Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
431 AM AST Wed Jun 19 2019

.SYNOPSIS...Surface high pressure across the central Atlantic
will cause an easterly breeze across the local islands for the
next several days. A tropical wave will pass just south of the
local islands on Thursday, increasing moisture, while an upper
level trough axis gets close to the local islands, which could
increase instability. Dry air to move in on Friday, which will
prevail until Monday when the next tropical wave is expected.
Haze due to Saharan dust expected for the next several days.

&&

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

A drier air mass and Saharan dust will continue to hold over the
area today with hazy and partly cloudy skies. The stable air mass
will limit shower activity during the afternoon for many areas.
However, isolated to scattered showers may develop, as a result, of
local and diurnal effects. Later this evening low-level moisture is
forecast to increase as a tropical wave moves into the southern
Caribbean waters. Moisture will spread across the U.S. Virgin
Islands and Puerto Rico during the overnight hours and early
Thursday morning. The added moisture will aid in the development of
showers and possible isolated thunderstorms. Then by mid-day on
Thursday the bulk of the moisture will spread across the interior
and western areas of Puerto Rico. Additionally, the local and
diurnal effects merging with the moisture will induce showers and
possible isolated thunderstorms across the interior and western
areas of Puerto Rico during the afternoon on Thursday.

At this time instability parameters look meager with 500 mb heights
ranging from -6 to -7 degrees Celsius. Additionally, MU AND SB cape
are relatively weak, therefore thunderstorm development is not a
sure thing.

Friday, the moisture is forecast to be west of Puerto Rico with a
drier air mass and Saharan dust moving over the region on Friday.
However, showers are possible as a result of local and diurnal
effects during the afternoon.

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

Fair weather with haze due to Saharan dust is expected for most of
the long term forecast period. The mid to upper levels will not
cause any sort of significant instability through the weekend and
any showers that occur in the afternoon will be locally induced
across western PR. Due to the presence of Saharan dust and drier
than normal air mass, the afternoon convection may be limited in
terms of coverage. However, a broad upper level trough may cause
an increase in the local instability on Monday, at the same time a
tropical wave is forecast to move in, which will increase
moisture. At this time, the long range models are suggesting an
increase in showers and thunderstorms on Monday, but drying out
quickly on Tuesday into Wednesday.

&&

.AVIATION...VFR conds will continue to prevail across all terminal
sites through 19/18Z. Then SHRA/TSRA are possible mainly across the
western areas of Puerto Rico or near terminal sites TJBQ and TJMZ
with conds improving by 19/22Z. SHRA/TSRA could cause brief MVRF
conds. Sfc winds out of the east at 15 to 20 kts with higher gusts
possible. Suspended Saharan dust particulates will continue to
affect the local flying area for the through today, but VIS should
remain P6SM.

&&

.MARINE...The local seas will be choppy today as the winds
gradually increase. For today, the local seas are expected to be
up to 6 feet and the winds up to 20 knots. However, the winds are
expected to increase across the local Caribbean waters and
passages, resulting in an increase in seas up to 7 feet starting
this evening. For that reason, a small craft advisory will be in
effect starting this evening, continuing through Friday. There is
a moderate risk of rip currents across most of the local beaches,
but a low risk is forecast for western PR, western Saint Croix,
and most of Saint Thomas and Saint John.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 89 78 / 20 30 40 20
STT 88 80 87 79 / 20 40 30 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
332 AM AST Thu Jun 20 2019

.SYNOPSIS...

A tropical wave has moved into the southern Caribbean waters
during the overnight hours. This wave will increase low-level
moisture across the region today. However, the bulk of the
moisture is expected to remain south of the forecast area, but
scattered showers could develop and move across the local islands.
Tonight the moisture rapidly moves west of Puerto Rico thus
giving way to a dry Saharan air mass. The dry Saharan air mass is
forecast to hold across the region through the weekend. Then
another tropical wave is forecast to move into the Caribbean
waters Sunday night into Monday

&&

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

A tropical wave is forecast to pass south of the local islands
today, which could bring some increase in moisture. The satellite
derived blended total precipitable water imagery indicates that the
moisture associated with the wave reaches latitude 19N and has
precipitable water values almost to 2 inches, moving west. Guidance
is consistent with this, and it shows that the moisture will be
highest across the local waters, USVI, and coastal areas of PR
today. However, there is some Saharan dust and the precipitation
potential seems to be very limited, as suggested by both global and
high resolution models. The main area of convection associated with
the wave is expected to remain to our south, and current satellite
imagery shows the convection (associated with the tropical wave and
an upper trough to our NE) occurring south and southeast of the local
islands at about latitudes 15-16N. Therefore, we toned down the
precipitation potential a little, limiting it mostly to the
northwestern quadrant of PR in the afternoon hours as sea breeze
convergence and available moisture will combine with diurnal heating
to cause some shower development across portions of NW-PR.
Otherwise, we expect a warm to hot day with higher humidity, which
could cause the apparent temperature to reach temps around 105
degrees.

By late tonight into Friday, the Saharan dust concentration will
increase and the available moisture will plummet to around 1.25 or
so inches, which is close to 2 standard deviations below normal for
the month. The very dry air will likely result in fair weather with
hazy skies and warm to hot temperatures. Similar conditions are
expected for Saturday as there is no significant changes expected
between Friday and Saturday except maybe even drier air moving in on
Saturday.

&&

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

A tropical wave and its associated moisture is forecast to move
into the southern Caribbean waters late Sunday, and continue to
pool over Puerto Rico, and the adjacent islands through Monday.
The increasing low-level moisture combined with local and diurnal
effects will increase showers and possibly isolated thunderstorms
during the afternoon on Monday. Then late Monday the moisture
rapidly moves west of Puerto Rico thus giving way to a dry Saharan
air mass. The dry Saharan air is forecast to hold through the end
of the workweek. Therefore, expect fair weather with hazy skies
to prevail over the region with limited shower activity during
the afternoon.

&&

.AVIATION...

VFR conds expected across the local terminals for the
next 24 hours. However, brief VCSH is expected at TJBQ and TJMZ
between 20-17 and 20-21Z due to SCT SHRA developing across NW-PR.
SFC winds will be from the east at 15 to 20 kts with higher gusts
and sea breeze variations. Some Saharan dust is expected but VIS
will be P6SM.

&&

.MARINE...

Seas will range from 4 to 6 feet with easterly winds of 15 to 20
kts with higher gusts across the north Atlantic waters and local
waters north of Puerto Rico. Across the Caribbean waters seas will
build up to 7 feet due to increasing winds and the passage of a
weak tropical wave. Therefore, small craft advisory is in effect
for the Caribbean waters. Elsewhere, small craft operators are
urged to exercise caution.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 89 79 / 20 10 10 20
STT 87 79 88 79 / 10 10 10 10

[cycloneye]

 https://twitter.com/TTWeatherCenter/status/1141773780857032705




 https://twitter.com/TTWeatherCenter/status/1141773796304723968

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
421 AM AST Fri Jun 21 2019

.SYNOPSIS...

A surface high pressure in the Atlantic will continue to cause
brisk easterly trade winds through Sunday. During this time
relatively tranquil weather conditions will prevail. Then by
Sunday afternoon a tropical wave is forecast to move into the
Caribbean waters. This wave will increase low-level moisture and
rain chances during the beginning of the workweek.

&&

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

Fair weather is expected for the local area for the next few days.
The tropical wave has passed and dry air is now dominating over the
local area. Saharan dust is present and it will continue through the
next few days, causing hazy skies. The latest guidance suggests that
the precipitable water will be around 1.25 inches to 1.5 inches
across the local forecast area, which is drier than normal. There is
still the potential for locally induced showers across western PR in
the afternoons but the presence of Saharan dust and the lack of
upper level support will likely limit the shower activity in terms
of coverage, intensity and duration.

Slightly better moisture and less concentration of Saharan dust on
Saturday and Sunday may cause a bit more shower activity across
western PR than on Friday, but still limited activity is expected.
That said, a developing upper trough across the western Caribbean
may provide some support to the convection on Sunday afternoon
depending on the exact positioning and strength of the trough, so as
of now the high resolution models have slightly more shower
activity on Sunday for a small section of northwestern PR.

&&

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

A tropical wave will increase moisture across the region during
the beginning of the workweek. Precipitable water values will
range from 2.0 to 2.1 inches; this will be the highest values
during the long-term period. The increasing moisture will combine with
local and diurnal effects to induce showers and isolated
thunderstorms on Monday and Tuesday. Additionally, due to the
lack of upper-level forcing widespread rain is not expected at
this time. The tropical wave is forecast to move away from Puerto
Rico by Tuesday evening, but moisture is expected to linger
across the Atlantic waters just north of Puerto Rico. The linger
moisture could cause showers to develop across northern and
western areas of Puerto Rico.

The rest of the long- term period a drier air mass is forecast to
will prevail over the region with moisture embedded in the
easterly trades periodically moving in. Therefore, expect showers
during the early part of the long-term period as a result of
moisture from the tropical wave. Then by mid-week, shower activity
will be limited due to meager low-level moisture, and a drier air
mass.

&&

.AVIATION...

VFR conds expected across the local terminals for the
next 24 hours. However, brief VCSH is possible at TJBQ and TJMZ
between 21/16 and 21/20Z due to ISOLD SHRA across NW-PR. SFC winds
will prevail from the east but sea breeze variations are expected,
wind speeds to be at 15 to 20 kts with higher gusts. Haze due to
Saharan dust is expected but VIS should be P6SM.

&&

.MARINE...

A Small craft advisory is in effect for the Caribbean Offshore
waters and the Mona Passage until late this afternoon due to seas
up ranging from 6 to 7 feet, and winds up to 20 kts. Elsewhere,
seas will range from 4 to 5 feet with easterly winds of 15 to 20
kts.

A moderate risk of rip currents will continue for most of the
local beaches today, except for the coastlines of western Puerto
Rico and northern Saint Thomas and Saint John, where the rip
current risk will be low.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 79 88 79 / 10 20 20 20
STT 88 80 86 80 / 10 10 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
502 AM AST Sat Jun 22 2019

SYNOPSIS...An overall dry and stable airmass will prevail across
the region today; along with suspended Saharan dust particulates
which will affect the forecast area but will slowly diminish by
Sunday afternoon. Limited shower activity is forecast with hot
and hazy conditions expected for most areas during the rest of the
weekend. Maximum temperatures will be in the upper 80s to low 90s
with heat indices in the upper 90s to low 100s. The next tropical
wave is forecast to move across the eastern Caribbean by late Sunday
night and on Monday. This will increase the potential for shower and
isolated thunderstorms in and around the islands. Improving weather
conditions one again by the middle of next week.

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

Fair weather is expected for the local area today and early on
Sunday. Saharan dust is still present and it will continue through
this evening, causing hazy skies once again today. However, the dust
concentration is expected to gradually improve late tonight into Sunday.
The latest guidance has some but much lower dust concentration on Sunday
and Monday. Also, even though the Saharan dust is expected to diminish
tonight into Sunday, the dry air stays over the area until Sunday evening.
The latest GFS guidance indicates that the precipitable water will be
around 1.25 inches to 1.4 inches across the local forecast area, which
is significantly drier than normal. However, there is a chance of showers
across western PR in the afternoon today due to local effects, but these
showers, if any, are expected to be brief and light to moderate. The
forecast soundings show a temperature inversion that would be too much
to have anything significant develop. The hi-res models have very little
rainfall in the forecast.

Slightly better moisture and less concentration of Saharan dust on
Sunday may cause a bit more shower activity across western PR,
but still somewhat limited activity is expected. That said, a
developing upper trough across the western Caribbean may provide
some support to the convection on Sunday afternoon as the moisture
gradually increases, even though it would still be below normal
for the time of max heating, there may still be enough moisture
for some shower development. A tropical wave will move in starting
Sunday night, but the peak of the moisture will be on Monday afternoon
at around 18Z, which will coincide with the peak heating and also
with an upper trough that will develop to the west of the local
area, causing diffluence in the upper levels over the local area.
For that reason, there is a better chance for showers and
thunderstorms across the local area on Monday.

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

The tropical wave is forecast to exit the region by Tuesday,
however trailing moisture will linger across the region. This will
favor the development of isolated to scattered showers during the
afternoon hours. Activity however should be of short duration and
no significnat rainfall is expected. Additionally, overall stable
condition aloft will not support significant convective development.
Expect afternoon cloudiness and convection to quickly diminish and
disappear across the islands during the early evening hours on
Tuesday.

By Wednesday and at least through Friday, expect a surface high pressure
across the west and central Atlantic to help maintain a moderate east
to southeast wind flow across the region. Weak pertubations in the
easterlies will move across the area along with shallow fragments
of low level moisture. This will support isolated to scattered
showers across portions of the islands or just off shore, mainly
during the early morning and afternoon hours.

By Saturday and through Sunday another weak tropical wave is forecast
to enter and move across the eastern Caribbean. This will bring additional
moisture to the region. However, lack of good mid to upper level support
will limited enhanced early morning and afternoon convection across
the islands with no widespread or significant amount of rainfall expected
at this time.

&&

.AVIATION...VFR conds expected across the local terminals for the
next 24 hours. However, brief VCSH is possible at TJBQ and TJMZ between
22/16Z and 22/20Z due to ISOLD/SCT SHRA across W-PR. SFC winds will
prevail from the east but sea breeze variations are expected, wind speeds
to be at around 15 kts with higher gusts. Haze due to Saharan dust
is expected but VIS should be P6SM as concentrations will gradually
decrease this afternoon into tonight.

&&

.MARINE...Marine conditions will continue to improve. Mariners
can expect seas mainly between 3 to 5 feet across exposed waters
and passages and between 1 to 3 feet across protected waters. Winds
will continue from the east-southeast at 10 to 20 knots creating a
slight chop across the local waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 89 78 / 10 10 20 20
STT 88 79 88 78 / 0 10 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
437 AM AST Sun Jun 23 2019

.SYNOPSIS...
Overall dry and stable air mass prevailed across the region with
only shallow patches of low level trade wind moisture noted moving
across the area from time to time. A few light showers affected
the near shower waters and local passages under a prevailing east
northeast wind flow. Low- level moisture is to gradually increase
by late afternoon and evening hours, ahead of a weak tropical wave
now approaching the Lesser Antilles. Tropical moisture along the
northern periphery and trailing this wave is expected to move
across the region late Sunday through Monday. Consequently,the
increasing low- level moisture convergence will bring better
potential for shower development across the forecast area at
least through Tuesday. By mid week low level moisture transport
will again be cut off resulting in a mostly fair weather pattern.

&&

.SHORT TERM...Today through Tuesday...
Upper level trough located along the western Caribbean will remain
in place at least during the short-term forecast periods. In the
meantime, upper level ridge will build across the region during the
first half of the workweek. Haze will linger across the local area,
but it will continue to diminish through Tuesday. A mainly fair
weather pattern is expected most of today. However, showers are
expected to develop across the northwestern sections of Puerto
Rico by the afternoon hours. Later tonight, a weak tropical wave
will cross the eastern Caribbean and approach the area. This will
bring an increase in low level moisture to the region. This in
combination with upper level diffluence caused by the
aforementionedtrough and ridge pattern aloft could enhance
showers and isolated thunderstorm activity across the local waters
and islands on Monday.

By Tuesday, moisture associated with the trailing edge of the tropical
wave will result in another round of showers for the islands with
morning activity possible over USVI and eastern Puerto Rico,followed
by afternoon convection in portions of western Puerto Rico. However,
ridging aloft will create subsidence over the area, limiting the
strength and duration of the activity.

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

By Wednesday and at least through Friday, expect a surface high
pressure anchored across the west and central Atlantic to help
maintain a moderate east to southeast wind flow across the region.
Mid to upper level ridge will hold across the region at least through
the end of the work week. Weak pertubations in the easterlies will
however bring periods of shallow low level moisture and passing
showers across the area. This will favor isolated to scattered
showers over portions of the islands or just off shore during the
early morning; followed by locally and diurnally induced afternoon
showers mainly over the west interior sections of Puerto Rico.
Mostly fair weather skies will prevail elsewhere during the
afternoon hours.

By Saturday through Sunday another weak tropical wave is forecast
to enter and move across the eastern Caribbean. This could again
bring an increase in moisture to the region. At this time however
model guidance continued to suggest that most of the associated
moisture accompanying the wave should move mainly south of the
area. In addition lack of good mid to upper level support should
limit enhanced early morning and afternoon convection across the
islands. The upper trough is forecast to retrograde slightly
westward across the areas but presently we should remain on the
subsident side and therefore no widespread or significant amount
of rainfall is expected. Improving conditions and mostly sunny
and fair weather conditions are so far forecast for Monday.

&&

.AVIATION...HZ due to Saharan Dust is expected to continue across
the local area, but visibility will remain P6SM. VFR conditions are
expected to prevail across all TAF sites through the forecast period.
Winds are expected out of the E to ESE at 10 to 20 knots at FL050.

&&

.MARINE...Mariners can expect seas of 3 to 5 feet across exposed
waters and between 1 and 3 feet across protected waters. Winds
will continue from the east- southeast between 10 to 20 knots with
occasionally higher gusts and a light to moderate chop.

&&

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

[Gustywind]

Feeling pretty hot (is an euphemisma) with amazing highs T at Cuba yesterday... 2 stations reported 99.8 F ouch!

000
AXNT20 KNHC 231048
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
648 AM EDT Sun Jun 23 2019
CARIBBEAN SEA...


Because of the Saharan Air Layer and robust mid to low-level ridge dominating the area, Cuba experienced very warm conditions
on Saturday. Veguitas, Granma recorded a high temperature of 99.8 degrees Fahrenheit. There were 28 stations across Cuba that
reported maximum temperatures of 95 degrees Fahrenheit or higher, with 10 of these stations recording near 97 degrees.


$$
AKR

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
513 AM AST Mon Jun 24 2019

.SYNOPSIS...
Surface high pressure anchored across the west and central Atlantic
and a weak tropical wave moving across the eastern Caribbean, will
maintain moderate east to southeast wind flow across the region
today through Tuesday. Increasing moisture accompanying the tropical
wave along with local and diurnal effects will favor better potential
for shower development mainly over central and west portions of Puerto
Rico and parts of the San juan metro. The building anticyclonic flow
aloft will also provide sufficient ventilation for possible isolated
afternoon thunderstorm activity over the west interior and northwest
Puerto Rico.

&&

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

Upper level trough will continue across the western Caribbean
during the next few days, while upper level ridge builds over the
region. Moisture associated with a tropical wave will continue to
advance into the local area on Monday. This combined with local
effects will result in showers and isolated thunderstorms activity
mainly across the interior and northwestern Puerto Rico with
additional shower activity over portions of eastern Puerto Rico,
the U.S. Virgin Islands as well across the local waters. On Tuesday,
the bulk of the moisture will arrive to the islands, but the intensity
of the activity will be limited by the lack of upper level support.
However, once again, passing showers will be possible for the U.S.
Virgin Islands and eastern Puerto Rico followed by afternoon convection
along the interior and northwestern Puerto Rico. On Wednesday, a low
level perturbation will arrive into the area, aiding in the development
of afternoon showers across western Puerto Rico.

Temperature wise, southeast winds and upper level ridging will result
in heat indices near 105 degrees for the coastal municipalities of
Puerto Rico, as well as Vieques and St. Croix. This pattern will
continue at least until mid-week. Low concentration of Saharan dust
will continue until Tuesday, then a moderate layer will arrive on
Wednesday.


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

By Thursday and at least into the following weekend, expect a
surface high pressure to remain anchored across the west and
central Atlantic. This will favor moderate east to southeast
winds across the region. Mid to upper level ridge will also hold
across the region through the end of the work week. However weak
pertubations in the easterlies will bring periods of shallow low
level moisture and passing showers across the area. This will
support isolated to scattered shower development over portions of
the islands or just off shore during the early morning; followed
by locally and diurnally induced afternoon showers mainly over the
west interior sections of Puerto Rico. Mostly fair weather skies
will prevail elsewhere during the afternoon hours. Another surge
of moderate concentrations of suspended saharan dust is also forecast
during the early part of the period.

By Saturday through Sunday another weak tropical wave is forecast to
enter and move across the eastern Caribbean. This may again bring
an increase in tropical moisture to the region. At this time
however model guidance continued to suggest that most of the
associated moisture accompanying the wave should remain south of
the area. In addition lack of good mid to upper level support
should limit enhanced early morning and afternoon convection
across the islands. The upper trough is forecast to retrograde
slightly westward toward the area but presently guidance continued
to suggest our area on the subsident side and therefore no widespread
or significant amount of rainfall is expected. Improving dry and
stable conditions with mostly sunny skies and generally a fair
weather pattern is so far forecast for Monday and Tuesday.

&&

.AVIATION...HZ due to Saharan dust is expected to diminish across
the local flying area today. VFR conditions are expected to prevail
across all terminals. VCTS are expected for TJMZ/TJBQ after 24/16Z.
Surface winds will be out of the ESE at 10 to 20 knots at FL050.

&&

.MARINE...Mariners can expect overall seas between 3 and 5 feet
across exposed waters and between 1 and 3 feet across protected
waters. Winds will continue from the east to southeast between 10
to 20 knots with occasionally higher gusts.

A moderate risk of rip currents will continue for some of the the
northern coast of Puerto Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 88 77 / 30 40 40 20
STT 90 80 87 78 / 30 40 40 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
453 AM AST Tue Jun 25 2019

.SYNOPSIS...
A tropical wave will bring an increase in showers and isolated
thunderstorms activity across the area today. A Saharan air layer
will result in hazy skies and a drier weather pattern across the
region on Wednesday through the end of the workweek. Weak easterly
perturbations will move over the area by Friday and then again on
Sunday and for the middle part of next week, resulting in an
increase in showers activity across the local islands. Drier
weather conditions are expected in between these perturbations.

&&

.SHORT TERM...
Shower and isolated thunderstorm activity persisted over the
regional waters accompanying the tropical wave now crossing the
eastern Caribbean and forecast area. This activity will continue to
spread low level moisture and cloudiness across region during the
rest of the day. Periods of moderate to heavy rains have already
affected portions of the U.S. Virgin islands and will continue to
spread westward while affecting the east and northern portions of
Puerto Rico and the adjacent islands.

Model guidance continued to suggest sufficient moisture convergence
and instability to linger across the region during the rest of
today. This along with the high pressure ridge building northwards
over the region will provide sufficient ventilation and instability
aloft to favor afternoon shower and thunderstorm development. In
addition, local and diurnal effects will support enhanced afternoon
convection with possibly strong thunderstorms over portions of the
central and west to northwest sections of Puerto Rico, including
areas around the San Juan metro. Lesser shower activity is expected
over the U.S. Virgin islands during the afternoon hours, but some
lingering showers may still be possible.

By Wednesday and Thursday all model guidance continue to suggest a
rapid drying trend with another surge of the Saharan air layer (SAL)
and suspended dust particulates expected to move in across the
region and linger during the rest of the period. That said, drier
and more stable but hot and hazy conditions can be expected to
prevail. Local and diurnal effects along with pockets of low level
trade wind moisture may however aid in the development of isolated
to scattered showers each day. Activity is so far expected to be
limited and of short duration.

Over Puerto Rico...The temperatures will be near normal with highs
in the upper 80s to low 90s across the lower elevations and in the
upper 70s to mid 80s across the higher elevations. The minimum temps
will range from the mid 70s to near 80 degrees across the lower
elevations while the higher elevations will be in the mid 60s to low
70s. For the USVI...The high temps will be in the mid 80s and the
minimum temps should range between the mid to upper 70s.

.LONG TERM...
A surface high pressure located over the eastern Caribbean will
continue to promote a moderate east-southeasterly wind flow across
the area at least until the weekend. A mid-level ridge just north of
the region will stay in place through the weekend. An upper level
trough will move northeast of the Lesser Antilles, leaving the
forecast area in its subsidence side at least until Monday. Then,
another upper level trough will develop across the western
Caribbean, resulting in better upper level support for afternoon
convection by Tuesday and Wednesday.

A weak perturbation in the lower levels will move over the area on
Friday, bringing an increase in showers. However, due to the lack of
upper level dynamics, any activity should be limited in both
strength and coverage. A weak tropical wave will arrive late
Saturday into Sunday, but the bulk of the moisture should remain
south of the area. On Monday and Tuesday, drier air will promote
mainly fair weather conditions. However, morning passing showers
are still possible across the eastern half of Puerto Rico and the
U.S. Virgin Islands, followed by afternoon convection across the
western half of Puerto Rico. Then, by late Tuesday or early
Wednesday, another weak tropical wave will reach the local
islands, resulting in another round of showers activity.

&&

.AVIATION... Prevailing VFR conds at all local terminals durg the
prd. At least til 25/14Z SHRA/Isold TSRA psbl vcty TNCM/TKPK/TIST/
TISX. SCT ocnl BKN nr FL022...FL050 BKN-OVC lyrs nr FL090...and ABV
FL120. Tropical wave crossing the region during the rest of today
will also aid in producing aftn SHRA/isold TSRA at 25/16z-25/22z at
TJBQ/TJSJ/TJMZ. Sfc wnds mainly fm E-SE 10 knots or less bcmg 10-15
knots with sea breeze variations and ocnly hir gusts aft 25/14z.


&&

.MARINE...
A surface high pressure and a tropical wave will maintain an
easterly southeasterly wind flow across the local waters today.
Showers and isolated thunderstorms are expected today as a result
of the aftermentioned tropical wave. Seas are expected to remain
at 1 to 4 feet with winds out of the east at 10 to 15 knots. There
is a low risk of rip currents for the local beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 89 79 / 50 20 20 30
STT 87 79 89 78 / 50 20 30 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
358 AM AST Wed Jun 26 2019

.SYNOPSIS...Mid to upper level high pressure ridge will build and
remain anchored across the region through the period. The surface
high pressure will reestablish itself across the western and
central Atlantic to maintain a light to moderate east to southeast
wind flow across the region through Thursday; then become
moderate to strong and breezy by Friday as the local pressure
gradient tightens across the area in response to high pressure
strengthening north of the region.

&&

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

Recent satellite imagery and the doppler weather radar both
suggest diminishing cloud coverage along with continued decrease
in shower activity across the region during the overnight and
early morning hours as a drier airmass moved in across the region.
However, previous TJSJ 26/00z evening sounding as well as
satellite derived precipitable water products both suggest layered
precipitable water values still between 1.75-2.00 inches across
the forecast area. Both Naaps forecast model guidance and
Satellite aerosol optical thickness imagery also showed increasing
Saharan dust concentration across the region today through
Thursday. Therefore hazy skies can be expected.

Although instability will decrease aloft still expect sufficient
moisture available to combine with local effects and daytime heating
to support afternoon convection with showers and possible isolated
thunderstorm development particularly over parts of central and
western Puerto Rico today. Elsewhere there will be a slight chance
for isolated showers but overall mostly fair weather and hazy skies
can be expected including in and around the U.S.Virgin islands.

On Thursday, a continued drying trend is forecast but locally and
diurnally induced afternoon convection will remain possible. The
activity should however be of short duration and in the form of
streamers as the local trade winds and steering flow is expected to
increase in response to the tightening pressure gradient. On Friday
the forecast area is to remain on the convergent side of the upper
ridge and trough pattern and consequently maintain stable conditions
aloft. However, a weakly induced easterly perturbation is forecast
to bring a quick surge of low level moisture to the region and
therefore favor a better chance for passing late evening and early
morning showers. This will be followed by periods of isolated to
scattered afternoon convection. Hazy conditions should also diminish
by Friday as the Saharan air layer is expected to move farther west
of the area. All in all lesser shower activity expected for the
latter part of the period, but isolated to scattered shower
development can be expect each afternoon, mainly over the central
and west section of Puerto Rico with a few streamers of short
duration possible in and around the San Juan metro area.

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

An upper-level trough will be positioned just to the northeast of
the eastern Caribbean into the weekend. This will leave the forecast
area on the subsidence side of the trough, limiting upper level
support for rainfall activity across the region. At the surface,
high pressure located over the central eastern Atlantic Ocean will
promote a moderate to strong east-southeasterly wind flow through
early next week.

A pair of weak easterly waves will move over the region during
the weekend, bringing an increase in moisture to the area.
However, only passing morning showers are expected across portions
of eastern Puerto Rico and the U.S. Virgin Islands, followed by
afternoon convection across the interior and western Puerto Rico.
By early next week, patches of moisture embedded in the trade
winds will advance into the local islands. The latest guidance
shows that moisture will be capped to the lower levels of the
atmosphere, hence the coverage and duration of the shower activity
should be limited. Regardless, expect a seasonable weather
pattern with early showers in the eastern half of the forecast
area, followed by afternoon activity across portions of western
Puerto Rico.

&&

.AVIATION...VFR conds durg prd. SHRA/ Isold TSRA psbl vcty
TJMZ/TJBQ with brief MVFR psbl btwn 26/17-23z. Sfc wnds calm to
light and variable bcmg E-ESE between 10 and 15 knots with sea
breeze variations after 26/14z. L/Lvl wnds fm E 5-15 kts BLO
FL200. No other sig wx impacts attm.

&&

.MARINE...Across the local waters, expect seas to remain at 1 to
4 feet with winds out of the east at 10 to 15 knots. Winds will
increase up to 20 knots by late Wednesday. There is a moderate
risk of rip currents for the northern coast of Puerto Rico today,
extending to the southern coast, Vieques, Culebra and St. Croix
tomorrow.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
452 AM AST Thu Jun 27 2019

.SYNOPSIS...
Strengthening high pressure north of the local islands will tighten
the pressure gradient across the area, resulting in increasing
winds. A drier air pattern is expected through the end of the week.
However, showers and thunderstorms are still expected to develop
across portions of the interior and western Puerto Rico this
afternoon. Passing showers are possible elsewhere as well.
Temperatures will be running hot with heat indices near 100 degrees.
Hazy skies due to Saharan dust are expected at least through
today.

&&

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

Low level winds will increase and turn east southeast today and
tonight as high pressure builds to the north and low pressure
remains relatively deep in the southwest Caribbean Sea. Winds will
continue to increase through Saturday and the GFS has some 30 kt
winds around the area Friday night (29/06Z). The MIMIC product
shows the band of moisture that brought the showers overnight
Wednesday night will persist through at least today. Have raised
expectations for showers and isolated thunderstorms in western and
interior Puerto Rico with some chance for urban and small stream
flooding. Then, despite precipitable water values sliding to a
minimum below 1.2 inches by Friday 28/15Z, lower levels at and
below 850 mb remain quite moist and showers are expected to
persist overnight tonight and in eastern Puerto Rico during the
morning hours Friday. Light showers are also expected to affect
the U.S. Virgin Islands during the period. By Saturday evening
precipitable water values will rebound and showers and a chance of
thunderstorms will increase-- mainly over western Puerto Rico.

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

Upper level trough will remain just northeast of the eastern
Caribbean Sea until Sunday. Then, a cut-off upper level low will
develop from this system and will move across the region toward the
central Caribbean Sea on Sunday and Monday. This should result in
better upper level support for shower and thunderstorm activity
across the region during this period. Additionally, a tropical wave
will move south of the area on Sunday, but will bring an increase in
moisture to the local islands.

As the pressure gradient weakens, expect winds to decrease by
Tuesday into the end of the workweek. The wind flow will be from the
east to east southeast until Tuesday. By Wednesday, winds will shift
from the east northeast in response of a high pressure in the low
levels, located just north of the region, that will move farther
away toward the west. Then, winds will shift back to the east-
southeast by the latter part of the week as another high pressure
builds across the central Atlantic Ocean. No significant weather
features through the long-term forecast period are anticipated.
Nevertheless, patches of moisture embedded in the trade winds will
move across the area from time to time. Therefore, expect a
seasonable weather pattern with passing showers across the eastern
half of Puerto Rico and the U.S. Virgin Islands during the morning
hours, followed by afternoon convection across portions of western
Puerto Rico.

&&

.AVIATION...SHRA sct are ovr most lcl waters and movg ovr ern PR
and arnd the Leeward Islands this morning. Aft 27/16Z SHRA/Isold
TSRA to dvlp ovr wrn and interior PR with areas of MVFR/IFR and
mtn obscurations till arnd 27/22Z. Drying to occur slowly aft
28/02Z. Sfc winds east incrg by 27/14Z to 10-20kt with gusts to
30kt psbl. Max winds easterly 12-22 kt blo FL330.

&&

.MARINE...Across the local waters, expect seas to slightly
increase to 2 to 5 feet with winds out of the east at 15 to 20
knots. Small craft operators are urged to exercise caution due to
high winds. There is a moderate risk of rip currents for most of
the local beaches in Puerto Rico, including Vieques and Culebra,
and for St. Croix in the U.S. Virgin Islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 89 78 / 50 40 40 40
STT 88 80 89 81 / 40 40 40 30

[cycloneye]

FXCA62 TJSJ 280900
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST Fri Jun 28 2019

.SYNOPSIS...A moderate to fresh east to southeast wind flow will
prevail through the weekend, but diminishing by early next week.
Overall, a seasonal weather pattern is expected across the
forecast area with patches of low-level moisture bringing
overnight and morning showers to eastern Puerto Rico and the U.S.
Virgin Islands. Showers and possible isolated thunderstorms are
expected along the interior and western Puerto Rico each
afternoon. Choppy marine conditions will hold through at least
Sunday. Elevated fire danger conditions can also be expected
through the weekend.



&&

.SHORT TERM...Friday through Sunday...

High pressure over the sub-tropical Atlantic is interrupted by
several fronts off of minor lows around 40 degrees north latitude.
Low pressure in the southwest Caribbean remains vigorous, however,
and is generating moderate to fresh east southeast trade winds over
the area. A trough in the lower levels will move through shortly
(28/12Z) and brought an area of drier air, but moisture is visible
in the MIMIC product moving into the Leeward Islands with shower
activity in a narrow band moving toward Saint Kitts. This moisture
is moving at 8-9 degrees of longitude every 24 hours and should
arrive in Puerto Rico by late this afternoon. The 850 mb GFS is
already showing high relative humidities just southeast and
observations showed a scattered to broken layer of altocumulus at
around 8-9 kft. This is expected to make showers likely across
western Puerto Rico again today.

Alternating bands of moist and dry air move through at 850 mb with
drying on Friday night and again on Saturday night before a more
extensive area of drier air amasses over the U.S. Virgin Islands.
This drier air seems to stall there while Puerto Rico sees some low
level moisture during the day Sunday as well.

With some convection, and warm temperatures continuing or even
increasing, as 1000-850 mb thicknesses edge upward while 500 mb
temperatures cool 1-2 degrees Saturday, have opted to leave isolated
thunderstorms over western Puerto Rico each afternoon. Also models
note some east southeast flow--if not at the surface (where sea
breezes on the northeast coast will easily overcome it) then at
least after the trough passage this morning. This will allow
temperatures to reach or exceed 90 degrees in many lower elevations.
And since the MEX was 2 degrees too cool yesterday, calling for 90
to 91 degrees just inland from the San Juan airport seems like a
safe bet.

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

A surface high pressure extending across the central Atlantic will
hold a moderate to locally fresh east to southeast wind flow through
late Monday night. As the pressure gradient relaxes, winds are
expected to weaken on Tuesday and continue through the workweek.
By Wednesday into Thursday, winds are to briefly turn from the
east-northeast, but an east-southeast flow will return and
hold through the weekend. In general, a seasonal weather pattern
is expected. In terms of shower activity, this means trade wind
showers streaming over the waters with a few moving into portions
of eastern Puerto Rico and the U.S. Virgin Islands during the
overnight and early morning hours. Although relatively drier air
will dominate the region through this period (GFS-model estimated
PW ranging around 1.0 to 1.4 inches), there is still a chance for
locally induced showers developing over portions of the interior
and western Puerto Rico each afternoon. So far, model guidance
suggest that the lack of upper level support will inhibit deep
and organized convection, as well as the likelihood for
thunderstorms. However, a slight increase in the intensity and
areal coverage of showers can be expected on Wednesday and Friday
as a weak surface trough and tropical wave enhance moisture
advection with GFS- model estimated PW values briefly peaking at
1.65 and 1.75 inches, respectively. Confidence in this forecast is
low since these features are expected by the latter part of the
forecast period.


&&

.AVIATION...SHRA are sct ovr most lcl waters and movg ovr ern PR and
arnd the TKPK this morning. Aft 28/16Z SHRA/Isold TSRA to dvlp ovr
wrn and interior PR with areas of MVFR/IFR and mtn obscurations till
arnd 28/22Z. Drying to occur slowly aft 29/02Z. Sfc winds east incrg
by 28/14Z to 10-20kt with gusts to 30kt psbl. Max winds easterly 15-
21 kt blo FL180 and north 15-20 kt btwn FL350-450.


&&

.MARINE...Choppy marine conditions are expected across all
regional waters with seas up to 6 feet and east to southeast winds
up to 20 knots. As a result, small craft operators are urged to
exercise caution. These conditions are expected to hold through
at least Sunday, improving by early next week as winds begin to
diminish. A moderate risk of rip currents continues for all but
beaches along the north coast of Saint Thomas and Saint John, as
well as beaches along the west coast of Puerto Rico.


.FIRE...A surface high pressure will maintain a moderate to
locally fresh east to southeast wind flow across the region that
will peak at 15-20 mph with sea breeze variations and possible
gusts up to 30 mph. Recent KBDI observations support dry soil
conditions across the southern coastal plains of Puerto Rico with
values above critical thresholds between 690-720. The forecast
calls for relative humidity to drop into the low 50s and mid 40s
at Cabo Rojo and Camp Santiago areas, respectively. Since wetting
rains are not expected and given the expected conditions, a Fire
Danger Statement has been issued for the southern coastal plains
of Puerto Rico for elevated fire danger conditions.



&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 89 78 / 50 50 50 40
STT 90 80 90 80 / 30 30 50 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
403 AM AST Sat Jun 29 2019

.SYNOPSIS...
The islands remain on the subsident side of a trough digging into
the northeast Caribbean. A strong trade wind cap will erodes the
available moisture across the islands. Satellite and model
guidances are showing a dry air mass with Saharan Air Particles
approaching the Lesser Antilles. Daytime high temperatures are
forecast to be near the upper 80s to the lower 90s in lower
elevations.

&&

.SHORT TERM...Saturday through Monday...

High pressure at the surface over the sub-tropical Atlantic combined
with low pressure in the southwest Caribbean will maintain moderate
to fresh east to east southeast trade wind flow over the local area.
Drier air will move into the area today at levels at and above 850
mb. And, the 850 mb level will also see some warming that will
suppress much of the convection of the past several days. Residual
moisture, however, will be enough to generate scattered showers
today with a little moisture adding to this on Sunday afternoon in
western Puerto Rico, otherwise the trend is for drying through
Monday and beyond. Also precipitable water values drop from a peak
of around 1.9 inches Friday evening, (yesterday) to just over 1.1
inches on Wednesday afternoon.

Traces of Saharan dust will become evident again and hazy skies will
return tonight through Monday. Temperatures are also expected to
warm slightly with increased sunshine and winds sporting a weak
southerly component. The GFS also adds several meters to the 1000-
850 mb thicknesses during the period.

Upper levels will play little role in the local weather for the time
being. A 250 mb low is almost 700 miles east northeast of the area
and will continue to recede to the east northeast. The trough
extending to its southwest and located just southeast of the
southeastern most corner of our forecast area now, will gradually
move to a position directly over Puerto Rico by Monday.

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

A dry air mass with Saharan dust particulates will persist
through at least late Thursday or Friday, when model guidance are
suggesting the arrival of a tropical wave. Before the arrival of
this wave, patches of moisture embedded in the trades will move
at times across the region. Another dry air mass is forecast to
filter in by Saturday. In general, a seasonal weather pattern is
expected to persist through the long term period. Therefore,
expect trade wind showers streaming over the waters with a few
moving into portions of eastern Puerto Rico and the U.S. Virgin
Islands during the overnight and early morning hours. Locally
induced showers with isolated thunderstorms will remain possible
over portions of the interior and western Puerto Rico each
afternoon.

&&

.AVIATION...Isold -SHRA are arnd PR and the USVI ovr the lcl
waters, but drier this morning than last. Aft 29/16Z SHRA/Isold
TSRA to dvlp ovr wrn PR with areas of MVFR and mtn obscurations
till arnd 28/22Z. Then, VFR conds thru at least 30/12Z. Sfc winds
east incrg by 28/14Z to 10-20kt with gusts to 30kt psbl. Max winds
easterly 20- 25 kt btwn FL015-065. Winds less than 10 kt btwn
FL085-125.

&&

.MARINE...
East winds up to 20 kts will cause choppy seas up to 6 feet across
the regional waters this weekend into next week. A moderate risk
of rip currents for all the beaches of Puerto Rico and the U.S.
Virgin Islands, except along the coastlines of western PR and the
northern Saint Thomas and Saint John.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
533 AM AST Sun Jun 30 2019

.SYNOPSIS...Drier conditions will prevail until Thursday with
saharan dust and minimal shower activity each day. A weak
disturbance will move through Wednesday afternoon and evening,
followed by a tropical wave Thursday and Thursday night that will
bring a dramatic increase in moisture.


&&

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

A dry and relatively quiet weather pattern will prevail through the
short term forecast period. This is the result of a drier air mass
moving into the forecast area under a moderate to fresh east to east
southeast trade wind flow, peaking at 15-20 mph with higher
gusts. This flow is the result of a surface high pressure
extending across the Atlantic and a surface low pressure located
over the southwest Caribbean. Upper level support is not expected
since ridging aloft will help sustain the trade winds inversion
around the 850 mb layer while favoring erosion of available
moisture. So far, GFS-model estimated PW values support a
decreasing columnar moisture and drying pattern with 1.4 inches
on Sunday morning dropping to 1.1 inches by Tuesday afternoon.
Nevertheless, patches of low-level moisture may still bring a few
showers to portions of eastern Puerto Rico and the U.S. Virgin
Islands from time to time. Although a hostile environment is
expected, limited moisture content supported by diurnal heating
and local effects may still promote the development of locally
induced showers and possible isolated thunderstorms over portions
of western Puerto Rico each afternoon. Isolated rainfall
accumulations should range between a quarter to half an inch with
the strongest activity.

A plume of suspended Saharan dust accompanying the drier air mass
will continue to move over the local area and hold through at least
Tuesday, resulting in hazy skies. The forecast calls for daytime
high temperatures to reach the upper 80s to the lower 90s in lower
elevations, and the lower 70s to middle 80s in higher elevations.

.LONG TERM...Wednesday through Monday

With high pressure at the surface in the east central Atlantic our
moderate east southeast trade wind flow will continue with little
change. The main features in this period will be some convection
behind a westward moving low-level trough that will cross through
the area Wednesday afternoon and Wednesday night. Then, on
Thursday the moisture topping the apex of a tropical wave will
move into the area, with increasing showers and thunderstorms.
Moisture from the wave itself will then move through overnight on
Thursday and prolong the shower activity--mainly on the southeast
coast of Puerto Rico and in the U.S. Virgin Islands. A period of
drier weather follows Saturday. On Sunday some moisture will move
in from the southeast and bring scattered showers in the morning
and showers and isolated thunderstorms in the afternoon. That
moisture is short-lived however.

&&

.AVIATION...
Mainly VFR conditions are expected during the next 24 hours.
However, isolated SHRA/TSRA activity may bring VCSH/VCSH to
TJMZ/TJBQ between 30/16-22Z, resulting in brief MVFR conds. Surface
winds up to 10 knots early this morning, increasing to 15-20 with
occasional gusts and sea breeze variations after 30/14Z.

&&

.MARINE...Winds and seas will increase somewhat tonight and
Sunday, but the overall trend will be subsiding winds and seas
until Thursday. Seas of 7 feet will be possible Friday through
Saturday at the end of the week.

&&

.FIRE WEATHER...
Relative humidities fell below critical levels on the south coast
yesterday and fuel moisture at Camp Santiago was also at critical
levels. Winds have been relatively strong and conditions would be
red flag warning except that sea breezes have been bringing in
better relative humidities midday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 77 91 77 / 20 20 10 20
STT 89 79 88 80 / 10 10 10 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
523 AM AST Mon Jul 1 2019

.SYNOPSIS...Dry weather through Wednesday will be followed by a
weak trough Wednesday night and a tropical wave Thursday and
Thursday night accompanied by heavier showers and some
thunderstorms. Saturday should be relatively dry, but Sunday into
early next week will see scattered passing showers.

&&

.SHORT TERM...Monday through Wednesday...

Recent model guidance continues to suggest that a dry and
relatively stable weather pattern will prevail across the
forecast area. This is the result of a drier air mass that
continues to dominate the local weather conditions as it moves in
from the east under a moderate to fresh east to east-southeast
trade wind flow. This flow is the result of a surface high
pressure extending across the Atlantic, which is expected to peak
at 15-20 knots with higher gusts, during the late morning into
the afternoon hours. Under this flow and accompanying the drier
air mass, pockets of Saharan dusts will also continue to move over
the area. Although concentrations are expect to diminish during
the next few days, hazy skies can be expected through midweek.
Ridging aloft and the presence of Saharan dust will sustain a
strong inversion around the 850 mb layer, which will keep moisture
in the low-levels while inhibiting the development of deep and
organized convection. So far, the GFS model suggests that
precipitable water values should remain below 1.20 inches through
most of the short-term forecast period. Nevertheless, patches of
low-level moisture may still bring a few showers to portions of
eastern Puerto Rico and the U.S. Virgin Islands from time to time.
Although a hostile environment is expected, limited moisture
content supported by diurnal heating and local effects may still
promote the development of locally induced showers over portions
of western Puerto Rico each afternoon. Isolated rainfall
accumulations should remain around a quarter of an inch with the
strongest activity.

A slight increase in the frequency and areal coverage of showers can
be expected on Wednesday as an extended patch of low-level
moisture in a weak trough approaches the area. This may result in
PW values to briefly peak around 1.40 inches. However, lack of
upper level support will limit the intensity of any shower that
develops. Thus, significant rainfall accumulations are not
expected at this time.

Daytime high temperatures are forecast to be near the upper 80s to
the lower 90s in lower elevations, and the lower 70s to middle 80s
in higher elevations.

.LONG TERM...Thursday through Wednesday...

After the weak trough of Wednesday, drier air will pass through
Wednesday night followed immediately by moisture that is driving
west northwest over the top of a tropical wave on Thursday. Much
better moisture follows the axis of the tropical wave as it moves
through on Thursday night with showers and possibly isolated
thunderstorms. Low level moisture clears during the day Friday,
and rather dry conditions persist through Saturday, although a
chance of showers will be seen in western Puerto Rico due to low
level moisture and surface convergence. On Sunday, moisture moves
into the area from the southeast. East southeast flow will carry
morning showers into the southeast third of Puerto Rico followed
by a good chance of showers in western Puerto Rico in the
afternoon.

Monday through Wednesday, moisture levels remain relatively stable
with around 1.5 inches of precipitable water, but areas of good
low-level moisture move through the area yielding the typical
summer pattern of night and morning passing showers in eastern
Puerto Rico and heavier showers in the afternoons with some
thunderstorms in western Puerto Rico. Although this pattern will
not be quite as generous for the U.S. Virgin Islands, some light
showers are expected and streamers are likely to form downstream.

At upper levels, low pressure is close at hand during the tropical
wave passage and is expected to enhance the amount of
thunderstorms seen in the area. Some overnight thunderstorms on
Thursday may even be heard in southeast Puerto Rico and around the
U.S. Virgin Islands. Ridging aloft will enhance the drier weather
on Saturday, but troughiness over or near the area should also
aid some afternoon thunderstorm development each day Sunday
through Wednesday.

&&

.AVIATION...Mainly VFR conditions expected during the next 24 hours.
However, SHRA may bring VCSH to TJMZ/TJBQ between 01/15-23Z and
brief MVFR conditions with mtn obscurations possible. Variable
and light surface winds through 01/14Z, increasing to 15-20 with
occasional higher gusts and sea breeze variations thereafter.
Maximum winds less than 20 knots at all levels.

&&

.MARINE...Marine conditions are expected to continue to improve
through Wednesday. Current models indicate 30 knot winds at 850 mb
during the wave passage on Thursday night with stronger winds
(than seen lately) at the surface following the passage. Seas up
to 8 feet are indicated for the southwest local outer Caribbean
waters through Saturday. 20 to 25 knots winds are also locally
possible there with higher gusts.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 77 91 79 / 10 20 20 20
STT 89 80 89 81 / 10 20 20 20

[cycloneye]

AFDSJU

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
414 AM AST Tue Jul 2 2019

.SYNOPSIS...Strong surface high pressure across the central
Atlantic is dominating the local wind flow for the next few days.
Saharan dust concentration is diminishing but will return this
weekend after the tropical wave moves away from the local area,
which is expected on Thursday and Friday. Locally induced showers
are expected across central to western PR today.

&&

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

A drier than normal air mass, with precipitable water values ranging
between 1.2 and 1.4 inches, will continue to prevail today. This
will continue to result in mainly fair weather conditions across
most of the local area. Low-level flow is expected to diminish
today, to less than 10 knots, as the combination of a frontal system
located well north of the area and surface high pressure across east-
central Atlantic will relax the local pressure gradient. Even though
most of the local area will experience mainly fair weather
conditions, showers and a few thunderstorms are expected to develop
mainly across interior Puerto Rico this afternoon due to strong
diurnal heating and local effects. Given that the low-level flow
will be weak, the showers that do develop will be slow-movers,
therefore, some higher accumulations compared to previous days are
possible. However, given the drier than normal air mass in place,
the activity should be short-lived and not result in significant
rainfall accumulations.

For Wednesday, a weak low-level trough will be moving across the
area. This will increase the low-level moisture slightly. Therefore,
the afternoon activity across interior and western Puerto Rico could
be more enhanced with more significant rainfall accumulations
possible. Across the rest of the area, only some isolated showers
are expected.

Moisture will begin to increase significantly in the low to mid-
levels by later Thursday afternoon and Thursday Night, ahead of a
tropical wave located near 40W longitude as of this morning.
Therefore, showers and isolated thunderstorms are expected across
western Puerto Rico during the afternoon hours. Then, during the
evening and overnight hours, showers and isolated thunderstorms are
expected to increase in coverage across the Caribbean waters and
move into the USVI and eastern Puerto Rico.

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

Relatively deep moisture associated with a tropical wave is
expected to be affecting the local area on Friday. This will cause
an increase in cloud cover and shower activity across the local
area. That said, the mid to upper levels do not look particularly
favorable for instability and the forecast soundings indicate
saturated upper levels, which could mean cloud cover in the upper
levels and some good rainfall but not particularly heavy except in
isolated areas. Thereafter, it dries up significantly, the latest
guidance shows the precipitable water going from over 2 inches on
Friday to under 1.5 inches on Saturday. It remains fairly dry
through the weekend but another tropical wave could reach the
local area in on Tuesday, causing an increase in the local
moisture and shower activity once again. Early next week, an upper
trough develops west of the local islands, which could contribute
to an increase in instability and play a factor in the shower and
thunderstorm activity expected.


&&

.AVIATION...VFR conditions expected to prevail across the local
area. SHRA and isolated TSRA expected mostly across interior PR
between 02/17z and 02/22z, resulting in VCSH across TJMZ and TJPS.
Winds will be light and variable through 02/12z, increasing to 10
to 15 knots from the E with some higher gusts and sea breeze
variations after 02/14z.

&&

.MARINE...Tranquil marine conditions expected today and on
Wednesday. Seas mainly between 1 and 4 feet and winds up to 15
knots today, increasing up to 5 feet on Wednesday night and up to
6 feet by Thursday. Winds are also expected to increase on
Thursday as a tropical wave moves across the local area. There is
a low risk for rip currents today across the local beaches.

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 88 78 / 20 20 20 20
STT88 78 89 79 / 20 20 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
410 AM AST Wed Jul 3 2019

.SYNOPSIS...Strong surface high pressure across the central
Atlantic will dominate the local wind flow for the next few days.
Saharan dust concentration continues to diminish, causing a bit of
haze but will increase once again this weekend. A tropical wave
is expected to affect the local area on Friday. Locally induced
showers and isolated thunderstorms are expected across central to
southwestern PR today as the local wind flow will have an east
northeast component.

&&

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

Mainly fair weather conditions expected through the morning hours
across the area as a dry air mass will prevail. A low-level trough
is then expected to move westward across the area during the
afternoon and evening hours. Ahead of the trough axis, low-level
winds will be out of the east-northeast. Therefore, during the
afternoon hours, showers and isolated thunderstorms are expected to
develop across the interior and southwestern quadrant of Puerto
Rico. Activity across these areas could be more enhanced today
compared to the previous afternoons, therefore, more significant
rainfall accumulations that may lead to some urban and small stream
flooding is possible. A separate area of moisture, located just
behind the trough axis will be moving across the USVI this afternoon
and across eastern Puerto Rico during the evening hours, resulting
in scattered showers across these areas. At this point, not
expecting anything too organized. Therefore, rainfall accumulations
should remain on the light side.

By later during the overnight hours, as the low-level trough and
associated moisture field move away, an area much drier air will be
moving overhead and will prevail during the morning hours of
Thursday. This will result in mainly fair weather conditions. By
Thursday Night and during the day on Friday, unsettled weather
conditions are expected as a tropical wave located near 50W
longitude as of this morning will be moving overhead and will
increase the shower and thunderstorm activity across portions of the
local area. Showers will be increasing in coverage across the local
waters and move into portions of the USVI and eastern Puerto Rico
during the overnight and morning hours of Friday. Then, the activity
will spread into western Puerto Rico during the afternoon hours of
Friday.

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

Some moisture from the tropical wave could linger into Saturday
morning, but even drier air is expected to move in by Saturday
afternoon. The latest guidance shows the precipitable water going
from over 2 inches on Friday to just over 1.5 inches on Saturday
morning to around 1.4 inches on Saturday late afternoon. It
remains fairly dry through the weekend with below normal moisture
and another round of Saharan dust, but another tropical wave
could reach the local area late Monday into Tuesday, causing an
increase in the local moisture and shower activity once again.
Early next week, an upper trough develops west of the local
islands, which could contribute to an increase in instability and
play a factor in the shower and thunderstorm activity expected
with the tropical wave that could move in at the same time. Drier
air returns for Wednesday into early Thursday.

&&

.AVIATION...Mainly VFR conditions expected. Patches of low-level
clouds will result in brief BKN ceilings and VCSH at times across
the TNCM/TKPK through 03/22z. SHRA and TSRA expected across interior
and western PR between 03/16z and 03/22z. This may result in TEMPO
MVFR conditions, mainly across TJMZ. VCSH expected across the USVI
after 03/18z and across eastern PR after 03/22z. Light and variable
winds through 03/12z, increasing to 10 to 20 kts from the E-ENE with
higher gusts and sea breeze variations after 03/14z.


&&

.MARINE...Tranquil marine conditions expected once again today.
Seas mainly between 1 and 4 feet and winds up to 15 knots today,
increasing up to 5 feet late tonight into Thursday, and up to 6
feet by Friday. Winds are also expected to increase on Friday as
a tropical wave moves across the local area. There is a low risk
for rip currents today across the local beaches.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 90 76 / 50 50 20 50
STT 89 79 89 79 / 40 40 40 50

[cycloneye]

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
555 AM AST Thu Jul 4 2019

.SYNOPSIS...A drying trend late today and early tonight will be
interrupted by a tropical wave late Thursday night and into
Friday. A weak disturbance will move through on Sunday. A tropical
wave will move through on Tuesday. Each will be accompanied by an
increase in shower and thunderstorm activity.

&&

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

Fair weather conditions are expected to prevail across most of the
forecast area through much of the daylight hours today as a drier
than normal air mass with precipitable water values as low as 1.1
inches moves overhead. Therefore, shower activity is expected to
remain at a minimum across most of the region. However, scattered
showers and isolated thunderstorms are still expected to develop
across western Puerto Rico this afternoon due to the strong daytime
heating and sea breeze convergence.

Low to mid-level moisture is then expected to increase in earnest
during the overnight hours as an active tropical wave begins to
approach the region. Therefore, scattered showers and isolated
thunderstorms will increase in coverage across the regional waters
and some of the activity will move into portions of the USVI and
across eastern and southeastern portions of Puerto Rico. Moisture is
expected to further increase into the morning and afternoon hours of
Friday as the axis of the tropical moves across. In fact, the latest
model guidance is hinting of precipitable water values peaking as
high as 2.3 inches. Therefore, the potential exists for enhanced
shower and thunderstorm activity across portions of the area.
Showers and isolated thunderstorms will be concentrated across the
USVI and the eastern half of Puerto Rico during the morning hours.
Then, during the late morning into the afternoon hours, the activity
will spread into western and northwest Puerto Rico. Given the high
moisture content in place, the potential will exist for urban and
small stream flooding across areas that receive a prolonged period
of heavy rainfall activity.

The tropical wave will then move away by Friday night and behind
the wave, a rapid drying trend is expected as well as an increase
in Saharan dust concentration. Therefore, much tranquil weather
conditions along with hazy skies can be expected for Saturday.
However, showers and isolated thunderstorms will be possible
across western Puerto Rico during the afternoon as a result of
strong daytime heating and sea breeze convergence.


.LONG TERM...Sunday through Saturday...
An upper level trough will extend southwest out of the Atlantic
Sunday and Monday, then it will begin to lift northwest allowing
high pressure to briefly appear Wednesday before the trough
returns on Friday.

At lower levels a weak trough moves through the area Sunday with
patches of moisture improving shower chances. A weak tropical wave
then moves through on Tuesday followed by patchy moisture for
much of the rest of the week. The trough and the wave will each
have an increase in shower and thunderstorm activity--mainly in
the west and interior portions of Puerto Rico. The waves will be
mildly productive rain producers for the U.S. Virgin Islands, but
drought relieving rains are not expected during the next 7 days.

A gradual warming trend begins on Sunday and ends with the
passage of the wave on Tuesday. 500 mb temperatures will also cool
until Tuesday. Therefore with upper level divergence and cool 500
mb temperatures on Tuesday the tropical wave at that time should
be convectively active. Nevertheless, conditions are now such that
even during the drier periods there is enough moisture to trigger
some shower and thunderstorms each day over Puerto Rico and that
a few showers will continue to form over the local water during
the night and early morning hours even outside of the tropical
wave passages expected. Temperatures during the period will
remain in a fairly tight range 0 to 2 degrees above normal.


&&

.AVIATION...Mainly VFR conditions expected. SHRA and isolated TSRA
expected across western PR between 04/17z and 04/22z, affecting TJMZ
and TJBQ with TEMPO MVFR conditions possible. SHRA activity to
increase after 04/20z across the Leeward terminals as moisture from
tropical wave approaches. Winds less than 10 knots through 04/12z,
increasing to 10 to 20 knots from the E-ESE with higher gusts and
sea breeze variations after 04/14z. Maximum winds ESE 15-25 kt blo
FL240. Winds less than 10 kt btwn FL330-540.

&&

.MARINE...With each tropical wave passage, Friday and Tuesday,
winds and seas will increase. At this time expect that seas will
remain below 7 feet, but may become choppy with the wind surges
behind the waves.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 79 88 77 / 20 50 50 20
STT 90 79 88 78 / 40 50 50 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
448 AM AST Fri Jul 5 2019

.SYNOPSIS...A tropical wave moving across the area today will
bring periods of showers and thunderstorms. A drier and more
stable weather pattern along with Saharan dust is expected
through the upcoming weekend with afternoon convection across
western Puerto Rico. Another tropical wave will affect the area
late Monday into Tuesday, resulting in another round of more
widespread shower and thunderstorm activity.

&&

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

The axis of the tropical wave will slowly approach the islands
today. Shower and thunderstorm activity will increase in frequency
and intensity across the islands throughout the day. The activity
will affect the local waters, the U.S. Virgin Islands and the
eastern half portion of Puerto Rico during the morning hours.
Showers will slowly spread across the interior and western Puerto
Rico by mid-morning into the afternoon hours. GOES-Total
Precipitable Water imageries showed values of 2.0 inches or more
approaching the islands. In fact, the latest model guidance is
showing TPW between 2.0 and 2.5 inches over and across the region
throughout the day. Under this weather pattern, the potential for
urban and small stream flooding across areas that receive a
prolonged period of heavy rainfall activity is high. Also, this
tropical wave will bring easterly winds between 15 and 20 mph
across the region.

A dry air mass with Saharan air particles will reach the local
islands after the passage of the tropical wave. Model guidance
doesn`t show favorable upper-level dynamics through at least
Sunday. However, passing showers should not be ruled out each day,
followed by afternoon convection across the western sections due
to the strong daytime heating and sea breeze convergence. An
upper-level trough will slowly dig into the region by late Sunday
night into Monday, which will increase the upper level dynamics.

Daytime high temperatures are forecast to peak in the upper 80s to
low 90s along coastal areas, and in the upper 70s to mid 80s at
higher elevations each day.

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

Latest model guidance indicates that another active tropical wave,
with precipitable water values approaching 2 inches, will affect
the region late Monday and during the day on Tuesday. This will
increase the shower and thunderstorm activity across the area.
An upper-level low will be positioned over the southwest Atlantic
around the same time of the wave passage, therefore, the
potential exists for the rainfall activity to be enhanced. After
the wave passage late Tuesday, a drier air mass returns to the
region and will prevail through the end of the work week. This
will result in mostly fair weather conditions across most of the
region, however, showers and isolated thunderstorms are still
expected to develop over western Puerto Rico each afternoon as a
result of strong daytime heating and local effects.

&&

.AVIATION...A tropical wave will bring SHRA/TSRA across the
region. The activity will affect the E-PR/USVI and the Leeward
Islands terminals during the morning hrs. The western terminals will
be impacted by SHRA/TSRA between 05/16-23z. MVFR conditions will be
possible at western terminals during the afternoon hrs. Winds less
than 10 knots through 05/12z, increasing to 10 to 20 knots from the
E-ESE with higher gusts and sea breeze variations after 05/14z.

&&

.MARINE...Tropical wave moving across the area today will result
in fresh trade winds of up to 20 knots across most of the regional
waters. This will result in seas of up to 6 feet across the
nearshore waters and up to 7 feet across the offshore waters
and local passages. Periods of showers and thunderstorms with
frequent wind gusts are also likely across the regional waters
throughout the day. Seas are expected to diminish on Saturday as
the winds diminish.

A moderate risk of rip currents is in effect for most of the local
beaches of the islands, except along the west coast of Puerto
Rico, where the rip current risk will remain low. A high risk of
rip currents is in effect for Cramer Park Beach in Saint Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 88 78 / 60 20 20 30
STT 90 79 90 78 / 40 20 20 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
448 AM AST Sat Jul 6 2019

.SYNOPSIS...A drier and more stable weather pattern along with
some Saharan dust will prevail throughout the weekend. Afternoon
convection is still expected across western Puerto Rico during the
afternoon hours. Another tropical wave is still expected to
affect the area late Monday into Tuesday, resulting an increase in
shower and thunderstorm activity. More stable weather conditions
will follow by the middle and latter half of the work week.

&&

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

A dry air mass with Saharan air particles will move across the
islands today. Model guidance continues to indicate stable weather
conditions through the rest of the weekend. However, moisture
embedded in the trades will bring passing showers across the local
waters at times. Showers and thunderstorms will develop across the
western sections of Puerto Rico due to the strong daytime heating
and sea breeze convergence. Local effects will aid in the
development of showers downwind from the U.S. Virgin Islands each
afternoon.

Daytime high temperatures are forecast to peak in the upper 80s to
low 90s along coastal areas, and in the upper 70s to mid 80s at
higher elevations each day. The Virgin Islands will observe heat
indices in the low and to mid 100s today.

An upper-level trough will slowly dig into the region increasing
instability by late Sunday night into Monday. This upper level
feature will interact with the leading edge of a tropical wave,
which is forecast to reach the islands by late Monday night or early
Tuesday. This will increase the intensity and frequency of showers
and thunderstorms across the area.

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

The axis of the tropical wave is still on track to move across
the area on Tuesday with precipitable water values approaching 2
inches. At the same time, an upper-level trough will be located
just north of Haiti. Therefore, this upper-level trough could aid
in enhancing the rainfall activity that this wave brings. The
tropical wave departs by Tuesday night and behind it, a drier air
mass follows for Wednesday.

For Thursday through Saturday, patches of low-level moisture
embedded within the easterlies will be moving across the area.
Therefore, some passing showers may affect the regional waters and
eastern portions of Puerto Rico and the USVI during the overnight
and morning hours followed by convection developing across
western Puerto Rico during the afternoon hours as a result of
daytime heating and local effects.

&&

.AVIATION...VFR conditions expected throughout the day. SHRA/TSRA
are expected to develop over western Puerto Rico between 06/16-22z.
This may impact JMZ. Winds less than 10 knots through 06/13z,
increasing around 15 knots from the E with higher gusts and sea
breeze variations after 06/13z.

&&

.MARINE...Moderate to fresh easterly trades between 15 and 20
knots will continue to result in rough and choppy seas across
the regional waters through this afternoon. A small craft
advisory continues in effect through 8 am this morning for the
offshore Atlantic waters and through 2 pm this afternoon for the
offshore Caribbean waters and Mona Passage due to seas of up to 7
feet. Seas of up to 6 feet are expected across the nearshore
Atlantic and Caribbean waters. More tranquil seas are expected by
this evening through Monday as the winds diminish.

For beachgoers, there is a moderate risk of rip currents for most
of the local beaches of the islands, except along the west coast
of Puerto Rico and along the northern coast of Saint Thomas and
Saint John.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 89 78 / 0 30 30 50
STT 90 79 90 79 / 10 40 30 50