Caribbean - Central America Weather

[cycloneye]

How’s everyone doing in the islands?

All is fine in Puerto Rico after Karen moved thru.Only some flooding but nothing bad.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
1007 AM AST Thu Sep 26 2019

.UPDATE...No changes to the forecast grids after the 7:24 AM AST
update. Showers and a few isolated thunderstorms continued to
move across the local waters into portions of southern and eastern
Puerto Rico during the last few hours. Some of this activity
reached portions of eastern interior. An Urban and Small Stream
Advisory was issued for this areas, but expired at 8:45 AM AST.
Another Flood Advisory for Rapid Rises was issued for Rio Grande
de Patillas given that river gauge reported a height of 9.28 feet
and the flood level is 10.0 feet. The latter also expired at 9:45
AM AST. Shower activity is diminishing and skies are clearing,
which may provide a favorable environment for afternoon
convection to develop, favoring the northeastern quadrant of the
island. Given that soils are saturated due to previous rains,
there is a potential for urban and small stream flooding across
these areas.


&&

.AVIATION...Mainly VFR conditions will prevail across all local
terminals. However, VCSH/VCTS are possible across TJSJ, TIST and
Leeward terminals between 26/18-23Z. This could result in brief
MVFR conditions. Winds at FL03-050 between 15-25 knots. Surface
winds will be out from the S-SE at 10-15 knots with higher gusts.


&&

.MARINE...No changes to the inherited forecast. Tranquil marine
conditions with seas below 5 feet and south to southwest winds
between 5-15 knots are expected across the regional waters. Th
Lorenzo is forecast to bring an easterly swell across the local
Atlantic waters by Saturday, resulting in hazardous marine
conditions. ere
is a moderate risk of rip currents for a few beaches along the
north coast of Puerto Rico, Culebra and Saint Thomas.


&&

.PREV DISCUSSION... /issued 724 AM AST Thu Sep 26 2019/

UPDATE...Adjustments to the inherited forecast, particularly to
the 10Z weather grids, were performed to add isolated
thunderstorms. Showers and isolated thunderstorms developed over
the waters and moved over coastal areas of southern and
southeastern Puerto Rico. So far, rainfall accumulations up to an
inch has been observed over the area and additional rainfall
between one and two inches are expected. As a result, an Urban and
Small Stream Flooding Advisory is in effect until 845 AM AST for
coastal municipalities from Santa Isabel eastward to Maunabo.

PREV DISCUSSION... /issued 325 AM AST Thu Sep 26 2019/

SYNOPSIS...
Enhanced moisture remains in place over the region, pushing
through the area from the south. This will aid in the development
of showers and thunderstorms caused by local effects and daytime
heating. With soils still saturated following the previous days`
rain, additional rainfall, especially if significant, has the
potential to cause urban and small stream flooding, as well as
mudslides in steep terrain. Another tropical wave will push into
the region this weekend, bringing additional moisture to the
islands lasting into Sunday. Late on Sunday, a slow, gradual
trend towards somewhat drier conditions will begin, lasting
through mid- week.

SHORT TERM...Today through Saturday...

Deep southerly flow will continue to prevail across the area
throughout the day today. This will continue to result in showers
and isolated thunderstorms across the local Caribbean waters
through the early- to mid-morning hours, affecting portions of
the southern half of Puerto Rico. Then, during the afternoon
hours, the combination of daytime heating and sea breeze
convergence could result in the development of showers and
isolated thunderstorms across the northern half of Puerto Rico,
including the San Juan metro area. Given that the soils are
saturated from the previous days` rains, any prolonged period of
heavy rainfall activity could result in some urban and small
stream flooding. Across the USVI, mainly fair weather conditions
with just a few showers are expected, as a drier air mass moves
across the islands. With the southerly flow in place,
temperatures along the northern coast of Puerto Rico could rise
into the lower 90s with heat indices reaching the low- to mid-
100s.

On Friday, the steering flow is expected to become very light
(around 5 kts). This will favor afternoon convection, mainly
across interior Puerto Rico. With the steering flow expected to be
very light, the shower and thunderstorm activity that develops is
expected to be slow-moving, with the possibility for more
significant rainfall accumulations. Therefore, there is a greater
potential for urban and small stream flooding, as well as
mudslides in areas of steep terrain.

By later Friday and into the day on Saturday, the flow is expected
to change to a northeasterly direction out ahead of a tropical wave.
Abundant moisture will be in place with precipitable water values
expected to increase to above 2.00 inches. Therefore, scattered
showers will be possible across eastern Puerto Rico and the USVI
during the overnight and morning hours, followed by the
development of more enhanced shower and thunderstorm activity
across the interior and southwestern quadrant of Puerto Rico
during the afternoon hours.

LONG TERM...Sunday through Friday...

There will remain lingering moisture on Sunday as a tropical wave
pulls away from the region slowly to the west. There will be some
suppression of shower activity with the slow and slight drying
trend behind the wave starting late on Sunday. However, local
effects and diurnal heating will still lead to the development of
showers and isolated thunderstorms in the afternoon, especially in
northwestern, northern, and interior portions of Puerto Rico.

Patches of moisture embedded within the otherwise somewhat drier
airmass will impact the islands on Monday and through much of the
rest of the early part of the week. This will aid in the development
of local-effect showers and thunderstorms during the afternoon and
evening hours each day. With soils expected to remain wet/near
saturation, the potential for locally heavy rain caused by these
showers and isolated thunderstorms could lead to urban and small
stream flooding, as well as mudslides in steep terrain.

An increase in the drying trend is expected late in the week.
Suppression of some of the typical shower activity is forecast,
though afternoon showers are still anticipated, especially in
western and northwestern portions of Puerto Rico.

AVIATION...
Mainly VFR conditions should prevail across the flying terminals
during the next 24 hours. SHRA and iso TS expected across southern
PR through 26/14z, affecting the vicinity of TJPS. SHRA and iso TS
possible across the northern half of PR, including the San Juan
metro area, between 26/16z and 26/22z, affecting mainly the vicinity
of TJSJ. Winds light and variable through 26/14Z, increasing to
10-15 kts from the S-SSW with some sea breeze variations
afterwards.

MARINE...Marine conditions will continue to improve with gentle
to moderate winds from the south to southwest at 15 knots or less.
Seas will remain below 5 feet across the open waters and passages,
and below 4 feet across protected waters. The distant Hurricane
Lorenzo is forecast to generate an easterly swell across portions
of the local Atlantic waters by Saturday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 93 79 91 80 / 50 20 30 50
STT 87 80 87 78 / 20 20 30 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
553 AM AST Fri Sep 27 2019

.SYNOPSIS...
Though somewhat drier air is now in place over the region today,
there remains the potential for some urban and small stream
flooding associated with the convection from diurnal and local
effects due to a weak steering flow. This weak flow could lead to
slow-moving showers and isolated thunderstorms in affected areas
- namely western and interior Puerto Rico. Tomorrow into Sunday, a
tropical wave will push through the islands, bringing increased
moisture; moving in tandem with a TUTT, this will bring about a
somewhat wetter pattern for the weekend. A slow and slight
decrease in moisture is expected for early in the work week, and
drier than normal conditions are likely mid-week through the end
of the work week.

&&

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

For the rest of today, the southerly winds are forecast to shift
more from the southeast to the east while becoming very light.
This will shift the focus of diurnal convection to mainly along
the central interior and west sections of Puerto Rico. Urban and
small stream flooding in isolated areas will be the main threat
due to light steering winds and slow moving shower activity. On
Saturday, a tropical wave is still forecast to reach the eastern
Caribbean and local area in tandem with a TUTT induced low to mid
level trough. This is forecast to bring a somewhat wetter pattern
across the region through at least early Sunday. The prevailing
winds are then forecast to shift more from the east northeast on
Saturday with nocturnal showers expected to increase across the
USVI and northeastern sections of PR during the overnight and
early morning hours. During the afternoon, scattered to numerous
showers and isolated thunderstorms will develop across the
interior and west/southwest or PR. Scattered afternoon showers
with a slight chance for isolated thunderstorms can be expected
inland around the USVI on Saturday.

Trailing moisture and a more southeasterly wind flow is forecast for
Sunday, as the tropical wave pulls away from the region. Overall
shower activity should be lesser in coverage, however there will
be sufficient available moisture to combine with local effects and
daytime heating to favor afternoon convection. The shower
activity should then be focused over the central, northwest and
northern portions of Puerto Rico. Meanwhile in the USVI, only
isolated afternoon showers are forecast and they should be mainly
downwind or just off the northwest coast of the islands. A slow
but gradual drying trend is expected by late on Sunday.

.LONG TERM...Monday through Saturday...

On Monday, the slow drying trend will continue. There will,
however, remain sufficient moisture to aid in the development of
showers and isolated thunderstorms caused by local effects and
diurnal heating during the afternoon, especially in northern
portions of Puerto Rico. A similar situation is anticipated again
on Tuesday; a forecast shift in the wind flow becoming more
southeasterly will likely lead to the shower activity shifting so
that the peak is in the northwestern and interior portions of
Puerto Rico. With soils likely to remain near saturation, there
will be the risk for urban and small stream flooding in areas that
see any isolated higher rainfall amounts, as well as a risk for
mudslides in steep terrain.

On Wednesday and through the later part of the work week, a drier
air mass will be in place over the forecast region. Diurnal
heating and local effects will likely still cause some showers and
a risk of isolated thunderstorms, but overall, shower and
convective activity will likely be suppressed compared to normal.
The flow will generally bring winds out of the east and southeast,
such that the highest activity levels will likely be in the west
or northwest and interior Puerto Rico during those days.

As we move into the weekend, there will be a slight increase in
moisture. This moisture will aid in the development of showers and
isolated thunderstorms during the afternoon caused by local and
diurnal effects. However, the increase does not presently look
like it will be substantial, just enough to mitigate some of the
suppression seen in the days prior.


&&

.AVIATION...
VFR conds durg PR. Sfc wnd lgt/vrb bcmg SE-E 5-15kt with
sea breeze variations aft 27/14Z. SHRA/Isold TSRA 27/17-22z
mainly ovr ctrl and west interior of PR with VCSH/ psbl VCTS at
TJMZ/TJBQ. No other sig wx impacts attm.

&&

.MARINE...Seas will remain less than 5 feet until Saturday when a
long period swell from the east will arrive from Category 4
Hurricane Lorenzo. This will generate seas of 4 to 6 feet mainly
in the outer Atlantic waters and the Anegada Passage.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 80 88 77 / 30 50 50 40
STT 88 79 88 78 / 30 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
444 AM AST Sat Sep 28 2019

.SYNOPSIS...Unstable weather conditions are expected throughout
the weekend as a tropical wave affects the area, enhancing shower
and thunderstorm activity. Above normal moisture will continue
through early next week, with enhanced shower and thunderstorm
activity continuing, mainly across the northern half of Puerto
Rico during the afternoon hours. A drier and more stable weather
pattern is expected during the middle to latter of next week.

&&

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

Low level flow, currently light and from the east northeast ahead of
a tropical wave moving across the Lesser Antilles, will turn more
southeasterly Saturday night and Sunday with the passage of the wave
in Puerto Rico. Although there is drier air behind the wave at 700
mb, moisture tends to remain over Puerto Rico until later on Sunday.
This will bring scattered showers and thunderstorms to the area with
a much better chance over western and interior Puerto Rico each
afternoon. Precipitable water values, already above 2 inches will
increase to 2.3 inches later tonight and continue above 2 inches
until Sunday night. A trough over western Venezuela and high
pressure at 700 mb moving into the eastern Caribbean will sweep some
moisture out of the southeastern Caribbean toward the area on Monday
to maintain some showers in the forecast each day.

At upper levels high pressure is found north of Puerto Rico and the
U.S. Virgin Islands. It drifts westward today and Sunday. On Monday
a weakening TUTT will move across the forecast area. Some areas of
moderate divergence aloft are seen later on Saturday and off the
coast of western Puerto Rico on Sunday. But, strong convergence
Sunday night should assure a fairly quick shut down of shower
activity Sunday evening after the wave passage at lower levels. With
500 mb temperatures minus 5 to minus 6, some thunderstorms are
expected, but the approach of the TUTT should also aid thunderstorm
development despite the diminishing moisture on Monday.

Southeast to south flow after the trough passage will give
temperatures a little boost on the north coast of Puerto Rico Sunday
and Monday.

.LONG TERM...Tuesday through Sunday...

A moist south to southeasterly wind flow is expected to linger
across the local area on Tuesday. This will aid in enhancing
shower and thunderstorm activity during the afternoon hours mainly
across interior and northern Puerto Rico. A drier and more stable
weather pattern is then expected during the middle and latter of
the work week as a mid to upper-level ridge builds overhead.
Therefore, mainly fair weather conditions can be expected across
most of the local area. However, afternoon convection is still
possible across the western half of Puerto Rico as sufficient low-
level moisture combines with strong daytime heating and local
effects. Moisture is then forecast to increase by next weekend as
another tropical wave moves across the area with increased rain
chances possible once again.

&&

.AVIATION...VFR conds will prevail across the Leeward Islands and
the USVI thru 29/12Z and across PR til arnd 28/16Z. Aft 28/16Z areas
of +SHRA/TSRA with MVFR/IFR conds and mtn obscurations will devlp
vcnty the Cordillera Central and spread north. MVFR conds if any
should be brief at TJMZ/TJBQ or TJPS. Maximum winds ENE 25-35 kt
btwn FL370-540. A trop wave will pass through the Leeward Islands
Saturday and PR on Sunday.

&&

.MARINE...Relatively tranquil marine conditions with seas up to 5
feet and winds up to 10 knots are expected through this
afternoon. By later tonight, a long dominant period easterly swell
generated by Hurricane Lorenzo, located well east-northeast of
the area, will begin to affect the local Atlantic waters and
continue through Monday. This swell event is expected to result
in choppy seas of up to 6 feet, however, across the offshore
Atlantic waters seas of up to 7 feet are possible on Sunday.
Therefore, a small craft advisory is in effect for these waters.

For beachgoers, there is a moderate risk of rip currents for the
northwestern and southeastern beaches of Puerto Rico, the
southern beaches of Vieques, and most of the beaches of Saint
Croix. Elsewhere, the rip current risk is expected to remain low.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 77 89 78 / 70 70 60 30
STT 88 78 87 79 / 50 60 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
520 AM AST Sun Sep 29 2019

.SYNOPSIS...A tropical wave moving across the area is expected to
enhance shower and thunderstorm activity, mainly across Puerto Rico,
for today. Moisture is expected to gradually decrease Monday and
Tuesday with afternoon convection still expected, mainly across
interior and northern half of Puerto Rico. Drier and more stable
weather conditions are expected during the middle and latter of
the work week.

&&

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

Showers with some thunderstorms developed after midnight over the
local waters surrounding Puerto Rico. A few showers were also
seen east and south of Saint Croix. Isolated tops were seen over
50 kft. Expect showers to continue over the local waters due to a
tropical wave now entering the forecast area from the southeast.
Heavy rains due to precipitable water values of 2.3-2.5 inches are
expected-- especially over higher terrain. The GFS is quite
aggressive in bringing high omega and strong divergence aloft over
interior Puerto Rico today. Other models including the NMM and
the WRF show local amounts of rainfall from 2 to 4 inches in
interior Puerto Rico during the afternoon hours. Localized heavy
amounts are therefore expected and urban and small stream flooding
is very likely in some areas. Moisture diminishes overnight
Sunday as the wave moves out of the area, but some moisture
returns on Monday to fuel another round of showers and
thunderstorms in southerly flow. These will not be as strong but
some areas could still get urban and small stream flooding. Upper
levels continue to be favorable under an approaching TUTT,
although it does stall east of the area with high pressure
continuing to dominate the pattern over much of the Caribbean Sea.
Southerly flow will continue on Tuesday and temperatures will
begin to climb as cloudiness decreases, however there should still
be enough moisture to fuel showers and thunderstorms during the
afternoon.

.LONG TERM...Wednesday through Monday...

A mid to upper ridge is expected to build overhead during the middle
and latter half of the work week. This will produce a somewhat drier
and more stable weather conditions with mainly fair weather
conditions expected across most of the area. However, there will
still be sufficient low-level moisture available that it will
combine with strong daytime heating and local effects to generate
some afternoon convection across the western half of Puerto Rico.
A weak tropical wave may affect the local area by next Saturday,
increasing the rain chances once again. Then, a more potent
tropical wave may follow on its heels by early the following week.

&&

.AVIATION...A tropical wave is moving into the area today and will
pass through wrn PR arnd 29/18Z. Areas of MVFR in SHRA/isold TSRA in
ern PR then beginning arnd 29/16Z areas of SHRA/+TSRA with MVFR/IFR
and mtn obscurations spreading over most of PR. Sfc winds VRB 10 kt
or less except higher gusts near TSRA. Max winds NE 20-25 kt btwn
FL380-500.

&&

.MARINE...A long dominant period east northeast swell generated by
Hurricane Lorenzo, located well east northeast of the region, is
expected to affect the local waters today through the first half
of the work week. This will result in choppy and rough seas of up
to 7-8 feet across portions of the local Atlantic waters, where
small craft advisories are in effect. Across the Caribbean waters,
seas of less than 5 feet are expected. A tropical wave currently
moving across the area will result in periods of showers and
thunderstorms for today.

For beachgoers, there is a high risk of rip currents for the
northwestern beaches of Puerto Rico. Elsewhere, there is a low to
moderate risk of rip currents.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 91 79 / 90 20 70 10
STT 87 79 86 79 / 90 40 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
442 AM AST Mon Sep 30 2019

.SYNOPSIS...Drier air and relatively tranquil conditions will
persist through the week, despite the daily recurrence of
afternoon thunderstorms in northwestern or western Puerto Rico and
occasional early morning showers on the windward sides of the
islands. The next significant tropical wave does not arrive until
Sunday, but a second quickly follows on the following Tuesday.

&&

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

The tropical wave that has produced unstable weather conditions
throughout the weekend has moved away and behind it a somewhat drier
air mass has moved in from the east. Therefore, afternoon convection
is expected to be less compared to previous days. The area that has
the highest probability of observing some afternoon shower and
thunderstorm activity is across the northwestern quadrant of Puerto
Rico with significant flooding not expected at this time. Across
the rest of the forecast area, including the USVI, mainly fair
weather conditions are expected with just some isolated showers
possible in a few locations. With more sunshine expected today,
afternoon temperatures across many of the lower elevations areas
will likely reach the lower 90s with heat indices in the lower to
mid 100s.

This drier air mass is expected to remain over the area Tuesday
and Wednesday. Therefore, the rainfall activity is expected to
remain quite limited across the area. However, there will still be
enough low-level moisture and instability available to combine
with daytime heating and local effects to generate scattered
showers and isolated thunderstorms--mainly across northwestern
Puerto Rico during the afternoon hours.

Models indicate a whiff of Saharan dust will come across the area
today and fade tonight and Tuesday. This could bring visibilities
down to 10 to 15 miles.

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

Southeast flow on Thursday at lower levels will bring drier air
at first, then a weak easterly wave with a patch of moisture will
come through on Friday. On Saturday moisture increases again,
until the next and more significant tropical wave moves through
the area on Sunday. Drying on Monday will be followed by even
better moisture on Tuesday with another tropical wave. At upper
levels, low pressure will move west into the Caribbean while
higher pressure is draped across the western Atlantic just north
of Puerto Rico. The high and the low will both move west and away
from the area Friday and Saturday leaving northeast flow over the
area. That flow will continue through Tuesday as a strong TUTT
low approaches the Caribbean on Sunday but weakens before moving
across on Tuesday. Models show enhanced divergence on Sunday
afternoon with the passage of the first significant tropical wave.

At this time the driest period looks to be Wednesday and Thursday,
while Saturday and Sunday and possibly the Tuesday after next will
have the best moisture for shower and thunderstorm activity. Mid
level temperatures will also decrease a degree or two Sunday
through Tuesday to add some extra instability.

&&

.AVIATION...

Mainly VFR conditions should prevail across the local
area throughout the period. Sct SHRA and iso TSRA are possible
across NW PR between 30/16z and 30/22z, affecting mainly the
vicinity of TJBQ. Winds light and variable through 30/12z,
increasing up to 10 kts from the south with some sea breeze
variations developing after 30/14z. Maximum winds today ENE 20-25
kt btwn FL400-460.

&&

.MARINE...

Swell from Major Hurricane Lorenzo were still arriving
in the water north of our outer Atlantic waters with 8 feet every
12 seconds seen as recently as 30/0930Z. Therefore will continue
the small craft advisory for AMZ710. Some shoaling may also occur
in the shallow waters northeast of Saint John and 7 foot seas are
possible there as well. Seas will slowly subside in the Atlantic
through Saturday. Seas in the caribbean will remain relatively
tranquil until next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 78 93 78 / 30 10 20 10
STT 86 81 88 80 / 20 10 10 10

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
435 AM AST Tue Oct 1 2019

.SYNOPSIS...Drier air is edging in from the east and will reduce
showers and thunderstorms around the area. Temperatures will
continue above normal until gentle to moderate winds shift from
southerly to easterly from Wednesday to Friday. Showers return
late Friday through Tuesday with intrusions of moisture from weak
tropical waves passing through the area.

&&

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

A fair weather pattern is expected across the local area during the
short-term period as a building mid-level ridge settles over the
area, resulting in a drier and more stable air mass. Therefore,
shower activity is expected to be quite limited. Having said this,
scattered showers and isolated thunderstorms can still be expected,
mainly across northwestern Puerto Rico during the afternoon hours,
as the combination of available low-level moisture combining with
strong daytime heating and sea breeze convergence will spark some
activity. Rainfall accumulations, however, are expected to remain
modest with ponding of water on roadways and in low-lying areas
expected to be the main hazard.

The low-level flow is expected to remain southeasterly throughout
the period. This will result in warmer than average temperatures,
especially along the northern coastal areas of Puerto Rico, with
temperatures expected to climb into the lower 90s and heat indices
topping out in excess of 102 degrees--with some heat indices
exceeding advisory criteria.

.LONG TERM...Friday through Tuesday...
Moisture begins to increase again as weak easterly waves move
through the Caribbean. The strongest wave will pass through later
on Sunday and will have the best moisture as well. Moisture for
the week peaks on Sunday night and Monday morning with
precipitable water values above 2 inches. 500 mb temperatures will
begin to decline on Sunday and cause instability to increase over
the area fueling showers and thunderstorms with the passage of
the wave on Sunday. Another tropical wave pushes through on
Tuesday before moisture can abate.

At upper levels a TUTT low moves west across the area on Thursday
and Friday after which high pressure becomes the dominant
influence. The GFS is indicating that areas of strong divergence
do occur Sunday through Tuesday, but tend to be centered over the
local waters rather than over land. This will likely mean that
thunderstorms will persist over the warm waters surrounding the
islands during the overnight hours over the weekend and the first
part of next week.

&&

.AVIATION...Mainly VFR conditions are expected to prevail
across all terminals during the next 24 hours. Sct SHRA and iso
TSRA are possible across wrn and nwrn PR between 01/16z and
01/22z, affecting the vicinity of TJMZ and TJBQ. Winds light and
variable through 01/12z, increasing to up to 10 kts from the SE
with sea breeze variations after 01/14z.


&&

.MARINE...Subsiding swell from Hurricane Lorenzo and light to
moderate winds will allow seas to drop below 5 feet by the end of
the week. Increasing winds due to high pressure squeezing up
against a tropical wave expected on Tuesday will cause seas to
increase to 7 feet or more by Tuesday.

&&

.CLIMATE...Temperatures for September ran 1.3-1.4 degrees above
normal on average. This warm trend is continuing into the first
part of the month of October. Although it is unlikely that San
Juan will reach a record high today, since that was 96 degrees set
back in 1982, temperatures will drive into the lower and mid 90s
today in some lower elevations. With dew points in the upper 70s
this will cause heat indices in northern, southeastern and
southern portions of Puerto Rico to reach 100-111 degrees. A heat
advisory has been issued from mid-morning to late afternoon.
Mostly sunny conditions with light winds will also exasperate
these conditions.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 94 78 92 78 / 20 10 20 10
STT 88 80 88 79 / 10 10 10 10

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
424 AM AST Wed Oct 2 2019

.SYNOPSIS...Moisture lingers across the Mona Channel today
allowing some showers and isolated thunderstorms to develop over
the area during the afternoon--mainly in western Puerto Rico.
Minor disturbances move through Thursday through Saturday to
bring a few more showers to the area. On Sunday a better tropical
wave will move through late in the day with showers and
thunderstorms. Then, Monday through Wednesday of next week moisture
will decrease dramatically.

&&

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

A mid-level ridge will continue to influence our weather pattern
today and most of Thursday, resulting in a drier and more stable air
mass across the area. Therefore, mainly fair weather conditions with
limited shower activity can be expected across most of the region.
However, showers and isolated thunderstorms are still expected--
mainly across the northwestern quadrant of Puerto Rico during the
afternoon hours--as the available low-level moisture combines
with strong daytime heating and sea breeze convergence. Rainfall
accumulations for the most part should remain modest with ponding
of water on roadways and in low-lying and poor-drainage areas
being the main hazard. With the low-level flow prevailing from the
southeast, temperatures are expected to once again climb into the
lower 90s with heat indices ranging between 100 and 105 degrees
Fahrenheit. This will most likely occur along the northern
coastal areas of Puerto Rico.

By Thursday night into Friday, a weak easterly disturbance at low-
levels is expected to move across the area. This will bring an
increase in moisture as well as an increase in showers. Therefore,
scattered showers are possible during the overnight and morning
hours across portions of the USVI and eastern Puerto Rico. Rainfall
accumulations for the most part should remain on the light side so
as to not cause any significant impacts. Then, this moisture is
expected to combine with the strong daytime heating and sea breeze
convergence to generate more enhanced showers and isolated
thunderstorm activity across the northwestern quadrant of Puerto
Rico during the afternoon hours.

.LONG TERM...Saturday through Wednesday...
High pressure at the surface remains over the eastern Atlantic at
mid latitudes until Monday when it is absorbed and overwhelmed by
a stronger high that enters the western Atlantic from the
northeastern U.S. on Saturday night and spreads across the ocean.
Once it moves into the far northeastern Atlantic low pressure will
deepen in the mid-Atlantic and cause surface winds to shift to the
northeast.

Moisture from a weak tropical wave will pass over and south of the
area on Saturday. Drier air will move in on Saturday night
followed by a mediocre tropical wave Sunday night into Monday.
Moisture then drops considerably Monday through Wednesday along
with the occurrence of showers and thunderstorms. On Wednesday,
flow at lower levels becomes more northeasterly and moisture
enters the area over the Atlantic waters from the northeast.

Flow at upper levels remains generally northeast during the period
under the influence of high pressure northwest of us. A TUTT low
east of the Leeward Islands will drift slowly west during the
period but will remain in the tropical Atlantic.

&&

.AVIATION...Mainly VFR conditions expected across the area. SHRA and
isold TSRA expected across wrn and nrn PR between 02/16z and
02/22z, affecting the vcnty of TJMZ and TJBQ. TEMPO MVFR
conditions are possible. Winds light and vrb overnight,
increasing up to 10 knots from the ESE-SE with sea breeze
variations after 02/14z.

&&

.MARINE...Swell from distant Hurricane Lorenzo is fading slowly
across the area. Long period swell of up to 5 feet every 13
seconds are bringing a high risk rip currents to coasts with
northeastern exposure and this will spread tonight and tomorrow
from Puerto Rico to include Saint Croix. Conditions will improve
considerably on Friday. But, swell from the east will spread into
the area beginning on Sunday and 7 foot seas are possible
beginning Monday night--mainly in the outer Atlantic waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 92 78 91 78 / 10 10 20 30
STT 88 79 89 79 / 20 10 30 30

[cycloneye]

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
524 AM AST Thu Oct 3 2019

.SYNOPSIS...

Fairly typical weather is expected into the weekend, with plenty
of sunshine but also the usual shower activity as well. The best
chance for showers today is for western Puerto Rico near
Mayaguez, though impacts are expected to be minimal. The wettest
days for the next week look to be Saturday and Sunday, as a few
tropical waves move in. However, there will still be plenty of dry
periods for the weekend. The next work week looks drier, with
Saharan dust moving in bringing hazy conditions.

&&

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

A weak mid-level ridge northeast of the area will continue to
promote drier air across the region today. Forecast soundings are
indicating below normal precipitable water between 1.50-1.70 inches
through at least Friday, when a weak trough moves from the east.
However, diurnally induced afternoon showers with possible isolated
thunderstorms are expected to develop over the interior and western
sections of Puerto Rico each day. As the ridge weakens on Friday,
scattered showers are expected to develop from el Yunque area into
the San Juan metro area.

Mostly fair weather conditions are expected to prevail across the
U.S. Virgin Islands until Saturday, when a tropical wave moves
across the southeastern Caribbean and moisture increases over the
region. As the tropical wave moves across the region through the day
on Saturday, showers and thunderstorms are expected to increase in
coverage and intensity over mainland Puerto Rico. Under an east to
southeast wind flow, maximum temperatures should continue to range
in the high 80s to low 90s across the lower elevations of the
islands. Light to moderate trades will prevail through the short
term period.

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

Two tropical waves are expected to move in Sunday and Monday,
bringing more chances for showers across the region. These appear
to be very weak waves, surrounded by dry air, so impacts will be
fairly minimal. Steering winds are forecasted to be around 10-20
knots in the lower atmosphere, so showers should move along fairly
quickly. Decent concentrations of Saharan dust are also expected
to move in for the beginning of next week, resulting in widespread
hazy conditions. This should also help to suppress the showers.
Thereafter, the haze will continue through the remainder of the
workweek, with even drier air moving in. In fact, by next
Wednesday, model guidance suggests precipitable water values
roughly 2 standard deviations below average. Though some shower
activity is possible Tuesday and Wednesday, a better chance exists
Thursday as a batch of moisture rides in on the easterly trade
winds.


&&

.AVIATION...

Mainly VFR conditions are expected to prevail across all
terminals through the forecast period. However, areas of MVFR
expected over the western interior between 03/16z-22z could impact
TJMZ/TJBQ. E-ESE winds expected to continue at less than 12 kt with
sea breeze variations after 06/14z.


&&

.MARINE...

The swell from Post-Hurricane Lorenzo is fading, and the outer
Atlantic waters will drop below 5 feet today. Seas will remain
calm for the next several days, though long range models hint at
the chance for another northerly swell for the middle of next
week. Isolated showers are possible across our regional waters
today, particularly west of western Puerto Rico in the afternoon.
A high risk for rip currents remains in effect for the remainder
of today in northern Puerto Rico.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 79 90 78 / 10 40 40 40
STT 88 80 89 79 / 20 40 40 40

[cycloneye]

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
508 AM AST Fri Oct 4 2019

.SYNOPSIS...

A few weak surges of moisture are expected to move in and bring
isolated to scattered showers across the region through the
weekend. As usual, the best chances for showers will be in
western Puerto Rico in the afternoon hours. Thereafter, dry air
and a moderate Saharan dust event will begin early next week.
Hazy skies and only a few isolated showers are likely. Finally,
another swell event is forecasted for Tuesday.

&&

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

An induced easterly perturbation is moving across the Atlantic
waters just north of the U.S. Virgin Islands. This is bringing a
surge of low level moisture with passing showers between the USVI
and eastern PR. Light steering easterly winds are expected to
prevail with sea breeze variations across coastal areas. For this
afternoon, diurnally induced showers and thunderstorms are
expected to develop along the interior and western sections of PR.
Slow moving showers could lead to urban and small stream flooding
as well as quick river rises along these areas. Also, showers
with isolated thunderstorms are expected to develop from el Yunque
area into the San Juan metro area. Maximum temperatures should
range in the high 80s to low 90s, with a heat index up to 102
degrees across the lower elevations of northern PR.

A tropical wave is forecast to move across the region on Saturday
with lingering moisture on Sunday. Therefore, expect showers with
isolated thunderstorms to increase gradually from the Anegada
Passage and Caribbean waters into the USVI and eastern PR by
Saturday morning and spreading across the rest of the region through
Saturday night. The main threat will be flooding across mainland PR
and strong gusty winds with the thunderstorms. On Sunday, enough low
level moisture behind the wave will aid in the development of
afternoon showers and thunderstorms across the usual areas of
mainland PR. A drier air mass is expected to filter from the east
and across the USVI by Sunday night.

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

High pressure and dry air will take hold for much of next week.
Beginning Monday, moisture associated with a weak pressure
purturbation will move into the area. Some isolated showers are
possible across the region, with scattered showers over western
Puerto Rico. However, the drier air will limit the duration and
intensity of these showers. Furthermore, a moderate Saharan dust
event will peak on Monday, so hazy skies are expected.

The haze will continue into the middle of the week, and the driest
conditions will occur Tuesday and Wednesday. A few showers are
possible in western Puerto Rico, but high pressure will dominate
through Wednesday. For Thursday and Friday, it appears a western
moving area of mid-level high pressure will force some moisture
over the region, bringing the chance for some showers to end the
workweek. Precipitable water values from forecast model soundings
of both the European and American models keep values below average
for both days. Models also project an upper tropopheric trough
just to our south for Thursday into Friday, so that may provide
additional upward motion to help intensify any developing showers.
However, at this point this next rain event looks unimpressive.

&&

.AVIATION...

Mainly VFR conditions are expected to prevail through at least
16z. SHRA/TSRA between 16z-22z will cause areas of MVFR/brief IFR
over the interior and western sections of Puerto Rico. Impacting
mainly TJBQ/TJMZ, at TJSJ and TJPS mainly VCSH/VCTS should prevail
during the afternoon hours. East winds expected between 8-13 kt
with sea breeze variations after 04/14z.

&&

.MARINE...

Calm marine conditions are expected to prevail through the weekend
and into next week. Seas will stay below 5 feet, with winds
generally out of the east at 10 knots. Isolated showers are
possible across local waters, especially west of western Puerto
Rico for the next several afternoons. A swell event is forecasted
to begin next monday night. This event will occur as a result of
two seperate systems. A wind surge to our south will drive rough
seas for Tuesday. During the same period, a trough of low pressure
and an intensifying surface low north of the region will also
bring 7 foot seas to the Atlantic waters.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 89 78 / 40 40 60 60
STT 89 80 88 79 / 40 50 60 60

&&

[cycloneye]

AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
444 AM AST Sat Oct 5 2019

.SYNOPSIS...

More showers and thunderstorms will occur today as a tropical
wave moves in from the east. Drier air will begin to filter in
thereafter, along with Saharan dust for next week. Minimal shower
activity is expected until Thursday, when another batch of
moisture moves in from the northeast. The tropical Atlantic has
really calmed down, and no storms are expected this next week.

&&

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

A weak tropical wave is expected to move across the region today.
This will increase showers and thunderstorms over the Atlantic and
Caribbean waters and across the USVI and eastern portions of Puerto
Rico through the morning hours. Afternoon convection today will be
enhanced by the passage of the wave as it moves west and across
Puerto Rico. Under a light east to southeast steering wind flow,
thunderstorms are expected to develop from el Yunque area into the
San Juan area around noon and along the Cordillera Central and
west/northwest PR through the late afternoon hours. Flooding is
expected with this activity as well as strong gusty winds.

Lingering moisture behind the tropical wave will persist overnight
and into Sunday morning. Therefore, showers with possible isolated
thunderstorms could continue through the late evening hours over
western PR and during the overnight hours across the USVI and
eastern PR. For Sunday and Monday, trade wind perturbations induced
by an upper level low to the east of the Leeward Islands will aid in
the development of typical morning showers across the USVI/Eastern
PR, followed by afternoon thunderstorms over western PR. A drier air
mass is expected to filter from the east and across the USVI by late
Sunday night and a Saharan Air Layer will follow quickly and persist
through early next week. This will cause mostly hazy skies and fair
weather conditions across the region.

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

After Saharan dust peaks on Monday, hazy conditions will continue
into the middle of the week. Along with the dust, dry conditions
will continue across the region through Thursday early morning as
high pressure dominates the Atlantic waters. Showers will be limited
to western Puerto Rico in the afternoon for Tuesday and Wednesday,
and these showers will be weak with minimal accumulations.

Into Thursday, moisture associated with an area of low pressure to
the north will be forced down from the north into our forecast
area. Also, long range models suggest a weak upper-level low just
to our west for Thursday afternoon, which could provide ideal
conditions for a few strong thunderstorms to occur over western
Puerto Rico. Lower atmospheric winds look light for Thursday
afternoon, so showers could persist over a given area for long
enough to cause some urban and stream flooding. The upper-level
low and moisture will still be in place for Friday, so similar
conditions are expected. As for next weekend, forecast model
solutions disagree on weather conditions. However, typical October
conditions are likely.

&&

.AVIATION...

Mainly VFR conditions are expected to prevail early in
the forecast period. A weak tropical wave will increase SHRA/TSRA
across the regional waters through the day. MVFR/brief IFR
conditions possible at TJBQ/TJMZ/TJSJ/TJPS between 05/16z-23z. Tempo
MVFR conds are possible at TIST/TISX through late tonight. ESE winds
expected between 5-15 kt with sea breeze variations after 05/14z.

&&

.MARINE...

Calm marine conditions are expected to continue into the weekend,
with seas at or below 5 feet. Winds will be out of the east
between 5-15 knots. Into next week, higher seas of up to 7 feet
are possible as swell moves in next Tuesday. A low risk for rip
currents exists for the rest of today, except for a moderate risk
for the northern beaches of Puerto Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 91 78 / 60 60 40 30
STT 88 79 88 79 / 60 60 30 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
429 AM AST Sun Oct 6 2019

.SYNOPSIS...

For the next several days our weather will become more calm and
hazy. Scattered showers are still expected today across the
region, including in the metro area. However, a moderate Saharan
dust event will occur beginning today, peaking tomorrow, and
lasting into midweek. Given much drier conditions, coupled with
the dust, not much shower activity is expected through Wednesday.
A swell event will begin tomorrow evening.

&&

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

Lingering moisture behind a tropical wave will continue to result in
scattered showers across the regional waters and across portions of
the USVI and east/southern PR during the morning hours. For this
afternoon, the combination of the available low level moisture, day
time heating and sea breeze convergence will result in scattered to
locally numerous showers with thunderstorms...mainly over western
PR. Streamers off the USVI and from el Yunque into the San Juan
metro area are also expected this afternoon. East to southeast winds
will prevail today and maximum temperatures could reach the low 90s
across coastal areas of the islands.

A drier air mass with Saharan dust is expected to gradually filter
from the east from late tonight into Monday and it is expected to
continue through at least the first part of the week over the
region. This will inhibit widespread shower activity across the
islands and promote hazy skies and mostly fair weather conditions.
However, shallow moisture embedded on the trades will cause light
passing showers across the USVI/Eastern PR sections during the
morning hours and shallow afternoon convection over western PR each
day.

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

The trend of very dry conditions continues into Wednesday. Though
not as hazy as earlier in the week, Saharan dust will still be
around to help suppress convection. Only a few showers in western
Puerto Rico are possible, with just sunshine elsewhere. All that changes
Thursday as some moisture drops in from the northeast associated
with a dying low pressure system. Moisture levels increase, but
forecast models suggest they`ll still be below average. Long range
models also still are suggesting an upper level trough nearby for
Thursday and Friday. Putting this all together for Thursday...despite
somewhat low moisture content, showers are still likely and some
may be strong given the help from the upper level trough. Minimal
steering flow may cause higher rainfall amounts, leading to the
possibility of some flooding. Conditions don`t change much for
Friday, so similar conditions are expected.


As for the next weekend, the weather looks fairly typical for
this time of year. Lingering moisture coupled with diurnal effects
will lead to isolated showers across the region, with a higher
chance for showers and thunderstorms in the afternoon for western
Puerto Rico. Finally, it should be noted that the tropical
Atlantic has really calmed down as far as storm activity, with no
named or developing storms occurring or expected in the next week.

&&

.AVIATION...

Mainly VFR conditions are expected to prevail across
all terminals through the forecast period. However, SHRA/TSRA over
west PR could cause tempo MVFR/brief IFR conds at TJBQ/TJMZ btw
06/16z-23z. VCTS possible at TJSJ/TJPS. ESE winds at 5-15 kt with
sea breeze variations after 06/14z.

&&

.MARINE...

Calm marine conditions will continue into tomorrow with seas below
5 feet. There is currently a low risk for rip currents across all
islands. However, a swell event will occur beginning tomorrow
evening for the Atlantic waters, with seas expected up to 7-8
feet. Furthermore, and wind surge will occur early Tuesday,
resulting in rough seas for the Caribbean waters as well. Rough
seas will continue into the middle of the week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 79 90 78 / 40 20 10 10
STT 89 80 89 79 / 30 30 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
422 AM AST Mon Oct 7 2019

.SYNOPSIS...

A weak tropical wave will move through the Caribbean waters and
increase rain chances today. Then a drier air mass is expected to
filter into the region from the east, and hold through the remainder
of the week. Showers and isolated thunderstorms are possible during
the afternoons as a result of local and diurnal effects.

&&

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

An air mass with Saharan dust particles will create hazy skies
today. However, pocket of moisture embedded in the trades will bring
quick passing clouds and showers across the regional waters and the
windward sections of the U.S. Virgin Islands and eastern Puerto Rico
throughout the day. Local effects combined with diurnal heating and
sea breeze convergence will aid in the development of showers and
isolated thunderstorms across west Puerto Rico during the afternoon.
Streamers off the USVI and from el Yunque into the San Juan metro
area are also expected this afternoon. In general, east to east-
southeast winds will prevail today and the maximum temperatures are
expected along the coastal areas, where the thermometer could reach
the low 90s this afternoon.

Another tropical wave is forecast to move quickly across the
Caribbean Sea late this afternoon through Tuesday. This wave will
create the best chance for shower and thunderstorm development in
the short-term period. This activity is expected mainly across the
Caribbean waters but some of them will move over the Virgin Isles
and east and south Puerto Rico. After this wave, dry air with
Saharan dust will gradually return from the east. This will inhibit
widespread shower activity across the islands and promote hazy skies
and mostly fair weather conditions. However, showers embedded in the
trades should not be ruled out across the USVI/Eastern PR sections,
followed by afternoon convection over western PR.

.LONG TERM...

A drier air mass will cause precipitable water values to plummet
to 1.1 to 1.4 inches through Friday. This drier air mass will
limit the development of widespread convection during the
afternoon, however, as a result of sea breeze convergence, diurnal
heating, and local effects, showers are expected to develop across
the interior and western areas of Puerto Rico. Recent guidance
shows patches of moisture moving into the area from a diffused
front in the Central Atlantic on Friday through Saturday. The
additional moisture could contribute to an increase in showers
during the afternoon over the local waters and coastal areas of
Puerto Rico.

Sunday, moisture will increase from east to west as a result of a
weak tropical wave that will move through the Caribbean waters.
Therefore, expect scattered to numerous showers and thunderstorms
over the interior, and western areas of Puerto Rico, and the U.S.
Virgin Islands. The bulk of the moisture is forecast to arrive
over Puerto Rico Monday afternoon during the peak of daytime
heating. Due to this, widely scattered to numerous showers with
thunderstorms are expected to develop across most of Puerto Rico
and the U.S. Virgin Islands.

&&

.AVIATION...

Mainly VFR conditions are expected to prevail across
all terminals through the forecast period. SHRA will diminish
through the morning hours, but should not be ruled out across the
VCTY of E-PR/USVI/TKPK/TNCM at times. SHRA/TSRA are expected across
W-PR btwn 07/17-23z, which could affect JMZ/JBQ. Sfc winds will
continue calm to light and VRB thru 07/13z, then, returning from the
E at 10-15 kt with sea breeze variations.

&&

.MARINE...

Mainly tranquil marine conditions this morning through this
afternoon. Then marine conditions are forecast to become hazardous
later this evening due to the combination of a northerly swell,
and a wind surge. Seas up to 7 feet or greater is expected through
Wednesday morning. A high risk of rip currents for the northern,
central, northeastern, northwestern beaches of Puerto Rico later
this evening. In addition, a high risk of rip currents for the
northern beaches of Culebra, and St. Johns and St. Thomas.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 90 76 / 40 50 40 10
STT 89 79 88 78 / 30 30 20 10

[cycloneye]

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
433 AM AST Tue Oct 8 2019

.SYNOPSIS...

Hazy conditions is expected across the region today before a weak
tropical wave moves into the area today. The wave and its
associated moisture will increase the chance for showers tonight
through tomorrow afternoon. Then moisture is forecast to plummet
through the rest of the week as a stable air mass filters into the
region from the east. The high pressure aloft and limited low-
level moisture will result in stable weather conditions.

&&

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

The tropical wave will exit the region faster than previously
thought, leaving a Saharan Air Layer and hazy skies over the
islands. This Saharan air mass will dominate the local weather
conditions through the short-term period. Therefore, continue to
expect hazy skies, warm temperatures and little or no shower
activity.

Although drier than normal conditions will persist, pocket of
moisture embedded in the trades will bring quick passing clouds and
showers each day. Therefore, the typical diurnal pattern with
morning convection over the USVI/E-PR, followed by afternoon
convection over the western sections and downwind from El Yunque and
the Virgin Isles is expected each day. Also, high temperatures will
hold along the coastal areas in the low 90s each afternoon.

&&

.LONG TERM...Friday through Wednesday...

A drier air mass will keep precipitable water values near the 25th
percentile for the month of October, with values ranging from 1.2
to 1.3 inches through early Saturday. Additionally, the dry air
shows up in the Skew-T diagram at 839 to 300 mb through Sunday
morning. The drier will limit the vertical development of showers,
which will cause any showers that do develop to be short-lived.
Nevertheless, showers are expected to develop as a result of
diurnal heating coupled with local effects during the afternoons.
Also, moisture from a diffused front north of Puerto Rico will
move into the area periodically starting on Thursday through
Sunday. The additional moisture could contribute to an increase
in showers during the afternoons over the local waters and coastal
areas of Puerto Rico.

Sunday, moisture is forecast to lift from the Caribbean, and erode
the drier air in the mid-level of the atmosphere across the
region. The bulk of the moisture from the Caribbean will remain
south of the region, and not have a major affect on the local
islands. Monday moisture ahead of a weak tropical wave will into
the local area, and increase showers and thunderstorms during the
afternoon. Tuesday, the weak tropical wave and its associated
moisture will cause scattered showers and thunderstorms during
the afternoon. The tropical wave is expected to exit the local
area Wednesday afternoon, however, some moisture is expected to
linger behind the wave. The lingering moisture coupled with
diurnal heating and local effects will aid in the development of
showers during the day on Wednesday.

&&

.AVIATION...

Mainly VFR conditions are expected to prevail across
all terminals through the forecast period. Hazy skies will persist
as a Saharan Air Layer holds over the islands. However, VIS should
remain P6SM. Passing SHRA should not be ruled out at times. SHRA and
maybe one or two TSRA could develops across W-PR btwn 08/17-23z. Sfc
winds will continue calm to light/variable thru 08/13z. A wind surge
will bring E winds at around 15 knots with higher gusts after
08/13z. Sea breeze variations are expected too.


&&

.MARINE...

Seas are expected to range from 7 to 8 feet across the regional
waters today through Wednesday as a result of a northerly swell
that moved into the regional waters during the overnight hours.
There is a high risk of rip currents for most of the north facing
beaches of the local Islands. Also, a high surf advisory is in
effect until 6 AM Wednesday mainly for the northern beaches of the
local Islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 77 90 77 / 10 10 10 20
STT 88 79 88 78 / 10 10 10 20

[cycloneye]

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
450 AM AST Wed Oct 9 2019

.SYNOPSIS...

Fair weather with hazy skies will continue to prevail across the
region over the next several days. Isolated to scattered showers
are possible during the afternoons as a result of diurnal heating
coupled with local effects. Saturday moisture will lift out of
the southern Caribbean waters, and erode away the drier air over
the area. An increase in showers and isolated are expected to
begin on Sunday through early next week as several weak tropical
waves move over the area.

&&

.SHORT TERM...

A Saharan Air Layer (SAL) is supporting a drying trend
with hazy skies across the islands. This feature will dominate the
local weather conditions through at least Thursday. Although pockets
of moisture embedded in the trades could bring isolated showers
across the region at times, most of the activity, if any, will be
confined over the western sections during the afternoon due to local
effects and diurnal heating.

As the Saharan dust concentration diminish Thursday afternoon,
the potential for scattered to numerous showers may increase over
western Puerto Rico. Also, model guidances is indicating a slight
increase in the available moisture on Friday with the arrival of a
surface trough from the southeast. Therefore, the chances for
convective activity may increase during the afternoon into the
evening hours.

&&

.LONG TERM...

Saturday, model guidance shows moisture lifting out of the
southern Caribbean waters and clipping the southern coastal areas
of Puerto Rico. The bulk of the deep tropical moisture is
expected to remain over the Dominican Republic. In addition,
moisture from a diffused frontal boundary in the central Atlantic
will push into the region from the north. The added moisture
combined with local and diurnal effects will produce showers and
possibly thunderstorms during the afternoons through the weekend.
Also, the increasing moisture will cause precipitable waters
values to climb to 1.5 to 1.6 these values rank near the 50th
percentile compared to October`s precipitable water climatology.

Low-level moisture will continue to transverse the region through
the remainder of the long-term period. The combination of low-level
moisture coupled with local and diurnal effects will lead to the
development of showers and thunderstorms during the afternoons.
In addition, several weak tropical waves are expected to move
through the region early next week. The first tropical wave is
forecast to reach the forecast area on Tuesday before exiting the
local area Wednesday afternoon. However, moisture is expected to
linger behind the departed tropical wave through Thursday.
Therefore, expected a continuation from the previous days with
showers and isolated thunderstorms developing during the
afternoons across Puerto Rico. Elsewhere, scattered to isolated
showers are possible during the day.

&&

.AVIATION...

VFR conditions will persist through the fcst period. But, a Saharan
Air Layer will create hazy skies over the islands, which could
reduce VIS down to 6 miles at times. Although SHRA cannot be ruled
out at times, most of the activity, if any, will be confined over
western PR near TJMZ or TJBQ. This activity will be isolated to
scattered btwn 09/18-22z. Winds will continue calm to light and vrb,
returning from the E around 15 kt with higher gusts and sea breeze
variations after 09/13z.

&&

.MARINE...

Small craft advisories are still in effect for all the local and
outer waters except the southern coastal waters of Puerto Rico.
Seas will continue to subside throughout day as the northerly
swell energy continues to dissipate across the local and regional
waters. There is a high risk of rip currents for the northern,
eastern and western beaches of Puerto Rico. Also, a high risk of
rip currents for the beaches of the U.S. Virgin Islands. northern
beaches of Culebra, Thomas and St. Johns.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 77 90 76 / 10 10 10 10
STT 88 78 88 78 / 10 10 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
502 AM AST Thu Oct 10 2019

.SYNOPSIS...

A Saharan Air Layer (SAL) will continue to result in hazy skies
across the islands today. The mid-level ridge, which has been
aloft for the past few days, is forecast to weaken today.
Moisture associated with the remnants of a frontal boundary will
move over the islands from the Atlantic late this afternoon into
Friday. Tropical moisture will arrive from the southeast Caribbean
by Saturday.

&&

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

A dry Saharan air mass with patches of moisture embedded in the
easterly trades is forecast to prevail through the end of the
workweek. Also, 700 mb winds will pull moisture from a diffused
front in the central Atlantic over portions of northern Puerto Rico
through Friday. The combination of narrow moisture coupled with
diurnal heating and sea breeze convergence will lead to the
development of showers and isolated thunderstorms across the
interior and western areas of Puerto Rico. Showers and thunderstorms
that develop during the afternoons will be short-lived as a result
of limited moisture and drier air in the mid-levels of the
atmosphere.

Friday, winds shift to the east to southeast direction, this shift
in the winds will increase daytime high temperatures, and place the
development of showers and thunderstorms near the interior and
northwestern areas of Puerto Rico during the afternoon.

Saturday, deep tropical moisture from the southern Caribbean is
expected to lift north and over Puerto Rico. The added moisture
will erode away the drier air in the mid-levels of the atmosphere,
and increase rain chances across Puerto Rico. Scattered to
numerous showers are expected to develop as a result of deep
tropical moisture coupled with significant heating and local
effects. The moderate to heavy rain could cause urban and small
stream flooding and ponding of water on roadways.

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

The lingering moisture of Saturday`s surface perturbation will
exit the region by Sunday afternoon. However, this perturbation
will promote showers and thunderstorms across the region,
especially during the afternoon hours of Sunday.

A mid/upper-level trough, forecasted to be over the central
Atlantic, will induced an easterly perturbation which should move
across the U.S. Virgin Islands and Puerto Rico by Monday. Then,
model guidance is suggesting the arrival of another tropical wave
on Tuesday. On the other hand, the aforementioned upper level
feature will amplify near the region Tuesday into mid-week. If
model guidance is right, an unstable and wet pattern will be
possible through this period.

Friday, a zonal flow at upper levels with a high pressure at mid
levels will limit vertical development across the islands.
However, the lingering moisture and local effects will result in
the seasonal convective activity.

&&

.AVIATION...

VFR will continue to prevail through the fcst period. Hazy skies
is expected today due to Saharan Dust which could bring Vsbys down
to 6 SM though the fcst period. SHRA/TSRA are possible across
western PR through 10/22z, affecting mainly the vicinity of TJMZ.
SHRA/TSRA should dissipate by 11/00Z across the western areas of
PR. Winds out of the east at 10 to 15 kts with higher gusts
possible, and sea breeze variations after 10/13Z.

&&

.MARINE...
Small craft operators should exercise caution across most of the
local waters this morning due to seas up to 6 feet. The
northeasterly swell will drop below 7 feet across the local
Atlantic Waters and Caribbean Passages through early this
afternoon. However, the northeasterly swell will persist through
at least Saturday, when another northerly to northwesterly swell
is forecast to arrive Sunday into late Monday night. Therefore,
small craft operators are urge to exercise caution.

The Caribbean seas can expect seas below 5 feet through much of
the forecast period.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 90 78 / 10 10 30 50
STT 87 76 88 78 / 10 20 30 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
504 AM AST Sat Oct 12 2019

.SYNOPSIS...
Light winds continue today, out of the east/southeast. Drier than
average conditions are expected to persist as well, with haze
lingering into the week, though patches of moisture embedded in
the trade winds will likely make their way over the islands
through the week. This moisture is forecast to aid in the
development of shower and convective activity during the
afternoons. Another weak northerly/northwesterly swell will push
into the local waters early this week as well.

&&

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

A weak surface trough will persist just NNE of the local islands
today and Sunday morning, moving away by late Sunday. This trough
is keeping light SE winds across the local area, which are
expected to increase on Monday while turning more easterly. There
is also an upper level low to the NE of the Leewards, while
keeping the local islands under the ridge this weekend. However,
another upper level low will approach the local area and will have
its axis just to our east by late Monday. The available moisture
will increase gradually through the weekend. At this time there is
a narrow band of drier air that will be over portions of PR and
the USVI, but NW-PR will have higher than normal moisture, then
the deeper moisture will move north through the weekend, causing
us to have near normal to higher than normal moisture by Monday.

Given the current patterns, we expect mainly isolated and brief
showers across the local area in the morning and overnight hours,
but thunderstorms are expected across the northwestern quadrant of
PR this afternoon, with enough rainfall to cause urban and small
stream flooding. A similar pattern is expected on Sunday but mainly
across western PR as the sea breeze convergence is expected across
western PR and perhaps the southern slopes of PR. And for Monday,
showers and thunderstorms in the afternoon across western and
western interior of PR, but scattered showers and isolated
thunderstorms are expected elsewhere, partly due to the increase in
Moisture.

.LONG TERM...Tuesday through Saturday...
A relatively dry air mass will continue to be the dominant feature
over the area into the end of the week. However, there will be
patches of moisture carried within the trade winds that will likely
impact the region through the week and into the weekend. These areas
of moisture are expected to combine with local effects and daytime
heating to aid in the development of showers and the potential for a
thunderstorm or two, especially in western and interior Puerto Rico
in the afternoons each day.

An upper level trough to the northeast is expected to slowly
approach through the week, likely ending up very near or over the
region by the weekend. This trough is forecast to lead to greater
instability with cooling aloft and the potential for enhanced upper-
level divergence. Because of this, there could be an increase in
shower activity, even with the lower levels of moisture. Impacts of
this increase in precipitation and convective activity could include
frequent lightning, gusty winds, and heavy rain, possibly leading to
urban and small stream flooding. There is, however, some uncertainty
with respect to the timing of the arrival of this trough, with the
ECMWF placing the trough over the islands in the second half of the
work week, while the GFS moves it more slowly into the area.


&&

.AVIATION...
VFR conds expected across the local terminals through 12/16Z.
Thereafter, SHRA/TSRA could affect TJBQ and TJMZ, mainly between
12/17Z and 12/23Z, possibly causing TEMPO MVFR Conds at TJBQ.
However, at this time, most of the TSRA activity is expected in
the vicinity of TJMZ and TJBQ. Elsewhere, VCSH is possible through
the forecast period with only a slight chance of anything below
VFR. Winds will be light, but favoring a SE direction, but there
will be a strong sea breeze influence after 12/13Z.

&&

.MARINE...
Wave heights up to around 3-5 feet are expected to continue in the
local waters. A northerly/northwesterly swell is expected to begin
to push into our region later today/tonight, in association with Sub-
tropical Storm Melissa, which is located well to the north of the
region and forecast to remain well to our north throughout its
existence. Increased wave heights are therefore likely in Atlantic
waters, as well as possibly within local passages - namely the
Mona Passage - with heights up to 4-6 feet.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 77 89 77 / 20 20 30 20
STT 87 77 88 77 / 10 30 40 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
414 AM AST Sun Oct 13 2019

.SYNOPSIS...No organized weather systems are expected to affect
the local area during most of the upcoming work week at this
time. However, sufficient low-level moisture will be in place to
combine with strong daytime heating and local effects to generate
shower and thunderstorm activity, mainly across the western half
of Puerto Rico each afternoon. A wetter weather pattern is
possible by the end of the work week through next weekend as an
upper-level trough moves over the region with deeper moisture.

&&

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

A weak surface trough will persist just NNE of the local islands
today, moving away by tonight as it continues to weaken. This trough
is keeping light winds across the local area, which will be mostly
easterly today and also are expected to increase on Monday as the
trough is expected to have flattened and moved away by then. There
is also an upper level low to the NE of the Leewards, while keeping
the local islands under the ridge this weekend. However, another
upper level low will approach the local area and will have its axis
just to our east by late Monday into Tuesday, keeping the local area
with NW to N winds in the upper levels on Monday and Tuesday, which
normally is associated with limited instability. However, the
forecast soundings do put more CAPE and a higher K-index and a lower
LI for Tuesday than it does on Monday. There is still a narrow band
of drier air over southern PR an the Caribbean waters according to
satellite derived imagery. However, the available moisture will
increase gradually through the next few days.


Given the current patterns, we expect mainly isolated and brief
showers across the local area in the morning and overnight hours,
but thunderstorms are expected across the interior and western
sections of PR this afternoon, with enough rainfall to cause urban
and small stream flooding. A similar pattern is expected on Monday
and Tuesday. That said, the winds are expected to be stronger on
Monday and Tuesday, so the thunderstorm activity expected on those 2
days is expected to be more across the western municipalities,
rather than the western interior which is the case today. That said,
there is some disagreement among the local guidance, the GFS
forecast soundings do not indicate a great deal of instability for
this afternoon, and the NMM model agrees, being modest in its
rainfall accumulations, however the WRF model is much more bullish
with its rainfall forecast. For that reason we decided to split the
difference and highlight the areas that have the best chance of
showers and thunderstorms with relatively high POPs, but kept the
rainfall forecast more modest than the aggressive WRF.

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

An upper-level trough will be positioned north of the region by the
middle and the latter part of the workweek. There are differences in
the most recent global models on whether this feature will be
located east or west of the islands. The latest GFS model run
suggests that Puerto Rico and the U.S. Virgin Islands will be in the
subsidence side of the trough, while the ECMWF suggests that the
local islands will be on the divergent side of the trough. If the
European model is correct, then there will be better upper level
support and an increase rainfall potential across the forecast area.
On the other hand, if the GFS is correct, shower and thunderstorm
activity should be limited to local effects in the afternoon hours
mainly across the interior and western Puerto RIco.

For the weekend, an approaching tropical wave is expected to bring
an increase in moisture to the area. By then, an upper-level low is
expected to move over the islands. However, once again there are
discrepancies between the position of the low. Therefore,
uncertainty still exist on how this pattern will evolve later in the
forecast period.

&&

.AVIATION...VFR conds expected across the local terminals through 13/16Z.
Thereafter, SHRA/TSRA could affect TJBQ and TJMZ, mainly between
13/17Z and 13/23Z, possibly causing TEMPO MVFR Conds at TJMZ.
However, at this time, most of the TSRA activity is expected in the
vicinity of TJMZ and TJBQ. Elsewhere, VCSH is possible through the
forecast period. Winds will be light, favoring an easterly
direction, but there will be a strong sea breeze influence after
13/13Z.


&&

.MARINE...A northwesterly swell is expected to affect the Atlantic
waters and local passages today, resulting in seas between 5 and
6 feet. Seas of less than 5 feet are expected elsewhere. There is
a high risk of rip currents along the northwest to northeast
coastline of Puerto Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 77 89 77 / 10 10 40 30
STT 88 78 89 79 / 20 20 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST Mon Oct 14 2019

.SYNOPSIS...
Local effects and diurnal heating will bring showers and isolated
thunderstorms to the area, especially in western and interior
Puerto Rico this afternoon. A tropical wave will push into the
region late in the day today, and will likely enhance this shower
and convective activity. Though there will be somewhat less
moisture available tomorrow, similar conditions are likely.
Another tropical wave is forecast to make its way into the area on
Friday; higher moisture levels will last through the weekend.

&&

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

Light easterly winds are expected today as moisture gradually
increases. There is an upper level low to the north of the Leewards,
which will weaken, but an upper trough will remain north of the
Leewards and NE of the local islands. However, the upper trough will
then re-strengthen late on Wednesday. This will keep the local area
with NW to N winds in the upper levels on today through Wednesday.
Forecast soundings indicate some instability with the chance of
thunderstorms. The available moisture will increase gradually
through the next few days, especially late tonight into Tuesday as a
tropical wave approaches the local area.

Given the current patterns, we expect mainly scattered showers
across the local waters this morning and then tonight, but
thunderstorms are expected across the interior and western sections
of PR this afternoon, with enough rainfall to cause urban and small
stream flooding. A similar pattern is expected on Tuesday but with
less coverage and intensity, because it is expected for the moisture
to be decreasing at that time and cloud cover may inhibit some
afternoon convection. Similarly for Wednesday, convection expected
across western PR but even less activity is expected as the moisture
decreases further, albeit slightly, and we are still in the
subsident side of the upper trough.

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

On Friday, a tropical wave is expected push into the region,
bringing a marked increase in moisture levels over the local
islands. This is anticipated to bring an increase in shower and
thunderstorm activity caused by local effects and diurnal heating,
especially in western, northwestern, and interior portions of
Puerto Rico. The effects of this wave will be felt into the
weekend, with additional moisture making its way into the area on
Sunday.

On Thursday, an upper-level trough is forecast to be slowly
approaching the eastern portion of the region. There is increasing
agreement in long-range guidance with respect to the timing of
this system and the location at the start of the long-range
period, with the Euro also placing this feature to the east as
well in the most recent run. Beyond Thursday, there is increasing
uncertainty in the exact direction that this feature aloft takes,
but it is likely that it will initially track to the southwest
slightly, potentially tracking it just over the local islands or
just to the south. The GFS then shows it turning to the northwest,
while the Euro keeps it moving southwestward. With this lingering
uncertainty, there is also uncertainty in the degree to which
this low could enhance convection over the local islands. Should
the GFS solution verify, this upper-level low would be expected to
bring increased divergence aloft and upward motion to the islands
over the coming weekend, leading to an increase in shower and
convective activity.


&&

.AVIATION...

VCSH across the USVI terminals early in the morning. Mainly VFR
conds expected across the local terminals through 14/16Z. SHRA/TSRA
could affect TJBQ and TJMZ, between 14/17Z and 14/23Z. However, most
of the TSRA activity is expected in the vicinity of TJMZ and TJBQ.
Elsewhere, VCSH is possible through the forecast period. Winds will
be light, favoring an easterly direction with sea breeze variations
after 14/13Z.

&&

.MARINE...

There is a northwesterly swell persisting into the morning in
Atlantic waters from Tropical Storm Melissa, located, and to
remain, well north of the region. This swell will begin to
diminish today, and wave heights of around 3-5 feet are expected
for during the day today in Atlantic waters, with calmer seas to
the south of the local islands. Isolated to scattered showers, and
isolated thunderstorms, will be a continuing concern as well.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 77 89 77 / 30 40 50 50
STT 88 79 88 77 / 40 50 50 50

[cycloneye]

AFDSJU

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
544 AM AST Tue Oct 15 2019

.SYNOPSIS...

Similar conditions are expected for today as occurred yesterday.
Moisture from a tropical wave will combine with instability, local
effects, and diurnal heating to bring increased shower and
convective activity, especially to western and interior portions
of Puerto Rico during the afternoon. Potential impacts include a
risk of urban and small stream flooding, as well as rapid river
rises this afternoon. Somewhat drier conditions are anticipated
for tomorrow, but afternoon showers and isolated thunderstorms are
still likely. Another tropical wave is expected to provide us with
another increase in moisture for Friday.

&&

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

Light easterly winds and near normal low level moisture will
continue across the region today. The TUTT and weak upper low
northeast of the northern Leewards will remain in place, and is
still expected to become amplified and sink southwest across the
northern Leewards and northeast Caribbean by Wednesday while
strengthening. This will maintain a NW-N wind flow in the upper
levels today and Wednesday. Forecast soundings are suggesting that
the instability for today through Thursday will be similar to that
recently observed over the local area, which means that good
convection could occur over the next few days. An induced surface
trough and a tropical wave approaching the area will favor a fairly
unstable environment today. A gradually drying trend is expected to
start late on Wednesday as a drier air mass accompanying a saharan
air layer will move across the region.

The forecast for today is for mostly scattered showers with isolated
thunderstorms across the local waters during the rest of the
morning, some of those could affect the USVI and eastern PR.
Afternoon thunderstorm activity over land is expected across the
interior and western PR, but some showers and thunderstorms may be
observed near the San Juan metro area. The pattern today is not too
different to that observed yesterday, wit the exception that is is
expected to cover a larger area, so at least some urban and small
stream flooding as well as rapid river rises are expected this
afternoon.

On Wednesday, a drier airmass is forecast as an area of saharan dust
moved in behind the tropical wave. But the upper trough will still
be in place and the moisture will linger overnight from Tuesday into
early Wednesday. Therefore, early morning showers and thunderstorms
are expected across the local waters and portions of souther and
eastern PR as well as the USVI. Then in the afternoon, the local
effects will help in the development of showers and thunderstorms
across the interior and northern slopes of PR as the local winds will
be more southerly. Then for Thursday, the shower activity overnight
should be isolated to scattered as drier air prevails over the area,
then some afternoon convection is possible across central and
western PR, but the coverage and duration is expected to be more
limited compared to what we expect today.

.LONG TERM...Friday through Wednesday...
A tropical wave is expected to push into the forecast region late on
Thursday or early Friday, bringing increased moisture. This moisture
will aid in the development of showers and isolated thunderstorms
caused by local effects and diurnal heating, especially in western
and interior portions of Puerto Rico, as well as in the San Juan
metro area.

Potentially also aiding in the development of shower and
convective activity is a cutoff upper-level low. While there remains
some uncertainty with respect to the location of this feature, the
current most-likely scenario is that it will be to the south or
southwest of Puerto Rico moving to the southwest and then shifting
to a more westward or northwestward direction. With there still
being a lack of good agreement on this low from the guidance, the
uncertainty with respect to how much it will impact conditions
locally is high enough that a close eye will need to be kept on this
system and its trajectory between now and the end of the week. With
or without the assistance of this cutoff TUTT low, there remains the
potential for potentially hazardous conditions caused by locally
heavy rainfall, including the risk of urban and small stream
flooding.

The moisture will remain at relatively high levels through the
weekend, with another surge of moisture forecast to make its way
over the local islands on Sunday. Shower and isolated thunderstorms
are likely each afternoon, especially in, but not limited to western
and interior portions of Puerto Rico. Potential impacts include
locally heavy rain with the risk for urban and small stream flooding
as well as frequent lightning and locally gusty winds

A somewhat drier airmass is expected to make its way into the area
late Monday and Tuesday. Even with comparatively decreased moisture
available, local effects and daytime heating are still expected to
lead to the development of showers and isolated thunderstorms.

Wednesday into Thursday will see the arrival of another tropical
wave to the Caribbean waters. While it currently appears that the
bulk of the moisture will stay to the south and southeast of the
local islands by Thursday, it is likely that there will be at least
a slight increase in moisture over the area, which could aid in the
development of showers and isolated thunderstorms caused by local
effects and diurnal heating.


&&

.AVIATION...

SHRA activity expected through the forecast period across the local
flying area. This will cause at least VCSH across most of the local
terminals for the next 24 hours, with brief VCTS possible at the
USVI terminals. TSRA is expected over central and western PR today,
for that reason VCTS across all of the terminals in PR is likely
after 15/16Z, though TEMPO MVFR conds at TJMZ are possible. The
local winds will be easterly at 10kt or less, with sea breeze
variations.

&&

.MARINE...

The northwesterly swell will continue to diminish this morning.
Wave heights are expected to remain generally below five feet over
the next several days. There will remain a moderate risk of rip
currents on north-facing beaches in Puerto Rico, Culebra, and St.
Thomas today, subsiding a little tonight; there will be a low to
moderate risk tomorrow at north-facing beaches on mainland Puerto
Rico and Culebra.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 88 77 / 60 50 40 30
STT 88 77 87 77 / 50 50 20 10