77 83 74 / 70 60 70 50
STT 86 76 85 75 / 60 60 70 50
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here

User avatar
cycloneye
Admin
Admin
Posts: 139331
Age: 67
Joined: Thu Oct 10, 2002 10:54 am
Location: San Juan, Puerto Rico

Re: Caribbean - Central America Weather

#19860 Postby cycloneye » Thu May 30, 2019 5:00 am

Area Forecast Discussion
National Weather Service San Juan PR
530 AM AST Thu May 30 2019


.SYNOPSIS...
A Flash Flood Watch is in effect through Thursday
evening. A mid to upper-level trough and above normal low-level
moisture is causing unsettled weather across Puerto Rico and the
U.S. Virgin Islands. As a result of the instability and moisture,
showers and thunderstorms have continued to develop this morning.
These conditions are expected to continue through the rest of the
day. Moderate to heavy rainfall will result in accumulations of 1
to 3 inches across most of Puerto Rico and the U.S. Virgin
Islands with higher amounts likely today.

&&

.SHORT TERM....Today through Saturday...

...A Flash Flood Watch will remain in effect for Puerto Rico and the
U.S.Virgin Islands at least until 8 pm AST tonight as very moist and
unstable conditions will persist. The main impacts continues to be
the potential for flooding, rapid rivers rises, mudslides and
rockfall in high terrain areas.

Deep layered tropical moisture and southeasterly winds will remain
entrenched across the region through the end of the work week and
into the upcoming weekend. An amplified mid to upper-level trough
will continue across the northwestern Caribbean today through Friday
then gradually fill/weaken on Saturday as it lifts northeastward.

This upper level trough will provide strong divergence and
instability aloft to support enhanced convection across the region.
In addition, an upper level jet segment is to round the base of the
trough and move across region today through Friday also favoring
enhanced shower and thunderstorm development across Puerto Rico and
the U.S. Virgin Islands. Although the proximity of the upper trough
will maintain considerable mid to upper level cloudiness across the
region through Friday, expect sufficient breaks in cloud cover
during the day to support the rapid development of afternoon shower
and thunderstorm development across portions of the islands.

Furthermore, soils remain saturated from the previous days`
rainfall. Over the past several day`s estimated rainfall amounts
have ranged between an inch to three inches across eastern Puerto
Rico, and between two to five inches daily over the northwest
sections of Puerto Rico. The U.S.V.I have had estimated rainfall
amounts between half an inch to two inches daily with additional
amounts between one to three inches expected. In addition, during
the last couple of days there as been several reports of rivers and
small stream flooding as well as mudslides and rockfall in higher
terrain and areas of steep terrain.

Therefore, a high flood potential is expected to continue today as
a result of the abundance of tropical moisture and instability aloft
which will aid in the development of showers and thunderstorms
across much of Puerto Rico and the U.S. Virgin Islands.

On Friday low-level moisture is expected remain widespread,however
the upper level trough is forecast to weaken but persist over the
region. This along with breaks in cloud cover and local and diurnal
effects will again support early morning shower activity, followed
by shower and isolated thunderstorms across the islands during the
afternoon. By this time, overnight and early morning showers and
thunderstorms should be focused over eastern PR and the USVI.

On Saturday, a gradual improvement is expected so far but good low
level moisture convergence and instability will support overnight
and early morning shower followed by isolated to scattered afternoon
showers and thunderstorms activity.

&&

.LONG TERM...Sunday through Friday...

The mid to upper-level trough will move east of Puerto Rico and
the U.S. Virgin Islands on Sunday. A weak mid to upper-level ridge
will hold through the weekend into the middle of the week with
modest low-level moisture. The combination of the low-level
moisture, surface heating and local effects will induce showers
and isolated thunderstorms during the afternoon mainly over
portions of western and interior areas of Puerto Rico. Also,
showers are possible across portions of eastern Puerto Rico and
the U.S. Virgin Islands during the early morning.

Thursday model guidance shows a a trough developing across the
western Atlantic and deepening into the eastern Atlantic waters.
At this time model guidance keeps the trough well north of Puerto
Puerto Rico. Therefore, showers and isolated thunderstorms mainly
during the afternoon across western and interior areas of Puerto
Rico. Elsewhere, isolated to scattered showers are forecast during
the afternoon. Recent guidance develops a trough to the south of
Jamaica if this trough develops it will push mid to high clouds
across the western areas of the Islands during the overnight
hours.

&&

.AVIATION...

The potential for SHRA/TSRA will continue across the flying area
with TEMPO MVFR/brief IFR due to low CIG/SHRA. SHRA are expected
ovr/vcty TJSJ/TIST/TISX/TNCM/TKPK til 30/15z. TJBQ/TJMZ/TJPS/TJSJ
can expect SHRA/ ISOLD TSRA between 30/17-23z with MVFR/ brief IFR
conds psbl. SFC wnd light/vrb bcmg fm E-ESE at 10-15 kts with
higher gusts along coastal areas and with passing SHRA/TSRA.

&&

.MARINE...

Showers and thunderstorms will develop across the Caribbean and
Atlantic waters today. These thunderstorms will create choppy
marine conditions through Friday morning. Some thunderstorms
could produce winds up to 30 kts with higher gusts. Today winds
will be out of the east to southeast at 10 to 15 kts with higher
gusts likely. A increase in wind flow across the Caribbean waters
will cause to increase to 6 feet.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 74 86 76 / 60 50 40 30
STT 85 75 85 76 / 70 70 60 40
0 likes   
Visit the Caribbean-Central America Weather Thread where you can find at first post web cams,radars
and observations from Caribbean basin members Click Here


Return to “USA & Caribbean Weather”

Who is online

Users browsing this forum: No registered users and 16 guests