Caribbean - Central America Weather

[bvigal]

000
WGCA52 TJSJ 181225
FFWSJU
PRC151-181515-
/O.NEW.TJSJ.FF.W.0030.100518T1225Z-100518T1515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN JUAN PR
825 AM AST TUE MAY 18 2010

THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED A

* FLASH FLOOD WARNING FOR...
THE FOLLOWING MUNICIPALITY

IN PUERTO RICO
YABUCOA

* UNTIL 1115 AM AST

* AT 820 AM AST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED
TO INDICATE SHOWERS AND ISOLATED THUNDERSTORMS...SOME WITH VERY
HEAVY RAIN AFFECTING THIS MUNICIPALITY. IN ADDITION...U.S.G.S. RIVER
SENSORS INDICATED THAT THE LEVELS OF RIO GUAYANES AT CENTRAL ROIG
WERE RISING RAPIDLY AND WILL GO PAST FLOOD STAGE WITHING THE NEXT 15
MINUTES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE.

&&

LAT...LON 1807 6579 1804 6584 1805 6592 1807 6599
1809 6598

$$

BCS/FC

ADDITIONAL INFORMATION CAN BE FOUND AT /USE LOWER CASE LETTERS/:
HTTP://WWW.WEATHER.GOV/SANJUAN

[cycloneye]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE SAN JUAN PR
837 AM AST TUE MAY 18 2010

PRC015-057-095-109-151-181545-
/O.EXT.TJSJ.FA.Y.0124.000000T0000Z-100518T1545Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ARROYO PR-PATILLAS PR-MAUNABO PR-GUAYAMA PR-YABUCOA PR-
837 AM AST TUE MAY 18 2010

THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS EXTENDED THE

* URBAN AND SMALL STREAM FLOOD ADVISORY FOR RAPID RIVER RISES IN
FOR THE FOLLOWING MUNICIPALITIES...

IN PUERTO RICO
ARROYO...PATILLAS...MAUNABO...GUAYAMA AND YABUCOA

* UNTIL 1145 AM AST

* AT 832 AM AST DOPPLER RADAR INDICATED SHOWERS...WITH SOME LOCALLY
HEAVY RAIN ACROSS THESE AREAS. RADAR ESTIMATES AND U.S.G.S. RAIN
GAGES INDICATED THAT 1 TO 2 INCHES OF RAIN HAVE ALREADY FALLEN OVER
PARTS OF THE ADVISORY AREA AND IT CONTINUED TO RAIN. ADDITIONAL
RAINFALL AMOUNTS OF AT LEAST 1 INCH ARE EXPECTED THROUGH 1145 AM AST.

A FLASH FLOOD WARNING WAS ISSUED FOR YABUCOA AND ESPECIALLY FOR THE
RIO GUAYANES AT CENTRAL ROIG UNTIL 1115 AM AND THIS SUPERCEDES THE
URBAN AND SMALL STREAM FLOOD ADVISORY FOR THIS MUNICIPALITY.

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

[cycloneye]

Afternoon discussion by NWS San Juan


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
312 PM AST TUE MAY 18 2010

.SYNOPSIS...A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE ACROSS
OR JUST NORTH OF THE LOCAL AREA THROUGH THURSDAY AND WILL
INTERACT WITH A MOIST AND RELATIVELY UNSTABLE AIR MASS AND LOCAL
EFFECTS...TO PRODUCE ADDITIONAL PERIODS OF UNSETTLED WEATHER
ACROSS THE LOCAL ISLANDS. BY FRIDAY AND CONTINUING THROUGH THE
UPCOMING WEEKEND...A NEW...MID TO UPPER LEVEL TROUGH WILL BECOME
LOCATED WEST THROUGH NORTH OF THE LOCAL AREA AND SHOULD EVENTUALLY
AID IN THE DEVELOPMENT OF ADDITIONAL ACTIVE WEATHER.

&&

.DISCUSSION...FOR TONIGHT...BRIEF DRYING EARLY WILL BE REPLACED BY
A NEW BAND OF MOISTURE LATE TONIGHT AND LASTING THROUGH MUCH OF
WEDNESDAY. ONCE AGAIN DESPITE AN ATTEMPT AT SOME MID LEVEL
RIDGING...THIS NEW MOISTURE AND INSTABILITY...DECENT SURFACE
CONVERGENCE...OROGRAPHIC LIFTING AND LEFTOVER VENTILATION FROM
WESTERLIES AND A SERIES OF DISTURBANCES AT UPPER LEVELS...SHOULD
ALLOW FOR ADDITIONAL CLOUDINESS...SHOWERS AND A FEW THUNDERSTORMS
OVER PARTS OF THE LOCAL ISLANDS OVERNIGHT AND THROUGH WEDNESDAY.
ALTHOUGH NOT EXPECTED TO BE WIDESPREAD OR EXCESSIVE...ADDITIONAL
PERIODS OF HEAVY RAINFALL AND SOME URBAN AND SMALL STREAM
FLOODING ARE EXPECTED...WITH THE POTENTIAL FOR LOCALIZED FLASH
AND RIVER FLOODING. STILL APPEARS THAT BRIEF OVERALL DRYING WILL
OCCUR FOR WEDNESDAY NIGHT THROUGH VERY EARLY THURSDAY...BEFORE
MOISTURE INCREASES AGAIN THURSDAY THROUGH FRIDAY AND BEYOND.
ALTHOUGH NOT YET ETCHED IN STONE...THERE IS STILL THE "POTENTIAL"
FOR AT LEAST A COUPLE MORE DAYS OF ACTIVE WEATHER AND "POTENTIAL"
HEAVY RAINFALL AND FLOODING...ESPECIALLY AS WE TRANSITION INTO
THE UPCOMING WEEKEND AND EARLY NEXT WEEK. STAY TUNED.

&&

.AVIATION...SHRA WILL CONTINUE TO DEVELOP ALONG THE CORDILLERA
CENTRAL AND MOVE TO THE NORTHERN AND WESTERN SECTIONS OF PUERTO
RICO. ACROSS TJMZ AND TJBQ...TEMPO MVFR CONDITIONS AND MOUNTAIN
OBSCURATIONS ARE EXPECTED AT LEAST UNTIL 18/23Z. HOWEVER...
PREVAILING VFR CONDITIONS WITH SOME VCSH AND SCT CLOUDS ARE
EXPECTED FOR THE REST OF THE TAF SITES. SFC WINDS WILL REMAIN
FROM THE EAST SOUTHEAST BETWEEN 10 AND 20 KNOTS WITH SOME HIGHER
GUSTS.

&&

.MARINE...GENERALLY EXPECT WINDS OF 19 KNOTS OR LESS AND SEAS OF
6 FEET OR LESS ACROSS THE REGIONAL WATERS THROUGH AT LEAST
THURSDAY. SMALL BOAT OPERATORS SHOULD CONTINUE TO EXERCISE
CAUTION ACROSS MOST OF THE LOCAL COASTAL WATERS TONIGHT.

[Gustywind]

Hi Huc seems that Basse-Terre have nicely showered during the last two days.
The twaves are rolling right now so the opening cane season is not so far...
Regards
Gustywind

[Gustywind]

[cycloneye]

Good morning.Variable weather for today.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
523 AM AST WED MAY 19 2010

.SYNOPSIS...SURFACE HIGH PRESSURE WILL CONTINUE TO EXTEND FROM THE
CENTRAL ATLANTIC SOUTHWEST ACROSS THE SOUTHERN BAHAMAS THROUGH AT
LEAST THURSDAY...MAINTAINING A MODERATE TO FRESH EAST SOUTHEASTERLY
TRADE WIND FLOW ACROSS THE REGIONAL WATERS FOR THE NEXT SEVERAL
DAYS. MID TO UPPER LEVEL HIGH PRESSURE RIDGE WILL EXTEND ACROSS
THE NORTHEAST CARIBBEAN FROM THE EASTERN CARIBBEAN THROUGH AT LEAST
THURSDAY TO MAINTAIN A SOUTHWEST TO WEST MID TO UPPER LEVEL WIND
FLOW. EXPECT RIDGE TO FLATTEN/WEAKEN DURING THE LATTER PARTS OF THE
WEEK AND INTO THE UPCOMING WEEKEND AS SERIES OF SHORT WAVES WILL
PROPAGATE EASTWARD ACROSS THE WESTERN ATLANTIC.


&&

.DISCUSSION...
WHILE THE PREVAILING WESTERLY UPPER LEVEL FLOW CONTINUED TO
ADVECT HIGH LEVEL CLOUD DEBRIS ACROSS THE REGION... THE LOW TO
MID LEVELS WERE SLIGHTLY DRIER DURING THE EARLY MORNING HOURS
ACROSS THE ISLANDS AND SURROUNDING WATERS. HOWEVER...LATEST
SATELLITE AND DOPPLER WEATHER RADAR SHOWED ISOLATED TO SCATTERED
SHOWER ACTIVITY MOVING ACROSS THE COASTAL WATERS AND APPROACHING
THE EAST COASTAL SECTIONS OF PUERTO RICO...AS WELL AS PARTS OF
THE VIRGIN ISLANDS. IN ADDITION...ANOTHER PATCH OF TRADE WIND
MOISTURE WAS OBSERVED QUICKLY APPROACHING THE NORTHERN LEEWARD
ISLANDS. THIS AREA OF LOW TO MID LEVEL MOISTURE IS EXPECTED TO
REACH THE FORECAST AREA AND AGAIN INCREASE SHOWER ACTIVITY ACROSS
THE VIRGIN ISLANDS DURING THE MORNING HOURS...THEN SPREAD ACROSS
PUERTO RICO DURING THE REST OF THE DAY. THIS ADDITIONAL MOISTURE
COMBINED WITH DIURNAL AND LOCAL EFFECTS WILL ENHANCE AFTERNOON
CONVECTION ACROSS PARTS OF THE INTERIOR AND NORTHWEST SECTIONS OF
PUERTO RICO DURING THE AFTERNOON HOURS.

LATEST GFS MODEL GUIDANCE SUGGESTS WEAK MID TO UPPER LEVEL RIDGING
ACROSS THE REGION FOR AT LEAST THE NEXT DAY OR SO. THEREAFTER...
SEVERAL WEAK SHORTWAVE PERTURBATIONS IN THE MID TO UPPER LEVELS OF
THE ATMOSPHERE ARE FORECAST TO PASS OVER OR JUST NORTH OF THE LOCAL
REGION. THIS WILL FURTHER ENHANCE SHOWER AND ISOLATED THUNDERSTORM
ACTIVITY ACROSS THE REGION...ESPECIALLY DURING THE AFTERNOON HOURS
FOR THE REMAINDER OF THE WEEK AND INTO THE UPCOMING WEEKEND. BASED
ON LATEST MODEL GUIDANCE EXPECT SUFFICIENT TROPICAL/ITCZ MOISTURE
ADVECTION AND INSTABILITY ACROSS THE REGION TO MAINTAIN AN OVERALL
WARM AND MOIST ENVIRONMENT FOR THE NEXT SEVERAL DAYS. THIS WILL RESULT
IN PERIODS OF EARLY MORNING AND AFTERNOON CONVECTION ACROSS THE ISLANDS...
PARTICULARLY OVER PUERTO RICO WHERE LOCAL TERRAIN AND DIURNAL INFLUENCES
WOULD BE MORE DOMINANT. THEREFORE EXPECT POTENTIAL FOR LOCALIZED URBAN
AND SMALL STREAM FLOODING TO CONTINUE DURING MOST OF THE WEEK..AS WELL
AS POSSIBLE MUDSLIDES IN AREAS OF STEEP TERRAIN.

&&

.AVIATION...PREVAILING VFR CONDITIONS WITH SOME VCSH AND SCT CLOUDS
ARE EXPECTED FOR ALL TAF SITES DURING THE REST OF THE MORNING HOURS.
FOR THIS AFTERNOON...EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP
ALONG THE CORDILLERA CENTRAL AND WESTERN PORTIONS OF PUERTO RICO...
THEREFORE AFFECTING THE TJMZ AND TJBQ TERMINALS BETWEEN 19/17Z
AND 19/22Z. TJSJ 19/00Z SOUNDING INDICATED AN EAST SOUTHEAST TRADE
WIND FLOW FROM THE SURFACE TO AROUND 10K FEET...BECOMING LIGHT AND
VARIABLE FROM 10-20K FEET AND THEN WESTERLY AND STRONGER ALOFT.


&&

.MARINE...SURFACE HIGH PRESSURE ACROSS THE CENTRAL ATLANTIC EXTENDING
SOUTHWEST INTO THE NORTHEAST CARIBBEAN WILL HELP MAINTAIN A MODERATE
TO FRESH TRADE WIND FLOW ACROSS THE LOCAL OFFSHORE ATLANTIC WATERS
THIS AFTERNOON THROUGH AT LEAST THURSDAY AFTERNOON. THIS WILL RESULT
IN CHOPPY AND HAZARDOUS SEA CONDITIONS MAINLY ACROSS THE LOCAL OFFSHORE
NORTHEAST ATLANTIC WATERS.

&&

.CLIMATE...A TOTAL OF 1.32 INCHES OF RAIN FELL AT THE LUIS MUNOZ
MARIN INTERNATIONAL AIRPORT IN SAN JUAN ON TUESDAY 18TH MAY 2010.
THIS TIED THE PREVIOUS DAILY RECORD OF 1.32 INCHES WHICH WAS SET
IN 1965. FOR MORE INFORMATION ABOUT THIS RECORD AND YEAR TO DATE
RAINFALL STATISTICS...PLEASE SEE THE LATEST NEWS HEADLINE POSTED
AT http://WWW.WEATHER.GOV/SANJUAN.

[cycloneye]

000
FXCA62 TJSJ 191541 AAA
AFDSJU

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
1141 AM AST WED MAY 19 2010

.UPDATE...SATELLITE IMAGERY SHOWED MAINLY HIGH CLOUDS ACROSS
THE REGION DRIFTING IN THE WESTERLY UPPER LEVEL FLOW. THIS CLOUD
COVER WILL CONTINUE TO DIMINISH OVER THE LOCAL AREA DURING THE
NEXT COUPLE OF HOURS...ALLOWING THE SUNSHINE TO REACH THE SURFACE.
LATEST 19/12Z SOUNDING AND GPS MET DATA SHOWED PWAT VALUES OF 2
INCHES...BUT DECREASING. MEANWHILE...THE COMBINATION OF THE
AVAILABLE MOISTURE...DIURNAL HEATING AND LOCAL TERRAIN EFFECTS
WILL PRODUCE SHOWERS AND A FEW THUNDERSTORMS ACROSS THE INTERIOR
AND WESTERN SECTIONS OF THE ISLAND DURING AFTERNOON HOURS. AT THIS
TIME...THE DOPPLER RADAR IS DETECTING ONLY A FEW ISOLATED SHOWERS
MAINLY ACROSS THE SURROUNDING WATERS. A SMALL CRAFT ADVISORY WILL
BE IN EFFECT FOR THE OFFSHORE ATLANTIC WATERS DUE TO HIGH WINDS
AND SEAS DURING THE EVENING HOURS.

&&

.AVIATION...VCSH MAY AFFECT THE TERMINALS BEFORE THE SHOWERS AND
THUNDERSTORMS DEVELOP ACROSS THE INTERIOR AND WESTERN SECTIONS OF
PUERTO RICO DURING THE AFTERNOON HOURS...DELIVERING SHORT PERIODS
OF MVFR/IFR CONDITIONS...ESPECIALLY ACROSS TJMZ AND TJBQ. THE
PREVAILING SFC WINDS WILL REMAIN FROM THE EAST SOUTHEAST AT 10 TO
15 MPH...WITH SOME HIGHER GUSTS.

[cycloneye]

Afternoon discussion by NWS San Juan

It looks like bad weather will arrive to the NE Caribbean by friday.


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
235 PM AST WED MAY 19 2010

.SYNOPSIS...STRONG SURFACE HIGH PRESSURE WILL CONTINUE TO EXTEND
FROM THE CENTRAL ATLANTIC SOUTHWEST ACROSS THE NORTHEASTERN
CARIBBEAN THROUGH AT LEAST THURSDAY. THIS WILL HELP MAINTAIN A
MODERATE TO LOCALLY FRESH EAST SOUTHEASTERLY TRADE WIND FLOW
ACROSS THE REGIONAL WATERS THROUGH THE END OF THE WEEK. LOW
PRESSURE IS FORECAST TO DEVELOP ACROSS THE WESTERN ATLANTIC LATE
SUNDAY. DEEP TROPICAL MOISTURE EXPECTED TO AFFECT THE LOCAL AREA
NEXT WEEK.

&&

.DISCUSSION...IN GENERAL...MOSTLY SUNNY TO PARTLY CLOUDY SKIES
PREVAILED ACROSS THE LOCAL REGION DURING MOST OF THE DAY. ONLY
SCATTERED SHOWERS WERE NOTED ACROSS THE NORTHWEST SECTION OF
PUERTO RICO. ALTHOUGH LATEST 12Z TJSJ SOUNDING CAME MOIST...WINDS
HAVE BEEN TOO STRONG TO ALLOW SEA BREEZE TO DEVELOP...AND LATEST
SATELLITE IMAGES AS WELL AS MIMIC TPW PRODUCT FROM CIMSS SHOWED AN
AREA OF RELATIVELY DRY AIR HAVE MOVED OVER THE LOCAL AREA THE LAST
24 HOURS. THIS...IN COMBINATION WITH AN UPPER LEVEL RIDGE...IS
MAINTAINING RELATIVELY STABLE ATMOSPHERIC CONDITIONS ACROSS THE
NORTHEAST CARIBBEAN. STRONG HIGH PRESSURE AT THE SURFACE IS THE
MAIN WEATHER FEATURE CONTROLLING THE WEATHER ACROSS THE REGION.
HOWEVER...A MUCH WETTER PATTERN IS EXPECTED TO DEVELOP ACROSS THE
NORTHEAST CARIBBEAN STARTING LATE THIS WEEK. COMPUTER MODELS
SUGGEST AN AREA OF LOW PRESSURE WILL DEVELOP ACROSS THE BAHAMAS
DURING THE WEEKEND. THIS SYSTEM IS EXPECTED TO MOVE TOWARD THE
NORTHEAST...WHICH WILL INDUCE A SOUTHEAST TO SOUTH WIND FLOW
ACROSS THE LOCAL AREA. THIS FLOW WILL BRING WITH IT...DEEP
TROPICAL MOISTURE...WHICH IS EXPECTED TO LAST SEVERAL DAYS.
ALTHOUGH IS TOO EARLY TO KNOW EXACTLY HOW THIS WILL
EVOLVE...DEFINITELY WE WILL SEE A SIGNIFICANT INCREASE IN MOISTURE
ACROSS THE LOCAL AREA...COMPARED TO WHAT WE SAW TODAY.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS MOST OF THE TAF
SITES. AFTERNOON CONVECTION SHOULD BE MORE ISOLATED TODAY...BUT
EXPECT A FEW SHRA ACROSS THE WESTERN INTERIOR AND NORTHWESTERN
PORTIONS OF PUERTO RICO...DELIVERING SHORT PERIODS OF MVFR
CONDITIONS...ESPECIALLY ACROSS TJMZ AND TJBQ. THE PREVAILING SFC
WINDS WILL REMAIN FROM THE EAST SOUTHEAST AT 10 TO 20 MPH...WITH
HIGHER GUSTS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 77 91 78 90 / 30 30 40 40
STT 79 88 80 87 / 30 30 50 50

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&

$$

06/71

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1033 PM AST WED MAY 19 2010

.UPDATE...PATCHY MOISTURE WILL RESULT IN A FEW SHOWERS ACROSS THE
VI...EASTERN AND SOUTHEASTERN SECTIONS OF PUERTO RICO OVERNIGHT
THROUGH MID MORNING THURSDAY. AFTERWARDS...EXPECT AVAILABLE
MOISTURE TO COMBINE WITH LOCAL EFFECTS...RESULTING IN DIURNALLY
DRIVEN SHOWERS OVER THE INTERIOR AND WESTERN SECTIONS OF PUERTO
RICO TOMORROW AFTERNOON. WEAK RIDGING IN THE MID TO UPPER LEVELS
OF THE ATMOSPHERE WILL LIKELY HELP TO LIMIT SHOWER ACTIVITY
FURTHER ACROSS THE REGION ON FRIDAY...BEFORE A DEVELOPING AREA OF
LOW PRESSURE ACROSS THE BAHAMAS SHIFTS THE WINDS TO THE SOUTHEAST
AND STEERS MUCH DEEPER MOISTURE TOWARDS PUERTO RICO AND THE U.S.
VIRGIN ISLANDS OVER THE UPCOMING WEEKEND.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS MOST OF THE TAF
SITES FOR THE NEXT 24 HOURS. THE PREVAILING SFC WINDS WILL REMAIN
FROM THE EAST SOUTHEAST AT 10 TO 20 MPH.

[cycloneye]

Good morning to all. It looks like the weekend will be wet.

FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
422 AM AST THU MAY 20 2010

.SYNOPSIS...SURFACE RIDGE EXTENDING ACROSS THE NORTHEAST CARIBBEAN
FROM THE ATLANTIC HIGH NOW ACROSS THE NORTH CENTRAL ATLANTIC...
WILL RECEDE NORTHEASTWARD THROUGH FRIDAY ...AS A TROUGH DEVELOPS
ACROSS THE BAHAMAS AND SLOWLY LIFTS NORTH NORTHEAST ACROSS THE WEST
ATLANTIC DURING THE REMAINDER OF THE WORK WEEK...AND THROUGH THE
WEEKEND. THIS WILL RELAX THE SURFACE PRESSURE GRADIENT ACROSS THE
LOCAL AREA RESULTING IN DIMINISHING TRADE WINDS. IN THE MEANTIME...
THE PREVAILING EASTERLY TRADE WILL CONTINUE TO ADVECT PATCHES OF LOW
LEVEL MOISTURE ACROSS THE NORTHERN LEEWARDS TO INCLUDE THE LOCAL
ISLANDS.

&&

.DISCUSSION...SURGES OF QUICK PASSING LOW LEVEL MOISTURE TRANSPORTED
BY THE MODERATE TRADE WIND FLOW...WILL CONTINUE EASTWARD ACROSS THE
REGIONAL WATERS...RESULTING IN ISOLATED TO SCATTERED SHOWED ACROSS
PARTS OF THE VIRGIN ISLANDS...AND THE EAST AND NORTHEAST SECTIONS
OF PUERTO RICO DURING THE MORNING HOURS. FOR THE REST OF THE
DAY...EXPECT AVAILABLE MOISTURE TO COMBINE WITH DIURNAL AND LOCAL
TERRAIN EFFECTS...TO RESULT IN SHOWER DEVELOPMENT MAINLY OVER THE
PARTS OF THE CENTRAL INTERIOR AND WEST SECTIONS OF PUERTO RICO.
HOWEVER...FAIRLY WEAK RIDGING IN THE MID TO UPPER LEVELS OF THE
ATMOSPHERE WILL LIMIT SIGNIFICANT CONVECTIVE DEVELOPMENT ACROSS
THE ISLANDS TODAY THROUGH FRIDAY. GFS MODEL GUIDANCE..WHICH HAS SO
FAR INITIALIZED FAIRLY WELL...ALONG WITH LATEST WATER VAPOR
IMAGERY... CONTINUED TO SUGGEST THE DEVELOPMENT OF AN AREA OF LOW
PRESSURE ACROSS THE BAHAMAS. THIS WILL RESULT IN A GENERAL SHIFT
IN THE LOCAL WINDS ACROSS THE REGION TO MORE OF AN SOUTHEAST FLOW
AS THIS AREA OF LOW PRESSURE SLOWLY LIFTS NORTHWARD ACROSS THE
WESTERN ATLANTIC. THIS GENERAL WIND FLOW PATTERN WILL THEN BRING
DEEPER TROPICAL MOISTURE ACROSS THE REGION...AND THEREFORE INCREASE
THE CHANCES FOR MORE ACTIVE WEATHER OVER THE UPCOMING WEEKEND AND
INTO THE EARLY PART OF THE NEXT WEEK. IN ADDITION...AS THE MID TO
UPPER RIDGE NOW IN PLACE ACROSS THE REGION BREAKS DOWN...EXPECT A
SERIES OF SHORT WAVE PERTURBATIONS TO MAKE THEIR WAY ACROSS THE
AREA... THUS ALLOWING FOR MORE FAVORABLE CONDITIONS ESPECIALLY FOR
AFTERNOON CONVECTION. THEREFORE...STILL LOOKING FOR A SLIGHTLY WETTER
PATTERN ACROSS PARTS OF THE ISLANDS LATE FRIDAY AND THROUGH THE WEEKEND
AS PRECIPITABLE WATER WILL REMAIN NEAR OR ABOVE TWO INCHES. WILL
HOWEVER CONTINUE TO MONITOR AND REMAIN CONSERVATIVE WITH THE POPS
AND WEATHER FOR NOW...AS ALL IS DEPENDENT ON HOW MUCH AND EXACTLY
WHERE THE ABOVE MENTIONED AREA OF LOW PRESSURE DEVELOPS.

&&

.AVIATION...INTERMITTENT PERIODS OF MVFR IN PASSING SHOWERS WILL
PREVAIL ACROSS TIST...TISX AND TJSJ UNTIL 20/14Z. ELSEWHERE ACROSS
THE LOCAL TAF SITES PREVAILING VFR CONDITIONS ARE EXPECTED UNTIL
20/14Z. AFTERNOON CONVECTION WILL DEVELOP...WITH SHRA ACROSS THE
WESTERN INTERIOR AND NORTHWESTERN PORTIONS OF PUERTO RICO...
DELIVERING PERIODS OF MVFR CONDITIONS...ESPECIALLY ACROSS TJMZ AND
TJBQ AFTER 20/17Z. 20/00Z TJSJ SOUNDING INDICATED A MODERATE EAST
SOUTHEAST TRADE WIND FLOW FROM THE SURFACE TO AROUND 10K FEET...
BECOMING LIGHT FROM 10-20K FEET AND THEN WESTERLY AND STRONGER ABOVE
20K FEET.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
242 PM AST THU MAY 20 2010

.SYNOPSIS...SURFACE HIGH PRESSURE WILL CONTINUE TO EXTEND FROM
THE CENTRAL ATLANTIC SOUTHWEST ACROSS THE NORTHEASTERN CARIBBEAN
THROUGH AT LEAST FRIDAY. LOW PRESSURE IS FORECAST TO DEVELOP
ACROSS THE WESTERN ATLANTIC. THIS WILL RELAX THE SURFACE PRESSURE
GRADIENT ACROSS THE LOCAL AREA RESULTING IN DIMINISHING TRADE
WINDS. DEEP TROPICAL MOISTURE EXPECTED TO AFFECT THE LOCAL AREA
NEXT WEEK.

&&

.DISCUSSION...NOT MUCH GOING ON ACROSS THE LOCAL ISLANDS THIS
AFTERNOON. ONLY ISOLATED TO SCATTERED SHOWERS WILL CONTINUE TO
AFFECT THE NORTHWESTERN SECTION OF PUERTO RICO THROUGH
SUNSET..BUT OVERALL...SHOULD REMAIN WITH VARIABLY CLOUDY SKIES ACROSS
MOST OF THE AREA...WITH ONLY PASSING SHOWERS EXPECTED FOR TONIGHT.
HIGH PRESSURE CONTINUES DOMINATING THE NORTHEAST CARIBBEAN. THIS
HIGH PRESSURE IS PRODUCING A STRONG TRADE WIND FLOW ACROSS THE
LOCAL AREA. THEREFORE...SHOWERS ARE MOVING QUICKLY...AND RAINFALL
ACCUMULATIONS ARE NOT EXPECTED TO BE SIGNIFICANT. HOWEVER...FOR
TOMORROW...WINDS ARE EXPECTED TO DIMINISH SIGNIFICANTLY ACROSS THE
LOCAL AREA. THIS WILL ALLOW THE SEA BREEZE TO DEVELOP TOMORROW
AFTERNOON...AND WILL COMBINE WITH OROGRAPHIC EFFECTS AND BETTER
MOISTURE ACROSS THE NORTHEAST CARIBBEAN TO PRODUCE BETTER CHANCES
FOR SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL AREA

DURING THE WEEKEND...AN AREA OF LOW PRESSURE IS EXPECTED TO
DEVELOP ACROSS THE BAHAMAS...AND WILL LINGER WEST OF OUR AREA FOR THE
BEGINNING OF NEXT WEEK. THIS WILL INDUCE A SOUTHEASTERLY WIND FLOW
WHICH WILL BRING WITH IT...DEEP TROPICAL MOISTURE ACROSS THE
NORTHEAST CARIBBEAN. IF THIS OCCUR...THEN A WET WEEK WILL BE IN
STORE FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS. AT THIS
TIME...MOST MODELS AGREED IN THIS SCENARIO...WITH PLENTY OF
MOISTURE AFFECTING THE LOCAL AREA NEXT WEEK. STAY TUNED.

&&

.AVIATION...MVFR CIGS AT JMZ AND JBQ WITH PASSING SHRA THRU 20/22Z
THEN VFR THRU 21/15Z. SCT TSRA EXPECTED TOMORROW AFTERNOON WITH MVFR
CONDITIONS LIKELY AT JMZ/JBQ. VFR ELSEWHERE WITH JUST VCSH.

[Macrocane]

The SNET in El Salvador has issued a special advisory about dangerous swells in the Pacific coast of Central America. In summary this is what they are saying:

From Friday through Sunday an increase in the height of the waves will be experienced.

Friday May 21: wave heights will be in the 2.3-3 m range (7.5-9.8 ft)
Saturday May 22: The maximum wave heights will be experienced with waves in the 2.6-3.4 m (8.5-11 ft) range.
Sunday May 23: Wave heights between 2.5-3.3 m (8.2-10.9 ft) will be experienced.

The speed of the swells will be in the 45-60 km/h range (28-37 mph).

The normal height and speed of the waves in the Salvadorian coast is 1.2 m (4 ft) and 35 km/h (22 mph) respectively.

The NHC talks about this event too in their TWD:

CROSS-EQUATORIAL LONG PERIOD SW SWELL HAS REACHED MUCH OF THE
PACIFIC COASTLINE WITHIN THE FORECAST AREA WITH WAVE HEIGHTS IN
THE 4-7 FT RANGE...WITH THE EXCEPTION OF THE W COAST OF BAJA
CALIFORNIA WHERE NW WIND WAVES HAVE DRIVEN SEAS UP TO 6-9 FT.
THIS WAVE TRAIN IS EXCEPTED TO REACH THE MEXICAN AND CENTRAL
AMERICAN COAST BY FRI MORNING AND WILL INCREASE WAVES TO 10 FT
IN 20 SECOND SWELL IN THE COASTAL WATERS FRI INTO THE
WEEKEND...MAKING FOR DANGEROUS SURF CONDITIONS ESPECIALLY ON
SOUTH FACING BEACHES. SEAS ARE EXPECTED TO RISE ABOVE 8 FEET
OVER THE ENTIRE FORECAST AREA BY SAT MORNING AS THE SW SWELL
SPREADS NORTH THROUGH THE REGION.

[tropicana]

Regional Weather Summary
Thu May 20 2010

Thursday's Highs and rain (if any)

Piarco, C. Trinidad 33.2C 92F 1.2mm
Crown Point, Tobago 32.0C 90F

Point Salines, Grenada 30.5C 87F
Grantley Adams, Barbados 31.1C 88F 1.5mm
Arnos Vale, St Vincent 31.0C 88F 4.0mm
Hewannora, St Lucia 32.1C 90F 1.0mm
Vigie, St Lucia 31.3C 88F 2.6mm

Melville Hall, Dominica 30.2C 86F 2.7mm
Canefield, Dominica 32.0C 90F 2.8mm
Le Lamentin, Martinique 31.8C 89F 0.8mm
Le Raizet, Guadeloupe 29.6C 85F 7.9mm

Golden Rock, St Kitts 30.1C 86 6.8m
VC Bird, Antigua 30.2C 86F 3.0mm
St Maarten, VI 30.2C 86F 0.2mm
San Juan, Puerto Rico 30.6C 87F 1.3mm

Norman Manley, Jamaica 32.9C 91F trace
Sangster, Montego Bay, Jamaica 33.8C 93F 13.0mm
Owen Roberts, Grand Cayman 32.1C 90F 10.0mm
Havana, Cuba 30.7C 87F 0.2mm ( after 20.0mm on Wed 19th)

Nassau, Bahamas 28.2C 82F 2.0mm (*after 67.0mm on Wed 19th)
Hamilton, Bermuda 26.0C 78F

Cayenne, French Guiana 31.7C 89F 2.0mm

[cycloneye]

Good morning. Here we go with the moist period for us in the Caribbean.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
602 AM AST FRI MAY 21 2010

.SYNOPSIS...AT UPPER LEVELS...A MODEST WEST TO EAST JET WILL
CONTINUE OVER THE SOUTHEAST BAHAMA ISLANDS THROUGH MUCH OF THE
NEXT 7 DAYS...WITH A WEAK SHORT WAVE PASSING JUST NORTH OF THE
AREA ON SUNDAY. UNDULATIONS IN THE JET WILL BRING PERIODS OF UPPER
LEVEL DIVERGENCE THAT WILL ENHANCE CONVECTION IN AN ALREADY MOIST
AND UNSTABLE ATMOSPHERE.

AT MID LEVELS...HIGH PRESSURE OVER THE CARIBBEAN AND ACROSS THE
TROPICAL ATLANTIC WILL WEAKEN IN THE WESTERN CARIBBEAN AS LOW
PRESSURE FORMS NORTH OF HISPANIOLA OVER THE WEEKEND. WITH HIGH
PRESSURE OVER THE TROPICAL ATLANTIC AND NORTHEAST OF THE
WINDWARD ISLANDS AND A WELL-DEVELOPED LOW PRESSURE IN THE WESTERN
ATLANTIC...WIND FLOW OVER THE LOCAL AREA IS EXPECTED TO BECOME
SOUTHWEST AND SLOWLY MOISTEN DURING THE WEEK AND FOLLOWING
WEEKEND.

AT LOWER LEVELS...HIGH PRESSURE WHICH DOMINATED THE CENTRAL
ATLANTIC WILL WEAKEN AS ANOTHER HIGH MOVES SOUTHEAST OUT OF
CANADA AND INTO THE NORTHWEST ATLANTIC. AT THE SAME TIME A LOW
WILL DEVELOP NORTH OF HISPANIOLA AND MOVE NORTH UNTIL WEDNESDAY.
THIS WILL LEAVE THE LOCAL AREA IN LIGHTER BUT DECIDEDLY SOUTHEAST
FLOW FROM TODAY UNTIL NEXT WEEKEND. THIS LOW PRESSURE AND ONE THAT
FORMS IN THE SOUTHWEST CARIBBEAN WILL PULL DEEP MOISTURE ACROSS
THE LOCAL AREA THAT WILL GENERATE HEAVY RAINS FROM TIME TO TIME
DURING THE NEXT 10 DAYS.


&&

.DISCUSSION...MODELS ALL AGREE ON GENERALLY HUMID AND UNSTABLE
CONDITIONS PREVAILING IN THE AREA FOR THE NEXT 10 DAYS...BUT VARY
CONSIDERABLY ON TIMING OF MOISTURE AND DYNAMICS AS WELL AS THE
LOCATION OF LOWS THAT FORM. FLOW HAS BEEN TURNING SLOWLY TOWARD
THE SOUTHEAST IN THE LOWEST LEVELS EARLY THIS MORNING CONFIRMING
THE TREND EXPECTED IN THE GFS...NAM AND THE ECMWF. MODELS DIFFER
ON THE AMOUNT OF MOISTURE EXPECTED EVEN IN THE NEAR TERM AND HAVE
TAKEN A MIDDLE ROAD WITH THE FORECAST. EXACT AMOUNTS WILL DEPEND
ON WHERE THE LOW EXPECTED TO FORM NORTH OF HISPANIOLA ACTUALLY
FORMS. THE NAM 00Z SOLUTION DEVELOPED IT EAST OF PUERTO RICO AND
MOVED IT NORTH. THE 06Z SOLUTION STILL BROUGHT SOUTHWEST WINDS IN
THE LOWER LEVELS ON SUNDAY BUT MOVED THE INITIAL POSITION OF THE
LOW TO THE NORTHEAST. SO...GENERALLY FAVOR THE SOLUTION OF THE
GFS AND ECMWF WHICH FORM THE LOW TO THE NORTH OF HISPANIOLA
CONSISTENTLY AND PULL MOISTURE FROM THE SOUTHEAST IN SEVERAL
CONVERGING BANDS. AFTER THE LOW PULLS NORTH BOTH THE ECMWF AND
GFS BRING MOISTURE FROM ANOTHER LOW IN THE SOUTHWEST CARIBBEAN
OVER THE LOCAL AREA OVER THE FOLLOWING WEEKEND OR MONDAY AT THE
LATEST.

ONLY MODERATE CONFIDENCE CAN BE GIVEN TO ANY ONE SOLUTION IN THESE
RUNS. TOO MANY FACTORS WILL AFFECT THE TIMING AND INTENSITY OF THE
LOWS AND THEIR ASSOCIATED WEATHER. THE PROXIMITY OF A BRANCH OF
THE SUB-TROPICAL JET WITH 60-100 KNOT WINDS WILL BRING VARIOUS
PULSES OF DIVERGENCE ALOFT OVER THE LOCAL AREA THAT WILL INTERACT
WITH THE MOISTURE AND UNSTABLE CONDITIONS TO PRODUCE PERIODS OF
HEAVY RAIN IN SOME AREAS FROM TIME TO TIME. THE FORMATION OF THE
LOW IN THE SOUTHWEST CARIBBEAN AND THE EXACT POSITION OF THE LOW
OVER THE SOUTHEAST BAHAMAS WILL COMPLICATE FACTORS SINCE THE
MODELS TYPICALLY DO NOT HANDLE THE FORMATIONS TO THESE SYSTEMS
WELL. AND FINALLY THE AMOUNT OF CLOUD COVER GENERATED WILL ALSO
AFFECT THE LOCAL MESO SCALE FORMATION OF SHOWERS AND THUNDERSTORMS
OVER THE AREA. CONSIDERING THAT THIS MAY IS ALREADY WELL ABOVE
NORMAL AND THIS YEAR IS THE WETTEST SO FAR ON RECORD IT DOES NOT
SEEM UNREASONABLE WITH THE HIGH PRECIPITABLE WATERS OVER SUCH A
LONG PERIOD TO FORECAST ABNORMALLY HIGH POPS AND QPF OVER MUCH OF
THE AREA WITH AN EYE TO THE POSSIBLE ATTENDANT CONSEQUENCES OF
MUDSLIDES AND LOCAL FLOODING SOMETIME DURING THE NEXT 10 DAYS OR
POSSIBLY EVEN SEVERAL DIFFERENT EPISODES THIS WEEKEND AND NEXT
WEEKEND AND EVEN MID-WEEK.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL ACROSS MOST OF THE TAF SITES.
EXPECT ANOTHER DIURNAL INCREASE IN CLOUDINESS AND SHOWERS ACROSS
THE INTERIOR AND WESTERN SECTIONS OF PR DURING AFTERNOON HOURS.
TEMPO PERIODS OF MVFR/IFR CONDITIONS AND MOUNTAIN OBSCURATIONS IN
SHRA/TSRA ACROSS TJMZ AND TJBQ BETWEEN 21/17Z TO 21/22Z. LATEST
TJSJ SOUNDING AT 21/00Z INDICATED EAST SOUTHEAST TRADE WIND FLOW
FROM THE SFC TO AROUND 10 KFT... BECOMING LIGHT AND VARIABLE FROM
10-20 KFT AND THEN STRONGER WESTERLY ABOVE 20 KFT.

&&

.MARINE...CONDITIONS REMAIN BELOW SMALL CRAFT ADVISORY LEVELS AND
LOW PRESSURE DEVELOPING NORTH OF HISPANIOLA WILL TEND TO SUPPRESS
WINDS EVEN FURTHER...SUCH THAT CONDITIONS IMPROVE A LITTLE THROUGH
MONDAY. NEVERTHELESS THE INCREASE IN MOISTURE WILL RESULT IN AREAS
OF THUNDERSTORMS THAT WILL CONTAIN LOCALLY GUSTY WINDS AND HIGHER
SEAS.

[cycloneye]

Hey Caribbean gang,lets watch what will occur in the next few days as a wet pattern for the Caribbean for sure will develop so keep in mind that.


AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
254 PM AST FRI MAY 21 2010

.SYNOPSIS...SURFACE RIDGE NORTH OF THE AREA WILL WEAKEN OVER THE NEXT COUPLE
OF DAYS AS LOW PRESSURE OVER THE BAHAMAS MOVES NORTH ROUGHLY ALONG
70 WEST RESULTING IN FURTHER WEAKENING OF THE TRADE WIND FLOW. A
BROAD AREA OF LOW PRESSURE MAY ALSO FORM ACROSS THE SW CARIBBEAN
EARLY NEXT WEEK.

&&

.DISCUSSION...TPW VALUES AS LOW AS THEY ARE GOING TO BE AT THE
PRESENT MOMENT AS GUIDANCE SHOWS VALUES CLIMBING TO 2.0 INCHES
TONIGHT AND REMAINING AT OR ABOVE 2.0 INCHES THROUGH THE NEXT
SEVEN DAYS. LIGHTER WIND FLOW AS A RESULT OF WEAKENING SFC RIDGE
TO THE NORTH AND LOW PRES LIFTING TO THE NORTH WILL ALLOW FOR
STRONG SEA BREEZE AND MOISTURE CONVERGENCE EACH AFTERNOON ALLOWING
FOR INTENSE AND SLOW MOVING CONVECTION WITH THE POTENTIAL FOR
FLASH FLOODING. KEY FEATURE TO WATCH IS TROUGH OF LOW PRES NORTH
OF THE BAHAMAS WHICH COULD DEVELOP INTO A SUBTROPICAL DEPRESSION
OVER THE NEXT COUPLE OF DAYS. EVENTUAL TRACK AND STRENGTH OF THIS
SYSTEM WILL DETERMINE WHETHER ANY ADDITIONAL MOISTURE CAN ADVECT
INTO THE AREA. MODEL GUIDANCE SUGGESTS THIS SYSTEM WILL TRACK
NORTH ROUGHLY ALONG 70W WITH MOISTURE TONGUE LIKELY TO REMAIN TO
THE NORTHEAST OF THE LEEWARD ISLANDS BUT A TRACK MUCH FURTHER TO
THE WEST COULD BRING THIS TONGUE OF HIGH PW AIR INTO THE U.S.
VIRGIN ISLANDS.

A BROAD AREA OF LOW PRES MAY ALSO FORM IN THE SW CARIBBEAN NEXT
WEEK. CLIMATOLOGY FOR THE MONTH OF MAY SUGGESTS ANY DEVELOPMENT
WILL STAY WEST OF 70W AND MODELS HAVE BEEN INDICATING DEEP
TROPICAL MOISTURE AFFECTING HISPANIOLA NEXT WEEK.


&&

.AVIATION...MVFR CIGS AT JBQ/JMZ EACH AFTERNOON WITH TSRA. OTHERS
TAF SITES LIKELY TO REMAIN VFR WITH JUST VCSH.

&&

.MARINE...SEAS GENERALLY 2-4 FT ATLC WATERS AND 1-3 FT CARIBBEAN
SEA. TSTMS MOVING OFF THE NORTHWEST COAST IN THE LATE AFTERNOON THE MAIN
HAZARD. OTHERWISE...NO OTHER MARINE CONCERNS AT THIS TIME.

[cycloneye]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE SAN JUAN PR
316 PM AST FRI MAY 21 2010

PRC053-089-212215-
/O.NEW.TJSJ.FA.Y.0129.100521T1916Z-100521T2215Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LUQUILLO PR-FAJARDO PR-
316 PM AST FRI MAY 21 2010

THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED AN

* URBAN AND SMALL STREAM FLOOD ADVISORY
FOR THE FOLLOWING MUNICIPALITIES...

IN PUERTO RICO
LUQUILLO AND FAJARDO

* UNTIL 615 PM AST

* AT 315 PM AST DOPPLER RADAR INDICATED SHOWERS AND THUNDERSTORMS IN
THE ADVISORY AREA. THESE AREAS OF SHOWERS AND THUNDERSTORMS HAVE THE
CAPABILITY OF PRODUCING MODERATE TO HEAVY RAINFALL WHICH WILL LEAD
TO RAPID RISES ON SMALL STREAMS AND CREEKS...AS WELL AS MINOR
FLOODING ALONG ROADWAYS...THROUGH AT LEAST THOUGH 6:15 PM AST.

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
932 PM AST FRI MAY 21 2010

.UPDATE...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THAT AFFECTED
THE WESTERN SECTIONS OF PUERTO RICO LATE IN THE AFTERNOON AND EARLY
IN THE EVENING...DISSIPATED RAPIDLY AFTER SUNSET LEAVING ONLY PARTLY
CLOUDY SKIES ACROSS THE REGION. LATEST RADAR OBSERVATION SHOWED
ISOLATED TO SCATTERED SHOWERS DEVELOPING ACROSS THE CARIBBEAN
WATERS. FEW OF THEM AFFECTED VIEQUES...ST THOMAS AND ST CROIX...WITH
MINIMAL RAINFALL ACCUMULATIONS SO FAR. ACCORDINGLY TO THE GFS MODEL
GUIDANCE THE PWAT VALUES WILL CONTINUE TO SLIGHTLY INCREASE ACROSS
THE REGION...WITH VALUES ABOVE 2.0 INCHES THROUGH THE NEXT SEVERAL
DAYS. SURFACE RIDGE WILL CONTINUE TO WEAKEN AND AS A RESULT THE
TRADE WIND FLOW WILL BECOME LIGHT FROM THE SOUTHEAST FOR THE NEXT
SEVERAL DAYS. THE EXPECTED INCREASING MOISTURE...IN COMBINATION WITH
LIGHT TRADE WIND FLOW...WILL ALLOW TO INCREASE THE INSTABILITY
ACROSS THE REGION... INDUCING THE DEVELOPMENT OF SCATTERED SHOWERS
AND THUNDERSTORMS MAINLY ACROSS WESTERN AND INTERIOR SECTIONS OF
PUERTO RICO EACH AFTERNOON. SCATTERED SHOWERS WILL ALSO DEVELOP
ACROSS EASTERN SECTIONS OF THE ISLAND DURING THE NIGHT AND EARLY
MORNING HOURS.

THE INTENSITY OF THE PCPN FOR THE NEXT SEVERAL DAYS SHOULD BE
DICTATED BY THE EVENTUAL TRACK AND STRENGTH OF THE LOW
PRESSURE CENTER NORTH OF THE BAHAMAS...NEAR 25 N...72 WEST THIS
EVENING. AS INDICATED IN THE PREVIOUS DISCUSSION...MODEL GUIDANCE
SUGGESTS THAT THIS SYSTEM WILL TRACK NORTH ROUGHLY ALONG 70W WITH
MOISTURE TONGUE LIKELY TO REMAIN TO THE NORTHEAST OF THE LEEWARD
ISLANDS BUT A TRACK MUCH FURTHER TO THE WEST COULD BRING THIS TONGUE
OF HIGH PW AIR INTO THE U.S. VIRGIN ISLANDS AND PUERTO RICO.

LOOKING WELL AHEAD...21/18Z GFS MODEL GUIDANCE SUGGESTS THAT A LOW
PRESSURE CENTER WILL DEVELOP VERY CLOSE TO THE FA BY THE UPCOMING
WEEKEND...ADVECTING ABUNDANT TROPICAL MOISTURE ACROSS THE REGION.
STAY TUNED.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED ACROSS ALL TAF SITES AT
LEAST THROUGH 22/16Z. BRIEF PERIODS OF MVFR ARE POSSIBLE ACROSS TJMZ
AND TJBQ AFT 22/17Z...DUE TO SHRA/TSRA.

[Gustywind]

[Gustywind]

Good morning to all. Rain rain in store...

000
FXCA62 TJSJ 220927
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
527 AM AST SAT MAY 22 2010

.SYNOPSIS...AT UPPER LEVELS...LOW PRESSURE WILL DIG SOUTH OVER
HISPANIOLA DURING THE FIRST PART OF NEXT WEEK. A BRANCH OF THE SUB
TROPICAL JET WILL INTENSIFY JUST NORTH OF THE LOCAL AREA WEDNESDAY
THROUGH SUNDAY. FLOW REMAINS WEST OR SOUTHWEST THROUGH THE PERIOD.

AT MID LEVELS...LOW PRESSURE ABOUT 400 MILES NORTH OF ARECIBO WILL
DEEPEN AND MOVE NORTHWEST UNTIL WEDNESDAY. MEANWHILE HIGH PRESSURE
OVER THE CARIBBEAN WILL RE-GROUP IN THE WESTERN TROPICAL
ATLANTIC...MAINTAINING WEST SOUTHWEST FLOW. MOISTURE IS WEAKER AT
MID LEVELS SUNDAY THROUGH THURSDAY.

AT LOWER LEVELS...LOW PRESSURE ABOUT 400 MILES NORTH OF ARECIBO
WILL DEEPEN AND MOVE NORTHWEST UNTIL WEDNESDAY. NORTH FLOW AROUND
THE WEST SIDE OF THE LOW WILL FORCE A PLUME OF MOISTURE OVER THE
LOCAL AREA FRIDAY AND EARLY SATURDAY IF MODEL SOLUTIONS HOLD.

&&

.DISCUSSION...YESTERDAY HEAVY RAINS FELL IN NORTHWEST PUERTO RICO
AND IN RIO GRANDE...LEAVING OTHER AREAS MOSTLY SUNNY. OVERNIGHT
SHOWERS OVER THE CARIBBEAN MOVED THROUGH THE NORTHERN VIRGIN
ISLANDS AND ALSO ONTO THE SOUTHEAST COAST OF PUERTO RICO. AS
MOISTURE CONVERGES AROUND A DEVELOPING LOW...BANDS OF PRECIPITATION
MAY FORM AND EACH MODEL ATTEMPTS TO LOCATE THE POSITION OF THESE
BANDS AND SOLVE FOR RAIN AMOUNTS FROM THEM. FORMATION OF THE LOW
APPEARS TO BE NEARLY CERTAIN...ALTHOUGH THE BANDS MAY NOT BE AS
CLEARLY DEFINED AS THE NAM WOULD HAVE IT. THUS CHANCE OF RAIN FOR
TODAY AND THE NEXT SEVERAL DAYS IS MODERATED BY THE UNCERTAINTY OF
THE EXACT POSITION OF THE ZONE OF CONVERGENCE AND LOCALLY INDUCED
CONVERGENCE OF STREAMERS AND THE MESO-LOW OVER WESTERN OR
NORTHWESTERN PUERTO RICO COMPLICATED BY THE SHADOW OF TERRAIN IN
A SOUTHEAST FLOW. LEVELS OF MOISTURE ARE HIGH WITH PRECIPITABLE WATER
AGAIN PUSHING PAST 2.1 INCHES. EXPECT RAIN TO BE GREATER IN
COVERAGE AND AMOUNT THAN YESTERDAY...ALTHOUGH AREAS WHICH RECEIVED
THE MOST RAIN YESTERDAY SHOULD NOT RECEIVE THE MOST TODAY SINCE WINDS
WILL BE A LITTLE MORE SOUTHEAST DURING THE DAY THAN YESTERDAY.
THIS WILL ALSO MEAN ANOTHER DAY PUSHING 90 DEGREES IN THE SAN JUAN
METRO AREA.

MODELS CONTINUE TO BRING IN MOISTURE FROM THE SOUTHEAST ACROSS
THE AREA AND INTO THE LOW FORMING TO OUR NORTH DURING THE FIRST
DAYS OF NEXT WEEK AND THIS WILL KEEP THE AREA WET. THERE MAY BE AN
INTERMISSION ON THURSDAY ACCORDING TO THE GFS...BUT IT WILL BE
FOLLOWED BY THE RICHEST PLUME OF MOISTURE SEEN SINCE LAST YEAR ON
FRIDAY...AGAIN SHOULD THE GFS VERIFY. THIS COULD LEAD TO EXCEPTIONAL
RAINS AND A MONTH OF MAY THAT WILL LIKELY RANK IN THE TOP 5 MAYS
IF IT DOES NOT BREAK THE RECORD RAINFALL FOR THE MONTH. MORE
DETAILS WILL BE ISSUED ONCE THE MODELS SEEM TO SETTLE ON A
SOLUTION THAT DOES NOT BEAR WHAT LOOK LIKE ARTIFICIAL EXTREMES IN
THE WIND AND RAIN PATTERNS CURRENTLY IN THE SOLUTION LATE NEXT
WEEK.
&&

.AVIATION...
SHRA AND ISOLATED THUNDERSTORMS WILL DEVELOP ALONG THE CORDILLERA
CENTRAL AND MOVE TO THE NORTHERN AND WESTERN SECTIONS OF PUERTO
RICO THIS AFTERNOON. ACROSS TJMZ AND TJBQ...TEMPO MVFR CONDITIONS
AND MOUNTAIN OBSCURATIONS ARE EXPECTED BETWEEN 22/17Z TO 22/22Z.
HOWEVER... PREVAILING VFR CONDITIONS WITH SOME VCSH AND SCT CLOUDS
ARE EXPECTED FOR THE REST OF THE TAF SITES. LATEST TJSJ SOUNDING
AT 22/00Z INDICATED VRB WINDS AT 10 KTS OR LESS BETWEEN SFC TO
15 KFT.

&&

.MARINE...WINDS AND SEAS WILL SUBSIDE BEGINNING TODAY AND WILL
REMAIN BELOW SMALL CRAFT ADVISORY CONDITIONS THROUGH THE NEXT 10
DAYS EXCEPT WHERE THUNDERSTORMS MAY PRODUCE LOCALLY GUSTY WINDS
AND ELEVATED SEAS. CONDITIONS MAY DETERIORATE WITH RESPECT TO
WEATHER LATE NEXT WEEK WHEN SHOWERS AND THUNDERSTORMS INCREASE.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 88 77 / 40 40 40 40
STT 87 79 87 79 / 50 50 40 40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
&&

$$

11/12

[Gustywind]

Given our Pro mets of Guadeloupe, we should endure some nice amounts of water during the next couple of hours and especially tommorow and Monday. Yellow alert should come quickly this afternoon, i will keep you informed. Weather is grey and sad, with little showers in my area, wind is calm.