Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
420 AM AST Sat Feb 1 2020

.SYNOPSIS...Fair weather conditions are expected to prevail across
the area throughout the weekend as a drier air mass moves
overhead. However, some locally induced showers are still possible
across interior Puerto Rico during the afternoon hours. Surface
high pressure is expected to move across the western and central
Atlantic during most of next week. This will push the remnants of
a frontal boundary over the area, increasing somewhat the shower
activity. In addition, as the local pressure gradient tightens,
the winds are also expected to increase.

&&

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

Mid/upper-level ridge will promote a trade wind cap and dry air
aloft. Satellite images detect at the surface, a dry air mass moving
and approaching the northeast Caribbean. That said, fair weather
conditions will prevail through the weekend, with a mixture of
sunshine and clouds. At times, quick passing showers will move
over the eastern half portion of Puerto Rico and the U.S. Virgin
Islands. The western and interior sections can expect some showers
due to local effects during the afternoon hours. This weather
pattern will prevail today and Sunday.

A surface low and its associated frontal boundary, which is moving
across the western Atlantic, will approach the islands from the
northwest by Monday. This front is forecast to induce a pre-frontal
trough near the region. At the same time, an upper-level short wave
trough will increase somewhat local instability aloft. If models are
right, these features will increase the potential for the
development of some isolated thunderstorms near the islands by
early next week.

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

A ridge aloft is expected to prevail over the area throughout the
period. This will prevent any organized convective activity from
materializing. Therefore, thunderstorms are not expected. At
lower levels, a broad surface high pressure is expected to move
across the western Atlantic on Tuesday and Wednesday. This will
push the remnants of a frontal boundary across the area,
increasing the low-level moisture. Thus, an increase shower
activity is expected. Showers are expected across the eastern half
of Puerto Rico and the USVI during the overnight and morning
hours followed by additional development across western and
southwestern Puerto Rico during the afternoon hours due to diurnal
heating and local effects.

As the aformentioned surface high pressure moves across the
central Atlantic during the middle to latter half of the week and
strengthens, the local pressure gradient is expected to tighten
somewhat. Therefore, an increase in the winds is expected. This
will also push patches of low-level moisture into the region with
passing shower activity expected across portions of the area from
time to time.

&&

.AVIATION...VFR conds expected through the forecast period. VCSH
possible at the eastern terminals of PR/USVI and the Leeward islands
at times. However, this activity, if any, will be brief. SHRA will
develop across the mountain areas and near JBQ/JMZ between 01/16-
02/00z. SHRA could also stream off the USVI, causing VCSH. Winds
will be calm to light and VRB, returning from the E-ESE at around 10
kts with sea breeze variations after 01/12Z.

&&

.MARINE...Fairly tranquil seas of up to 5 feet will prevail across
the regional waters throughout the weekend. A northerly swell is
expected to move across the Atlantic waters and local passages
Monday night into Tuesday, causing seas to become choppy. A
moderate risk of rip currents is expected for the northern beaches
of Puerto Rico, Culebra, and Botany Beach in Saint Thomas as well
as for some of the beaches across southwest Puerto Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 87 75 86 / 30 20 30 20
STT 74 84 72 84 / 20 20 30 10

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
410 AM AST Sun Feb 2 2020

.SYNOPSIS...Mainly fair weather conditions are expected today as a
drier than normal air mass prevails over the area. A frontal
boundary will approach from the northwest, before stalling just
north of the region during the start of the work week. A broad
surface high pressure will move across the Atlantic basin during
most of the upcoming week. This will cause winds to increase as
well as push the remnants of the frontal boundary towards the area
with increasing shower activity expected during the middle to
latter half of the work week.

&&

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

A ridge pattern aloft, promoting stable atmospheric conditions, and
a dry air mass at the surface will result in the typical tropical
conditions with periods of sunshine interrupted by the arrival of
patches of clouds from time to time. A trough with an associated
frontal boundary will shift the winds from the south increasing
daytime maximum temperatures across the northern section.
Temperatures will range in the mid and upper 80s across coastal
sections. The weather pattern will change as this boundary
approaches the islands from the northwest and stalls off to the
north of the forecast area late tonight into Monday. This feature
will increase somewhat local instability, thus the potential for
inducing isolated thunderstorms across the interior and western
sections of Puerto Rico on Monday afternoon. The limiting factor for
the convection will be the lack of moisture across the region.

A migratory surface high pressure moving westward across the
Atlantic Ocean will keep the remnants and associated moisture of
the aforementioned frontal boundary close to the region on Tuesday.
A mid/upper-level high pressure building aloft will limit the
vertical development of the clouds and showers.


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

The ridge aloft will remain in place through most of the period.
This will prevent any deep convective activity from materializing.
At lower-levels, a strengthening surface high pressure will move
across the central Atlantic. This will push the remnants of a
frontal boundary towards the area for Wednesday and Thursday.
Therefore, scattered shower activity can be expected across the
region. With the low-level flow becoming east-southeast,
scattered showers can be expected across portions of the USVI and
across eastern and southeastern Puerto Rico during the overnight
and morning hours followed by additional activity across western
and northwestern Puerto Rico during the afternoon hours due to
diurnal heating and local effects. In addition to an increase in
shower activity, winds are expected to increase as the local
pressure gradient from the strengthening surface high pressure
tightens.

As the surface high pressure continues to hold in strength over
the central Atlantic Friday and through next weekend, brisk
easterly trade winds will continue. This will drive patches of
low-level moisture into the area from time to time, resulting in
passing shower activity.

&&

.AVIATION...VFR conds expected through the forecast period.
Passing SHRA should not be ruled out at TJSJ/TIST/TNCM/TKPK. VCSH
possible after 02/18Z as SHRA develops across the interior, as well
as downwind from the USVI. Winds will be calm to light and VRB,
becoming from the S-SE at around 10kt with occasional higher gusts,
with sea breeze variations after 02/13z.

&&

.MARINE...Fairly tranquil marine conditions will prevail today
through Monday afternoon with seas up to 5 feet expected. By
Monday night into Tuesday, a northerly swell is forecast to
affect the Atlantic waters and local passages with seas increasing
up to 6 feet. However, across the northwestern portion of the
outer Atlantic waters, seas may briefly reach 7 feet. As winds
increase by the latter half of the work week, seas are expected
to become hazardous and therefore, small craft advisories are
likely.

For beachgoers, there is a moderate risk of rip currents for the
northern beaches of Puerto Rico, Culebra, Vieques, and Saint
Thomas as well as for Cramer Park beach in Saint Croix. Elsewhere,
the rip current risk will be low.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 74 86 74 / 30 30 20 30
STT 81 74 84 74 / 10 10 30 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
435 AM AST Mon Feb 3 2020

.SYNOPSIS...
A relative dry air mass will settle over the region today. A cold
front will approaches from the northwest and stalls off to the
north of the islands across the Atlantic Waters. A pre-frontal
trough combined with local effects will aid in the development of
showers across the mountains and southwest quadrant of Puerto Rico
this afternoon. Surface high pressure will move westward across
the Atlantic Ocean throughout this week.

&&

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

A cold front located just north of the Dominican Republic will
continue to slowly inch southeastward throughout the day today
before stalling just northwest of the region. This feature is
expected to induce a prefrontal trough, which will move over the
forecast area today. At upper-levels, a mid to upper-level shortwave
trough is also expected to move over the area. These features will
help induce more shower activity this afternoon, mainly across
interior and southwestern Puerto Rico. However, the main limiting
factor for any significant rainfall activity is very dry air above
750 mb that is currently overhead and is expected to remain in place
today. Therefore, even though more showers are expected this
afternoon compared to previous afternoons, the amount of dry air
present will limit the duration as well as the intensity.

As the mid to upper-level shortwave trough pulls away, a mid to
upper-level ridge will establish over the area by Tuesday.
This feature along with below normal moisture, will produce mainly
fair weather conditions across the area with just limited shower
activity expected, mainly across western Puerto Rico during the
afternoon hours.

On Wednesday, a broad surface high pressure will be building over
the western and central Atlantic basin. This feature will push low-
level moisture, associated with the remnants of the aforementioned
cold front, over the area. Therefore, an increase in shower
activity can be expected over the area. Scattered showers can be
expected across the USVI and eastern Puerto Rico during the morning
hours followed by the development of additional showers across
western Puerto Rico during the afternoon hours as a result of
diurnal heating and local effects.

.LONG TERM...Thursday through Monday...
The aforementioned mid- to upper-level ridge will remain in place
through most of the long term period. A TUTT-low forecasted to
amplify over the Central Atlantic will squeeze the ridge pattern
during the weekend. However, it is not until Monday, when the
ridge is forecasted to erodes. That said, deep convection is not
expected to affect the region through this period. On the other
hand, a surface high pressure moving across the central Atlantic
will push patches of moisture with clouds and showers across the
region each day. In the meantime, this high-pressure will tight
the local pressure gradient increasing winds across the northeast
Caribbean.

&&

.AVIATION...
Mainly VFR conds expected through the forecast period. Sct SHRA
expected to develop across interior and SW-PR between 03/16z and
03/22z, affecting the vicinity of TJPS and TJMZ. Light and
variable winds expected throughout the period with sea breeze
variations developing after 03/14z.

&&

.MARINE...
Tranquil marine conditions will persist through late this
afternoon. Mariners can expect seas up to 4 feet and winds at 10
knots or less. However, the combination of a small northerly swell
and increasing winds will create choppy seas this evening into
Tuesday. Surface high pressure forecasted to move westward across
the Atlantic Ocean will increase winds and seas across the region
after mid-week. Stay tuned to follow the evolution of the marine
conditions.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 74 85 75 / 10 20 20 40
STT 84 74 84 75 / 20 20 20 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
517 AM AST Tue Feb 4 2020

.SYNOPSIS...

A frontal boundary off to the north of the islands will bring a
slight increase in moisture today. This boundary will stalls and
weaken just north of the region, while a surface high pressure
moves westward across the Central Atlantic Ocean. This high
pressure will push additional moisture and will increase seas and
winds through the rest of the week. Model guidance are suggesting
unstable weather conditions may develop by the first part of next
week.

&&

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

A decaying cold front is currently located just north of the area.
This has sparked scattered showers over the Atlantic waters, moving
in a northeast to southwest fashion. Some of these showers may
briefly affect the northern coast of Puerto Rico through the morning
hours. Mainly fair weather conditions are expected across most of
the area as the combination of below normal moisture and a ridge
aloft will act to limit shower activity once again for today. Some
showers may still manage to develop across western Puerto Rico
during the afternoon hours due to diurnal heating and local effects.

The ridge aloft will continue to hold through the rest of the work
week, limiting any organized convective activity. Meanwhile, at
lower levels, a broad surface high pressure will be moving across
the western and central Atlantic while also strengthening. This
will result in a tightening of the pressure gradient and
therefore, brisk easterly trade winds can be expected across the
area for both Wednesday and Thursday. The surface high pressure
will also serve to push the low-level moisture associated with the
remnants of the aformentioned cold front over the area. As a
result, an increase in trade wind shower activity can be expected
for both Wednesday and Thursday. Given the relatively fast low-
level flow expected, these showers are expected to be fast-moving
and thus brief, with only minor accumulations expected. As it is
usually the case with this type of pattern, most of the shower
activity will be concentrated across the eastern half of Puerto
Rico and the USVI. However, some showers will be possible across
western Puerto Rico during the afternoon hours as a result of
diurnal and local effects.

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

The aforementioned mid- to upper-level ridge will remain in place,
however, a TUTT-low forecasted to amplify over the Central
Atlantic will weaken it during the weekend. Although deep
convection is not expected to affect the region, the available
moisture will bring periods of rain from time to time across the
windward sections of PR/USVI, making its way into the interior
and western sections of PR during the afternoon.

The eroding ridge will make its way for unstable weather
conditions early next week. Model guidance is suggesting the
development of unstable weather conditions after Sunday. At mid-
and upper-upper levels, 500mb temperatures and 250mb heights may
drop suddenly after Sunday. In addition, mid-level humidity, as
well as low-level and mid-level instability, may increase. That
said, and if models are correct, the potential for the development
of organized convection across the region will increase during
that time.

&&

.AVIATION...

Mainly VFR conds are expected through the forecast period. Sct
SHRA across the Atlantic waters may briefly affect the NW coast of
PR through 04/14z, affecting the vicinity of TJBQ. Sct SHRA
possible across western PR between 04/17Z and 04/22z, affecting
mainly the vicinity of TJMZ. No significant impacts to operations
expected with these SHRA. Winds light and variable through 04/12z,
increasing to 10-15 kts with higher gusts from the ENE-E after
04/14z with sea breeze variations.

&&

.MARINE...

41043 detected a northerly swell moving across the Atlantic
Offshore Waters and will moves into the local Offshore waters
from this morning through this evening. Mariners can expect seas
between 5 and 7 feet with occasional seas up to 9 feet. Therefore,
a Small Craft Advisory is in effect for the Atlantic Offshore
Waters of Puerto Rico and USVI from 10 NM to 19.5N. Elsewhere
mariners should exercise caution due to seas up to 6 feet. Winds
will continue from the east at 15 knots or less.

A surface high pressure moving westward across the Atlantic Ocean
will increase winds and seas after Wednesday night creating
hazardous marine conditions the rest of the forecast period. Stay
tuned and track the marine forecast.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 76 85 73 / 20 40 40 40
STT 84 74 84 74 / 20 30 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
518 AM AST Wed Feb 5 2020

.SYNOPSIS...

A strong surface-high-pressure will promote a moist trade wind
flow across the islands today. This high will strengthen over the
Atlantic Ocean increasing winds and the transport of surface
moisture. Besides, this surface high will deteriorate the marine
and coastal conditions from Thursday and continuing through the
weekend. Model guidance are suggesting inclement weather conditions
may develop by the first part of next week.

&&

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

A broad surface high pressure across the Atlantic basin will promote
a brisk easterly trade wind flow today, becoming more east-southeast
Thursday and Friday. This brisk trade wind flow will carry patches
of low-level moisture from time to time across the area during the
short-term period. Therefore, expect a mixture of sun and clouds
with periods of passing showers. As it is usually the case under
this type of weather pattern, most of the passing shower activity
will be concentrated mainly across portions of eastern Puerto Rico
and the USVI, however, additional showers are still expected across
western Puerto Rico during the afternoon hours as a result of
diurnal heating and local effects. Given the fast low-level flow and
the scattered nature of the showers, rainfall activity will be brief
with just minor accumulations expected. Therefore, some minor
ponding of water on roadways and in poor-drainage areas will be the
main hazard. Sustained winds between 15 and 20 mph with higher gusts
are expected today. Winds in excess of 20 mph with gusts in excess
of 30 mph are possible for both Thursday and Friday, as the pressure
gradient from the surface higher pressure tightens even more.

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

The mid- to upper- level ridge that are being dominating the
local weather conditions will erodes through the weekend. The
aforementioned surface high pressure will promote an advective
pattern with periods of rain from time to time across the windward
sections of PR/USVI, making its way into the interior and western
sections of PR during the afternoon.

GFS and ECMWF agreed to suggest and unstable weather pattern by
the first part of next week. Both guidance has been suggesting a
sharp drop of the 250mb heights and 500mb temperatures after
Sunday. Also are indicating an increasing trend on the mid-level
humidity, as well as low-level and mid-level instability. If
models are correct, the development of deep convection across the
region will be possible Monday through Wednesday.


&&

.AVIATION...

Mainly VFR conditions expected through the period. Iso-Sct SHRA
expected over local waters and in route between the islands at
times, resulting in VCSH across TJSJ/TIST/TISX/TNCM/TKPK. Sct
SHRA expected across western PR between 05/17 and 05/22z,
affecting the VCSH of TJBQ and TJMZ. Winds light and variable
through 05/12z, increasing to between 12 and 18 kts with higher
gusts and sea breeze variations after 05/14z.

&&

.MARINE...
A small northerly swell will fade across the islands through the
morning hours. Mariners can expect winds between 10 and 20 knots
and seas at 4 to 6 feet across most of the local waters.
Therefore, small craft operators should exercise caution.

Seas and winds will increase by Thursday afternoon and continuing
through the weekend in response to a strong surface high pressure
over the Atlantic Waters. As a result, a Small Craft Advisory is
in effect from Thursday afternoon through Friday for the Atlantic
Offshore waters of Puerto Rico and the U.S. Virgin Islands, the
northern coastal waters of Puerto Rico and the Mona Passage. As
winds and seas increase hazardous marine conditions will spread
across the rest of the local waters through the weekend. These
hazardous conditions will required the extension and expansion to
the weekend and other areas of the advisory later today. Stay
tuned and monitor the local marine products [Coastal Water
Forecast (CFWSJU) and Marine Weather Message (MWWSJU)] for more
details.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 86 74 / 50 40 40 40
STT 84 74 85 75 / 40 30 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
535 AM AST Thu Feb 6 2020

.SYNOPSIS...Moderate to fresh easterly trade winds will continue
as surface high pressure holds over the region for the next few
days. This will result in hazardous marine conditions at least
through the weekend. A more active weather pattern is expected for
the first part of the workweek due to an increase in moisture and
instability aloft.


&&

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

Variably cloudy skies prevailed across the local islands overnight
with frequent passing showers observed across the east coastal areas
of Puerto Rico as well as the outlying islands. Rainfall
accumulations associated with these showers, however, were minimal.
Winds were from the east at 10 MPH or less with coastal temperatures
in the mid 70s.

A mid to upper level ridge will hold across the forecast area
through at least the end of the workweek. This feature is expected
to weaken Saturday onwards as a TUTT establishes east of the local
area. At lower levels, a high pressure across the central Atlantic
will continue to yield moderate to fresh east southeast winds. The
aforementioned east southeast wind flow will continue to bring
patches of low level moisture across the local islands which are
associated with remnants of old frontal boundaries. The latest
guidance suggested that available moisture will remain confined
below 850 MB.

As a result, due to the lack of upper level dynamics and low level
moisture near or slightly below the normal range, the chance for
passing showers across the east coastal sections of Puerto Rico as
well as the outlying islands continues today through Saturday.
Locally induced afternoon showers cant be ruled out. The chance for
shower activity will increase Saturday onwards as the ridge aloft
collapses.

.LONG TERM...Sunday through Thursday

GFS model suggests a slight increase in moisture starting Sunday
into the beggining of the workeek. This will enhance shower
activity over the region. However, no significat rainfall
accumulation is expected with this activity. This is due to the
fact that moderate to fresh easterly wind will prevail over land
and thus generating showers of a fast-paced nature. The surface
high pressure will aid in the advetive weather pattern that leads
to period of fast-moving showers from time to time across eastern
sectors of PR and USVI during the morning hours. Then, showers
will tend to focus over the interior and western sectors of the
islnads due to diurnal and local effects.

By mid-week, model guidance suggest better dynamics at the mid to
upper levels. Also, 500mb temperature is suggested to drop to -7
K. This will increase instability and moisture aloft, thus
promoting a favorable environment for the development of
thunderstroms mainly over the local Atlantic waters. Isolated
thunderstorm activity is also possible over the interior and
western PR during the afternoon hours.



&&

.AVIATION...VFR conds will continue to prevail with VCSH possible in
and around the Leeward and USVI TAF sites as well as JSJ in the
morning hours. Aft 06/16z brief period of MVFR conds will remain
possible at JBQ in SHRA. ESE winds at around 15 knots with sea
breeze variations and higher gusts are expected today.


&&

.MARINE...A moderate to locally fresh easterly wind flow will hold across the
local waters. A strong surface high pressure will increase winds and
seas, creating hazardous marine conditions today and continuing
through the weekend. As resutl, small craft advisories will go in
effect starting this morning through Saturday for the off shore
Atlantic waters and the Mona Passage. Moderate risk of rip current
is expected to continue, at least until Saturday, for most of the
local beahes.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 75 86 74 / 40 40 40 70
STT 86 76 85 74 / 50 40 50 70

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
457 AM AST Fri Feb 7 2020

.SYNOPSIS...A surface high pressure across the central
Atlantic will continue to promote fresh to locally strong east
southeast winds. Therefore, brief and frequent passing showers
are expected across the region for the forecast period. An upper-
level trough will support mid to upper level instability and
moisture aloft to enhance and increase shower activity with
possible isolated thunderstorm during the afternoons by mid- week.
Wind-driven seas will continue to generate hazardous marine
conditions through the weekend.



&&

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

Mostly clear skies prevailed across the local islands overnight with
isolated shower activity focused over the local waters. Winds were
from the east at 10 MPH or less with coastal temperatures in the mid
70s.

The short term forecast is still on track. The ridge pattern aloft
will continue to weaken as a TUTT establishes east of the forecast
area. At lower levels, a surface high pressure across the central
Atlantic will continue to yield a fresh to locally strong east
southeast winds. The aforementioned east southeast wind flow will
continue to bring patches of low-level moisture across the forecast
area, particularly throughout the day today. This will continue to
result in passing showers across the east and southeast coastal
areas of Puerto Rico as well as the outlying islands. These showers,
however, will be brief and therefore minor rainfall accumulations
are expected. Latest guidance suggested somewhat drier conditions on
Saturday with PWAT values dropping to near one inch which is well
below the normal range for the month of February. The chance for
shower activity will increase once again on Sunday as the TUTT moves
closer to the forecast area enhancing trade wind shower activity and
the prevailing wind flow shifts east northeast.

.LONG TERM...Monday through Friday

GFS model continues suggesting a slight increase in low-level
moisture on Sunday into the beginning of the next workweek. This,
combined with the deepening of an upper low and associated trough
just east of the northern Leeward Islands, will enhance shower
activity over the region, at least through Tuesday. No significant
rainfall accumulation for this activity is anticipated over land.
This is mainly due to the fact that moderate to strong easterly
winds will prevail, resulting in the generation of fast-moving
low-level clouds and more frequent periods of embedded trade wind
showers. This advective weather pattern is expected to continue
into early next week as the strong Atlantic surface high pressure,
together with the upper-level trough east of the region will
continue to enhance and maintain available moisture. The periods
of fast-moving showers can be expected across the coastal waters
and eastern sectors of Puerto Rico and the U.S. Virgin Islands
during the morning hours. This will be followed by locally
induced afternoon showers, which should be focused over the
interior and western sectors of the islands.

Starting mid-week through Friday, better mid to upper level
moisture and instability, although less with slightly less
intensity, continues to be suggested by the model guidance. The
500 millibar temperatures are expected to drop to -8 degrees C or
even lower across the region by then, which indicates increased
instability aloft. In addition, sufficient moisture advection is
expected to continue across the region, also promoting a favorable
environment and better potential for the possible development of
isolated thunderstorms mainly across interior and western PR and
St. Thomas during the afternoon hours.


&&

.AVIATION...Mostly VFR conds will continue to prevail with VCSH/-RA
possible in and around the Leeward and USVI TAF sites as well as JSJ
through the morning hours. Aft 07/16z isolated shower activity is
expected in and around JBQ/JMZ through about 07/23z. ESE winds at
around 15 knots with sea breeze variations and higher gusts to
continue.


&&

.MARINE... Moderate to strong easterly winds are expected to
continue for the rest of the forecast period due to the strong
surface high pressure across the central Atlantic. Therefore, a
wind-driven seas event will prevail through the weekend. Seas
continue between 5 to 7 with winds up to 20 knots with higher
gusts. Small craft advisories are in effect for the off shore
local waters and passages. There is a high risk of rip currents
for Saint Croix and northwestern Puerto Rico through Sunday
morning.



&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 75 85 75 / 40 20 20 70
STT 86 75 85 75 / 50 30 20 70

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
543 AM AST Sat Feb 8 2020

.SYNOPSIS...Drier air is expected to move in, but an increase in
moisture is expected on Sunday. A strong surface high pressure
over the Atlantic will cause easterly winds between 15-20 mph with
occasional gusts today. Mainly fair weather is expected today but
scattered to locally numerous showers are expected on Sunday as
moisture increases. A surface high pressure will prevail over the
Atlantic for the next several days. Upper level ridge will also
dominate over the next several days, except on Tuesday night into
Wednesday when an upper trough could briefly affect the local
islands, causing an increase in shower activity.


&&

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

Satellite imagery shows a small area of a drier air mass
approaching the forecast area. This will promote mainly fair
weather conditions with moments of brief passing showers during
the morning hours. Locally induced afternoon showers, although
limited, are possible across western and interior PR, as well
across the San Juan metropolitan area. Model guidance continues
to suggest an increase in low level moisture that will enhance
shower activity over the region on Sunday into Monday. Therefore,
trade wind showers are expected. Shower activity is also expected
in the afternoons due to the local and diurnal effects over
portions of western PR and the San Juan metropolitan area, while
portions of St. Thomas could observe showers as they stream off.

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

Surface high pressure across the Atlantic will prevail through the
long term period, causing mainly easterly winds across the local
area. The available moisture will be near normal with precipitable
water values near 1.2 to 1.4 inches. Therefore, the main
contributor to rainfall across the local area will be tradewind
showers for the USVI and eastern PR, then locally induced showers
in the afternoon across western PR. That said, there is an
inverted trough in the upper levels that could approach the local
area on Tuesday night into Wednesday. This trough could help in
the development of showers, some of them moderate to heavy,
across eastern PR and the USVI from Tuesday night into Wednesday.
Otherwise, there is no significant feature that would produce
significant rainfall in the long term.

&&

.AVIATION...Mainly VFR conditions are expected through the forecast
period across all terminals. VCSH are expected across the area from
09/22Z. Winds remain strong, blowing from ESE at 15-20 knots with
stronger gusts.


&&

.MARINE...Small craft advisories are in effect for most of the
local waters. Winds will be from the east at 15-25 knots and seas
will be up to 8 feet. There is also a high risk of rip currents
across some of the local beaches of PR and in Saint Croix today.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 73 84 73 / 30 50 70 40
STT 85 74 84 74 / 30 50 70 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
531 AM AST Sun Feb 9 2020

.SYNOPSIS...An increase in moisture is expected today across the
local area. A strong surface high pressure over the Atlantic will
continue to cause easterly winds between 15-20 mph with
occasional gusts. Scattered to locally numerous showers are
expected today as the deeper moisture moves in. The surface high
pressure will prevail over the Atlantic for the next several days,
keeping a moderate to strong easterly wind flow. Upper level
ridge will also dominate over the next several days, except on
Tuesday night into Wednesday when an upper trough could briefly
affect the local islands, causing an increase in shower activity
and possibly even causing isolated thunderstorms as the trough
also coincides with colder than normal mid-level temperatures.

&&

.SHORT TERM...Today through Tuesday

A strong surface high pressure over the western Atlantic will
maintain strong trade winds over the eastern Caribbean trough the
forecast period. Winds will be ranging between 15 to 20 mph, with
occasional gusts. An area of moisture, will reach the forecast
area this morning, resulting in an increase of shower activity.
However, since winds are expected to remain strong, the showers
will move quickly. Locally induced afternoon showers could
develop across western Puerto Rico due to the available moisture.
The expected rainfall accumulations could cause ponding of water
on roadways and poor drainage areas. A similar weather pattern is
expected for the rest of the forecast period, although with less
moisture available on Tuesday. Nonetheless, rain activity is
expected over portions of eastern PR and USVI during the morning
hours. Then, areas of clouds and showers carried by the trade
winds will combine with local and diurnal effects to generate
brief showers over portions of western and interior of Puerto
Rico. The USVI will have isolated to scattered shower activity.

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

Surface high pressure across the Atlantic will dominate the local
wind flow pattern through the long term period, causing mainly
moderate to locally strong easterly winds across the local area.
The latest guidance indicates that the available moisture will be
near normal with precipitable water values near 1.2 to 1.4 inches.
Therefore, the main contributor to rainfall across the local area
will be tradewind showers for the USVI and eastern PR, then
locally induced showers in the afternoon across western PR.
However, there is an inverted trough in the upper levels that
could approach the local area late Tuesday into Wednesday. This
trough, along with much colder than normal 500mb temperatures of
-11C, could help in the development of showers, some of them
moderate to heavy, across eastern PR and the USVI. Isolated
thunderstorms were added to the forecast due to the positioning
of the upper trough and the cold mid-level temperatures.
Otherwise, for the rest of the long term period, there is no
significant feature that would produce significant rainfall.


&&

.AVIATION...VFR conditions are expected through the forecast period
across the local terminals. Trade wind showers could cause VCSH
for TJBQ, TJSJ and TISX, possible brief moments of MVFR
at TIST due to SHRA passing by in the morning. Winds continue to
be from the east at around 15-20 kts with higher gusts until
09/22Z.

&&

.MARINE...Small craft advisories continue in effect for many of
the local waters. The local winds are expected to increase even
more across the Caribbean late on Monday, which could cause the
nearshore Caribbean waters and the waters of SW-PR to meet small
craft advisory criteria due to winds. Otherwise, many of the
local seas will be up to 7 or 8 feet today. There is also a high
risk of rip currents today across the beaches of northwestern
Puerto Rico and Cramer Park in Saint Croix.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 84 73 / 50 40 40 40
STT 85 74 83 72 / 30 40 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
519 AM AST Mon Feb 10 2020

.SYNOPSIS...

A potent surface high pressure anchored over the Atlantic waters
will promote a moderate to strong easterly wind flow across the
local waters. The easterly winds will push patches of moisture
over the area from time to time across Puerto Rico and adjacent
islands. Later today , a developing short-wave trough will
continue to move east across the Atlantic waters and weaken the
ridging over the area, and aid in the development of a TUTT low
over the Atlantic waters. The developing TUTT low/trough will
increase instability over the region, the combination of adequate
low- level moisture, as well as local and diurnal effects, could
lead to the development of isolated thunderstorms Tuesday through
Thursday.

&&

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

Strong surface high pressure anchored across the central and
Northeast atlantic, will continue to aid in transporting occasional
patches of moisture with embedded showers across the islands.
Short Wave trough moving across the west atlantic today will move
eastward and aid in eroding the ridge in place overhead, and at
the same time Help to amplify a tutt low and associated trough
which will sink Southwards across the region by tuesday and
wednesday. In the Meantime, the moderate to strong easterly trades
will bring Occasional surges of moisture across the forecast area
from time to Time, leading to periods of moderate to locally
heavy rainfall over The coastal waters, and also along parts of
the north and eastern Coastal areas of the islands during the
morning hours. Afternoon convection should be focused over the
central and west interior Sections of puerto rico, but so far
activity will continue to be Fast moving and of short duration,
with minimal rainfall Accumulations expected today. For the u.s.
Virgin islands, quick Passing morning showers will be followed by
mostly isolated Afternoon showers around the islands. However, the
afternoon rains Should be mainly downwind or just off the west
end of the islands. The remainder of the surrounding islands will
enjoy a mixture of sunshine and clouds with minimal shower
activity the rest of today.

Recent model guidance as well as present weather conditions and
analyses continued to suggest the arrival of the amplifying Tutt
over the region by Tuesday and Wednesday. This feature, combined
with colder mid level temperatures, will provide enough
instability aloft and low level moisture convergence to erode the
trade wind cap inversion. This in turn will better support the
formation of thunderstorms across the islands, especially across
the interior and higher elevations, where forcing will be better
enhanced. There is also potential some enhanced shower activity
and slight chance for isolated thunderstorms in and around the
U.S. Virgin Islands on Tuesday and Wednesday as well. Widespread
and significant rainfall accumulations are however not expected at
this, but minor urban and small stream flooding as well as
ponding of water on roadways and poor drainage areas will be
possible in isolated areas especially on Tuesday and Wednesday.

&&

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

The GFS and Euro continue to show a surface ridge of high pressure
over the Atlantic waters and the local forecast area through the
long-term period; the surface winds will promote an easterly wind
flow over the local waters and islands. A moderate to strong wind
flow will usher in patches of moisture periodically into Puerto
Rico and adjacent islands. Precipitable water values will range
from 1.3 to 1.5 inches during the period. Analysis of the GFS
cross-sections shows moisture trapped between the 1000 to 700 mb
level; this coincides with the GFS TJSJ Skew-T that keeps a drier
air mass in the mid to upper-levels of the atmosphere through most
of the long-term period.

Thursday and Friday, the GFS and EURO show a TUTT low/trough near
or slightly east of Puerto Rico. If the TUTT materializes, it
will increase upper-level instability over the region. The 10/00Z
GFS shows 500 MB temperatures ranging from -11 to -8 degrees
celsius. The colder mid-level temperatures, added upper-level
instability, adequate low-level moisture, as well as local and
diurnal effects could lead to the development of isolated
thunderstorms late in the week. At this time, isolated
thunderstorms were not add to the forecast; however, if the GFS
and EURO continue to show the TUTT low/trough and increasing
moisture over the area, thunderstorms will most likely be added to
the forecast.

During the weekend into early next week, guideline shows an
increase in moisture as a front move across the Atlantic waters
and weakens the surface to mid-level ridges over the area. The
weakening of the low to mid to upper ridge will allow moisture to
move underneath the ridges and across Puerto Rico and adjacent
islands.


&&

.AVIATION...

VFR conds durg prd at all terminals. However,
Isold-Sct SHRA en route btw PR and northern Leeward Islands with
SCT-BKN lyrs nr FL025...FL050...FL080. Brief MVFR conds and MTN TOP
OBSCR ovr E PR til 10/14z with VCSH at TKPK/TNCM/TIST/TISX/TJSJ/TJPS.
Sfc winds fm E 5-15 kt BCMG 15-20 kts aft 10/14z, with higher gusts
to near 30 Kts psbl durg prd.

&&

.MARINE...

A strong surface high pressure will promote moderate to strong
easterly wind flow across the local and regional waters today. As
a result a small craft advisories are are in effect for most of
the local waters except for the northern and southern near-shore
waters of Puerto Rico. Later this afternoon a small craft
advisory will be in effect for the northern near-shore waters of
Puerto Rico. Mariners can expect seas between 6 and 8 feet with
seas occasionally reaching 9 feet. Winds will be from the east
ranging from 15 to 20 kts with higher gusts. There is a high risk
of rip currents for the northwestern and central beaches of Puerto
Rico, as well as the northeastern beach of the U.S. Virgin
Islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 75 85 73 / 50 50 50 50
STT 85 75 85 73 / 50 30 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
510 AM AST Tue Feb 11 2020

.SYNOPSIS...
Fair weather conditions prevailed over Puerto Rico during the
overnight hours with some passing showers observed across the
local waters and portions of interior Puerto Rico. For tomorrow,
some passing showers can reach the eastern coast of Puerto Rico
and some sections of the U.S. Virgin Islands in the morning hours.
Then, in the afternoon hours scattered to numerous showers are
expected with some isolated thunderstorms over the western,
northwestern, interior, northeastern Puerto Rico, as well Culebra.


&&

...SHORT TERM...Tuesday through Thursday...

The dominant surface high pressure spread across the central and
northeastern Atlantic, will maintain its hold across the region.
This will promote moderate to strong trade winds across the forecast
area through Thursday. This pattern will aid in transporting
frequent patches of moisture with embedded showers across the
islands and regional waters. A short Wave trough now crossing the
west atlantic and moving north of the region today will continue to
erode the ridge aloft, and at the same time reinforce and amplify a
TUTT low and associated trough which will develop and sink
Southwards across the region today through Wednesday.

The fairly strong low level winds will continue to bring quick
surges of shallow moisture across the forecast area, resulting in
periods of moderate to locally heavy rainfall over portions of the
local waters, and along parts of the north and eastern coastal areas
of the islands especially during the early morning hours.
Thereafter, afternoon convection should will be focused mainly over
the central and west sections of Puerto Rico. Due to the strong
steering winds, expect afternoon showers to be fast moving and of
short duration. However due to the proximity of the short wave
trough and the increasing instability aloft, some of the afternoon
convection will be enhanced also aided by daytime heating and local
effects. Periods of moderate to locally heavy rains will be possible
but should be mainly over the west sections of Puerto rico. For the
U.S. Virgin Islands, quick passing morning showers in and around the
islands, will be followed by isolated afternoon convection with only
a slight chance of an isolated thunderstorms forming mainly downwind
of the islands or just offshore. The remainder of the surrounding
islands will enjoy a mostly sunny skies, but an isolated afternoon
shower cannot be ruled out today.

Model guidance suggests increasing instability aloft over the next
couple of days with continued shallow moisture advective pattern
through Wednesday. The increasing instability aloft due to the
amplification of the aforementioned Tutt low across the northeastern
Caribbean, along with good low level moisture transport and speed
convergence, should all support afternoon convection over parts of
the islands. However expect most of the afternoon shower development
to be in the west sections of Puerto Rico, as well as around San
Juan metro in the form of streamers due to the strong steering wind
flow. In addition, the proximity of the Tutt, combined with the
colder mid level temperatures, will provide good instability aloft
and support low level moisture convergence. This will provide a
better chance for enhanced afternoon convection. At this time, do
not anticipate widespread activity, as most of the convection will
be limited and isolated due to the fairly dry conditions aloft. The
formation of isolated thunderstorms in and around the islands will
however remain possible through Wednesday. Therefore, minor urban
and small stream flooding as well as ponding of water on roadways
and poor drainage areas will be possible in isolated areas.

Rapidly improving conditions is forecast for Thursday, as the ridge
will again reestablish and build aloft, leading to stable conditions
and the strengthening of the trade wind cap inversion resulting in
the erosion of low level moisture transport. Passing showers during
the early morning hours will remain possible but less frequent. Any
afternoon convection should be limited to mainly the west interior
sections of Puerto Rico. Mostly fair and sunny weather conditions
expected elsewhere including around the U.S.Virgin Islands on
Thursday.


.LONG TERM...Friday through Wednesday...
A surface high pressure located at western Atlantic will continue to
promote easterly winds across the local region through the long-
term period. The precipitable water values from the GFS guidance
suggest a dry air mass across the region and this can limited the
shower activity across the islands. However, afternoon convection
still possible due to some fragments of moisture embedded in the
trade winds and the local effects. Afternoon convection should be
focused over the central and west interior Sections of puerto
Rico. At mid and upper levels, a Tropical Upper Tropospheric
Trough (TUTT) is located at the east of Puerto Rico. This feature
at the upper levels can enhanced the instability over the region
and shower activity is possible in the afternoon hours across the
local islands for Thursday through Friday. If the model guidance
remain consistent, exist a chance for isolated thunderstorms in
the afternoon hours across Puerto Rico and the U.S. Virgin Islands
as well.

Recent model guidance present a building surface high pressure
located in the northwestern Atlantic and this will move across
the central Atlantic on Monday though at least Wednesday. This
feature will promote a easterly-southeasterly wind flow over the
region and will push some fragments of moisture from the
Caribbean. This moisture will enhanced the shower activity across
the local islands in the afternoon hours for these days.



&&

.AVIATION...
VFR conds to prevail for all TAF, except durg aftn vcty
TJBQ/TJMZ. Mtn Tops obscr ovr ctrl Mtn range and the wrn foothills
due to SHRA till 11/22Z, also vcty ern PR til 11/14Z. Sfc wnds fm
E 10 kts of less bcmg fm E-SE 15-20 kts with ocnl hir gusts along
coastal areas of PR til 11/23Z with sea breeze influences. Max
winds fm NW 60-70 kt btwn FL300-FL350.


&&

.MARINE...
A surface high pressure will continue to promote moderate
easterly wind flow across the regional waters. Therefore, hazardous
marine conditions will continue across the majority of the marine
zones, except across the coastal waters of southern and western
Puerto Rico. Mariners can expect seas up to 8 feet with occasional
seas up to 10 feet across the regional waters. Winds will be from
the east ranging from 15 to 21 kts with higher gusts. There is a
high risk of rip currents for the north-central beaches of Puerto
Rico, as well as the northeastern beach of St. Croix from this
evening.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 74 84 73 / 40 50 40 50
STT 84 74 84 73 / 50 40 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
534 AM AST Wed Feb 12 2020

.SYNOPSIS...
During the overnight hours, some passing showers were observed
across northeast and north sections of Puerto Rico and over the
local waters as well. Then shower activity are expected to
develop once again across western and interior Puerto Rico in the
afternoon hours. Given the upper-level conditions today exist a
slight chance for isolated thunderstorms with the heavy showers. A
strong surface high pressure over the Atlantic waters will
continue to promote a easterly wind flow across the local waters.
Therefore, hazardous marine conditions are expected for at least
Friday. As a result a small craft advisories and high risk of rip
current are in effect for most of the local waters.

&&

.SHORT TERM...Today through Friday...
The moderate to strong trade winds will persist though Friday and
will continue to transport frequent patches of low to mid level
moisture with embedded showers across portions of the islands and
regional waters during the rest of the morning hours. An amplifying
TUTT low and associated trough will continue to develop as it sinks
southwards across the region today.

Recent satellite imagery along with the doppler weather radar both
initialized fairly well with latest model guidance, which suggested
a surge of low to mid level moisture moving across the region today.
The showers associated with this moisture surge was being enhanced
as they moved westwards and brushed the north and east sections of
the islands. Periods of moderate to locally heavy rains were
experienced during the overnight and early morning. Estimated
rainfall amounts were between half and inch to an inch along the
north and east coastal areas of Puerto Rico.

For the rest of the day, expect a gradual break on cloud cover and
shower activity by late morning. During the afternoon, convection
should will be focused over the central interior and west sections
of Puerto Rico. Due to the persistent and strong steering flow,
expect afternoon showers to be fast moving and of short duration.
However, the instability aloft along with sufficient moisture
convergence should be enough to produce areas of enhanced shower
activity and possibly isolated thunderstorms over these areas.
Periods of moderate to locally heavy rains will remain possible
mainly over the west sections of Puerto Rico. For the U.S. Virgin
Islands, quick passing morning showers will be followed by isolated
afternoon convection forming mainly downwind of the islands or just
offshore.

By Thursday and through Friday a rapidly improving and drier trend
is expected, as the moisture transport diminishes, in response to an
upper level ridge building aloft, and a surface high pressure ridge
strengthening north of the region. This overall pattern should
promote stable conditions aloft as well as the strengthening of the
trade wind cap inversion by the end of the work week. However,
passing trade wind showers will remain possible during the early
morning hours but will be less frequent. Afternoon convection should
be limited to mainly the west interior sections of Puerto Rico.
Mostly fair and sunny weather conditions is expected elsewhere
including around the U.S.Virgin Islands on Thursday and Friday.


.LONG TERM...Saturday through Thursday...
A widespread strong surface high pressure will continue to generate
easterly wind flow across the local waters until Sunday when the
high pressure move to the east out of the Atlantic waters. For
Sunday, a southeasterly wind flow will carry low-level moisture
across the region. These moisture can enhanced the showers
activity in the morning hours over the north and eastern sections
of Puerto Rico. Then, by the afternoon hours the shower activity
can develop across western and interior Puerto Rico. At mid and
upper levels, the model guidance suggest the Tropical Upper
Tropospheric Trough (TUTT) is located well at the east of Puerto
Rico, but still the potential of instability over the region.

Early next week model guidance suggest another surface high pressure
over the north Atlantic. These high pressure will generate a
easterly wind flow and a increase in low-level moisture over the
local area. Therefore, scattered showers are expected across the
eastern Puerto Rico in the morning hours and across the interior and
western Puerto Rico in the afternoon hours.



&&

.AVIATION...
Prevailing VFR conds to prevail at all terminals but
brief MVFR expected with passing SHRA til 12/14Z. Mtn top obscr ovr
E pr due to passing low CIG and SHRA. Isold TSRA may develop btw
12/17-12/22z across the western PR but this activity will be short
lived. Wnds will continue fm E at 15-20 kt aft 12/14z with ocnl
higher gust at local terminals.



&&

.MARINE...
Hazardous marine conditions will continue across the regional waters
and local passages due to a easterly wind flow generate from a
surface high pressure over the Atlantic waters. Mariners can expect
seas up to 8 feet with occasional seas up to 10 feet across the
regional waters. Winds will be from the east ranging from 15 to 24
kts with higher gusts. There is a high risk of rip currents for the
north-central, northeastern beaches of Puerto Rico, as well as the
northeastern beach of St. Croix. These conditions are expected to
continue at least until Friday. Passing showers will affect the
local waters and passages and exist a slight chance of isolated
thunderstorms over the regional waters.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 83 73 / 60 30 30 30
STT 83 73 84 73 / 50 30 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
456 AM AST Thu Feb 13 2020

.SYNOPSIS...
Most fair weather conditions with some isolated showers over the
local waters were observed across the region in the night hours.
For today, less low-level moisture can limited the shower activity
across the islands. However, some isolated showers still
possibles across eastern PR and USVi in the morning hours, then in
the afternoon hours over the interior and western PR. A strong
surface high pressure will continue to generate easterly wind flow
across the local waters and hazardous marine conditions through
at least Saturday morning.


&&

.SHORT TERM...Thursday through Saturday...
Tutt low and associated trough will continue to sink southeast and
linger across the northern Leeward islands while slowly weakening
as an upper ridge builds just west of the forecast area. This will
place the region on the subsident side of the upper level trough
axis, resulting in drier and stable conditions across the region
today and through Friday. However the Atlantic Surface high
pressure will remain in place to maintain moderate to strong
easterly trades through today. This will continue to bring
occasional patches of low level moisture across the region from
time to time. Periods of passing showers over the coastal waters
and parts of the coastal areas of the islands can be expected
during the early morning hours. Afternoon shower activity today
should be limited to parts of the west sections of Puerto rico and
just downwind of the U.S. Virgin Islands steered by the
prevailing easterlies. Although no significant rainfall
accumulations is expected across the islands today, isolated areas
of moderate to locally heavy rainfall will remain possible mainly
in the west sections of Puerto Rico. This may cause minor ponding
of waters on roadways and in poor drainage areas but this will be
of short-lived.

The easterly trade winds are still forecast to gradually taper
off Friday into Saturday wile becoming more east southeast.
However, a weak easterly perturbation will bring a quick surge of
moisture across the region late friday through Saturday and this
in turn will increase the potential for the development of early
morning passing showers, along with a better chance for locally
and diurnally induced afternoon convection over parts of the
islands but with the the best chance still expected over the west
sections of Puerto Rico.

.LONG TERM...Sunday through Friday...
By Sunday, the GFS model guidance suggest a trough at 700 mb over
the Anegada passage. This feature at the mid level will pull
moisture across the region. Therefore, scattered showers are
expected across eastern Puerto Rico in the morning hours and across
the interior and western Puerto Rico in the afternoon hours. The
biggest pulse of moisture is expected for Sunday, but then by Monday
another pulse of moisture can create the same weather scenario. By
Tuesday late in the afternoon, model guidance suggest dry air at mid
levels with precipitable water around 1.00-1.10. This dry pattern
can limit the development of rainfall activity across the region
through at least Friday. However, some little fragments of
moisture are expected to reach the local region and these in
combination with the local effects can result in afternoon
convection for sections over western and southwestern Puerto Rico.



&&

.AVIATION...
VFR conds thru fcst prd. Passing SHRA ovr regional
waters and en route btw PR and the northern Leeward Islands as well
as nr TKPK and TNCM til 13/14Z. . SCT-BKN lyr nr FL025...FL050. brief
Mtn top obscr ovr Ern PR due to SHRA/ low clds. VCSH at TJMZ/TJBQ fm
13/17Z-13/23Z. SFC wnds fm E 10 knots or less...increasing to 15-20
kt with higher gusts after 13/14z.


&&

.MARINE...
Hazardous marine conditions will continue across the regional waters
and local passages due to a easterly wind flow generate from a
surface high pressure over the Atlantic waters. There is a high risk
of rip currents for the north-central, northeastern beaches of
Puerto Rico, as well as the northeastern beach of St. Croix. These
conditions are expected to continue to at least Saturday for the
Atlantic waters, but return once again on Monday.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 84 73 / 40 40 40 40
STT 84 74 83 74 / 30 40 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
545 AM AST Fri Feb 14 2020

.SYNOPSIS...

In the night hours, passing showers were observed over the
regional waters and a few coastal sections of Puerto Rico. A
widespread high pressure will continue to generate a easterly wind
flow and this will push low-level moisture across the region.
Therefore, isolated showers may move from the waters into
portions of eastern and northern Puerto Rico from time-to-time in
the morning hours. Then in the afternoon hours, scattered showers
may develop across interior and western Puerto Rico, as well the
San Juan metro area. For today, in the afternoon hours still a
slight chance for isolated thunderstorms. Across the regional
waters, hazardous marine conditions are expected to continue to at
least Saturday. Therefore, a small Craft advisory and a High Risk
of rip current are in effect.


&&

.SHORT TERM...Today through Sunday...
Surface high pressure across the west and central Atlantic will
slowly shift eastwards today through Saturday while relaxing the
local pressure gradient. Consequently this will weaken the
easterly trade winds across the region through Saturday. In the
meantime, , the low level winds will be strong enough to continue
to transport fragments of low level moisture across the area
during the rest of the overnight and morning hours. Upper level
tutt low and associated mid level trough will meander just east of
the region. This will aid in enhancing showers development as
they move westward across the regional waters. These showers will
make their way across the forecast area and brush parts of the
islands from time to time. Brief periods of mostly light to
moderate showers can therefore be expected for some areas for the
rest of the early morning.

For the rest of today, expect sufficient moisture available to aid
in afternoon shower development across parts of the islands.
However, again no widespread rainfall accumulations are so far
forecast for most of the islands. Afternoon convection with possible
isolated thunderstorms should be focused over portions of the west
interior and northern half of Puerto Rico Rico including isolated
areas around the San Juan metro area today. Mostly fair weather
skies should prevail around the USVI in the afternoon but a few
passing showers cannot be ruled out as well.

Additional moisture advection and increasing upper level instability
is forecast for Saturday through Sunday, as the ridge aloft erodes
and a short wave trough crosses the west Atlantic. This along with
an induced low level trough and associated moisture will move across
the region late Saturday through Sunday. Low-level moisture will
increase from this easterly perturbation, with precipitable water
values forecast to range between 1.5 to 1.7 inches. The proximity of
the short wave trough will create sufficient instability aloft along
with the influx of low level moisture Saturday through Sunday.
Therefore . the combination of these factors will support enhanced
convection especially late Saturday through Sunday. Due to the
anticipated instability aloft and good moisture convergence during
the period, especially during the afternoon hours , ponding of water
on roadways and in poor-drainage areas can be expected, as well as
minor urban and small stream flooding in areas that do receive more
persistent and heavier shower activity.


.LONG TERM...Monday through Saturday...
Model guidance today suggest more low-level moisture across the
region for Monday. For this reason, the weather forecast increase
the potential for showers in the morning over the eastern and
northern Puerto Rico and in the afternoon hours over the interior
and western Puerto Rico. By Tuesday, a widespread high pressure
located well at north of the region will result in a easterly wind
flow across the region. These wind flow will push fragments of
low-level moisture over the region thorough at least Saturday.
Periods of passing showers over the coastal waters and parts of
the coastal areas of the islands can be expected during the early
morning hours. Then in the afternoon hours, isolated to scattered
showers are possible over the interior and western sections of
Puerto Rico. This showers may cause minor ponding of waters on
roadways and in poor drainage areas. However, rainfall estimates
are not expected to be significant.

&&

.AVIATION...
VFR conds expected to prevail for next 24 hours at all terminals,
but brief MVFR psbl with passing SHRA ovr regional waters and en
route btw local islands. Passing showers will continue to impact
parts of the northern leeward islands/USVI/Ern PR til 14/14Z.
brief Mtn top obscr ovr E PR til 14/12Z due to VCSH/low clouds.
Sfc wnds fm east at 10 knots or lower at most terminals, except
around 15 knots at TNCM/TKPK til 14/13z. Winds bcmg 15-20 kts aft
14/14Z with hir gusts at all terminals. VCSH at TJBQ fm
14/15z-14/22z. VCTS at TJMZ fm 14/17z-14/22z.

&&

.MARINE...
Hazardous marine conditions will slowly subside, and
seas are expected to be below 7 feet by Saturday night over the Atlantic
waters. Hazardous seas will return n tuesday. Rip current hazards
risk will all subside from high to moderate by Saturday in the
morning, but will also return with the heightened seas Tuesday.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 83 73 83 74 / 50 40 20 40
STT 83 74 83 72 / 40 40 40 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
542 AM AST Sat Feb 15 2020

.SYNOPSIS...

More scattered showers are expected today as moisture from an
upper level low continues to impact the region. However, tomorrow
looks even wetter as even more moisture streams in. Urban and
small stream flooding is possible for the next few days,
especially where the more persistent showers set up. Seas
continue to come down, though another swell is expected to start
on Monday and last through Wednesday.

&&


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

Low pressure in the northeast Caribbean at mid and upper levels will
move eastward into the tropical Atlantic Sunday and weaken on Monday
as high pressure over the central Caribbean flattens out and spreads
in behind it. Upper levels will remain dry, but some moisture will
dominate the mid levels through Monday while gradually subsiding.

The mid and upper level features are throwing considerable low-level
moisture over the area and this is expected to increase overnight
tonight and into Sunday. This moisture will be driven along in the
easterly low level flow to create late night and early morning
showers tonight and Sunday, and showers in western Puerto Rico
during the afternoons. Some thunderstorms are possible today,
tonight and Sunday, but will be isolated. Drier air will move in on
Monday at lower levels and mid and upper levels will become dry
during the day. This will cause showers to decrease.

The upper level low east southeast of Puerto Rico has brought very
cool mid level temperatures, with as low as minus 11 degrees
expected early this morning. But, as the low moves to the east, 500
mb temperatures will warm dramatically and will approach minus 5
degrees Monday. With exception of an isolated thunderstorm in
western Puerto Rico thunderstorms formation will become difficult by
Monday.


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

Our weather for the middle of next week looks to return to a more
normal pattern, with low level easterly winds bringing in patches of
moisture. However, forecast models suggest ample moisture associated
with these patches, so conditions will likely be wetter than
normal. Thus, scattered showers will be likely for especially the
east coast of Puerto Rico in the morning hours for Tuesday, and
western Puerto Rico in the afternoon. Even more moisture moves in
for Wednesday and Thursday, so scattered to numerous showers will
prevail. Thunderstorms for this period look to be unlikely, as the
upper level atmospheric support looks unfavorable. However, with
plenty of low level of moisture in place, the areas that receive
more persistent showers have the possibility for some localized
flooding as well. At least low-level winds look fairly breezy,
which will help the showers to move along quickly.

Long-range models are hinting at somewhat drier conditions for
next Friday, but there will still likely be isolated to scattered
showers around. There is decent agreement in the models of an
approaching front for next weekend. However, the American model
suggests it will arrive for Saturday, while the European model
keeps it to our northwest till Monday. At this point, both models
suggest plenty of moisture in this front, so this will be
something to monitor throughout the next week.

&&


.AVIATION...

MVFR conds are psbl in TNCM/TKPK in numrs SHRA due to CIGS and
briefly heavy rain during the period. Brief MVFR conds are psbl
TIST/TISX aft 15/14Z, and in TJMZ aft 15/17Z. Mtn obscurations
expected aft 15/15Z. Sfc winds incrg to 10-20 kts with gusts to 30kt
in SHRA. Max winds N-NNE 40-50 kt btwn FL260-380.

&&


.MARINE...

Regional winds continue to relax, thus helping the marine
situation. Waves have been coming down and only the outer Atlantic
waters are under a Small Craft Advisory till this evening.
However, hazardous seas are once again expected for Monday,
and will continue at least through Wednesday, where wave heights
across the region are expected at 5-8 feet.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 74 84 73 / 60 70 70 60
STT 84 72 85 74 / 70 80 60 40

[cycloneye]

AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
526 AM AST Sun Feb 16 2020

.SYNOPSIS...

More active weather is expected today, as moisture from an upper
level trough pushes into the region. By this afternoon, scattered
to numerous showers can be expected, though the thunderstorm
threat will be very minimal. Heading into the workweek, showers
are still likely, but drier conditions aloft and warmer mid-level
temperatures will limit the intensity of these showers. Another
swell will impact the region beginning tomorrow.

&&


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

Low pressure in the far western tropical Atlantic near 17.5 north at
mid and upper levels will move eastward while weakening Monday and
Tuesday as high pressure over the central Caribbean flattens out and
northwesterly flow spreads over the area at 250 mb. Upper levels
will remain dry, but some moisture will dominate the mid levels
through Monday while gradually subsiding.

A second pulse of low level moisture will move into the area later
today and reinvigorate the shower activity that had slackened during
the second half of the night due to a patch of drier air moving
through. Although drier air moves into the eastern half of the
forecast area, that is eastern Puerto Rico and the U.S. Virgin
Islands, briefly late Sunday night, better moisture follows and will
cause showers over the eastern end of Puerto Rico early Monday
morning. Then another pulse of moisture moves over the area on
Monday. Drier air follows immediately and showers in eastern Puerto
Rico may clear late afternoon on Monday, but another area of
moisture arrives Tuesday morning. The time height section over San
Juan shows considerable vertical motion below 850 mb each morning
that has in the past been a reliable indicator of numerous passing
showers at least for eastern Puerto Rico and the U.S. Virgin Islands.

Given that very few thunderstorms were observed in the local area
yesterday or overnight today and 500 mb temperatures will continue
to warm several more degrees today and also late Monday. The mention
of thunderstorms has been removed from the forecast.

Owing to the surface gradient over the area breezy conditions are
expected to continue and gusts in showers of 30 mph cannot be ruled
out.


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

The long-term forecast appears to be moderately active with
shower activity, but these showers will likely not be very strong.
For next Wednesday, Thursday, and Friday, a mid to upper level
trough will develop to the east of the region, and produce
showers. Low- to mid-level easterly flow will then push these
showers in our direction, thus producing scattered to possibly
numerous showers. We will be on the side of the trough that
produces sinking motion and reduces the threat for thunderstorms,
and warm temperatures aloft will inhibit that threat further.
Furthermore, model soundings suggest very dry conditions in the
mid-level atmosphere. Still however, with ample low level moisture
in place, urban and small stream flooding will be a threat.

Heading into the weekend, a cold front will approach the region.
Models suggest that this front will lose organization as it
approaches, and models still generally disagree about the timing of
greatest impact for our region. Still however, wetter conditions
will likely prevail as moisture out ahead of the front produces
showers. Thus, Saturday will have showers, but Sunday and Monday
at this point appear wetter as the front moves closer. The
atmosphere appears minimally favorable for thunderstorms, but
there very well could be some given the instability from the
front, and colder air at upper levels from the trough aloft.

&&


.AVIATION...

MVFR conds are psbl in TNCM/TKPK due to CIGS. Brief MVFR conds are
psbl TIST/TISX aft 16/14Z, and in TJMZ aft 16/17Z. Mtn obscurations
expected aft 16/15Z. Easterly sfc winds incrg to 10-20 kts with
gusts to 30kt in SHRA. Max winds NW 40-50 kt btwn FL330-420.

&&


.MARINE...

Choppy seas will continue today for most of our local waters, with
the outer Atlantic just barely below Small Craft Advisory
criteria. However, a northerly swell plus windy conditions will
result in hazardous seas once again, beginning Monday morning and
lasting for much of the week. For the most part, waves are not
expected to exceed 6-8 feet.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 73 84 74 / 40 60 40 50
STT 85 73 84 74 / 60 40 40 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
521 AM AST Mon Feb 17 2020

.SYNOPSIS...Drier air will move into the area for reduced shower
activity today and tonight. A shallow moist layer will still allow
some scattered showers over windward slopes and in western Puerto
Rico during the afternoons. A pulse of moisture will cause
increased shower activity Wednesday through Friday, but drying
returns for the weekend. An approaching frontal system next week
will bring cooler, wetter weather.

&&

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

Generally conditions have been calmer this morning compared to
yesterday morning. A patch of higher moisture content with
precipitable water values of roughly 1.6-1.8 is moving out of the
region. There has been some weak shower activity collocated with
the moisture, though most showers have been out over the water.
Behind the showers to the east, much drier air is moving in, with
precipitable water values of around 1.0-1.3. Thus, minimal shower
activity is expected this morning, with one notable exception being
the eastern coast of Puerto Rico including El Yunque.

The mid- to upper-level trough that has been the moisture producer
over the past few days is now moving off to the east, and conditions
are generally becoming drier. At lower levels, high pressure over
the central Atlantic is extending into our region, enhancing local
pressure gradients and resulting in higher wind speeds. As described
in the marine section, this will impact the marine situation for the
next several days, and fire weather conditions will also be
negatively impacted.

As far as weather conditions go, today and tomorrow look similar
with drier conditions than the past few days, but still a chance for
isolated to scattered showers across the region. The thunderstorm
threat is nonexistent, as the mid-troposphere has warmed and dried
out quite a bit. Moving into Wednesday however, another mid to upper
level trough develops to our east and will help to produce increased
shower activity across the region. Still, these showers will be
fairly shallow and not very intense. With windier than normal
conditions continuing into Wednesday, these showers should be moving
fairly quickly was well. The best chance for thunderstorms on
Wednesday looks to be over the USVI and further east nearer to the
trough where the colder mid-tropospheric temperatures are.

.LONG TERM...Thursday through Monday...
At upper levels, the cut-off low will still be lingering in the
far western tropical Atlantic waters east of the area with a ridge
over Hispaniola. The ridge weakens and passes on Friday and the
cut-off low then moves away rapidly. Then, a long wave trough
moves into the Atlantic waters north of the area during the
weekend.

While lower levels will continue to have shallow moisture pretty
much throughout the period, a passing trough in the easterly flow
at 700 mb will help to enhance the moisture Thursday. Immediately
afterward 700 mb flow becomes southwest as a cold front approaches
Saturday and Sunday. Low pressure south of the area over the
Caribbean also at 700 mb will also enhance moisture south and
east of Puerto Rico. This will enhance the shower activity over
the area considerably. The GFS does show the front passing
through the area on Monday with drier and cooler air behind it,
but this is in contrast to the previous run. So, it is still not
certain whether this cold front passage will be accomplished or
not.

Current indications are that moisture will remain too shallow both
Thursday and Sunday for thunderstorms to occur. Shower activity on
those days, however, may be able to cause local urban and small
stream flooding.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across
all terminals, though ISOL -SHRA are possible for all terminals.
Winds will increasing to 15-20kt with occasional gusts to 28 kt after
17/13Z with sea breeze variations. CIGS will gradually improve
everywhere overnight with drier air moving in from east to west.
Maximum winds WNW 50-60 kt btwn FL380-460.

&&

.MARINE...A swell is enroute from the north but now looks like it
will not arrive into the local Atlantic waters before this
afternoon. Winds will also begin to increase and the combination
will cause seas to rise above 7 feet this afternoon through
Tuesday afternoon and continue through at least Wednesday in most
waters and at least Thursday night in the outer Atlantic waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 75 85 73 / 30 60 60 50
STT 85 75 85 73 / 40 40 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
529 AM AST Tue Feb 18 2020

.SYNOPSIS...Drier air punctuated with patches of moisture and
scattered showers will move through the area today through
Thursday. The driest conditions will occur on Friday with only a
few showers and weaker winds. A front will approach over the
weekend and winds will become gentle for the most part. Then the
moisture from the front will bring enhanced shower activity to the
area Monday and Tuesday.

&&

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

As we head into the middle of the week, the large-scale weather
pattern remains unfavorable for active weather. At the mid- to
upper- levels of the atmosphere, a trough resides to our east, and
is about to be reinforced by another trough digging just to our
east for tomorrow and Thursday. To our west is a ridge of high
pressure, driving sinking motion and subsequent warming aloft and
drying of our region. This is evident in model soundings, with
fairly warm temperatures at mid-levels resulting in very little
energy (CAPE) to drive upward motion so important for
thunderstorms. With this pattern in place for the next few days,
the flooding threat will be very low.

In the lower levels of the atmosphere, high surface pressure over
the central to east Atlantic, and another forming in the western
Atlantic, will drive enhanced local pressure gradients and windier
than normal conditions for the next few days. Winds will generally
be out of the east to east-northeast, and will help to bring in low
level moisture produced by the aforementioned trough to our east.
One such batch of moisture has just passed through, and light
showers were observed primarily over eastern Puerto Rico, and over
the Atlantic and Caribbean waters. Our weather for the next few days
will be determined primarily by these patches of higher moisture
content, with the large-scale pattern only allowing for weak shower
production. Looking at the models for the next few days, a period of
drier air is moving in currently, so expect fairly calm weather for
this morning with only light isolated showers occurring. A weak batch
of moisture moves in for this afternoon, and could produce weak
scattered showers across the region including the San Juan metro.
For tomorrow afternoon, models suggest a stronger patch of low-level
moisture that could produce more widespread scattered showers in the
afternoon. Higher regional moisture will persist overnight and
through Thursday morning, so expect scattered showers particularly
for eastern Puerto Rico and the offshore waters. Some scattered
showers are possible for Thursday afternoon over Puerto Rico as
drier air begins to move in again, but impacts will be minimal.


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

At mid and upper levels a vigorous trough with northeast-
southwest orientation across the western tropical Atlantic will
pull away on Friday leaving northwest flow over the area. On
Saturday a weak trough at upper levels will pass through the
area, then on Sunday a strong long wave trough will pass north of
the area over the Atlantic waters at both mid and upper levels.
As this trough at upper levels moves east, northwest flow will
resume.

At lower levels the passage of a weak trough on Friday and the
approach of a cold front from the northwest will cause low level
winds to become light and in places variable. Low moisture levels
on Friday will bring mostly sunny conditions with some above
normal temperatures over the islands. Low level moisture is patchy
and wind patterns are too light to predict over the weekend which
will lead to scattered showers of a local nature, generally over
higher terrain. During this period persistent showers in weak and
variable flow dominated by land and sea breezes could lead to
localized urban and small stream flooding. On Monday and Tuesday
moisture increases and the chance of showers improves, but very
moist conditions are localized and transitory, making shower
activity erratic. Winds at lower levels gradually become easterly
again, but remain light so interior Puerto Rico is the most likely
to see showers in sea breeze convergence with only scattered
showers elsewhere.

&&

.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals, particularly this morning with drier air moving in.
Showers may briefly cause -RA/VCSH and tempo MVFR cigs for terminals
this afternoon and into the nighttime as another batch of moisture
moves in. Low level winds will continue at around 10 kt this morning
with land breeze variations, then by mid morning from the east at
15-20 kt with sea breeze variations. Maximum winds WNW-NW 50-65 kt
btwn FL340-500. Strongest winds at FL460.

&&

.MARINE...Winds and seas will increase today and tonight to 6 to 8
feet and then slowly subside. A weak northerly swell of around 3
feet and 10-11 seconds has also been detected and will continue
through at least Wednesday. Seas of 7 feet may subside briefly in
some zones during the middle of the week and then return, but
current forecasts show seas of 6 feet or less in all zones by
Friday night.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 74 84 74 / 50 50 40 60
STT 85 74 84 74 / 40 50 40 50

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
453 AM AST Wed Feb 19 2020

.SYNOPSIS...High pressure northeast of the area will bring breezy
conditions today and Thursday with fast moving showers that will
visit the northeastern two thirds of Puerto Rico. Some drying will
occur on Friday, then an approaching front will bring a modest
increase in the moisture to the area.

&&

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

Little change is expected in the short-term forecast from yesterday.
The overall weather pattern continues to be unfavorable for
thunderstorms or intense rain showers. A trough is digging down to
our east at upper levels, with a ridge to our west providing warming
aloft. These warmer temperatures will suppress cloud development and
result in only shallow rain showers. At the surface, high pressure
to our north continues to drive breezy winds that will keep the
showers moving along and lessen their impact.

For today, isolated to scattered showers will continue this morning,
then increase in the afternoon as another patch of moisture moves
into the region and interacts with the sea breeze. Showers are most
likely over the higher terrain in Puerto Rico, and into the Atlantic
waters. The chance for flooding is very low, though ponding of water
on roadways is possible from passing showers. Showers will continue
into the nighttime, but drier air is expected to move in for
tomorrow. In fact, Saharan dust will make an appearance beginning
tomorrow, and though it won`t be a substantial dust event, there
will be a noticeable decline in visibilities. The dust is expected
to last into the weekend. This drier air and dust will reduce shower
chances, making later Thursday and all of Friday fairly uneventful
weatherwise.

.LONG TERM...Saturday through Wednesday...
The ridge that dominated the area during the week at upper levels will
move east of the area Saturday and a long wave trough will sink
south into the Atlantic waters north of the area Sunday. By
Monday it will pass to the east.

A cold front will begin to approach the local area on Saturday. A
pre-frontal trough will also develop in the western tropical
Atlantic with the aid of a trough moving toward the area. The weak
trough at 700 mb will push into the area Sunday and Monday while
the front approaches the northwest corner of the forecast area.
Current models have considerably drier air trapped between the
pre-frontal trough and the front and greatly reduce the amount of
rain expected in the area due to the front, since a jet of air
from the southeast at lower levels will tend to push back at the
front and hold it just north of the area. By Wednesday, however,
the moisture from the two features merge over the area and
northeasterly flow at lower levels carries the day and allows the
front to pass with considerably drier air behind it. Nevertheless
would expect at least scattered to numerous showers in the area
Tuesday and Wednesday due to the convergence of these systems.
But, because relative humidities are generally less than 30
percent above 12 kft for the entire period rainfall amounts will
be modest and generally less than one inch on the most favored
slopes.

&&

.AVIATION...VFR conditions will continue for the most part at
all terminals. However, passing SHRA could produce brief MVFR
conditions. Winds this morning will be from the east at around 10
kts, and between 10-20 kts by this afternoon with higher gusts,
particularly associated with the showers. Though all terminals have a
chance for showers this afternoon, the driest location is likely
TJPS, with the best chance for showers at TJMZ/TJSJ. Maximum winds
55-70 kt btwn FL290-480. Winds nr FL290 will be nearly north, but
will back around to WNW by FL400.

&&

.MARINE...Surface winds up to 25 knots will drive seas up to 8
feet today. Winds and seas will gradually diminish, but some outer
waters will continue to see 7 feet or better on Friday. While all
areas should have seas below 7 feet by Friday afternoon, a better
set of north northwest swell is expected to raise seas to 7 to 8
feet beginning Sunday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 85 74 85 74 / 50 50 50 50
STT 78 74 85 74 / 50 50 30 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
549 AM AST Thu Feb 20 2020

.SYNOPSIS...

Persisting surface high pressure to the north over the eastern
Atlantic is promoting continuing moderate to fresh trade winds
today. Patches of moisture are expected to stream across the area
embedded in these trade winds, aiding in the development of
afternoon showers, as well as some passing showers during the
morning and overnight hours. Decreasing winds and moisture are
forecast for Friday into the weekend, while Saharan dust will
likely see hazy skies over the area. Increasing moisture is
anticipated for the start of next week as a cold front approaches
the area, leading to a more active weather pattern.

&&

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

A broad surface high pressure over the eastern Atlantic will promote
moderate to fresh trade winds today. Areas of low level moisture
embedded in the trade winds will reach the islands from time to time
through the short term period. This will be enough to trigger
diurnally induced afternoon showers over portions of the interior
and west PR as well as from streamers developing off the USVI.
However, the overall moisture content decreases from 1.30 inches
early this morning to just under an inch of precipitable water
during the next couple of days. This is due to drier air moving in
from the east with Saharan dust. Although not a strong SAL event,
hazy skies are expected. Winds will gradually decrease on Friday and
Saturday, and turn more from the southeast as an area of low
pressure develops over the western Atlantic and an associated
frontal boundary stalls to the north of the region during the
weekend.

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

By Sunday, a cold front will be approaching the region from the
northwest. This front will likely not pass completely over the
region, stalling near the northwest of Puerto Rico. The central-
Atlantic ridge ahead of this frontal system is expected to continue
to pull away from the region to the northwest. These factors will
combine to continue the relatively light winds lasting into Monday
at least. Moisture associated with the aforementioned front will
push over the local islands starting late Sunday. Meanwhile, the
remnants of an old frontal boundary embedded in the trade winds will
also be making their way westward towards the area. The combination
of factors is also likely to lead to moisture convergence early in
the week, and this is when the highest rainfall amounts are likely.
Associated with these two boundaries, moisture levels at or above
seasonal normals are expected to persist into the end of the work
week next week. Therefore, shower activity is likely to be near or
above normal levels for February through the week. However,
conditions aloft are likely to be generally stable, with ridging
seen at both the mid- and upper-levels by late Monday; the 500 hPa
temperatures support this conclusion, generally staying warmer than
climatological normals for this time of the year through out the
long term period. As such, convection is unlikely, and rainfall
totals are not likely to be spectacular. Late in the week, late
Thursday into Friday, a trend towards drying conditions is
anticipated. Though the 0Z run of the GFS has slowed this drying
trend somewhat compared to previous runs, the trend does remain, and
still seems likely; as such, it is reflected in the forecast.

&&

.AVIATION...

Mainly VFR conditions are expected to prevail across all terminals
during the next 24 hours. However, diurnally induced afternoon showers
over western Puerto Rico could cause brief MVFR conds at TJMZ. HZ due
to Saharan dust is expected but vsby should remain P6SM. Sfc winds
increasing 15-20 kt from the east with higher gusts and sea breeze
variations after 14z.

&&

.MARINE...

Moderate to fresh trade winds continue to impact the area. This will
support persisting choppy and hazardous seas, with heights up to 7
feet across much of the regional waters. Winds, and therefore seas,
will begin to subside somewhat tonight into tomorrow. Conditions are
expected to improve enough to no longer meet small craft advisory
criteria by early tomorrow morning, except in the outer Atlantic
waters, where hazardous conditions are forecast into the afternoon.
Relatively tranquil conditions are then expected as we make our way
into the weekend. However, another northerly swell is anticipated
for Sunday, and will bring a return of hazardous marine
conditions.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 73 85 72 / 50 20 20 20
STT 84 72 82 71 / 30 30 30 20