Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
409 PM AST Sun May 21 2017

.SYNOPSIS...Showers and thunderstorms are once again occurring
this afternoon across central and western PR due to local effects
and available moisture. Weak tropical wave is expected to move to
the south of the local islands tonight while the induced trough
continues northeast through tonight before it weakens and
dissipated by Monday and a SFC high develops north of the local
islands. Haze due to Saharan Dust and warm temps are expected
through this week.

&&

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

The band of moisture as seen over the area in the MIMIC product is
thinning as it hold over Saint Thomas and southwest between Vieques
and Saint Croix. Although streamers with very light precipitation
(so far) have developed off of these islands little other effect has
been seen. Due to weaker moisture in the area showers are not as
widespread or intense as they were yesterday at 2 PM AST, but are
still developing. The GFS suggests that columnar moisture will peak
around 22/06Z and then drop below levels seen anytime in the last 48
hours, so showers may linger into the evening as well.

As what remains of an eastward moving ridge at upper levels passes
over Puerto Rico Monday night, convergence aloft will begin to help
suppress vertical motion. Northwest flow will have already begun and
This will greatly decrease the amount of shower coverage Monday
afternoon. It may not be enough to completely suppress
thunderstorms, however, as the model anticipates higher CAPE levels
than today or yesterday. This will be reversed on Tuesday when
divergence aloft will increase with the passage of a weak upper
level short wave and moisture temporarily increases Tuesday and
Wednesday. Nevertheless equivalent potential temperature values will
decrease considerably after tonight and remain low till at least
Tuesday afternoon in the presence of Saharan dust that will also
increase considerably between 22/15Z and 23/15Z. This will lead to
hazier skies and weakly developing clouds during the week.

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

A mid to upper level ridge will hold across the area through the
forecast period with some weakening expected Sunday and into early
next week. The ridge pattern aloft will promote limited moisture
with precipitable water values remaining below the normal range.
At lower levels, a broad high pressure will dominate the central
Atlantic, resulting in east southeast winds across the eastern
Caribbean Wed-Fri. Latest guidance continues to indicate the
Saharan Air Layer across the eastern Caribbean much of the
workweek, however, it looks particularly dense early in the week.

Therefore, under the influence of east southeast winds and a dry
and stable air mass with dust particles, a fair weather pattern
is expected with warm to hot temperatures and hazy skies much of
the workweek. As the ridge aloft erodes Sunday and into the next
week, an increase in low level moisture is expected with a better
chance for showers and thunderstorms. One more thing to note, the
latest guidance is indicating that the 100-850mb thickness is
expected to drop late this week, which could cause a few degrees
cooler minimum temperatures during the overnight hours if the
skies are clear and the wind is light.

&&

.AVIATION...VFR conds have prevailed across the local area and are
expected to continue except for TJMZ which has already seen some
SHRA/TSRA development and may have CIGS nr BKN030 til 21/21Z. Some
mtn obscurations over hir terrain expected til 21/04Z. Sfc winds
easterly with sea/land breeze variations 5 to 15 kt. Maximum winds
50 to 70 knots from FL390-470 by 22/18Z strongest at FL470.

&&

.MARINE...Seas are expected to continue 2-4 feet through Monday,
then increase gradually on Tuesday and Wednesday with potential of
up to 7 feet by Wednesday. There is a moderate risk of rip
currents for northern Puerto Rico and Culebra today and Monday,
low risk elsewhere.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 90 78 91 / 30 30 20 20
STT 79 88 80 89 / 30 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
503 AM AST Mon May 22 2017

.SYNOPSIS...Fair weather conditions will prevail most of the week.
Pulses of Saharan Dust will reach the Northeast Caribbean over the
next several days reducing somewhat the visibilities. A wetter
pattern is possible during the weekend and early next week as an
induced trough and a tropical wave moves across the region.

&&

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

Doppler radar indicated isolated shower activity mostly along the
northern sections of Puerto Rico as well as across the
surrounding waters overnight and early this morning. The induced
surface trough northeast of the region will continue to drift
northeastward and away from the region today as a surface high
develops north of the local islands. A weak easterly wave over the
central Caribbean will continue to move westward and also away
from the local area today. Model guidance suggests that Saharan
Air Layer is expected to increase considerably over the Region
today through midweek. This will maintain hazy skies and warmer
than normal temperatures across the region for the next several
days. GFS guidance indicated PWAT values at near 1.60 inches
today, decreasing below 1.50 inches Tuesday and thereafter as a
relatively dry and hazy air mass encompass the region from the
east. However, residual moisture will combine with strong daytime
heating, sea breeze convergence and mountains lifting to induce a
new round of showers and thunderstorms over central interior,
western and northwest Puerto Rico each afternoon. Not significant
precipitation is expected to affect the U.S. Virgin Islands.

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

Upper level ridge will dominate the Northeast Caribbean Thursday
and Friday while an upper level trough amplifies east of the
Lesser Antilles. At the surface...high pressure over the Central
Atlantic will continue to push Saharan Dust particles over the
local area. Therefore...conditions will remain hazy, dry and
relatively stable through the end of the work week. Then...an
induced surface trough will promote moisture convergence and
thunderstorm activity during the weekend. A tropical wave will
follow the surface trough keeping the conditions somewhat unstable
through at least early next week.

&&

.AVIATION...Mostly VFR conditions expected across the local flying
area for the next 24 hours. VCSH/VCTS is possible across TJMZ and
TJBQ after 22/17Z as afternoon convection develops over western and
northwest PR. Winds will increase at 10-15 knots after 22/13Z with
sea breeze variations. Latest TJSJ sounding indicated an easterly
wind flow up to 15 knots from the SFC to 6K feet, becoming light and
variable between 6k-30k feet and then westerly and stronger above
30k feet.

&&

.MARINE...High pressure will build over the Central Atlantic by
midweek resulting in seas building to 5-7 feet across the Atlantic
Waters. Marine conditions will gradually improve through the weekend
when seas will subside to 2-4 feet across most of the waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 91 78 / 30 20 20 20
STT 88 80 89 80 / 20 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
413 AM AST Tue May 23 2017

.SYNOPSIS...Mostly fair and stable weather conditions with high
concentrations of saharan dust particulates will continue across
the region for the next several days. A surface high across the
central Atlantic will maintain an easterly trade wind flow across
the region for most of the forecast period. A wetter pattern is
possible early next week as a tropical wave moves across the
region.

&&

.SHORT TERM...Today through Thursday...
Partly cloudy skies prevailed across Puerto Rico and the U.S. Virgin
Islands overnight. Doppler radar detected some light passing showers
mainly across the local waters. Some light passing showers can be
expected this morning, but overall dry and hazy conditions are
expected to prevail.

Model guidance suggests that Saharan Air Layer is expected to
continue affecting the local region today. This will maintain hazy
skies and warmer than normal temperatures across the region for the
next several days. However, residual moisture will combine with
strong daytime heating, sea breeze convergence and mountains lifting
to induce a new round of showers and possible thunderstorms over
central interior, western and northwest Puerto Rico each afternoon.
Significant precipitation is not expected to affect the U.S. Virgin
Islands.

.LONG TERM...Friday through Wednesday...
An upper level ridge will remain as the main weather feature
across the northeast Caribbean until at least Saturday. An upper
level low and an associated upper level trough is expected to
develop just to the east northeast of the region by the upcoming
weekend, eroding the upper ridge. However, the upper trough axis is
expected to remain to the east of the region maintaining the
local islands under the subsidence side of the trough. A Surface
high pressure across the central Atlantic is expected to produce a
moderate easterly trade winds across the region. Model guidance
also continue to indicated that a Saharan Air Layer will persist
over the area through most of the forecast period resulting in
hazy, relatively dry and stable airmass over the northeast
Caribbean into the upcoming weekend. A tropical wave along 40 West
this morning will continue to move westward approaching to the
Lesser Antilles on Monday an moving over the eastern Caribbean on
Tuesday and across the local islands late Tuesday and Wednesday.
This feature will result in an increase in cloudiness, showers and
thunderstorms over the local islands and surrounding waters late
in the forecast period.

&&

.AVIATION...VFR conditions will prevail across all TAF sites through
at least 23/16z. VCSH can be expected across TJMZ and TJBQ with
mountain obscurations. Low level winds will be mainly southeast at
10 to 15 kts with higher gusts.

&&

.MARINE...High pressure over the Central Atlantic will increase
the trade winds across the surrounding waters, resulting in
posible seas building up to 6 feet across the Atlantic Waters by
midweek. Marine conditions will then gradually improve through the
weekend when seas subsiding to 2-4 feet across most of the
waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 80 90 80 / 20 10 10 20
STT 89 80 90 80 / 20 10 10 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
404 PM AST Tue May 23 2017

.SYNOPSIS...So far only few showers were detected over the west
interior of Puerto Rico. Mostly sunny, hot and hazy conditions
prevailed elsewhere. The fairly dry air mass with suspended
Saharan dust particulates is expected to persist and affect the
forecast through the end of the week. An upper level ridge is
forecast to build across the islands,therefore, fair weather
conditions, warm temperatures and little or no shower activity
will continue through the end of the work week.

&&

.SHORT TERM...Rest of today through Thursday...
Model guidance suggests that Saharan Air Layer is expected to
linger across the region for the next several days, but lesser
concentration is expected by Thursday. Overall sunny and hazy
skies with warmer than normal temperatures are expected to prevail
across most of the region.

A strong mid level ridge will remain in place and limit convective
development, however, a short wave is expected to quickly move across
the region on Wednesday and reach the lesser antilles by Thursday.
This feature along with limited moisture availability, strong daytime
heating, sea breeze convergence and local forcing should aid in
the development of showers and possibly an isolated thunderstorm
on Wednesday afternoon. Lesser activity expected on Thursday. The
shower activity should be focused over the central interior, western
and northwest Puerto Rico each day. Little or no significant rainfall
is expected over the adjacent islands including the U.S. Virgin Islands
at this time as conditions are forecast to remain fairly dry.

.LONG TERM...Friday through Wednesday...
Mid to upper level upper level ridge will remain the main weather
feature across the northeast Caribbean through Saturday. An upper
level low and an associated trough is forecast to develop and linger
just east of the region through the upcoming weekend. The upper trough
axis is also forecast to remain east of the region maintaining the
islands on the subsidence side of the trough. Surface high pressure
across the central Atlantic is expected to maintain moderate easterly
trade winds across the region. Model guidance suggests that the Saharan
Air Layer will persist over the area through most of the weekend
resulting in hazy and a relatively dry airmass. However, a tropical
wave will move westward across the tropical Atlantic and approach to
the Lesser Antilles by Monday.It is then forecast to move over the
eastern Caribbean Tuesday through Wednesday. This feature should bring
an increase in tropical moisture transport and consequently increase
the chance for showers and thunderstorms over the local islands and
surrounding waters. Stay tuned.

&&

.AVIATION...VFR conds will prevail across all TAF sites. A Saharan
air layer will persist across the region, but vis is not expected
to decrease below 6SM. Although VFR conds expected, SHRA cannot be
ruled out across the NW quadrant of PR with VCSH at TJMZ/TJBQ til
23/22z. SKC durg overnight with ISOLD -SHRA en route from the Leeward
Islands and USVI. Sfc winds mainly southeast at 10-15 kts with higher
gusts. Winds are expected at 10 knots or less aft 23/23z.

&&

.MARINE...High pressure building north of the region will aid in
slightly increasing the trade winds across the surrounding waters,
resulting in posible seas building up to 6 feet across the Atlantic
waters and local passages through Wednesday. Marine conditions will
then gradually improve through the weekend when seas subsiding to
4 feet or less across most of the waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 80 92 79 90 / 10 10 10 20
STT 81 88 79 87 / 20 10 10 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
410 AM AST Wed May 24 2017

.SYNOPSIS...Mostly fair and relatively dry weather conditions
with high concentrations of saharan dust particulates will
continue through the end of the week. An upper level ridge is
forecast to hold over the region until at least Friday. Surface
high across the central Atlantic will maintain an easterly trade
wind flow across the region for most of the forecast period. A
wetter pattern is possible early next week as a tropical wave
moves across the local islands.

&&

.SHORT TERM...Today through Friday...
Partly cloudy skies prevailed across Puerto Rico and the U.S. Virgin
Islands overnight. No shower activity was observed over land areas.
A very dry airmass will continue to dominate the local region for
the next few days as an upper level ridge continues in total control
of the local weather. Saharan dust will continue across the region
today. As a result, hazy skies can be expected. A southeast wind
flow will promote higher than normal temperatures along the northern
slopes of Puerto Rico this afternoon.

Model guidance suggests that Saharan Air Layer is expected to
continue affecting the local region through at least Friday. This
will maintain hazy skies and warmer than normal temperatures across
the region for the next several days. However, by Friday an increase
in moisture is expected. Therefore, an increase in shower activity
is then expected as this moisture, combined with strong daytime
heating, sea breeze convergence and mountains lifting will induce
showers and possible thunderstorms development over central
interior, western and northwest Puerto Rico Friday afternoon.
Significant precipitation is not expected to affect the U.S. Virgin
Islands.

.LONG TERM...Saturday through Thursday...
An upper level low and an associated trough is forecast to develop
just to the east northeast of the region during the upcoming
weekend. This feature is expected to erode the mid to upper level
ridge that persisted over the region for the last few days.
However, the upper trough axis is forecast to remain east of the
region, maintaining the islands on the subsidence side of the
trough. Surface high pressure across the central Atlantic is
expected to maintain moderate easterly trade winds across the
region until early next week. Optical Thickness model guidance
suggests that the Saharan Air Layer will persist over the
region through most of the work week and into the upcoming
weekend, resulting in hazy and a relatively dry airmass across the
local islands. Latest surface analysis depicted a tropical wave
across the tropical Atlantic. This wave will continue to move
westward and approach to the Lesser Antilles late Monday and
Tuesday. It is then forecast to move over the eastern Caribbean
and over the local islands Tuesday through Wednesday. This feature
should bring an increase in tropical moisture transport and
consequently increase the chance for showers and thunderstorms
over the local islands and surrounding waters next week.

&&

.AVIATION...VFR conditions will prevail across all TAF sites through
at least 24/16z. VCSH can be expected across TJMZ and TJBQ with
mountain obscurations. Low level winds will be mainly southeast at
10 to 15 kts with higher gusts.

&&

.MARINE...High pressure building north of the region will aid in
slightly increasing the trade winds across the surrounding waters,
resulting in posible seas building up to 6 feet across the Atlantic
waters and local passages through Wednesday. Marine conditions will
then gradually improve through the weekend when seas subsiding to
4 feet or less across most of the waters.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 PM AST Wed May 24 2017

.SYNOPSIS...Broad surface high pressure will continue across the
Central Atlantic. SAL will linger through the end of the week.
Overall fair weather expected to continue through the weekend. An
upper level trough is forecast to move over the area by early
next week. A tropical wave is expected to enter the eastern
Caribbean by Tuesday.


&&

.SHORT TERM...Today through Friday...
Hazy skies and hot temperatures were observed today across the
forecast area. A few clouds developed over the mountains and
northwest portions of PR during the afternoon hours, however no
significant rainfall was detected over land areas. The temperature
at the international airport in San Juan reached 93 degrees, this
tied the record set in 1990.

Limited shower activity is expected to continue across the
islands. Saharan air layer will continue to result in hazy skies
and dry mid levels. Above normal temperatures will continue
through the short term period. A slight increase in moisture is
expected on Friday afternoon, this moisture in combination with
diurnal effects will lead to better chances for showers across the
islands. However, no significant rainfall amounts are expected at
the moment.


.LONG TERM/from previous discussion...Saturday through
Thursday...
An upper level low and an associated trough is forecast to
develop just to the east northeast of the region during the
upcoming weekend. This feature is expected to erode the mid to
upper level ridge that persisted over the region for the last few
days. However, the upper trough axis is forecast to remain east of
the region, maintaining the islands on the subsidence side of the
trough. Surface high pressure across the central Atlantic is
expected to maintain moderate easterly trade winds across the
region until early next week. Optical Thickness model guidance
suggests that the Saharan Air Layer will persist over the region
through most of the work week and into the upcoming weekend,
resulting in hazy and a relatively dry airmass across the local
islands. Latest surface analysis depicted a tropical wave across
the tropical Atlantic. This wave will continue to move westward
and approach to the Lesser Antilles late Monday and Tuesday. It is
then forecast to move over the eastern Caribbean and over the
local islands Tuesday through Wednesday. This feature should bring
an increase in tropical moisture transport and consequently
increase the chance for showers and thunderstorms over the local
islands and surrounding waters next week.


&&

.AVIATION...Mainly VFR conditions will prevail during the next 24
hours. Surface winds E-ESE at 10-15 knots. Light and variable
overnight. HZ due to Saharan dust will continue but vsby should
remain P6SM.


&&

.MARINE...San Juan and Rincon buoys were indicating a 13-14 second
northeasterly swell at 3-4 feet during the last couple of hours.
Winds are near 15 knots from the east with some gusts in the low
20s. A high rip current risk is in effect for the northern beaches
of Puerto Rico and Culebra through Thursday. Northerly swell will
peak overnight.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 89 77 88 / 10 10 10 20
STT 79 89 78 87 / 10 10 20 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
409 AM AST Thu May 25 2017

.SYNOPSIS...Broad surface high pressure will continue across the
Central Atlantic. SAL will linger through the end of the week.
Overall fair weather expected to continue through the weekend. An
upper level trough is forecast to move over the area by early
next week. A tropical wave is expected to enter the eastern
Caribbean by Tuesday.

&&

.SHORT TERM...Today through Saturday...
Partly cloudy skies prevailed across Puerto Rico and the U.S. Virgin
Islands overnight. Doppler radar detected some light showers mainly
across the coastal waters. A very dry airmass will continue to
dominate the local region for the next few days as an upper level
ridge continues dominating the region. Saharan dust will continue
across the region today. As a result, hazy skies can be expected.
Once again, A southeast wind flow will promote higher than normal
temperatures along the northern slopes of Puerto Rico this
afternoon. As a result, near record maximum temperatures can be
expected.

Upper level ridge will weaken by Friday. As a result, an increase in
moisture is expected for Friday and Saturday with a return to normal
weather conditions with shower and thunderstorm development expected
to occur across the interior and west sections of Puerto Rico
during the afternoons.

.LONG TERM...Sunday through Friday...
An upper level low and an associated trough to the east northeast
of the region is expected to drift northeastward while weakening
Sunday through early in the upcoming week. Another upper level
low and an associated trough is expected to develop over the
southwestern Atlantic early in the week, amplifying across the
northeast Caribbean Tuesday and Wednesday. Surface high pressure
across the central Atlantic is expected to maintain moderate
easterly trade winds across the region until early next week.
Winds are expected to become from the east to east northeast by
mid week and the from the east southeast for the rest of the
period. Optical Thickness model guidance suggests a relaxation in
the Saharan Air Layer across the region during the weekend and
for the upcoming week with only some particulates of dust
suspended in the air. Expect the continuation of a relatively dry
weather pattern across the local islands during the weekend with
only the typical diurnal induce afternoon shower activity over
western and interior PR. Latest surface analysis depicted a
tropical wave across the tropical Atlantic. This wave will
continue to move westward and approach to the Lesser Antilles
Sunday and Monday. It is then forecast to move over the eastern
Caribbean and over the local islands Tuesday through Wednesday.
This feature in combination with an upper trough should bring an
increase in tropical moisture transport and consequently increase
the chance for showers and thunderstorms over the local islands
and surrounding waters next week.

&&

.AVIATION...VFR conditions will prevail across all TAF sites through
at least 25/16z. VCSH can be expected across TJMZ and TJBQ with
mountain obscurations. Low level winds will be mainly southeast at
10 to 15 kts with higher gusts.

&&

.MARINE...
Long period northeasterly swell of 4 to 5 feet will continue to
affect the Atlantic waters and passages through late tonight.
There is a high risk of rip current for northwest through
north central and San Juan and vicinity beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 89 77 / 10 10 40 40
STT 90 78 87 77 / 10 10 40 40

[cycloneye]

Area Forecast Discussion...DELAYED
National Weather Service San Juan PR
449 PM AST Thu May 25 2017

SYNOPSIS...Broad surface high pressure will remain anchored across
the Central Atlantic to maintain moderate easterly winds. The overall
dry Saharan air layer/SAL will linger through the end of the week.
Overall fair weather expected to continue through the weekend. An upper
level trough is forecast to move over the area by early next week. A
tropical wave is forecast to enter and move across the eastern Caribbean
by Tuesday.

.SHORT TERM...Today through Saturday...
Mostly sunny and hazy skies prevailed across the region once again
today. Only a few light showers were noted over the west interior
of Puerto Rico during the late afternoon hours. However, the activity
was of short duration. Expect mostly clear skies during the overnight
hours with little or no measurable precipitation expected across the
forecast area.

A very dry and stable airmass will continue to dominate the local
region for the next few days as a strong low to mid level ridge
will dominate the region. Saharan dust will continue across the
region during the rest of the evening but lesser concentrations is
expected during the next few days. An east to southeast wind flow
will prevail through Saturday promoting near or slightly above normal
temperatures along the northern slopes of Puerto Rico. Elsewhere temperatures
will be near normal. On Friday, the upper level ridge will gradually
erode allowing for a slight increase in low level moisture transport
through Saturday. This should allow a better chance for early morning
showers followed by some afternoon showers and possibly isolated thunderstorm
development mainly over the interior and west sections of Puerto Rico.

.LONG TERM...Sunday through Friday...
An upper level low and an associated trough just east northeast of the
region is forecast to retrogress north northwest across the area
while weakening Sunday through Monday. However, another short wave
trough is expected to develop and move across the southwestern Atlantic
and reinforce the previously mentioned lingering trough. Surface
high pressure across the central Atlantic is forecast to maintain
moderate trade winds across the region through early. However,
winds are to become east to northeast by mid week and once again
east southeast for the rest of the period. All in all, expect
relatively dry weather pattern across the local islands during
most of the weekend with typical diurnally and locally induced
afternoon convection mainly over parts of the interior and west
sections of Puerto Rico. A tropical wave is still forecast to
approach to the Lesser Antilles Sunday and Monday and move across
the eastern Caribbean Tuesday through Wednesday. This feature in
combination with the proximity of an upper trough should bring an
increase in tropical moisture transport and consequently increase
the chance for showers and thunderstorms over the local islands
and surrounding waters early next week.

&&

.AVIATION...Suspended saharan dust will result in slight Hz with
slant VSBY btwn 6-9 nm durg prd. Some SHRA/-SHRA are possible in
the VCTY of TJMZ btwn 25/18-23z, then VFR conditions will prevail
during the next 24 hours. Surface winds E-ESE at 10-20 knots with
higher gusts. Light and variable overnight.

&&

.MARINE...A northerly swell at 3 to 5 feet continued to move across
the local Atlantic waters. This swell will continue to subside
during the rest of the evening hours. The nearshore buoys
continued to suggests easterly winds at 15 to 20 knots. Mariners
can therefore expect seas between 3 and 6 feet and winds at 15
knots or less.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 89 77 89 / 10 40 40 40
STT 78 87 77 88 / 10 40 40 40

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST Fri May 26 2017

.SYNOPSIS...An upper level trough is forecast to move over the
area by early next week. A tropical wave is forecast to enter and
move across the eastern Caribbean by Tuesday.

&&

Short Term... Friday through Sunday...

The Saharan dust that has been affecting the local area is expected
to clear off today but then increase slightly on Saturday into
Sunday. However, the concentrations do not seem to be as high as it
has been this past week. The available moisture is expected to also
increase today with precipitable water values at around 1.5 inches
and hanging on close to that value thorough the weekend. The local
winds will remain from the east at about 10-15 mph due to the strong
surface high pressure across the central Atlantic. There is an upper
low to the northeast of the local islands that is expected to move
west a little bit then north and east as it weakens and dissipates
by Sunday. This means that the upper level dynamics do not seem to
be particularly conducive to sustained thunderstorm development even
with less Saharan Dust concentrations. For that reason, the forecast
is for isolated to scattered showers with afternoon convection
occurring across western PR every afternoon this weekend.

Long Term...Monday through Saturday...

Latest model guidance indicated an upper level trough is forecast
to move over the area by early next week. Also, a tropical wave
is forecast to enter and move across the eastern Caribbean by
Tuesday. These two features promise to bring an increase in low
level moisture across the region beginning on Monday night and
continuing through most of next week. As a result, showers and
thunderstorms are expected to affect the region.

&&

.AVIATION...VFR conds expected through the forecast period. Winds
from the east with sea breeze variations at about 10-15kt and
occasional gusts. VCSH likely for TJMZ and TJBQ after 26/16Z due to
afternoon convection across western PR. SHRA activity to dissipate
mostly over PR by 26/23Z.

&&

.MARINE...Seas up to 6 feet and winds up to 20 knots can be
expected across the local waters. Small Craft should exercise
caution across the Atlantic water north of Puerto Rico. Moderate
risk of rip currents expected today across much of the beaches of
the islands.



&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
455 PM AST Fri May 26 2017

.SYNOPSIS...Weakening ridge aloft and lesser Saharan dust across
the region, allowed better transport of trade wind showers and
convective development across the coastal waters and parts of the
islands today. Tutt low and associated trough across the Lesser
Antilles will lift northwards across the region over the weekend.
Broad high pressure ridge across the central Atlantic will hold and
allow better transport of trade wind moisture across the forecast
areas overnight and through the weekend.

&&

.SHORT TERM...Rest of today through Sunday...
Recent satellite imagery and SAL products all suggests the Saharan
dust has diminished or moved away from the region. The weakening
of the mid to upper level ridge across the region has also allow
for better moisture transport in the easterlies and for afternoon
convective development especially over Puerto Rico. Expect activity
over land areas to diminish after sunset. However late evening and
overnight passing showers will remain possible over portions of the
coastal waters, with some brushing the east coastal sections some
of the the islands by early morning.

On Saturday through Sunday the gradual increase in the trade wind
moisture will allow for showers and isolated thunderstorm development
each afternoon. The activity however should be focused mainly over
parts of the central interior and west sections of Puerto Rico. Isolated
streamer like convection will remain possible over the east interior
and parts of the San Juan metro each day.

The Tutt is expected to lift north and east of the region through Sunday
while gradually weakening. Conditions aloft should therefore be less
favorable for significant convective development. However, isolated
to scattered afternoon showers will remain likely mainly over western
PR with lesser activity over the adjacent islands and the USVI.

.LONG TERM...Monday through Saturday...
Tutt low will linger north and east of the region, while a short wave
trough will move eastward across the west and southwest Atlantic. The
trough is forecast to become amplified just north and west of the region
Monday through Tuesday of next week. The deepening of this mid to upper
level trough along with the approach of a weak tropical wave will increase
the chance for showers and thunderstorms across the forecast area especially
during the early part of next week. So far models all in agreement on
the increase in precipitable water to near two inches across the area
through Tuesday of next week. This should result in increased potential
for convective development and instability at least until the middle
of next week.

For the rest of the week another surge of Saharan dust is expected
to accompany or trail the aforementioned wave. This should allow
for a gradual depletion of the trade wind moisture transport and
thus lesser chance for widespread convection. However, lingering
moisture across the islands as well as the proximity of the upper
trough will allow for afternoon convection each day mainly over
parts of the interior and west sections of Puerto Rico. By then
only isolated showers are forecast elsewhere.

&&

.AVIATION...Mtn Top obsc observed over the Cordillera Central of
PR with SHRA/TSRA resulting in SCT-BKN ceiling btwn FL020-FL080
at TJBQ/TJMZ and possibly at TJSJ til 26/23z. TEMPO included for
TJMZ due to this activity. Elsewhere Isold SHRA psbl at all other
TAF sites til 26/23z. Easterly winds 10-15 knots with higher gusts,
bcmg calm to light and variable aft 26/23z. VFR conds durg rmdr
of prd.

&&

.MARINE...Mariners can expect seas of 5 feet or less and winds 15
knots or less overnight, but increasing to 15 to 20 knots over
some of the local waters on Saturday. There is a moderate risk of
rip currents for the northwest to northeast beaches of Puerto Rico,
as well as some of the north facing beaches of Culebra and Saint
Thomas and Cramer park in Saint Croix overnight through Saturday
morning.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
455 AM AST Sat May 27 2017

.SYNOPSIS...Tutt low and associated trough across the Lesser
Antilles will lift northwards across the region over the weekend.
Broad high pressure ridge across the central Atlantic will hold
and allow better transport of trade wind moisture across the
forecast areas overnight and through the weekend. A tropical wave
will approach the local area Monday into Tuesday next week.

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

Clear to partly cloudy skies prevailed across the local islands
overnight and early this morning with a few passing showers noted
across the surrounding waters, USVI and E PR. Rainfall accumulations
associated with these showers were minimal. Overnight temperatures
were in the upper 70s to low 80s across the lower elevations and in
the low 70s across the higher elevations. Winds were mostly light
and variable.

Although a TUTT low to the northeast of the forecast area will
continue to move away while weakening, trofiness will return to the
northeast Caribbean late Monday into Tuesday. This feature will
interact with an approaching tropical wave to result in a better
chance for showers and thunderstorms Monday afternoon into Tuesday.
Meanwhile, during the weekend as well as Monday continue to expect
trade wind showers across windward areas in the morning hours
followed by locally induced afternoon showers and thunderstorms
across west and north portions of Puerto Rico. Elsewhere, mainly
fair weather will continue to prevail with a few passing showers
possible. With the heaviest showers during the afternoon hours,
minor urban flooding likely.

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

For Tuesday, a Tropical Wave is expected to affect the region
with an increase in showers and thunderstorms activity. A moist
weather pattern is forecast to prevail across the northeast
Caribbean next work week as a series of Tropical Waves and
trofiness aloft affect the region.

&&

.AVIATION...VFR conds expected at all TAF sites through the morning
hours with VCSH possible at the Leeward and USVI terminals as well
as JSJ. Aft 27/16z SHRA/TSRA expected over NE PR and this may result
in MVFR conds in and around JMZ/JBQ. VCSH at JSJ also possible this
afternoon. Easterly winds 10-15 knots with some sea breeze
variations after 27/12z.

&&

.MARINE...Seas between 3 to 5 feet and east winds at 5 to 15 knots are
expected across much of the local waters and passages. There is
a moderate risk of rip currents across the north facing beaches
of Puerto Rico and Culebra and Saint Croix in the U.S. Virgin
Islands.


&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
342 PM AST Sat May 27 2017

.SYNOPSIS...Mid to upper level trough with associated low pressure
area across the lesser antilles northeastward into the central
Atlantic will slowly drift westward through Sunday. A tropical
wave just east of the lesser antilles will approach the local area
Monday through Tuesday.


&&

.SHORT TERM...Tonight through Monday Night...Mid to upper trough
mentioned before will keep unstable conditions across the
northeast Caribbean through Monday. This, coupled with abundant
moisture and diurnal heating will result in an increased chance
for showers/thunderstorms across most of the area...especially
afternoons and early evening hours. On Monday night the leading
edge of a tropical wave currently east of the lesser antilles will
begin to impact the local islands. The interaction of the wave
with the mid/upper trough will result in a generalized increase in
showers/thunderstorms from east to west. Decided to increase the
chances for precipitation based on the expected interaction of the
two weather feature and the increase in available moisture.

.LONG TERM...Tuesday through Sunday...The tropical wave will still
moving across the local area and so the chances for rain will
remain moderate to high with scattered showers and isolated
thunderstorms. Models indicate a slight decrease in the chances
for rain after Tuesday...however it looks like the environment
will remain rather moist and unstable as trofiness at mid/high
level remains across the eastern Caribbean.


&&

.AVIATION...SHRA expected through the USVI which will cause at
least VCSH across the TIST and TISX terminals this afternoon.
VCTS likely at the terminals in Puerto Rico this afternoon. Winds
from the E-ESE with sea breeze variations at around 15KT with
occasional gusts. SHRA activity to diminish after 27/23Z and winds
to diminish as well into the overnight hours, however, VCSH is
possible for TIST, TISX, and TJSJ in brief passing showers.


&&

.MARINE...Pleasant marine conditions should remain in place
through Tuesday with winds at or below 15 kts and seas at or below
5 feet. Locally higher winds and rough conditions in the vicinity
of showers and thunderstorms...especially Monday night through
Tuesday as the tropical wave moves through the coastal waters.


&&

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

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
453 AM AST Mon May 29 2017

.SYNOPSIS...A tropical Wave will affect the local region through
Tuesday. A deep long wave trough will linger across the region
through much of the work week.

&&

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

Cloudy skies prevailed across the local islands overnight and early
this morning with numerous showers noted across the surrounding
waters, USVI and E PR. Rainfall accumulations associated with these
showers and thunderstorms were between 2 and 4 inches across NE
Puerto Rico. The overnight temperatures were in the upper 70s to low
80s across the lower elevations and in the low 70s across the higher
elevations. Winds were east southeast at 10 mph or less.

A developing mid to upper level trough across the west tropical
Atlantic and into the central and eastern Caribbean will continue to
interact with a tropical wave across the local area to result in
periods of showers and thunderstorms throughout the day. During the
early morning hours, the shower and thunder activity is expected
across the USVI and the eastern half of Puerto Rico, spreading
across the western half of Puerto Rico in the late morning and
afternoon hours. Although the tropical wave is expected to be away
from the forecast area on Tuesday, lingering moisture will continue
to prevail and due to the proximity of the aforementioned trough,
another round of showers and thunderstorms is likely. Low level
moisture is expected to decrease somewhat by midweek, but showers
and thunderstorms are still expected particularly across the
interior of Puerto Rico as well as the USVI. There is a high
potential for urban and small stream flooding early this week.

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

A deep long wave trough will linger across the region through the
forecast period. This feature will enhance the development of
showers and thunderstorms across the region. At the surface, a
weak tropical wave is expected to approach the local region by the
weekend. At this time, global models indicated main weather
associated with this wave will remain south of the local area.

&&

.AVIATION...Periods of MVFR conds in SHRA/TSRA will remain possible
at all TAF sites as a tropical wave and associated moisture moves
across the eastern Caribbean today. ESE winds 10-15 knots with sea
breeze variations are expected.

&&

.MARINE...A tropical wave will continue to move across the
regional waters through Tuesday. This will increase the chance for
thunderstorms with areas of locally heavy rainfall across the
regional waters. Local seas are expected to remain below 5 feet
for the next several days.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 84 77 / 60 50 50 20
STT 88 79 81 77 / 60 60 60 50

[msbee]

http://www.stormcarib.com/reports/curre ... rtin.shtml

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
327 PM AST Mon May 29 2017

.SYNOPSIS...A mid to upper level long wave trough extending from
the central Atlantic southwest to central Bahamas and central
Caribbean inducing a diffluence flow aloft over the eastern
Caribbean. A tropical wave over the eastern Caribbean with axis
already west of PR moving west at 15 to 20 kts. Satellite images
showed scattered showers and thunderstorms trailing this wave
extending northward to just North and Northeast of the local
islands.


&&

.SHORT TERM...Tonight through Wednesday night...Area of showers
and thunderstorms trailing the wave expected to spread over the
local islands tonight and Tuesday morning as the wave continues
to move westward. As it is often the case with these wave...will
expect most shower/thunderstorms activity to concentrate across
the U.S. Virgin Islands and eastern portions of PR with
significantly less activity over the western half of the big
island. Models show an upper level low developing within the
upper trough through the end of the week. Although this feature
may shift slowly eastward during this period, Upper level
divergence/diffluence associated with it should remain over the
eastern Caribbean. This will keep the region under unstable
conditions which, combined with ample moisture and local effects,
should continue to enhance the development of showers/thunderstorms.
Decided to keep scattered to numerous showers and isolated
thunderstorms Tuesday with a gradual decrease on Wednesday as a
slightly drier air mass moves into the eastern Caribbean.

.LONG TERM...Thursday through Tuesday...The mid/upper level
trough should continue across the eastern caribbean keeping all
areas from PR eastward under rather unstable conditions. The only
limiting factor would be a drier air mass over the region. Still
upper level dynamics could be strong enough to support the
development of the tipical afternoon convection across
western/interior PR and nighttime and early morning showers over
the U.S. Virgin Islands and eastern PR at least through the
upcoming weekend. Another tropical wave could approach the region
by Sunday...however long range models indicate that this wave
should remain as a low latitude wave with no significant impact
over the local area. The upper trough should begin to shift east
with an upper ridge building across the eastern Caribbean by the
beginning of next week. Although this is a long range forecast
with a great deal of uncertainty...convective activity should be
kept at a minimum with strong subsidence at the mid/upper level
over the local area.


&&

.AVIATION...SHRA expected for the rest of this afternoon around the terminals in
PR, which can cause brief moments of MVFR conditions, particularly
for TJSJ, TJMZ, and TJBQ. VCSH possible for TIST/TISX this afternoon
and tonight. Winds from the East to ESE at 10-15KT with occasional
gusts. Weather to improve after 29/23Z. Overnight weather to cause
VCSH across the USVI terminals and TJSJ. Winds to decrease to 5-10KT
but continued from the East to ESE.


&&

.MARINE...Tropical wave should move west of the local waters
tonight, however showers and thunderstorms should still impact
local waters Tonight and Tuesday. Seas are expected to remain
at or below 6 feet and winds at 15 knots or less most
areas...except 15 to 20 knots over the Caribbean and Mona Passage
waters due to the proximity of the wave. Mariners are advice to
exercise caution as winds and seas could be locally higher in the
vicinity of thunderstorms.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 77 88 76 87 / 50 50 20 40
STT 78 86 76 86 / 60 60 50 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
450 AM AST Tue May 30 2017

.SYNOPSIS...A trough aloft will continue to interact with
moisture associated with a departing tropical wave to result
in periods of showers and thunderstorms today. The proximity
of this trough will continue to enhance afternoon showers and
thunderstorms Wed-Thu. A more seasonable weather pattern is
expected Fri-Sat with the next tropical wave passage on Sunday.

&&

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

Abundant amounts of moisture trailing the tropical wave and the
instability aloft due to the lingering mid to upper level
trough/TUTT, continued to favor the development of showers and
isolated thunderstorms across the region during the overnight and
early morning hours. Expect these unstable conditions to continue
today, but with a slight break in cloudiness, shower and
thunderstorm activity by mid morning.

However, instability aloft and good moisture convergence along with
daytime heating will quickly give way to another round of afternoon
convection across the islands especially over the interior and west
sections of Puerto Rico. Showers and or isolated thunderstorms may
also form along the Yunque area then stream across the San Juan
metro area during the afternoon.

Expect the tropical wave to exit the region later today however
recent models guidance continued to suggest a TUTT low will
continue to develop and linger just north of the region through
Thursday. Although this feature will shift slowly eastward during
the period, Upper level divergence/diffluence associated with this
feature should persist over the northeastern Caribbean. This will
therefore maintain unstable conditions which in combination with
ample trade wind moisture transport and local effects, will
continue to enhance the development of showers/thunderstorms
across the regional waters and parts of the islands each day at
least through Thursday. The activity on Wednesday and Thursday
should however be less widespread as lesser moisture pooling is
expected due to somewhat drier air filtering from the east along
with a fine to moderate concentration of Saharan dust.

.LONG TERM...FRIDAY THROUGH WEDNESDAY...

The aforementioned mid to upper level trough/TUTT low...which is
now located north of Hispaniola...will move eastward while
weakening with its associated axis crossing the local islands on
Friday. As this feature weakens Sat-Sun, a weak mid level ridge
pattern is expected to slowly build across Caribbean. At lower
levels, a tropical wave will reach the eastern Caribbean on
Sunday, bringing once again plenty of tropical moisture to the
forecast area. After the wave passage, a broad surface high
pressure across the central Atlantic will promote east southeast
winds Monday through much of the next work week.

Therefore, if the long term forecast holds, expect a seasonal
weather pattern Friday and Saturday with locally induced showers
and thunderstorms, followed by a wetter period on Sunday and early
Monday associated with a wave passage. Fair weather conditions
with warm to hot temperatures are expected next work week under
a mid level ridge pattern and east southeast winds.

&&

.AVIATION...SHRA/ISOLD TSRA across the local flying til at least 30/12z.
This will result brief MVFR en route btw islands with VCSH or SHRA
at TJSJ/TJNR/TNCM/TKPK. Aft 30/16z...SHRA/ISOLD TSRA psbl at and
vcty TJMZ/TJBQ. Also, psbl MVFR at TJSJ due to isold streamer-
like SHRA/TSRA from el Yunque area. Latest TJSJ sounding indicated
ESE winds below FL050 at 10-22 kts. Sfc wnds lgt/vrb bcmg E-NE
10-15 kts at most terminals except for local sea breeze
variations.

&&

.MARINE...Moisture associated with a departing tropical wave will
continue to result in periods of showers and thunderstorms today.
Seas are expected to remain at or below 6 feet and winds at 15-20
knots, particularly across the Caribbean waters. Mariners are
advice to exercise caution as winds and seas could be locally
higher in the vicinity of thunderstorms. There is a moderate risk
of rip currents across most of the local beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 79 86 79 / 40 20 40 40
STT 89 80 87 80 / 40 50 50 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
435 AM AST Wed May 31 2017

.SYNOPSIS...The proximity of a mid to upper level trough will
continue to enhance periods of showers and Tstorms, particularly
across the interior and west sections of Puerto Rico during the
afternoon hours Wed-Thu. A more seasonable weather pattern is
expected Fri-Sat with the next tropical wave passage on Sunday.

&&

.SHORT TERM...Wednesday through Friday...

Partly to mostly cloudy skies prevailed across the local islands
overnight. The Doppler Radar detected showers and thunderstorms
moving across the Caribbean Waters and Passages. Thunderstorm
activity persisted overnight, however stayed over the surrounding
waters. A few passing showers with periods of moderate to heavy
showers moved inland but were brief and just left minimal rainfall
accumulations. The overnight temperatures were in the mid 70s to
low 80s across the lower elevations and in the mid 60s to low 70s
across the higher elevations. Winds were east to northeast at 10
mph or less.

A mid to upper level trough will linger over the eastern Caribbean
through the end of the work week. This feature will combine with the
available moisture enhancing shower and thunder activity across the
local region. Therefore, the thunderstorm activity, which is now
affecting the surrounding waters and moving inland, is expected to
continue through the sunrise.

Trade wind showers will move at times across the windward sections
of PR and USVI through the morning and evening hours each day,
followed by organized convection across across Puerto Rico. Shower
and maybe t-storm also possible downwind from the USVI. Although
this pattern is expected through the rest of the work week, the
intensity and coverage of showers and thunderstorms should
diminish through Friday.

.LONG TERM...SATURDAY THROUGH THURSDAY...

As a weakening mid to upper level trough across the northeast
Caribbean moves away from the forecast area the upcoming weekend,
a ridge pattern aloft will build and hold much of the next week.
At lower levels, a tropical wave will reach the eastern Caribbean on
Sunday, bringing once again deep tropical moisture to the forecast
area through at least Monday. After the wave passage, a broad
surface high pressure across the central Atlantic will promote east
southeast winds much of the next work week.

Therefore, if the long term forecast holds, expect a seasonal weather
pattern Saturday with locally induced showers and thunderstorms,
followed by a wetter period on Sunday and Monday associated with
the wave passage. Fair weather conditions with warm to hot temperatures
are expected Tuesday through at least the end of the next work
week under a mid level ridge pattern and east southeast winds.

&&

.AVIATION...TSRA expected to continue mainly across the surrounding
waters til around sunrise. However, trade wind SHRA are possible at
times across the Leeward/USVI/E-PR thru the morning hours. SHRA/TSRA
are expected to increase in coverage/intensity btwn 31/16-23z across
interior/west PR and USVI surrounding waters. Resulting in mainly
MVFR or even IFR conds at TJBQ/TJMZ/TJSJ and possibly BKN CIGS btwn
FL030-FL080 at TJPS/TIST/TISX. E-ENE winds at 5-10 kts incr at 10-15
with higher gusts and with sea breeze variations aft 31/13z.

&&

.MARINE...Seas 3 to 5 feet and winds around 15 knots are expected
to prevail across most of the local waters...except for winds up
to 20 knots and seas near 6 feet over the Caribbean waters, and
the Anegada and Mona Passages. The potential for periods of
showers and thunderstorms continues, therefore mariners should
always exercise caution in the vicinity of thunderstorms as winds
and seas could be locally higher.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 76 86 76 / 40 40 40 30
STT 87 77 86 77 / 60 50 40 40

[TheStormExpert]

Not sure if this is the best place to put this but I will be going to the Bahamas with two friends from June 7th-13th(The Abacos to be precise). I've noticed the GFS and Euro both show lower pressures throughout the area during that timeframe along with the GFS showing a good deal off cloud cover and precipitation. I was just curious on what your opinions might be in terms of how the weather might be during that timeframe.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
310 PM AST Wed May 31 2017

.SYNOPSIS...A mid to upper level trough continues to extend from
the north-central Atlantic southwest through Hispaniola and into
central Caribbean. Mid/upper level low embedded within the trough
just north of Hispaniola/Puerto Rico area with strong upper level
divergent flow across eastern Caribbean. At the lower
levels...Atlantic ridge centered near Bermuda yielding moderate
to fresh easterly trades across the eastern Caribbean.


&&

.SHORT TERM...Tonight through Friday Night...Upper trough/low
axis should remain west of PR/U.S. Virgin Islands region at least
through Thursday keeping the local area under a divergent flow
aloft and unstable conditions. The effect of this trough/low
across the area will greatly depend on several factors, i.e.
available moisture, convergent breezes, diurnal heating, orography
and the instability caused by the upper features. The combination
of these factors could definitely be enough to continue with
active weather conditions through this evening and tonight. Will
expect scattered to numerous afternoon showers/isolated
thunderstorms most areas of PR again through this evening with
the focus of precipitation shifting over eastern areas and U.S.
Virgin Islands overnight. Models indicate that the axis of the
trough/low should move slightly east by Thursday while at the same
time showing a slight drying. Based on this decided to keep lower
chances for rain thursday. However...moisture could return to the
local area thursday night and Friday and the trough axis could be
still close enough to induce the development of
showers/thunderstorms across the USVI and eastern PR thursday
night and Friday.

.LONG TERM...Saturday through Thursday...The mid/upper level
trough is expected to lift northeast. However...believe moisture
content will be high enough and combined with upper level
dynamics could support the development of afternoon convection
across western/interior PR and nighttime and early morning showers
over the U.S. Virgin Islands and eastern PR at least through the
upcoming weekend. Another tropical wave could approach the region
Saturday/Sunday. long range models continue to indicate that the
most active part of this wave should remain well south. However it
could result in additional moisture being advected to the
local area resulting in a chance of showers/thunderstorms through
at least the beginning part of next week. An upper level ridge is
expected to build across the Caribbean by the beginning of next
week. Models also indicate a drier air mass moving into the
caribbean from the east. This...combined with strong subsidence at
the mid/upper level should limit the convective activity over the
local area.


&&

.AVIATION...SHRA/TSRA are expected to continue btwn 31/16-23z
across most of PR and surrounding waters. Resulting in mainly
MVFR or even IFR conds at TJBQ/TJMZ/TJSJ and possibly BKN CIGS
btwn FL030-FL080 at TJPS. E-ENE winds at 10-15 with higher gusts
and with sea breeze variations aft 31/23z.


&&

.MARINE...Showers and thunderstorms across the adjacent waters of
PR...especially over the Mona Passage...should continue to move
west as they slowly dissipate by this evening. Seas are expected
to remain at or below 6 feet and winds at 15 knots or less most
areas...except 15 to 20 knots over the Caribbean and Mona
Passages waters. Mariners should always exercise caution in the
vicinity of thunderstorms as winds and seas could be locally
higher.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 86 76 87 / 40 40 30 40
STT 77 86 77 85 / 50 30 40 40

[cycloneye]

Area Forecast Discussion...DELAYED
National Weather Service San Juan PR
520 AM AST Thu Jun 1 2017

.SYNOPSIS...A mid to upper level trough will continue to prevail
across the forecast area through at least Friday, weakening during
the upcoming weekend. The next tropical wave passage is expected on
Sunday. A dry and stable air mass will prevail across the forecast
area the next week.

&&

.SHORT TERM...Thursday through Saturday...

Today, June 1st 2017, Atlantic Hurricane Season begins. 2017
Hurricane Season runs from June 1st to November 30th. During the
Hurricane Season, make a well-informed decision "BE PREPARED".

Showers slowly diminished across the local islands overnight.
Shower activity should continue to decrease in intensity and
coverage through the morning hours, as a drier air mass makes its
ways from the east into the local islands. Although a mid to upper
level trough is over the region, this dry slot is forecast to
limit afternoon convection over PR to the western sections of the
island. So the eastern half of the island as well as the USVI
should have only isolated to scattered showers.

A surge of moisture is expected to reach the islands tonight into
Friday, increasing the coverage and intensity of showers and
thunderstorms. By Saturday, the islands will be in the convergence
area of the left entrance of the mid-upper level trough. This will
limit the potential for showers and thunderstorms on Saturday.

.LONG TERM...SUNDAY THROUGH FRIDAY...

As a tropical wave moves across the eastern Caribbean but mainly
south of the area on Sunday; precipitable water is expected to
increase with values near or above the normal range which is 1.75
inches. However, moisture is expected to quickly erode as soon as
late Monday as a mid to upper level ridge builds across the forecast
area and hold much of the next week. At lower levels, a surface high
pressure across the central Atlantic will yield an east southeast
wind flow Sunday through at least Thursday.

As a result, if the forecast holds, the best chance for shower and
thunder activity is Sunday and Monday with passing showers across
the USVI and E PR during the morning hours followed by showers and
thunderstorms developing across west sections of Puerto Rico in the
afternoon. A fair weather pattern with warm to hot temperatures and
hazy skies is expected Tuesday and onwards.

&&

.AVIATION...VFR conds expected across the local terminals with VCSH
possible at USVI terminals as well as TJSJ and TJBQ. SHRA/TSRA
possible after 01/17Z across western PR which could affect TJMZ.
Winds will be mainly from the east at 5-10KT increasing aft 01/13z
at 10-15 kt with gusts up to 25 kts and sea breeze variations
along the coastal sections.

&&

.MARINE...Seas 3 to 5 feet and winds 15-20 knots are expected to
prevail across most of the local waters...except seas near 6 feet
over the Atlantic waters later today. Small boat operators should
exercise caution. There is moderate risk of rip currents across
most of the local beaches, increasing to high tomorrow night
across the north facing beaches of Puerto Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 78 87 78 / 30 40 40 20
STT 90 79 86 79 / 30 30 30 20