Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
550 AM AST Fri Jan 27 2017

.SYNOPSIS...Mid level ridge located west of the region will expand
over the Northeast Caribbean and the Tropical Atlantic through Saturday.
As the ridge builds over the area...dry and stable conditions will
prevail aloft. A few upper level short-wave troughs will swing
across the local area between Sunday and early next week...
increasing the instability across the local islands. The overall
moisture transport will be enhanced the first part of next week as
a trough pattern establishes across the Western Atlantic.

&&

.DISCUSSION...Surface high pressure north of the islands will
push the remnants the old frontal boundary over the U.S. Virgin
Islands and Puerto Rico later today. As a result...scattered
showers will affect the local islands at times. Winds will become
southeast this afternoon as surface high pressure relocates over
the Central Atlantic. This will result in warmer temperatures
along Northern Puerto Rico and scattered convection over Northwest
Puerto Rico this afternoon. At this time...no significant rainfall
accumulation is anticipated with the remnants of the front as mid
level ridge will inhibit deep convection across the islands today
and Saturday.

Weather conditions will become more favorable for showers early
next week as a few short-wave troughs move over the local region.
As a result...moisture transport will be enhanced between Sunday
and Monday under the influence of the upper troughs. Operational
models continue to suggest that this wetter pattern will likely
persist through at least midweek next week.

&&

.AVIATION...Mainly VFR conditions are expected across all terminals
during the next 24 hours. However, fragmented clouds and SHRA
embedded on trade winds could create brief MVFR cigs and -RA periods
across the Leeward/USVI terminals through the morning hours. Similar
conditions are expected after 16z across the PR terminals as SHRA
develops over the mountain ranges. Low level winds should prevail
from the east at 10-15 kts with sea breeze variations after 14z.

&&

.MARINE...Local buoy observations show the overall seas subsiding
to 3-5 feet across most of the coastal waters. The NW swell peaked
yesterday, however seas up to 6 feet still possible across the offshore
Atlantic waters through tonight. Marine conditions will continue to
improve through Saturday. Winds will increase slightly again Sunday
and Monday creating seas of 4-6 feet once again across the offshore
waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 84 75 86 73 / 10 10 10 10
STT 83 74 85 74 / 10 10 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
1253 PM AST Fri Jan 27 2017

.SYNOPSIS...
A trough aloft is moving across the region. However, a low to mid
level ridge pattern continues to dominate the forecast area. The
surface high pressure to the north of the region is pushing a
surge of moisture associated with the remnants of the frontal
boundary across the islands. As a result, showers are expected to
develop over the surrounding waters, the U.S. Virgin Islands and
over the interior and to the north of the Cordillera Central of
Puerto Rico. As well as period of light passing rains are
expected to affect the eastern sections of Puerto Rico at times.

&&

.DISCUSSION...
The Doppler Radar detected scattered showers across the
surrounding waters. Some of this showers moved across the southern
U.S. Virgin Islands and eastern Puerto Rico, but were brief and
no significant rainfall accumulation was detected. Satellite
imagery reveals a surge of moisture with clouds and showers moving
from the east over the region. As a result, passing showers are
expected to affect mainly the Caribbean surrounding waters, the
U.S. Virgin Islands and east Puerto Rico. Also, the available
moisture is expected to combine with the local effects to induce
the development of shallow showers across the west quadrant and
the interior sections of Puerto Rico.

For the upcoming week, troughs aloft are expected to swing across
the region. In addition, a surge of moisture is forecast to
increase somewhat on Sunday. If this pattern materializes,
weather conditions will become more favorable for shower activity
during the first part of the upcoming week.

&&

.AVIATION...
Some cloudiness and SHRA embedded on east southeast trade winds
could create brief MVFR cigs and -RA periods across the
Leeward/USVI terminals through 27/22Z. Similar conditions are
expected until 22Z across the PR terminals as SHRA develops over
the mountain ranges. Mostly VFR conditions are expected across the
local flying area after 28/00Z. Low level winds should prevail
from the east southeast at around 10 kts overnight.

&&

.MARINE...
A 6 feet northerly swell was observed at the San Juan and Rincon
buoys. Therefore, mariners can expect across the Mona Passage and
Atlantic waters seas up to 6 feet. Elsewhere, seas are expected
at 3 to 5 feet. Marine conditions will improve on Saturday, but
easter fresh winds will increase the seas at up to 6 feet by
Sunday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 87 74 87 / 0 10 10 10
STT 74 84 74 84 / 10 10 20 20

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
536 AM AST Sat Jan 28 2017

.SYNOPSIS...Mid level ridge will continue over the area through
the rest of the weekend as it moves over the Central Atlantic
through early next week. TUTT is forecast to move northeast of
the area by Monday. Surface high pressure will continue to build
across the Central Atlantic and into the Eastern Atlantic by mid
week next week as polar trof and associated frontal boundary moves
over the Western Atlantic. This will result in an east to
southeasterly trade wind flow for the next several days.


&&

.DISCUSSION...Mostly clear skies and limited shower activity was
observed during the overnight hours across the forecast area.
Showers were increasing late in the morning hours across the
offshore Atlantic waters to the northwest of the forecast area.
Temperatures were in the high 50s to low 60s across the higher
elevations and in the low 70s across the coastal areas of Puerto
Rico. In the U.S. Virgin Islands, overnight temps were in the low
70s. Winds were light and variable over land areas. However,
steering winds carrying the showers over the waters were from the
E-ESE around 10 knots.

For the rest of the morning hours mostly sunny skies are expected.
Later in the afternoon, a few clouds and light showers are
expected to develop from streamers off the USVI and over portions
of the north/northwest sections of PR. Trade wind showers are
expected to return during the overnight hours. Similar conditions
are expected on Sunday. By early next week, moisture is forecast
to increase over the area, as ridge aloft and surface high
pressure shifts further east across the Atlantic waters and a
weak TUTT establishes to the northeast of the forecast area.
Steering southeasterly winds will prevail through at least Tuesday.
However, at the moment this only favors a slight increase in
diurnal shower development over the interior and northwestern
sections of PR. Also, trade wind showers over the waters are
expected to move from time to time over portions of the islands
through much of next week.


&&

.AVIATION...VFR conds at all terminals during the forecast period.
Some clouds and scattered showers will move into the flying area
from the east after 18Z. In addition, sea breezes across western
PR this afternoon will help in the development of SHRA near TJMZ
and TJBQ between 18Z-22Z. East to southeast winds of 10-15 kt will
prevail below FL150.


&&

.MARINE...Northerly swell is fading away. Latest buoy readings as
of 5 AM are indicating seas under 4 feet across the coastal waters
of the islands. There is a moderate risk of rip currents across
much of the Atlantic beaches of the islands and the southern coast
of St. Croix. Seas are expected to range between 3-5 feet across
the offshore waters and 2-4 feet across the near shore waters
today. As winds increase between 15-20 knots from the east-
southeast tonight into Sunday...seas are expected to increase
between 4-6 feet across much of the regional waters and small
craft operators should exercise caution for the next few days.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
140 PM AST Sat Jan 28 2017

.SYNOPSIS...A seasonable weather pattern with a few passing showers
at times will continue to prevail through early next week. Passing
showers may increase by mid week next week as the mid level ridge
across the forecast area erodes and a frontal boundary approaches
from the west.

&&

.DISCUSSION...Mostly sunny skies and fair weather conditions were
observed across Puerto Rico and the U.S. Virgin Islands during the
morning hours as well as early this afternoon. Winds were east
southeast at 15 mph or less with coastal temperatures in the mid 80s.
Some sea breeze variations were also observed.

Surface high pressure across the central Atlantic will continue to
promote moderate to locally fresh east southeast winds during the
next several days. Even though mostly fair weather conditions are
expected tonight through Monday; cloudiness and a few passing
showers embedded in the wind flow may affect the east and
southeast coastal areas at times.

Low level moisture will then increase across the forecast area
Tue-Thu under a weakening mid level ridge and an approaching
surface boundary. Although, surface boundary will dissipate north
of the local islands, this feature will induce a surface trough
which will enhance moisture advection across the islands.
Therefore, expect an increase in passing showers across windward
areas particularly in the morning and evening hours. Locally
induced afternoon showers are also possible across western Puerto
Rico each day. By the end of the week, a mid level ridge pattern
will return to the forecast area.

&&

.AVIATION...Aviation...Mostly VFR conditions are expected across
the local area through 29/18z. Isold shra are possible over the
ern TAF sites, but no significant impact on operations expected.
Sfc winds will continue from the east to southeast at 10-14 kts
decreasing slightly overnight.

&&

.MARINE...The northerly swell will continue to subside. The local
buoy network is indicating seas under 4 feet across the coastal
waters. Moderate to locally fresh east southeast winds will
result in seas increasing between 4-6 feet across much of the
regional waters tonight and Sunday.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 86 74 86 / 20 20 10 20
STT 73 84 74 83 / 30 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
603 AM AST Sun Jan 29 2017

.SYNOPSIS...Upper level trough over the Northeast Caribbean will hold
through Tuesday. Mid level ridge has moved over the Central Atlantic.
At low levels...surface high pressure northeast of the region will
strengthen over the next few days. Under this pattern...moisture will
deepen across the local area through at least midweek.

&&

.DISCUSSION...Satellite derived precipitable water analysis indicated
a band of moisture moving across the local area during the overnight
hours. As a result...scattered showers were affecting the local
waters and portions of Eastern Puerto Rico...Culebra and Vieques
since midnight. Only light rainfall amounts have been observed
with this shower activity. Minimum temperatures ranged in the mid
60s to low 70s across the interior while coastal locations experienced
temps from mid 70s to around 80 degrees.

A generally fair weather conditions will prevail across the local
islands the rest of the morning as an area of drier air mass will
spread over the islands. Then...another band of moisture will
move over local region this afternoon. Moisture advection will
combine with the sea breeze convergence to produce scattered
showers across the local Atlantic Waters and portions of North and
Northwest Puerto Rico during the afternoon hours.

Decent moisture and high convective instability will prevail over
the next 48 hours due to the influence of the upper level trough.
Then...a frontal boundary will approach to the islands by midweek.
Although the front will remain north of the area, the pre-frontal
trough will bring additional rounds of scattered showers the
second part of the week.

&&

.AVIATION...Mostly VFR conditions expected across the local area for
the next 24 hours. However, ISOLD-SCT SHRA across the local area
will cause VCSH over the Leeward, USVI and TJSJ taf sites during the
rest of the morning hours. After 29/16Z VCSH are expected over TJMZ
and TJBQ, but no significant impact on operations expected. Winds
increasing after 29/13Z to 15-20KT with occasional gusts from the E
to ESE with sea breeze variations.

&&

.MARINE...Winds and seas will increase slightly today as surface
high pressure builds over the Central Atlantic. Seas to 3-5 feet
are expected across the nearshore waters and seas of 4-6 feet across
the offshore waters. Similar marine conditions will prevail through
midweek. However...no Small Craft Advisory is anticipated over
the next 5 days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 75 85 74 / 20 20 20 20
STT 83 74 82 73 / 20 30 30 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
147 PM AST Sun Jan 29 2017

.SYNOPSIS...A seasonable weather pattern will continue to prevail
across the local islands with a few passing showers possible. The
chance of showers may increase Monday afternoon - Thu as the mid
level ridge across the forecast area erodes and a frontal boundary
approaches from the west.

&&

.DISCUSSION...Mostly sunny skies and fair weather conditions were
observed across Puerto Rico and the U.S. Virgin Islands during the
morning hours as well as early this afternoon. Winds were east
southeast at 15 mph or less with coastal temperatures in the mid 80s.
Some sea breeze variations were also observed.

Surface high pressure across the central Atlantic will continue to
promote moderate to locally fresh east southeast winds during the
next several days. Even though mostly fair weather conditions are
expected through Monday morning; patches of clouds and showers
embedded in the trades will continue to move across the area from
time to time.

A sharp increase in low level moisture is expected across the
forecast area Monday afternoon - Thu under a weakening mid level
ridge and an approaching surface boundary. Although, surface
boundary will dissipate north of the local islands, this feature
will induce a surface trough which will enhance moisture advection
across the islands. Therefore, expect an increase in passing
showers across windward areas particularly in the morning and
evening hours. Locally induced afternoon showers are also possible
across western Puerto Rico each day. By the end of the week, a
mid level ridge pattern will return to the forecast area.

&&

.AVIATION...Mostly VFR conditions expected across the local area
for the next 24 hours. After 29/18Z VCSH are expected over TJMZ
and TJBQ, but no significant impact on operations expected. Winds
ESE 15-20KT with occasional gusts and sea breeze variations...
becoming light and variable overnight.

&&

.MARINE...Seas to 3-5 feet are expected across the nearshore
waters and seas of 4-6 feet across the offshore waters. Similar
marine conditions will prevail through midweek. No Small Craft
Advisory is anticipated over the next 5 days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 75 86 74 85 / 20 30 20 20
STT 74 83 73 85 / 30 30 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
456 AM AST Mon Jan 30 2017

.SYNOPSIS...Surface high pressure across the central Atlantic
will shift eastward today as a weak cold front will move across
the western Atlantic. This will help create weak troughiness across
the region and also diminish the local trade winds through Tuesday.
The high pressure ridge will again reestablish north of the area
during the latter parts of the week. Broad mid to upper level high
pressure will also remain in place across the central Atlantic to
maintain an overall dry and subsident pattern aloft for the next
several days.

&&

.DISCUSSION...Winds were calm to light and variable across the
islands overnight, but are expected to become more southeasterly
during the rest of the day except for local sea breeze variations
in some areas. A fairly dry airmass will remain in place across
the region, however the prevailing easterly trades will bring a
small surge of low to mid level moisture across the region by later
this afternoon and during the early evening. This moisture transport
along with diurnal and local effects will lead to some brief showers
across portions of the islands. No significant rainfall accumulations
is anticipated across the region. The prevailing southeast to south
low level wind flow will bring warmer temperatures across the northern
half of PR. Therefore expect afternoon high temperatures to be slightly
warmer than normal in some areas. However the expected increase in
afternoon cloudiness may limit the daytime heating.

For the long term ...winds will again become more easterly and slightly
increase by Wednesday as the surface high will reestablish and spread
north of the region. This will again result in the continued transport
of shallow low to mid leve moisture fragment across the regional waters
and portions of the islands from time to time. For the most part expect
mostly fair weather conditions to prevail for the next several days
with no significant weather feature in sight.

&&

.AVIATION...VCSH are possible across the Leewards, USVI TAF and TJSJ
sites until 30/16Z. Mostly VFR conditions expected across the rest
of the local flying area during the morning hours. After 30/18Z VCSH
are expected over TJMZ and TJBQ, but no significant impact on
operations expected. Winds ESE 15-20KT with occasional gusts and sea
breeze variations.

&&

.MARINE...Seas were up to 5 feet are offshore and less than 4 feet
over the near shore waters. Expect little change today and Tuesday
with easterly winds between 10 to 15 knots. By midweek...winds and
seas are so far forecast to increase to up to 7 feet as the local
pressure gradient tightens and a northerly swell is forecast to arrive
across the local Atlantic waters. By then small craft advisories may
be required for portions of the local waters.

&&


THE SAN JUAN AREA/PR CLIMATE NORMALS FOR TODAY

NORMAL RECORD YEAR
MAXIMUM TEMPERATURE (F) 83 89 1998
MINIMUM TEMPERATURE (F) 72 63 1965


SUNRISE AND SUNSET FOR SAN JUAN PR:

JANUARY 30 2017.......SUNRISE 658 AM AST SUNSET 617 PM AST

JANUARY 31 2017.......SUNRISE 658 AM AST SUNSET 618 PM AST

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 87 74 / 30 10 20 20
STT 82 73 84 74 / 30 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
135 PM AST Mon Jan 30 2017

.SYNOPSIS...Patch of moisture affecting the local islands today
is causing scattered showers across eastern PR early in the
afternoon and then developing across the interior into western PR.
A more persistent increase in moisture is expected at the end of
the workweek and the upcoming weekend. SFC high pressure across
the Central Atlantic is expected to very slowly move eastward as
the week progresses, keeping an east to east southeast wind flow
this week.

&&

.DISCUSSION...Visible satellite imagery indicates an increase in
cloud cover as an approaching patch of moisture brings clouds and
rain to the local area, when combined with the local effects such
as diurnal heating and sea breeze convergence, showers will
develop across the interior and western sections of PR while the
eastern sections, including the San Juan metro, will be affected
by some rain as the showers move in this afternoon. Little to no
shower activity is expected at this time for the U.S. Virgin
Islands.

Isolated to scattered showers are expected for the next several
days as moisture is expected to increase in the vicinity but not
be consistent until late this week. This means that somewhat
unsettled pattern is expected with a combination of sun and clouds
with brief showers in the general area. The showers that are
expected are not expected to cause any flooding.

&&

.AVIATION...VCSH are possible across the Leewards, USVI terminals
and TJSJ through mid afternoon. After 30/19Z -SHRA in and around
TJMZ and TJBQ likely, but no significant impacts are anticipated.
Winds around ESE 15KT with occasional gusts and sea breeze
variations, becoming light and variable overnight.


&&

.MARINE...Seas will generally be between 3-5 feet across the local
waters with some areas up to 6 feet across the Offshore Atlantic
waters tonight. Seas will increase by late Tuesday night into
Wednesday, possibly up to 7 feet. Winds will be from the East to
ESE at about 10-15 knots the rest of today and tonight.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 87 74 86 / 10 20 20 20
STT 73 84 74 85 / 20 20 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Tue Jan 31 2017

.SYNOPSIS...
Surface high pressure will remain anchored across the north
central Atlantic for the next several days but will continue to
spread westwards and north of the area through Friday. This will
maintain a gradually increasing light to moderate easterly wind
flow. A broad mid to upper level ridge will continue to build
across the northeastern Caribbean through the end of the week.
This will support upper level subsidence and strengthen the cap
inversion across the region.

&&

.DISCUSSION...
Recent satellite imagery and doppler weather radar as well as
latest model guidance, continued to suggest increasing cloudiness
as another surge of trade wind moisture made its way across the
region this morning. This has brought periods of light to moderate
showers across the coastal waters and will allow sufficient low
level moisture convergence for afternoon shower development. The
early morning showers will be focused over the coastal waters and
parts of the east sections of Puerto Rico and the surrounding
islands. Meanwhile, afternoon showers should develop mainly over
parts of the central interior and west sections of PR including
isolated areas n the San Juan metro. Rainfall accumulation are
still however expected to be minimal and of short duration.

For the rest of the week...expect an overall fair weather pattern
however the moderate easterly trade winds will continue to transport
shallow low level moisture with periods of isolated to scattered
showers across the area from time to time. This will result in a
mixture of sunshine and clouds with brief passing showers each
day.

&&

.AVIATION...Mostly VFR conditions are expected across the local area.
Isold shra are possible over the ern TAF sites, but no significant
impact on operations expected. Sfc winds will continue from the east
to southeast at 10-14 kts with higher gusts then decreasing slightly
overnight.

&&

.MARINE... Winds and Seas should be 10 to 15 knots and between
2-5 feet early today but gradually increasing to 15 to 20 knots
and 4-6 feet later this afternoon and tonight due to the tightening
of the local pressure gradient and the arrival of a northerly swell.
Moderate risk of rip currents will continue mainly across the north
and east facing beaches of the islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 73 86 74 / 20 20 20 20
STT 83 73 84 74 / 30 30 30 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
207 PM AST Tue Jan 31 2017

.SYNOPSIS...
Although a broad mid to upper level ridge is building across the
northeastern Caribbean, a short wave trough is observed over the
region today. TJSJ 31/12z data showed veering winds at mid to
upper level, and model guidance indicate moisture convergence at
the surface. Therefore, instability is expected to increase
somewhat over the region. As a result patches of clouds and
showers embedded in the trades will continue to move across the
area from time to time. Locally induced afternoon showers are also
possible across western Puerto Rico each day.

&&

.DISCUSSION...
TJSJ 31/12z showed a slight increase in moisture, and mid to
upper level veering winds. In addition, satellite imagery and
model guidance are indicating a surge of moisture with patches of
clouds and showers embedded in the trades. This will result in
periods of moderate to heavy showers mainly across the U.S. Virgin
Islands and the eastern sections of Puerto Rico, including the San
Juan Metro Area. The diurnal and local effect will also produce
afternoon convection across the interior and western sections of
Puerto Rico. For tonight, the shower activity should focus on the
windward sections of PR and the USVI.

For the rest of the week...expect an overall fair weather pattern.
However, under the prevailing weather pattern expect moisture
transport with patches of clouds and showers from time to time
each day.

&&

.AVIATION...
VCSH are possible across the Leewards and USVI terminals as well
as TJSJ through early this evening. After 31/19Z SHRA development
in and around TJMZ and TJBQ is expected which may result in brief
MVFR conds and mountain obscurations particularly at TMJZ through
31/22z. Winds ESE 10-15KT with occasional gusts and sea breeze
variations, becoming light and variable overnight.

&&

.MARINE...
Winds and Seas should be 10 to 15 knots and between 2-5 feet
early this afternoon but gradually increasing to 15 to 20 knots
and 4-6 feet tonight due to the tightening of the local pressure
gradient and the arrival of a northerly swell. Seas up to 7 feet
are expected across the Atlantic Offshore waters from Wednesday
morning into Thursday morning. Therefore, a small craft advisory
is in effect through this period.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 73 86 74 86 / 20 20 20 20
STT 73 84 74 84 / 30 30 20 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
452 AM AST Wed Feb 1 2017

.SYNOPSIS...
A mid level ridge will continue to build across the region today.
This feature will limit the vertical development of showers
across the local islands for the next couple of days. An upper
level trough to the east northeast of the local islands is
expected to lift northeastward while filling today. A surface high
pressure across the central Atlantic will continue to transport
patches of cloudiness and showers across the region for the next
several days.

&&

.DISCUSSION...
Doppler weather radar detected isolated to scattered showers
moving mainly westward from the surrounding waters across the U.S.
Virgin Islands, Vieques, Culebra as well as across the eastern
sections of Puerto Rico. The easterly trade winds associated with
a surface high pressure over the central Atlantic will continue
to transport patches of low level cloudiness and showers across
the local islands for the next several days. The available low
level moisture in combination with diurnal and local effect are
expected to induce some afternoon convection across western and
interior sections of Puerto Rico. However, not widespread or
significant precipitation is expected.

A mid level ridge over the region will inhibit the vertical
development of the showers and therefore thunderstorms
development are not expected at this moment. An upper level trough
to the east of the region is expected to lift northeast while
filling today and tonight. A weak frontal boundary north of the
region will provide some instability to aid in the development of
Showers across western and interior Puerto Rico this afternoon.


For the next several days an overall fair weather
pattern is expected across the region with some interruptions of
cloudiness and brief showers across the windward sections of the
local islands overnights and early in the mornings followed by
some convection during the afternoons over western and interior
sections of Puerto Rico.

&&

.AVIATION...
ISO-SCT SHRA expected through 01/12Z across the local flying area
will likely cause VCSH across most of the local terminals except
TJMZ and TJPS. SHRA becoming more ISOLD after 01/12Z but still
brief VCSH are possible. Winds will increase slightly after 01/12Z
to 10-15 KT but continued easterly with sea breeze variations.
SCT SHRA expected across western PR after 01/16Z possibly causing
VCSH at TJMZ and TJBQ.

&&

.MARINE...
Winds of 10 to 15 knots increasing to 15-20 knots tonight and
seas increasing up to 7 today mostly across the Atlantic waters are
expected across the local waters...due to the arrival of a
northerly swell. Therefore, a small craft advisory is in effect.
There is a high risk of rip current for the Atlantic beaches of
Puerto Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 84 74 / 20 20 40 20
STT 85 73 84 74 / 20 30 40 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST Thu Feb 2 2017

.SYNOPSIS...A developing weak upper level ridge will inhibit the
vertical development of convection across the local islands. A
surface high pressure across the north central Atlantic, northeast
of the region, will continue to induce a moderate easterly trade
winds across the region for the next couple of days. Patches of
low level cloudiness and showers embedded in the trades are
expected to move occasionally across the forecast area.

&&

.DISCUSSION...As occurred in previous days, Doppler weather radar
detected isolated to scattered showers moving mainly westward
from the surrounding waters across the U.S. Virgin Islands,
Vieques, Culebra as well as across the eastern sections of Puerto
Rico. The moderate easterly trades associated with a surface high
pressure over the north central Atlantic, northeast of the region,
will continue to transport patches of low level cloudiness and
showers across the local islands and surrounding waters for the
next several days. This moisture in combination with diurnal and
local effect are expected to induce some afternoon convection
across western and interior sections of Puerto Rico. However, not
widespread or significant precipitation is expected.

A developing weak upper level ridge will inhibit the vertical
development of convection and therefore thunderstorms development
are not expected at this moment. An upper level trough to the
east of the Lesser Antilles is expected to lift northeast while
weakening today.

For the next several days an overall fair weather pattern is
expected across the region with some interruptions of cloudiness
and brief showers across the windward sections of the local
islands overnights and early in the mornings followed by some
convection during the afternoons over western and interior
sections of Puerto Rico. Not changes in this weather pattern is
expected in the foreseeable future.

&&

.AVIATION...SCT-BKN cld lyrs nr FL025...Fl050...FL090 en route btw
islands with VCSH psbl across the Leeward islands TCNM/TKPK and
TISX/TIST til 02/14z. VFR conditions expected at all TAF sites
through 02/23z. Brief Mtn top psbl til 02/14z due to passing low
level clds low clds and SHRA. Light and variable winds expected TO
CONTINUE TIL 02/12z, bcmg E-SE at 10 to 15 kts after 02/14z.

&&

.MARINE...Winds of 10 to 15 knots and seas up to 7 are expected
today mostly across the offshore Atlantic waters...due to the
a northwesterly swell. Therefore, a small craft advisory is in
effect. There is a high risk of rip current for the Atlantic
beaches of Puerto Rico until 6AM AST this morning.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 84 74 / 20 30 30 20
STT 85 73 84 74 / 20 30 30 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
150 PM AST Thu Feb 2 2017

.SYNOPSIS...Passing showers at times and seasonable temperatures
will continue to prevail across the U.S. Virgin Islands and
Puerto Rico during the next seven days.

&&

.DISCUSSION....Passing showers were observed across the USVI, the
coastal areas of eastern PR as well as the Caribbean waters early
this morning. Afternoon shower development was also observed
across the northwest quadrant of PR but with minimal rainfall
accumulations so far. Winds were east southeast at 15-20 mph and
coastal temperatures were in the mid 80s. Some sea breeze
variations were also observed.

A mid to upper level trough over the Leeward Islands will continue
to enhance moisture advection across the eastern Caribbean while
weakening. As this feature collapses Fri-Sat, a weak ridge pattern
will build across the forecast area and hold much of the next
work week. At lower levels, migratory surface highs north of the
area will continue to promote moderate easterly winds during the
next several days.

Under this evolving pattern, low level moisture will continue to
increase across the local islands through at least Sat. This will
result in frequent passing showers across the USVI and the eastern
half of PR each day. Although there is no major forcing; locally
induced afternoon showers across west Puerto Rico cant be ruled
out Fri-Sat. Event though, mostly fair weather conditions are
then expected to prevail Sunday and much of next week, patches
of low level moisture will continue to move across the area at
times.

&&

.AVIATION...Trade winds are pushing clouds and showers across the
region. Therefore, SCT-BKN cld lyrs btwn FL025 amd FL090 expected
until 02/22z. Afternoon convection will produce Brief periods of
SHRA/+SHRA at all TAF sites til 02/23z. MVFR conds at TJSJ/TJMZ/TJBQ
are possible. E-SE winds at 10 to 20 kts with gusty winds btwn
20-30 kt, bcmg light and variable after 02/23z.

&&

.MARINE...A surface high pressure will remain anchored across
the north central Atlantic through the upcoming weekend. Choppy
seas are expected through early Friday morning as a northerly
swell subsides and a trade wind flow prevails across the area.
The nearshore buoy network indicated seas up to 5 feet and winds
around 18 knots. A small craft advisory continues in effect for
the Atlantic Offshore waters due to seas up to 7 feet and winds
at 15 to 20 knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 74 85 74 86 / 20 20 40 40
STT 74 83 73 85 / 20 20 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
713 AM AST Fri Feb 3 2017

.SYNOPSIS...The ridge pattern is flattening aloft. Trade wind
showers at times and seasonable temperatures will continue to
prevail across the U.S. Virgin Islands and Puerto Rico during the
next seven days.

&&

.DISCUSSION....Instability increased somewhat across the islands
as the ridge pattern flattens. Trade winds pushed showers mainly
across the regional waters overnight into early this morning.
Some of these showers moved across the windward sections of PR and
the USVI. Shower activity in the form of streamers are expected
downwind from the U.S. Virgin Islands and across east Puerto Rico.
In addition, locally induced afternoon showers are expected across
west Puerto Rico.

Under this evolving pattern, surge of moisture embedded in the
trades will continue to increase across the local islands through
at least tomorrow. This will result in frequent passing showers
across the USVI and the eastern half of PR each day. By Sunday a
drier air mass will result in a mixture of clouds and sunshine
with little shower activity.

Trade winds will continue to enhance moisture advection across
the eastern Caribbean while weakening. A ridge pattern will build
across the forecast area and hold much of the next work week. At
lower levels, migratory surface highs across the Atlantic Ocean
will continue to promote moderate easterly winds during the next
several days.

&&

.AVIATION...
VFR for much of the fcst prd at all terminals. Quick passing
-SHRA/shra possible ovr local waters and en route btw islands.
SCT-BKN cld lyrs nr FL025...FL050..FL080...few tops nr FL120. VCSH
fcst to develop ovr the interior and west sections of PR aft
03/16z, impacting mainly TJMZ where brief MVFR psbl in SHRA. L/lvl
wnds E-ESE 10-20 kts from e blo FL250. SFC wnd lgt/vrb to calm
bcmg fm E-SE..10-15 kts w/ocnl higher gusts aft 03/14z.

&&

.MARINE...Seas up to 6 feet and east winds at 10 to 15 knots are expected
to continue across most of the regional waters as the northerly
swell continued to fade and moderate easterly trade winds prevailed.
Small crafts should continue to exercise caution. There is a
moderate risk of rip currents for the majority of the north and
east facing beaches of Puerto Rico and the U.S. Virgin Islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 86 74 84 74 / 10 30 30 40
STT 84 75 84 74 / 20 30 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
507 AM AST Sat Feb 4 2017

.SYNOPSIS...Patches of moisture in the prevailing trade wind flow
will generate showers for eastern Puerto Rico and the U.S. Virgin
Islands during the overnight and morning hours and showers for
western and central interior Puerto Rico during the afternoons
into early next week.

At upper levels...A ridge extending north out of South America
across the eastern Caribbean will maintain westerly flow through
early next week. Then an equatorial jet will move toward the area
to meet an approaching long wave trough from the northwest such
that, although winds will increase, flow will remain westerly.

At mid levels...High pressure extends out of the central sub-
tropical Atlantic across the Greater Antilles through early next
week. Then weak low pressure forms on the periphery of mid
latitude troughs over the area through the end of next week. Mid
levels will see patches of moisture mingled with very dry air
through the period.

At lower levels...High pressures from the United States continue
to migrate across the mid latitude Atlantic ocean through early
next week. After mid week, the high pressure strengthens
significantly but also moves away from the local area. This will
maintain east or southeast trade wind flow over the area through
the entire 10 day period with patches of low level moisture. A
front will approach the area late in the period. But any passage
would happen after 15 February.

&&

.DISCUSSION...The MIMIC product showed Puerto Rico and the U.S.
Virgin Islands entering a somewhat drier air mass as trade wind
flow continues. And showers coverage has been less than the
previous night. A few showers were able to bring at least a trace
to eastern and northeastern Puerto Rico. The GFS shows that
moisture will increase through this evening and will increase
again after Sunday morning to peak on Monday morning. Also mid-
levels are no longer consistently dry, so despite the lower half
of the atmospheric column being barely more unstable than the
moist adiabatic lapse rate expect some showers consistent with our
usual diurnal pattern. Winds will increase somewhat now through
Tuesday but as the front approaches late next week winds will
diminish considerably. Overall no dramatic changes are expected
for the next 5 to 10 days except that a pre-frontal boundary
passing or perhaps simply forming late next week over the area
will usher in somewhat cooler weather that may be noticeable after
southeast wind flow and above normal temperatures for the north
coast.


&&

.AVIATION...VFR conds expected for the next 24 hours across the local
terminals except TJMZ and possibly TJBQ where MVFR conds are psbl
btwn 04/17Z and 04/21Z. Fair wx expected in the morning with brief -
SHRA. However, SHRA are expected to develop over the interior and
western sections of PR after 04/17z, affecting mainly TJMZ/TJBQ.
Also, SHRA streaming from the Luquillo MTN Range can affect the
vicinity of TJSJ. SFC winds will be light and easterly until
04/13Z then increasing to 10-15KT from the east with sea breeze
variations.

&&

.MARINE...Currently seas remain between 3 and 6 feet across the
great majority of the forecast area, flirt with 7 feet at the
outer buoy, 41043. This is expected to continue until around mid
week. Increasing trade wind flow to our east northeast early next
week will lead to the possibilities of 7 foot seas and small craft
advisory conditions by mid week next week. For now the risk of
rip currents remains no higher than moderate.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
200 PM AST Sat Feb 4 2017

.SYNOPSIS...
The proximity of the subtropical jet will induce upper level
perturbations across the region through early next week. At the
surface, surges of moisture will move across the region at times.
These surges will interact with the upper level disturbance to
produce periods of clouds and shower each day across the islands.
A ridge pattern is expected to return around the upcoming mid
week.

&&

.DISCUSSION...
A surge of moisture with clouds and showers is moving across the
region. This moisture will produce showers in the form of
streamers downwind from the islands of the U.S. Virgin Islands and
across Eastern Puerto Rico during the next few hours. In addition,
the available moisture will interact with the local topography,
diurnal effect and sea breeze convergence to produce scattered to
numerous showers over the West and Interior PR. Urban flooding is
possible in isolated spots of Northwestern PR and the San Juan
Metro Area later today.

Trade winds will continue to enhance moisture advection across
the eastern Caribbean. A ridge pattern will build across the
forecast area by the upcoming mid week.

&&

.AVIATION...
VFR conds will prevail across the flying area thru the forecast
period. Brief MVFR cigs possible near TJMZ and TJBQ between
04/18-21Z with the afternoon SHRA. East winds at 10-20 kts will
continue below FL050.

&&

.MARINE...
Mariners can expect winds of 10-15 kts and seas of 3-5 feet in
the nearshore waters and 4-6 feet in the offshore waters.
Therefore...small craft operators should exercise caution across
the offshore waters. Winds and seas are expected to increase
around 15-20 kt and 7 foot by early next week.

&&

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

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
543 AM AST Sun Feb 5 2017

.SYNOPSIS...Trade wind showers will continue as areas of moisture
pass through Puerto Rico and the U.S. Virgin Islands.

At upper levels...Westerly flow continues. A sub equatorial jet
will into the area from the southwest late this week as a long
wave trough moves into the western Atlantic over the following
weekend. It will be joined by the sub tropical jet Saturday or
Sunday.

At mid levels...High pressure extending over the area from the
east northeast will become focused over the sub- tropical
Atlantic to our east northeast and a weak trough will move into the
area by late in the week. Weak troughs can be seen just south of
the local islands near 600 mb. Mid levels will see bubbles of
moisture pass through mostly dry air.

At lower levels...High pressure is moving east in the mid
latitudes and will settle in the north central Atlantic Monday. A
second high will move into the western Atlantic on Monday and
reinforce the first high beginning mid week. A low developing on a
front north of the area late next week will form a trough over
the area Friday or Saturday with a pre frontal trough over the
area and the cold front approaching. Models are not clear if the
front will actually pass through the area.

&&

.DISCUSSION...Showers continued over the north coastal
municipalities--mainly west of Canovanas--through much of the
night and some of this activity remains off the northwest coast of
Puerto Rico as of 05/09Z. This activity has been shallow and
entirely under 20 kft, but persistent, and many hours of showers
caused flooding in Hatillo. The trough at 600 mb south of the
islands may have helped with favorable conditions for shallow
convection. This trough will persist through Tuesday.

Winds are shifting a little more to the east northeast today so
the best convection is expected to form closer to the Cordillera
Central this afternoon. Although there is to be a break in the
moisture later this afternoon and evening, it may not come early
enough to prevent heavy, though shallow, showers across southwest
and west Puerto Rico with the possibility of urban and small
stream flooding. Because of the break in moisture and the more
northeasterly orientation of the winds rain is not expected to
persist so long tonight. Another patch of moisture will move
through the area on Monday with good chances for rain. Then winds
will begin to respond to the pre-frontal trough that will form
late in the week with the aid of some upper level jets and rain
chances will continue, but southeast flow will then favor the
northwest corner of Puerto Rico. This band is expected to persist
into early next week with clouds and showers that will also
depress temperatures several degrees.

Limited showers are expected during the upcoming week
for the U.S. Virgin Islands, but measurable rain cannot be ruled
out.

&&

.AVIATION...ISOLD to SCT SHRA across the local area will cause VCSH
across the local terminals through 05/14Z except for TJMZ with E to
ENE winds between 5-10KT. After 05/14Z the local winds will increase
slightly to 10-15KT from the E to ENE with sea breeze variations.
Developing SHRA in the afternoon will cause VCSH at TJSJ, TJPS, and
particularly TJMZ where the SHRA may affect the station and cause
brief MVFR conds.

&&

.MARINE...Seas will respond to higher than usual winds and some
areas in the outer Atlantic will see 7 foot seas. Later on Monday
a rising northerly swell will cause sea heights to continue at or
above 7 feet possibly through the week and into early next week--
mainly in the northern and subsequently the northeastern corner of
the forecast area. Some parts of the Mona passage will be affected
as well. Currently it is expected that the risk of rip currents
will increase from moderate to high Monday afternoon.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
159 PM AST Sun Feb 5 2017

.SYNOPSIS...
The subtropical jet over the area will induce a few upper level
perturbations over Northeast Caribbean through early this week.
At the surface, migratory high pressures over the Western
Atlantic will move eastward north of the islands. These systems
will produce a moderate to fresh trade wind flow through the week.
Easterly flow will bring surges of moisture, which will interact
with the upper level disturbances to produce periods of clouds and
showers each day across the islands.

&&

.DISCUSSION...
A dry air mass encompassed the region, producing a mixture of
clouds and sunshine across the islands. Limited shower activity
was detected today. However, the lingering moisture is producing
moderate to heavy showers across the west municipalities of Puerto
Rico. Ponding of water and urban flooding are expected with these
showers. This activity is expected to diminish around sunset. For
the evening hours and early Monday morning, a band of surface
moisture will move from the east to produce showers across the
U.S. Virgin Islands and eastern PR.

Trade winds will continue to enhance moisture advection across
the eastern Caribbean. A ridge pattern will build across the
forecast area by the second part of the week.

&&

.AVIATION...
VFR conds will prevail across the flying area thru the
forecast period. Brief MVFR cigs possible near TJMZ between 05/18-
21Z with the afternoon SHRA. East winds at 15-25 kts will continue
below FL050.

&&

.MARINE...
Seas of 4-6 feet will prevail through tonight. Then seas will
build to 5-7 feet on Monday. Therefore...Small craft Advisory is
in effect from 6 AM AST Monday to 6 PM AST Tuesday.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
517 AM AST Mon Feb 6 2017

.SYNOPSIS...Surface high pressure north of the region will gradually
lift farther north into the north central Atlantic by Wednesday.
The ridge will then be reinforced by another high migrating west
to east and consequently strengthen and remain in place across
the north central Atlantic during the latter part of the work week
A cold front is forecast to enter and move across the western Atlantic
during the latter part of the week. High zonal flow aloft and weak
mid level ridging will allow for continued erosion of the trade wind
cap inversion. This will allow for better transport of low level moisture
across the region at least until Wednesday. The ridge is to build aloft
once again during the latter part of the work week.

&&

.DISCUSSION...
Weak induced low level trough in the prevailing easterlies will bring
another surge of low level moisture across the region today. Accompanying
showers will continue to affect the coastal waters and portions of
the north and east coastal sections of the islands from time to time.
Some showers may produce brief periods of moderate rainfall in isolated
spots but no widespread rainfall is expected this morning. The
availablemoisture along with local and diurnal effects will
support afternoon convection across the interior and west sections
of PR as well as in and around the San Juan metro area. Lesser
shower activity is expected across the U.S Virgin Islands during
the afternoon.

At least until Wednesday...the moderate to strong easterly wind
flow will continue to transport patches of shallow moisture across
the region. This will allow for periods of late evening and early
morning showers each day followed by isolated to scattered afternoon
showers mainly across portions of the interior and west sections of
Puerto Rico. Lesser moisture transport and showers activity is forecast
during the latter part of the week and into the weekend, as the ridge
will build aloft and the surface high pressure ridge will weaken across
the area in response to a polar trough and associated cold front forecast
to enter and move across western Atlantic.

&&

.AVIATION...SHRA and MVFR moving thru TIST before 06/10Z.
Then increasing moisture from the east thru 06/18z will cause
increasing clouds and lowering CIGS. By 06/14z some stations will
see brief periods of MVFR in SHRA including TIST, TISX, TNCM, TKPK.
Then clds and SHRA will develop over PR aft 06/15z with mtn
obscurations and pds of MVFR expected at TJMZ and psbl at TJBQ by
06/17z. Sfc winds east 10 to 15 kt with gusts to 25 kt in SHRA.
Winds shift from east to west btwn FL120-240. Maximum winds at west
at 65 kt at FL410.

&&

.MARINE...Seas will continue to deteriorate today as the easterly
trade winds are forecast to increase and a northeast swell will
move across the offshore Atlantic waters. Small Craft advisories
will be in effect for the local offshore waters today. Small craft
operators should exercise caution elsewhere. Seas increasing up
to 7 feet offshore Atlantic waters...and up to 6 feet elsewhere.
Winds between 15 to 20 knots can be expected.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
318 PM AST Mon Feb 6 2017

.SYNOPSIS...Surface trough is moving across the local region
today enhancing the shower activity across the region. In
addition...subtropical jet is inducing upper level pertubations
across the Northeast Caribbean. Both features have increased the
instability and moisture transport across the local islands.
Short- wave ridge will swing across the area by midweek increasing
somewhat the stability. Then...trough pattern will establish over
the Western Atlantic but it will have little impact in our region
as cold front remains to the north.

&&

.DISCUSSION...Satellite and radar imagery show clouds and showers
associated with a surface trough moving over the Northeast Caribbean
Region. This low level feature is enhancing the moisture convergence
across the local islands. The subtropical jet aloft is adding
some speed divergence over the region...increasing the
instability and the potential for showers. As a
result...scattered to numerous showers have been developing over
the area since mid- morning. The shower activity have been
affecting most of Puerto Rico except the south coastal plains.
Additional showers will continue to stream across Puerto Rico
through early this evening.

Easterly winds will return to the area on Tuesday as two high
pressures merge over the Central Atlantic. As a result...a trade
wind pattern will establish across the local area by midweek.
Bands of moisture embedded in the trade winds will bring clouds
and showers at times.

Trough pattern will establish over the Western Atlantic between
Thursday and Friday. This pattern will sustain a cold front but it
is forecast to remain north of the area. Another surface trough/easterly
wave will move across the islands on Thursday bringing an
increase in shower activity.

&&

.AVIATION...SHRA activity will cause VCSH across most of the local
terminals with TEMPO MVFR possible especially at TJBQ and TJMZ
through 06/22Z. Winds will continue from the east at about 10-15kt
with sea breeze variations. Winds decreasing overnight but VCSH
continues for many of the local terminals except maybe TJMZ after
07/00Z.

&&

.MARINE...Marine conditions will deteriorate over the next few days
as increasing winds will create choppy seas. Seas will build to 6-8
feet tonight into Tuesday...especially across the Offshore Waters
and Caribbean Passage. Therefore...Small Craft Advisory will continue
through midweek. In addition...the risk of rip currents will increase
to high late tonight into Tuesday.

&&

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