Puerto Rico Weather

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cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 6, 2016 4:43:37 GMT -6

Quote

Post by cycloneye on Sept 6, 2016 4:43:37 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
519 AM AST TUE SEP 6 2016

.SYNOPSIS...The tropical wave is now at about 70W and continues to
move west. However, deep moisture is expected to remain over the
local area today which will help in the development of showers
over the local area. Surface high pressure will promote an East
to ESE wind flow over the local area for the next several days.
Upper level ridge will dominate the area for most of this week
with an upper low passing through the area from Thursday to
Saturday.

&&

.DISCUSSION...The tropical wave that passed through the local area
left minimal rain accumulations across the USVI and eastern and
southern Puerto Rico during the overnight hours with the exception
of some sectors across the eastern interior and northeastern
portions of Puerto Rico where isolated areas received a half to
one inch of rain. The tropical wave is now over 70W and continues
to move west. However, there is still deep moisture trailing the
tropical wave with precipitable water values expected to be over 2
inches through the day today. Even though there is a ridge in the
upper levels, the latest guidance and observations indicate that
some showers and thunderstorms are likely this afternoon,
especially across western PR, isolated to scattered showers
elsewhere. Drier air is expected to move in on Wednesday
continuing through the rest of the week with some patches of
moisture, which would indicate that mainly locally induced showers
and thunderstorms are to be expected this week. having said that,
late this week, an upper low is expected to move through the local
area, which will cause an increase in the local instability
particularly late on Saturday when the upper low appears to
induce a surface trough moving close to the local islands.

&&

.AVIATION...Although the tropical wave will continue to move away
from the local area today...brief MVFR conds still possible in and
around the USVI terminals and JSJ in SHRA this morning. Aft 06/16z..
SHRA/TSRA development expected across W PR...and this may cause MVFR
conds and mountain obscurations in and around JMZ/JBQ till 06/22z.
Sfc winds will continue mainly from the E at around 15 kt with
higher gusts in/near SHRA/TSRA.

&&

.MARINE...Local buoys indicate that the coastal winds and the
local seas are subsiding. Latest guidance indicates that the local
winds and seas are expected to be up to 20 knots and up to 6 feet
respectively. Small craft operators should exercise caution. There
is a moderate risk of rip currents across many of the local
beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 77 89 78 / 20 20 10 30
STT 87 77 89 78 / 30 10 10 30

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 7, 2016 4:10:18 GMT -6

Quote

Post by cycloneye on Sept 7, 2016 4:10:18 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
521 AM AST WED SEP 7 2016

.SYNOPSIS...Upper level trough/TUTT east of the Lesser Antilles
will retrogress and move over the local region on Friday. This
trough aloft will increase the instability across the across the
local islands...enhancing the trade wind showers and the intensity
of the afternoon thunderstorms. A tropical wave is forecast to
reach the Northeast Caribbean Region on Saturday...bringing
another round of showers and thunderstorms.

&&

.DISCUSSION...Satellite imagery indicate drier than normal air
mass over the islands this morning. Low level moisture embedded in
the trade wind flow will bring a few showers across the windward
areas later this morning. Afternoon convection will likely develop
over the west interior and west portions of Puerto Rico this
afternoon. Similar pattern is forecast through Friday. GFS cross-
section and forecast sounding show dry air mass prevailing at mid
levels the rest of the work week. However...isolated strong
thunderstorms can not ruled out due to the proximity of the upper
level trough.

The next surge of moisture is associated with a tropical wave. At
this time...operational models suggest that the deep moisture
associated with the tropical wave will reach the local region on
Saturday. Therefore...showers and thunderstorms are likely as the
wave passes by. Moisture and instability will gradually diminish
early next week.

&&

.AVIATION...Mainly VFR conditions expected across the local
terminals. However, a few brief passing -SHRA are possible across
TJSJ/TIST/TISX/TNCM/TKPK through the morning hours. Then afternoon
convection across West PR and along the Cordillera Central, btwn
07/17-22z, will result in periods of MVFR conditions and mountain
obsc in/around TJMZ/TJBQ. Surface winds from the east at 10 to 15 kt
with higher gusts and sea breeze variations aft 07/13z.

&&

.MARINE...Seas are subsided to 3-5 feet across most of the waters.
Winds will continue between 10-20 knots. Therefore...Small Craft
Operations should exercise caution across the coastal waters of
northern Puerto Rico due to winds up to 20 knots. A small northerly
swell will continue to decay over the next few days. No Smal Craft
Advisories are anticipated in the next 5 days.

&&

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

&&

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 8, 2016 4:04:41 GMT -6

Quote

Post by cycloneye on Sept 8, 2016 4:04:41 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
529 AM AST THU SEP 8 2016

.SYNOPSIS...Upper level trough over the Lesser Antilles will
move across the region on Friday. This trough aloft will increase
the instability across the local islands...enhancing the trade
wind showers and the intensity of the afternoon thunderstorms over
the next few days. A tropical wave is forecast to cross the
islands on Saturday...bringing a few rounds of showers and
thunderstorms.

&&

.DISCUSSION...Low level moisture embedded in the trade winds
will continue to push showers across the windward areas the rest
of this morning. Afternoon convection will develop over the west
interior...west and northwest portions of Puerto Rico. Similar
pattern is forecast on Friday. Although...a relatively dry air
mass will prevail at mid levels the rest of the work week...the
proximity of the upper level trough will enhance the afternoon
convection. Therefore...expect isolated strong thunderstorms with
heavy rainfall over the west portions of the islands each afternoon.

The next surge of moisture is associated with a tropical wave.
At this time...operational models suggest that the deep moisture
associated with the tropical wave will spread over the local
islands on Saturday...when the winds shift from the southeast.
Therefore...showers and thunderstorms are likely develop and
affect portions of Puerto Rico from time to time. Moisture and
instability will diminish somewhat early next week. However...
near normal moisture and some conditional instability will
support scattered showers from Sunday to Tuesday.

&&

.AVIATION...Mainly VFR conditions expected across the local flying
area through the forecast period. However, trade wind showers with
tops around FL200 could briefly affect the leeward/USVI terminals.
SHRA/TSRA expected across western PR and along the Cordillera
Central, between 17-22Z, resulting in periods of MVFR conditions and
mountain obsc in/around TJMZ/TJBQ. Low level winds expected from the
east-southeast at 10-15 knots with sea breeze variations after
13Z.

&&

.MARINE...Seas are subsided to 3-5 feet across of the local waters.
Winds will continue between 10-15 knots...except in the coastal
waters of northern Puerto Rico where winds could reach 20 knots at
times. Therefore...Small Craft Operations should exercise caution
due to winds up to 20 knots. No Small Craft Advisories are anticipated
over the next 7 days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 80 93 80 / 20 10 30 20
STT 89 80 90 81 / 20 40 40 40

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 9, 2016 4:27:34 GMT -6

Quote

Post by cycloneye on Sept 9, 2016 4:27:34 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
522 AM AST FRI SEP 9 2016

.SYNOPSIS...Upper level trough/TUTT over the local region will
keep the atmosphere unstable over the next few days. This trough
aloft will enhance the trade wind showers and the intensity of
the afternoon convection through Saturday. A tropical wave is
forecast to cross the islands on late tonight into Saturday...
bringing an increase of the shower and thunderstorm activity.

&&

.DISCUSSION...Water Vapor Satellite imagery shows an upper level
trough/TUTT over Puerto Rico and the U.S. Virgin Islands. The
presence of the TUTT across the local area is enhancing the trade
wind showers across the regional waters this morning. Although
some showers moved inland during overnight hours...most of the
showers have remained over the waters early this morning. However...
additional showers will move over the windward areas the rest of
this morning. Then...afternoon convection will develop over the
portions of the San Juan Metro Area...the North and Northwest
Puerto Rico. The trough aloft will likely enhance the afternoon
convection...resulting in strong thunderstorms with heavy rainfall
and gusty winds.

Deeper moisture associated with a tropical wave will pool across
the local islands late tonight into Saturday. This will result in
organized convection affecting portions of Puerto Rico and the
U.S. Virgin Islands during the next 24-48 hours. At this time...the
most active period appears to be Saturday Morning and Saturday
Afternoon. Moisture and instability will diminish somewhat early
next week. However...normal moisture and some convective instability
will support the development of scattered showers between Sunday
and Tuesday. Drier and more stable conditions will likely return
by midweek next week.

&&

.AVIATION...Mainly VFR conditions expected early in the fcst period.
However, from 09/17z-09/23z SHRA/isold TSRA ovr W PR and the Ctrl
Mtn range of PR will result in TEMPO MVFR and Mtn Top obsc ovr/vcty
TJMZ/TJBQ/TJSJ/TJNR. SHRA/TSRA possible between leeward and USVI
terminals due to a tropical wave. Sfc winds will continue E-SE at 10-
15 kts with sea breeze variations aft 14z.

&&

.MARINE...Seas of 3-5 feet will prevail across most of the waters.
Winds will continue between 10-15 knots over the next several days.
Therefore...no Small Craft Advisories are anticipated over the
next 7 days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 80 90 80 / 30 30 40 30
STT 89 81 89 80 / 40 40 40 40

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 10, 2016 4:51:28 GMT -6

Quote

Post by cycloneye on Sept 10, 2016 4:51:28 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
558 AM AST SAT SEP 10 2016

.SYNOPSIS...UPPER LEVEL LOW OVER THE MONA PASSAGE AND INDUCED SURFACE
TROUGH WILL CONTINUE TO MOVE WEST ACROSS THE FORECAST AREA TODAY.
ON A SOUTHEASTERLY STEERING WIND FLOW...MORNING CONVECTION SHOULD FOCUS
OVER THE USVI/EASTERN PR AND SURROUNDING WATERS. SPREADING THROUGH
THE REST OF THE FORECAST AREA THROUGH THE DAY. SURFACE HIGH
PRESSURE WILL CONTINUE ACROSS THE NORTH CENTRAL ATLANTIC FOR THE
NEXT SEVERAL DAYS. ANOTHER TUTT BUILDS FROM THE NORTHEAST BY EARLY
NEXT WEEK. A STRONG TROPICAL WAVE AND ASSOCIATED AREA OF LOW
PRESSURE AROUND 45W IS FORECAST TO MOVE INTO THE CENTRAL ATLANTIC
BY EARLY NEXT WEEK.

&&

.DISCUSSION...A cluster of thunderstorms with frequent lightning
developed during the overnight hours across the offshore Atlantic
waters. Additional showers and thunderstorms developed between the
USVI with the northern USVI receiving the highest rainfall
amounts over land areas during the past few hours. The doppler
radar estimated between 1-2 inches of rain across St. Thomas and
St. John. Shower activity was also observed just after midnight across
the southeast/eastern coastal areas of PR. For the rest of the
morning hours, under southeasterly wind flow showers and possible
isolated thunderstorms should continue to affect sections of the
USVI and eastern Puerto Rico. As the day progresses, the upper low
interacting with the surface trough will enhance afternoon
convection along the mountain ranges of PR and affect the west and
northern areas of the island.

Moisture will linger across the forecast area through early next
week, with models showing an increase in PWAT on Sunday and
Tuesday. Overall, afternoon showers and thunderstorms are expected
each day through the forecast period. Steering winds will shift
from the east-northeast on Sunday and will favor convection over
the Cordillera Central and SW quadrant of the island. East trades
return by Monday. A strong tropical wave and associated area of
low pressure could develop into a tropical depression by early
next week but is forecast to move over the open Atlantic waters.

.AVIATION...SHRA/TSRA will continue to affect the USVI terminals
thru at least 12Z. MVFR/IFR conds possible at TIST with the
SHRA/TSRA. Then, SHRA/TSRA forecast to develop in and around TJBQ,
TJMZ and possibly TJSJ between 17Z-21Z. Brief MVFR/IFR possible
with the SHRA/TSRA. SE winds of 10-15 kt will prevail below FL200.

&&

.MARINE...Seas should continue between 4-6 feet across the
offshore Atlantic waters where small craft operator should
exercise caution. Elsewhere, seas should range between 3-5 feet
and east to southeast winds should prevail between 10-15 knots.
Scattered to locally numerous showers and thunderstorms are
expected Today across much of the waters as a surface trough moves
through the forecast area.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 80 89 78 / 50 40 40 60
STT 88 81 90 79 / 50 50 50 60

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 11, 2016 4:18:07 GMT -6

Quote

Post by cycloneye on Sept 11, 2016 4:18:07 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
552 AM AST SUN SEP 11 2016

.SYNOPSIS...Upper level low continues Today over Hispaniola while
another broad upper low over the Atlantic meanders to the northeast
of the Caribbean. Upper ridge is building from the east. Surface
high pressure continues across the Atlantic. A low pressure system
around 975 miles to the east of the Lesser Antilles is forecast to
move over the open Atlantic waters during the next few days.

&&

.DISCUSSION...Scattered showers and isolated thunderstorm affected
portions of eastern PR through the overnight hours. Between
half to one inch of rain was observed with the heaviest showers
with this activity. Meanwhile, a cluster of thunderstorms
continued over the offshore Atlantic waters with frequent
lightning noted. For today, divergence aloft associated to the
upper low over Hispaniola will aid in the development of showers
and thunderstorms across mainland PR. Brief periods of strong
gusty winds, frequent lightning and urban and small stream
flooding is expected.

Overall troughiness will continue over the central Caribbean basin
into the Atlantic waters to the north/northeast of the islands
during the next few days. Meanwhile an upper ridge builds from the
east through the medium range. Low level moisture will be
sufficient each day through at least Wednesday to aid in the
development of showers and thunderstorms during the afternoon
hours across the interior/western portions of PR. A low pressure
system around 975 miles east of the Lesser Antilles could develop
into a TC during the next day or so and is forecast to move over
the Central Atlantic with little effect on the local weather
conditions.

&&

.AVIATION...VFR conds will continue across the flying area through
at least 17Z. Some SHRA will move in and around TJSJ this morning
but VFR conds will likely prevail while SHRA passes by. Then
SHRA/TSRA will develop over the Cordillera Central, South and West
PR between 17Z-22Z. This SHRA/TSRA activity may lead to MVFR conds
over TJMZ and TJPS as well as Mountain Obscurations. Winds will
prevail from the East to Northeast around 10 kt. Higher gusts
possible near SHRA/TSRA.

&&

.MARINE...Seas at or below 5 feet are expected through the
forecast period. Easterly winds between 5-15 knots are expected
with sea breeze variations during the afternoon hours. Small
craft advisories conditions are not expected during the next
several days.

&&

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

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 12, 2016 3:59:02 GMT -6

Quote

Post by cycloneye on Sept 12, 2016 3:59:02 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
412 AM AST MON SEP 12 2016

.SYNOPSIS...
Mid to upper level tutt low and associated trough will linger
north to northeast of the region through at least Tuesday while
slowly shifting westwards. In the low levels High pressure ridge
extends across the west and Central atlantic, meanwhile at the
surface an area of low pressure located east northeast of the
leeward islands continued to produce a large area of cloudiness
and convection as it continued to move northwest towards the
Central Atlantic. This overall synoptic pattern will induce light
to moderate east to northeast low level wind flow across the
region for the next few days.

&&

.DISCUSSION...
Prevailing northeast wind flow continued to transport fragments
of moisture from the low pressure system towards and across the
local region. The proximity of the upper trough was also aiding in
enhancing some of these showers across the coastal waters as they
make their way over portions of the north and east coastal
sections of the islands. Some of the showers continue to produce
periods of moderate to locally heavy rainfall as the moved inland
and affected the coastal municipalities which included parts of
the San Juan metropolitan area. The shower activity is expected to
continue into the early morning hours, then diminish by late
morning. During the afternoon ...recent model guidance and both
the earlier 12/00z TJSJ upper air sounding as well as the forecast
sounding suggest pwat values to remain between 1.80 to 1.90
inches. This will be sufficient to allow for afternoon convection
each day across portions of the islands, especially over the
interior and west to southwest sections of Puerto Rico where the
prevailing wind flow and local forcing should focus most of the
afternoon activity. The afternoon shower and thunderstorms
over these areas should produce periods of locally heavy rainfall
which may lead to minor flooding of urban and poor drainage areas
as well as small streams.

For the latter part of the work week...so far models guidance
suggest somewhat drier airmass with lesser moisture advection
and decreasing precipitable water. Local wind flow is to become
more easterly as the area of low pressure lifts north northwest
across the Central Atlantic and the typical light to moderate
easterlies return to the forecast area. Other than a weakly
induced surface trough forecast to move across the area by
thursday, no significant weather feature is expect to affect the
forecast area at this time. However, do expect the occasional
early morning passing trade wind showers, followed by isolated to
scattered locally and diurnally induced afternoon convection each
day.

&&

.AVIATION...During the morning hours SCT SHRA will continue to move
from the Atlantic waters, causing brief periods of SHRA across the
Leeward, USVI and TJSJ TAF sites through 12/14Z. SHRA/TSRA expected
to develop after 12/16Z across, PR which will likely cause VCTS
across the terminals in PR with particular impact in TJMZ and TJPS
between 12/16Z-21Z and at TJBQ between 12/19Z-22Z where MVFR conds
are possible. winds are expected to increase after 12/12Z to about
10-15KT with sea breeze variations.

&&

.MARINE...Seas are forecast to remain below small craft advisory
criteria through the end of the week. An E to NE Swell from the
low pressure moving into the Central Atlantic over the next few
days will be minor in the local forecast area based on recent
marine model guidance. In the meantime winds and seas of 15 knots
or less and 5 feet or less respectively.

&&

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

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 13, 2016 4:25:23 GMT -6

Quote

Post by cycloneye on Sept 13, 2016 4:25:23 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
443 AM AST TUE SEP 13 2016

.SYNOPSIS...The TUTT Low across the Central Atlantic and associated
trough, will continue to move farther north and west of the forecast
area while weakening during the next few days. High pressure ridge
will continue to build and spread across the region during the
rest of the week. In the meantime, marginally unstable conditions
will continue across the forecast area today. Surface high pressure
across the West and North central Atlantic and Tropical Storm Ian
located some 900 miles East Northeast of the forecast area will help
to maintain a light to moderate East Northeast wind flow across the
region. Patches of low level moisture will therefore continue to be
transported across the area by the prevailing trades from time to
time.

&&

.DISCUSSION...Passing showers continued to develop and move over
the local waters during the overnight hours. Some of these showers
brushed parts of the U.S. Virgin Islands as well as the north and
east coastal sections of Puerto Rico producing periods of light to
moderate rainfall. Expect the low level cloudiness and shower activity
to diminish by the late morning leaving partly cloudy to mostly sunny
skies. However during the afternoon hours, locally and diurnally induced
showers and thunderstorms will again develop over the central and western
sections of Puerto Rico. Some of the afternoon convection may be locally
enhanced and could lead to minor flooding in urban and poor drainage
area.

A somewhat drier airmass will gradually spread across the region
during the latter part of the work week and continue through at
least Saturday of the upcoming weekend, as the wind flow weakens
and becomes more easterly. No significant weather feature is so
far expected to affect the forecast area for the next several days,
except for locally and diurnally induced showers over the islands
with possibly a few thunderstorms mainly over parts of the interior
sections of Puerto Rico.

&&

.AVIATION...Mostly VFR conditions expected this morning with SCT
SHRA moving across the local area, causing VCSH across the Leeward,
USVI and TJSJ taf sites through 13/14Z. SHRA/TSRA expected to
develop after 13/16Z across central, western and southwestern PR
which will likely cause VCTS and possible MVFR conds across TJMZ and
TJPS between 13/16Z-21Z. Winds will continue to be from the East to
ENE at 10KT or less through 13/13Z, increasing to about 10-15KT with
sea breeze variations after 13/13Z.

&&

.MARINE...Seas are expected to increase slightly as a small east northeast
swell from Tropical Storm Ian will spread across the local Atlantic
waters and the Anegada passage. Most of the Atlantic waters will
however remain below 6 feet, except for the local offshore Atlantic
waters where small craft should exercise caution. Otherwise, small
craft advisories are not anticipated during the next several days.

&&

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

&&

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 14, 2016 4:27:22 GMT -6

Quote

Post by cycloneye on Sept 14, 2016 4:27:22 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
320 AM AST WED SEP 14 2016

.SYNOPSIS...Upper level trough over Hispaniola will move further
westward, while and upper ridge build across the region from the
East. A surface high pressure across the West and North Central
Atlantic and Tropical Storm Ian, well northeast of the region will
help to maintain a light to moderate East Northeast wind flow
across the local islands. Not significant weather feature is
expected to affect the region for the next several days.

&&

.DISCUSSION...Doppler radar indicated brief isolated passing
showers embedded in the east to east northeast wind flow moving
from the Atlantic waters across the local islands overnight and
early in the morning. However the rainfall accumulations associated
with this activity were minimal.

The upper level trough that affected the northeast Caribbean for
the past few days will move westward and away from the local
islands today. As the same time, an upper level ridge is expected
to build today across the region from the east. This feature will
limit the moisture content of the local airmass for the next
several days. However, the persistent east northeast low level
wind flow will continue to transport small areas of moisture
across the region, sufficient to generate brief showers across
the U.S. Virgin Islands and across eastern and northern sections
of Puerto Rico overnight and early in the mornings. This moisture
will combine with daytime heating, sea breeze convergence and
other local effect to induce the development of showers and a
couple of thunderstorms over western and interior Puerto Rico each
afternoon.

Looking well ahead, not significant weather feature is expected
to affect the region in the foreseeable future.

&&

.AVIATION...Mostly VFR conditions expected this morning with brief
SHRA moving across the local area, causing VCSH across the
Leeward, USVI and TJSJ taf sites through 14/13Z. SHRA/TSRA
expected to develop after 14/16Z across central, western and
southwestern PR which will likely cause VCTS and possible MVFR
conds across TJMZ and TJPS between 14/16Z-21Z. Winds will
continue to be from the East to ENE at 10KT or less through
14/13Z, increasing to about 10-15KT with sea breeze variations
after 14/13Z.

&&

.MARINE...Seas up to 6 feet are expected across the offshore
Atlantic waters today, decreasing slowly to up to 5 feet tonight
and Thursday. Winds generally 10 to 15 knots from the East to
ENE.

&&

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

&&

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 15, 2016 4:37:02 GMT -6

Quote

Post by cycloneye on Sept 15, 2016 4:37:02 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
359 AM AST THU SEP 15 2016

.SYNOPSIS...A mid to upper level ridge will remain as the main
weather feature across the northeast Caribbean through Friday.
The upper ridge is then expected to erode rapidly as an upper
level trough return to the region during the upcoming weekend.
Surface high pressure across the western Atlantic and tropical
storm Ian well northeast of the local islands will maintain a
gentle to moderate easterly wind flow for the next few days.

&&

.DISCUSSION...Doppler radar indicated brief isolated passing
showers embedded in the easterly wind flow moving across the USVI
as well as across eastern coastal municipalities of Puerto Rico
overnight and early this morning. The rainfall accumulations
associated with this activity were generally minimal.

An upper level ridge will hold as the main weather feature across
the region until at least Friday. Although this feature will limit
the moisture content of the local airmass today, the available
moisture is expected to combine with daytime heating and local
effects this afternoon to produce a new round of showers and
thunderstorms mostly across western and interior sections of
Puerto.

An upper level trough is expected to amplify across the area
Saturday and Sunday. Expect only the typical afternoon shower
activity over western and interior sections of Puerto Rico during
the upcoming weekend. However, by early next week, the upper
trough is expected to positioning west of the region...producing
more moisture transport across the local islands for the
development of showers and thunderstorms.

&&

.AVIATION...VFR conds expected across most of the forecast area.
However...brief MVFR conds likely in and around TJMZ due to SHRA
development in W interior of Ctrl Mtn range FM 15/18Z-15/22Z. VCTS
also possible near TJPS and TJBQ. NE to E winds at 10-15 kt BLO
FL150. Except for sea breeze variations,SFC wnd mainly fm E 10-15
kts.

&&

.MARINE...Seas will remain up to 5 feet today. Winds will continue
from the East to ENE at 10-15 knots through the end of the
workweek.

&&

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

&&

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 16, 2016 5:11:58 GMT -6

Quote

Post by cycloneye on Sept 16, 2016 5:11:58 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
456 AM AST FRI SEP 16 2016

.SYNOPSIS...Slight drying will occur today and Saturday before the
reflection of an upper level low brings an increase in showers and
thunderstorms Sunday through Tuesday. Tropical Storm Karl is not
expected to reach this longitude until Thursday at the earliest.

At upper levels...A weak upper low northeast of the
Leeward Islands will move across the local area on Sunday. High
pressure is expected to build across the Atlantic waters north of
the area Thursday through the following Sunday.

At mid levels...An inverted trough north of the mouth of the
Amazon River will move slowly westward and into the local area on
Sunday. A second low, associated with Tropical Storm Karl is
expected to move west through the tropical Atlantic, turning
northwest as it approaches the windward islands.

At lower levels...A trough east of the local area is a reflection
of the upper level low. It will cross the local area just behind
that low on Sunday bringing an increase in showers and
thunderstorms. Tropical Storm Karl will reach the western end of
the tropical Atlantic on Wednesday night brining low level winds
sharply around to the northeast.

&&

.DISCUSSION...A few showers continued to stream around the U.S.
Virgin Islands and onto the eastern tip of Puerto Rico. Otherwise,
skies were mostly clear. Precipitable water is expected to reach a
minimum this evening. Although local effects will generate some
showers and thunderstorms, especially in the western interior of
Puerto Rico, activity is expected to be less than yesterday. And,
although moisture recovers somewhat Saturday, showers and
thunderstorms will again have less coverage than yesterday. The
upper level low is generating a trough at lower levels that will
bring better moisture and convective activity Sunday. This
moisture will linger through Tuesday. Tropical storm Karl will
remain surrounded by Saharan dust, models show it moving north of
20 north between Monday and Tuesday night. At this time it is not
expected to have much direct impact on Puerto Rico or the U.S.
Virgin Islands, but should pass northeast of the area, but it is
too early to say with a great deal certainty.

&&

.AVIATION...Mainly VFR conditions expected through the morning
hours across all the terminals. SHRA/TSRA developing between 16/17-
22z across the interior/SW quadrant of PR could impact mainly the
flying area of TJMZ/TJPS. BKN to OVC ceiling at FL020-FL040 and
mountain obscurations are expected with this activity. Sfc winds
will continue from the east to east northeast at 5-15 knots and
gusty near SHRA/TSRA and with sea breeze variations aft 16/13z.

&&

.MARINE...Seas will slowly increase through Monday in the
Caribbean and through Wednesday in the Atlantic. Nevertheless the
need for small craft advisories is not anticipated through
Wednesday of next week. Showers and thunderstorms will increase
beginning on Sunday and

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 79 90 78 / 30 0 10 20
STT 89 82 90 79 / 30 10 20 30

&&

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 17, 2016 4:32:28 GMT -6

Quote

Post by cycloneye on Sept 17, 2016 4:32:28 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
516 AM AST SAT SEP 17 2016

.SYNOPSIS...An induced trough will move across the area pulling
the showers and thunderstorms, now over the Lesser Antilles,
across the forecast area. Scattered showers and a few
thunderstorms will then continue for most of next week and early
into the following week.

At upper levels...a TUTT is over the northern Leeward Islands and
will continue across Puerto Rico and the U.S. Virgin Islands
tonight and Sunday. The center will pass south of Puerto Rico and
enter the Dominican Republic by Tuesday night. This will be
followed by a mild ridge by the end of the week. A 40 knot jet
will be found over the northeastern corner of the forecast area by
next weekend.

At mid levels...A weak trough over and just east of the Lesser
Antilles will move across the area Sunday. A second low,
representing Tropical Storm Karl, in the tropical Atlantic will
move to north of Puerto Rico on Thursday. When it finally leaves
high pressure will build across the Atlantic north of the area
early the following week.

At lower levels...The TUTT low moving across Puerto Rico and the
U.S. Virgin Islands has induced a trough at the surface which will
pull across the local area on Sunday. Currently it is producing
showers and thunderstorms over the Windward Islands and should do
the same for the U.S. Virgin Islands and Puerto Rico. Although
Karl is still expected to have little effect on the local area,
patches of modest moisture will keep showers and isolated
thunderstorms in the forecast for the foreseeable future.

&&

.DISCUSSION...Scattered showers were seen over the Atlantic and
Caribbean waters in the northwest and southeast part of the
forecast area and a few of these did move over eastern PuertoRico
in the east northeast flow. Although a few showers passed around
the U.S. Virgin Islands no rain was observed over land there.
Currently moisture is at a minimum ahead of a trough whose axis is
currently northeast/southwest over Guadeloupe. The best convection
is generally behind this axis. Thunderstorms were observed
northeast of the Leeward Islands and the IR loop indicates
persistent convection in the vicinity. The TUTT will move across
Puerto Rico on Sunday with the same moisture and similar
conditions are expected here on Sunday as were had there
overnight. Showers should move into the USVI on Sunday morning and
be well developed over most of Puerto Rico by mid-afternoon on
Sunday. Urban and small stream flooding over much of the islands
cannot be ruled out. Showers and moisture will continue through
Tuesday afternoon, with the attendant showers and isolated
thunderstorms in the familiar daily pattern. Since Karl will pass
more than 300 nm north of the area Thursday morning according to
most models and the National Hurricane Center, if indeed it does
not decay into an open wave or tropical depression first as the
GFS suggests, moisture will be very modest owing to the distance
north of the forecast area it is expected to pass and the fact
that the best moisture is now and will continue to be considerably
northeast of the center. Moisture in the southeast flow to follow
will be modest but that same southeast flow will send temperatures
on the north coast back into the lower 90s for Friday and the rest
of the weekend.

&&

.AVIATION...In general, VFR conditions expected across the
USVI/PR terminals. An induced trough will cause wx condtions to
deteriorate at TNCM/TKPK this morning, SHRA/TSRA will result in
MVFR conds. During the afternoon, mtn obscurations/SHRA/TSRA are
possible across the interior and west sections of PR. This
activity may impact mainly TJPS/TJMZ and the VCTY of TJBQ btwn
17/17-22z. Sfc winds will continue from the east to east northeast
at 5-15 knots with sea breeze variations after 17/13z and gusty
near SHRA/TSRA.

&&

.MARINE...Seas are forecast to increase slowly during the week
during the relatively distant passage of Tropical Storm Karl to
the northeast. They should peak around 7 feet at the outer buoy
and remain below 7 feet in the local Atlantic and Caribbean
waters. At this time small craft advisories are not expected
during the next 10 days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 89 76 / 10 20 50 60
STT 90 79 87 76 / 30 40 40 70

&&

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 18, 2016 4:11:16 GMT -6

Quote

Post by cycloneye on Sept 18, 2016 4:11:16 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
535 AM AST SUN SEP 18 2016

.SYNOPSIS...A trough crossing through Puerto Rico today will bring
an increase in showers and thunderstorms today and tonight for
much of the area. Tropical Storm Karl is expected to pass north of
the area Thursday with minimal effects and only a slight increase
in moisture. Drier weather is anticipated next weekend, but
scattered showers and a few thunderstorms will still occur in the
west during the afternoons with a few light showers in the
mornings around the U.S. Virgin Islands and the east coast of
Puerto Rico.

At upper levels...A trough with a low centered 200 miles south of
Vieques will cross through Puerto Rico this afternoon and move
out of the area late tonight. High pressure will cross north of
the area late Friday night.

At mid levels...High pressure dominates the central Atlantic. A
trough over Puerto Rico will continue westward. A low pressure
associated with Tropical Storm Karl will pass north of the local
area Wednesday night. High pressure across the Atlantic will then
sag slowly south over the area over the weekend. Mid levels remain
relative dry over the area after Tuesday.

At lower levels...A trough has passed Saint Croix and will move
through Puerto Rico during the day today. Moisture will then taper
off through Wednesday night. Tropical Storm Karl is about 1500
miles due east of San Juan, Puerto Rico and will pass north of the
area early Thursday morning with minimal effect, although there
will be some additional moisture Thursday and Friday. A ridge will
extend broadly over the area Saturday.

&&

.DISCUSSION...Showers and thunderstorms moved into the eastern
half of the forecast area and increased in number and intensity
until a little after 3 AM AST. Thereafter showers diminished
considerably and lightning strikes became sparse. Activity is
expected to increase again as the low level trough approaches the
Puerto Rican mainland and solar heating commences. Urban and small
stream flooding is possible in Puerto Rico and the U.S. Virgin
Islands, today and early tonight. Moisture diminishes slowly after
today, but showers and thunderstorms will continue, though,
somewhat abated. Tropical Storm Karl is expected to pass well
north of the local area with only a slight increase in moisture.
Low level winds will also weaken and turn much more northerly.
With light winds and somewhat increased moisture urban and small
stream flooding would be expected in some localized areas--mainly
in the interior Thursday and possibly Friday. Drier conditions
return for the weekend, but scattered showers and thunderstorms
will continue right into the beginning of Fall and temperatures in
the lower elevations of the USVI and on the north coast of Puerto
Rico will remain around 90 degrees.

&&

.AVIATION...A surface trough will continue to produce SHRA from time
to time across the local area. Most of the activity should diminish
during the morning hours, but SHRA/TSRA are expected to develop once
again during the late morning and into the afternoon hours. Periods
of MVFR conditions are expected mainly across TJBQ/TJMZ/TJPS btwn
18/16z-23z, but are possible across TJSJ too. Sfc winds from the E-
ESE at 10-15 kts with sea breeze variations after 18/13z and gusty
near SHRA/TSRA.

&&

.MARINE...Seas will increase through Thursday, but should remain
below 6 feet especially if winds fail to develop in Karl`s western
quadrant. Small craft advisories are not expected during the next
10 days.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 76 90 79 90 / 60 60 50 50
STT 77 89 79 89 / 70 60 50 50

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 19, 2016 4:26:34 GMT -6

Quote

Post by cycloneye on Sept 19, 2016 4:26:34 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
601 AM AST MON SEP 19 2016

.SYNOPSIS...
The interaction between an Upper level low/TUTT, to the South
West, and an Upper level high pressure, to the North of the local
islands, will produce enough instability. These two features will
combine with a Tropical Wave, which is moving across the region
today, to enhance the potential of showers and thunderstorms
across the islands. Then, moisture and instability will gradually
diminish during the rest of the week. However...surges of
moisture embedded in the trades will bring scattered showers each
day.

&&

.DISCUSSION...
Scattered showers with isolated thunderstorm were detected with the
Doppler Radar and Satellites imagery overnight. A thunderstorm
moved inland from Southeast to Northeast Puerto Rico. Also, other
thunderstorms were observed moving westward across the Atlantic
and Caribbean waters. Most of the thunderstorms moved away from
the County Warning Area or dissipated early this morning.

For the rest of this morning, showers are expected to continue
across the regional waters, some of these showers will move
over the windward sections of Puerto Rico and the U.S. Virgin
Islands. This activity is associated with a Tropical Wave, which
is moving across the islands today. As a result the potential for
isolated thunderstorms is present during the morning hours too.

The tropical wave is expected to interact with an upper level
trough to produce another round of showers and thunderstorms along
and to the North and West of the Cordillera Central this
afternoon. Some of these thunderstorms will be capable of produce
frequent lightning, minor flooding, gusty winds and hazardous
driving conditions. In addition, maximum temperatures will range
from the lower 90s on the south and west coasts to around the mid
70s in the highest mountain areas.

From Tuesday to Friday...A mid level ridge will build over the
Eastern Caribbean leading to generally stable conditions. But
surges of moisture embedded in the trade winds will bring periods
of showers across the region from time to time. Also, thunderstorm
development is possible each afternoon mainly across the interior
sections of PR. Tropical Storm Karl is expected to pass well
northeast of the local area.

&&

.AVIATION...
Mainly VFR conditions expected through the forecast
period across all terminals with possible VCSH across
TIST/TISX/TJSJ/TNCM/TKPK through 19/16Z. SHRA and possible TSRA
developing between 19/17-22z across the interior and western PR
impacting mainly TJMZ/TJBQ and vcnty of TJPS. Low level winds will
be light east southeasterly overnight, increasing to around 10-15KT
after 19/13Z with sea breeze variations developing. Winds FL170-450
diminishing to less than 25 kt and becoming southeast by 19/18z.

&&

.MARINE...
Mariners can expect tranquil marine weather conditions with seas
up to 4 feet and winds at less than 18 knots. However, showers
and thunderstorms are possible across the regional waters, as a
tropical wave moves across the region today. Winds are expected to
continue from the East to Southeast until tuesday, then are
turning from the Northeast to North as Tropical Storm Karl pass
off to the Northeast of the region. For the beach goers, there is
a slight risk of rip currents across most of the local waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 79 90 79 / 50 50 50 30
STT 88 79 89 78 / 50 40 40 30

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Sept 20, 2016 4:32:23 GMT -6

Quote

Post by cycloneye on Sept 20, 2016 4:32:23 GMT -6

Area Forecast Discussion
National Weather Service San Juan PR
540 AM AST TUE SEP 20 2016

.SYNOPSIS...
A trofiness pattern aloft is enhancing the potential of showers
and thunderstorms across the Central and Eastern Caribbean. This
pattern will keep the atmosphere unstable for the rest of the
work week. The available moisture and instability will gradually
diminish by the end of the work week as a mid to upper level ridge
builds near the region. However, patches of low level moisture
will result in trade wind showers during the night and morning
hours, followed by afternoon showers and thunderstorms across the
islands each day.

&&

.DISCUSSION...
The Doppler Radar detected trade wind showers across the local
waters, some of them affected the windward sections of Puerto Rico
and the U.S. Virgin Islands from time to time. The preliminary
rainfall totals identified isolated rainfall amounts around a
quarter of an inch near El Yunque Rainforest and portions of East
PR.

Showers across portions of the half East section of PR and
across the U.S. Virgin Islands will continue during the morning
hours. During the afternoon, the proximity of the upper level low,
the available moisture and local effect will result in another
round of showers and thunderstorms across and to the west of the
Cordillera Central. Also showers are expected to develop and move
downwind from the U.S. Virgin Islands and the islands of Vieques
and Culebra. Some of these showers or thunderstorms could affect
the east municipalities of mainland PR, and the San Juan Metro
Area. Although the available moisture is expected to diminish
somewhat, locally induced afternoon showers and thunderstorms are
expected to continue each day at least until the end of the
workweek due to the trofiness pattern aloft.

For the rest of the workweek, the local wind flow pattern will be
dominated by the influence of Tropical Storm Karl, which is
expected to move well off to the Northeast of the local islands.
Consequently, as the winds shift from the north to northeast on
Wednesday, afternoon activity will focus to the south of the
Cordillera. Then by Thursday, a Southerly wind field is expected
to focus the afternoon activity to the North of the Cordillera
Central and downwind off to the North of the U.S. Virgin Islands.
As these changes in the wind field occurs, the winds are also
expected to become light, resulting in slow movers and long
lasting showers and thunderstorms.

&&

.AVIATION...
Moisture wrapping around an upper level low from the south will
move west and out of the the Leeward islands arnd 20/18z and out
of USVI arnd 20/22z and PR aft 21/02z. This moisture will bring
isold MVFR cigs in SHRA to TNCM/TKPK and psbly TISX. Aft 20/17Z
areas of SHRA/TSRA will bring mtn obscurations and MVFR conds to
mainly wrn PR. Winds east less than 5 kt bcmg 5 to 15 kt with sea
breeze influence aft 20/14z. Max winds alf E 30 kt arnd FL410 but
diminishing to 15 kt by 21/00z.

&&

.MARINE...
Across the regional waters, mariners can continue to expect
relatively tranquil marine conditions with seas below 5 feet and
east winds between 5 and 15 knots. The beach goers should exercise
caution mainly across the Atlantic Beaches due to a moderate risk
of rip currents.

&&

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

Shoutbox

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Puerto Rico Weather

Post by cycloneye on Sept 6, 2016 4:43:37 GMT -6

Post by cycloneye on Sept 7, 2016 4:10:18 GMT -6

Post by cycloneye on Sept 8, 2016 4:04:41 GMT -6

Post by cycloneye on Sept 9, 2016 4:27:34 GMT -6

Post by cycloneye on Sept 10, 2016 4:51:28 GMT -6

Post by cycloneye on Sept 11, 2016 4:18:07 GMT -6

Post by cycloneye on Sept 12, 2016 3:59:02 GMT -6

Post by cycloneye on Sept 13, 2016 4:25:23 GMT -6

Post by cycloneye on Sept 14, 2016 4:27:22 GMT -6

Post by cycloneye on Sept 15, 2016 4:37:02 GMT -6

Post by cycloneye on Sept 16, 2016 5:11:58 GMT -6

Post by cycloneye on Sept 17, 2016 4:32:28 GMT -6

Post by cycloneye on Sept 18, 2016 4:11:16 GMT -6

Post by cycloneye on Sept 19, 2016 4:26:34 GMT -6

Post by cycloneye on Sept 20, 2016 4:32:23 GMT -6

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