Caribbean - Central America Weather

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000
FXCA62 TJSJ 110828
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
428 AM AST MON MAY 11 2009

.DISCUSSION...
LATEST SATELLITE IMAGERY AND THE DOPPLER WEATHER RADAR SHOWED
A BAND OF LOW TO MID LEVEL MOISTURE APPROACHING THE U.S. VIRGIN
ISLANDS DURING THE OVERNIGHT HOURS. THIS PATCH OF MOISTURE IS
EXPECTED TO REACH THE EASTERN SECTIONS OF PUERTO RICO DURING THE
MORNING HOURS...THEN SPREAD WESTWARDS DURING THE REST OF THE DAY.

LATEST GFS MODELS INITIALIZED FAIRLY WELL AND STILL SUGGEST A
CONTINUED INFLUX OF TROPICAL MOISTURE ACROSS THE REGION FOR MOST
OF THE WORK WEEK...AS A THE PREVAILING EASTERLY TRADE WIND FLOW
INCREASES ACROSS THE REGION. THIS OVERALL PATTERN WILL RESULT IN
GOOD CHANCES FOR SHOWER ACTIVITY EACH DAY...ESPECIALLY DURING THE
EARLY MORNINGS ACROSS THE EAST SECTIONS OF THE ISLANDS...THEN
SPREADING ACROSS THE NORTH CENTRAL AND WEST SECTIONS OF PUERTO
RICO DURING THE AFTERNOON HOURS.

LATEST WATER VAPOR SHOWED AN UPPER LEVEL SHORT WAVE MOVING ACROSS
THE SOUTHWEST ATLANTIC THIS MORNING. THIS IS FORECAST TO TRACK NORTH
OF THE AREA WITH MID TO UPPER LEVEL RIDGING EXPECTED TO REMAIN IN
PLACE OVERHEAD FOR THE NEXT FEW DAYS. BY THE LATTER PART OF THE
WEEK HOWEVER...AN UPPER LEVEL TROUGH IS EXPECTED TO AMPLIFY OVER THE
SOUTHWEST ATLANTIC AND ONCE AGAIN FLATTEN THE MID TO UPPER LEVEL
RIDGE BY THE END OF THE WEEK. THIS WILL ONCE AGAIN ENHANCE SHOWER
AND THUNDERSTORM ACTIVITY ACROSS THE REGION...AND INCREASE CHANCES
FOR INCLEMENT WEATHER...AS EASTERLY PERTURBATIONS ARE ALSO FORECAST
TO MOVE ACROSS THE LOCAL AREA DURING THAT TIME.

FOR TODAY EXPECT THE AVAILABLE MOISTURE ACROSS THE AREA...COMBINED WITH
DIURNAL AND LOCAL EFFECTS TO INDUCE SHOWERS AND A FEW THUNDERSTORMS
MAINLY OVER PARTS OF THE INTERIOR AND WEST SECTION OF PUERTO RICO...AS
WELL AS OVER PARTS OF THE U.S. VIRGIN ISLANDS. HOWEVER NO WIDESPREAD
RAINFALL IS ANTICIPATED AT THIS TIME.

&&

.AVIATION...
PATCHES OF LOW LEVEL CLOUDS WITH EMBEDDED SHOWERS AND A FEW
THUNDERSTORMS WILL CONTINUE TO MOVE EASTWARD ACROSS THE U.S.V.I.
AND EASTERN PUERTO RICO...PRODUCING PERIODS OF MVFR CONDITIONS
ACROSS TISX...TIST AND TJSJ UNTIL AT LEAST 16Z. THIS MOISTURE WILL
CONTINUE TO TRACK WESTWARD AND AFTER 17Z...SHOWERS AND A FEW
THUNDERSTORMS WILL DEVELOP OVER THE CORDILLERA CENTRAL OF PUERTO
RICO PRODUCING PERIODS OF MVFR ACROSS TJMZ AND TJBQ UNTIL AT LEAST
22Z. LATEST TJSJ 00Z SOUNDING INDICATED AN EASTERLY WIND FLOW UP
TO 20 KNOTS FROM THE SURFACE TO AROUND 7K FEET...BECOMING LIGHT
AND VARIABLE FROM 7-20K FEET AND THEN WEST NORTHWESTERLY AND
STRONGER ABOVE 20K FEET.

&&

.MARINE...
MARINERS SHOULD EXPECT WINDS OF 18 KNOTS OR LESS AND SEAS OF 6 FEET
OR LESS TODAY...WITH A GRADUALLY INCREASE IN WINDS AND SEAS ACROSS
THE LOCAL WATER LATER IN THE WEEK...AS THE LOCAL SURFACE PRESSURE
GRADIENT TIGHTENS ACROSS THE REGION...AND FURTHER INCREASES THE
PREVAILING TRADE WIND FLOW. SMALL CRAFT OPERATORS SHOULD THEREFORE
EXERCISE CAUTION ACROSS THE OFFSHORE ATLANTIC AND CARIBBEAN WATERS
TODAY...AS WELL AS THE MONA PASSAGE.

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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
337 PM AST TUE MAY 12 2009

.SYNOPSIS...FRESH TRADES WILL PERSIST ACROSS THE NORTHEAST
CARIBBEAN THROUGH THE END OF THE WEEK. WEAK TROUGH ALOFT AND
ABUNDANT MOISTURE WILL KEEP WET CONDITIONS THROUGH THE END OF THE
WEEK. MID LEVEL RIDGE WILL BUILD FOR THE WEEKEND BRINGING DRIER
CONDITIONS.

&&

.DISCUSSION...LATEST MICROWAVE IMAGERY SHOWS PLUME OF MOISTURE
WITH 2.0+ INCHES PRECIPITABLE WATER EXTENDING FROM 60W WNW THROUGH
THE LEEWARDS TO THE USVI/PR AND THE EASTERN PORTION OF THE
DOMINICAN REPUBLIC IS FCST TO REMAIN OVR THE NORTHEAST CARIBBEAN
OVR THE NEXT FEW DAYS. THIS IN COMBINATION WITH A SURFACE TROUGH
LOCATED ALONG 64W IN ADDITION TO LOW-LVL VORTICES AS SEEN ON
RECENT VISIBLE IMAGERY WILL KEEP A VERY WET FORECAST FOR THE NEXT
24 HRS. ABUNDANT MOISTURE AND WEAK TROUGH ALOFT LIKELY TO KEEP WET
CONDITIONS THROUGH THE END OF THE WORK WEEK. CONTEMPLATED ISSUING
A FLASH FLOOD WATCH FOR TOMORROW HOWEVER MODEL SOUNDINGS SHOW
WINDS IN THE BDRY LYR IN THE 20-25 KT RANGE WHICH SHOULD KEEP
SHOWERS MOVING ALONG AND PREVENTING RAINS FROM BECOMING TOO
EXCESSIVE. RAIN GAGES ACROSS NORTHEAST PR SHOW RAINFALL RATES OF
UP TO AN INCH IN ONE HOUR. LOCALIZED FLOODING LIKELY IN SOME AREAS
BUT DONT THINK WILL SEE WIDESPREAD FLOODING ATTM.

DRIER WILL WORK INTO THE NORTHEAST CARIBBEAN ON SAT ON BACKSIDE OF
UPPER LOW OVR THE CNTRL ATLC BRINGING A SIGNIFICANT IMPROVEMENT TO
THE WX CONDITIONS.

&&

.AVIATION...EXPECT MVFR CONDITIONS IN PASSING SHRA ACTIVITY AT ALL
SITES UNTIL AROUND 22Z. TSRA POSSIBLE TJMZ AND TJBQ 18Z TO 22Z WITH
TEMPO IFR LIKELY TJBQ. OTHERWISE...EXPECT SHOWERY CONDITIONS TO
CONTINUE WITH TEMP MVFR IN PASSING SHRA ACTIVITY...AND LOW LEVEL
WINDS TO 20 KNOTS DURING THE DAY TODAY AND TOMORROW.


&&

.MARINE...SCA IN EFFECT FOR SEVERAL MARINE ZONES. PLEASE REFER TO
MARINE WEATHER MESSAGE FOR MORE DETAILS.

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FXCA62 TJSJ 131042
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
642 AM AST WED MAY 13 2009

.SYNOPSIS...AT MID TO UPPER LEVELS...AN UPPER LEVEL LOW WILL
DEVELOP AND WILL MOVE SOUTH...NORTHEAST OF THE LOCAL
AREA...CREATING THROUGHINESS ACROSS THE NORTHEAST CARIBBEAN FOR
THE NEXT DAYS.

AT LOW LEVELS...SURFACE HIGH PRESSURE WILL BUILD ACROSS THE
WESTERN ATLANTIC AND WILL KEEP A FRESH TRADE WIND FLOW ACROSS THE
LOCAL AREA. THIS HIGH WILL WEAKEN AS AN AREA OF LOW PRESSURE
DEVELOPS NORTHEAST OF THE LOCAL AREA. ANOTHER AREA OF LOW PRESSURE
IS FORECAST TO DEVELOP EARLY NEXT WEEK WEST OF THE BAHAMAS
BRINGING MOISTURE OUT OF THE TROPICAL ATLANTIC TO OUR SOUTHEAST.

&&

.DISCUSSION...THE NEXT SEVERAL WEEKS OF MAY 2009 ARE NOT EXPECTED
TO DRY OUT. SCATTERED TO NUMEROUS SHOWERS ARE EXPECTED TO PREVAIL
AT LEAST THROUGH SATURDAY. LATEST COMPUTER MODELS SUGGEST THAT
THIS WEATHER PATTERN WILL NOT CHANGE TOO MUCH FOR THE FEW NEXT
DAYS. LATEST MIMIC TOTAL PRECIPITABLE WATER IMAGE SHOWED A WIDE AREA
OF MOISTURE EXTENDING A FEW HUNDRED MILES TO OUR SOUTHEAST...
MOVING NORTHWEST. THIS AREA OF MOISTURE...WILL STREAM INTO THE LOCAL
AREA AT LEAST THROUGH FRIDAY. HOWEVER...AN AREA OF LOW PRESSURE IS
EXPECTED TO DEVELOP NORTHEAST OF THE LOCAL AREA. THIS LOW PRESSURE
AREA WILL STAY SPINNING FOR A FEW DAYS...AND WILL MOVE SLOWLY
NORTHWEST...WHICH WILL ALLOW THE WIND FLOW TO TURN MORE
SOUTHEAST...AND WILL BRING DEEP TROPICAL MOISTURE OVER THE LOCAL
AREA...EARLY NEXT WEEK. LATEST SJU-GFS PROG SOUNDING INDICATED
THAT PRECIPITABLE WATER VALUES ARE NOT GOING TO DROP TOO MUCH
DURING THE NEXT FEW DAYS. ALTHOUGH PRECIPITABLE WATER VALUES ARE
EXPECTED TO DECREASE BELOW 2.0 INCHES DURING THE WEEKEND...THEY ARE
FORECAST TO INCREASE ONCE AGAIN TO AT LEAST 2.0 INCHES EARLY NEXT
WEEK...AS THE AFOREMENTIONED AREA OF DEEP MOISTURE MOVES ACROSS
THE LOCAL AREA. IF THIS WAS NOT ENOUGH...GFS360 COMPUTER MODEL
SUGGESTS THAT AN AREA OF LOW PRESSURE WILL DEVELOP ACROSS THE
WESTERN CARIBBEAN WHICH IS FORECAST TO TRANSPORT MORE TROPICAL
MOISTURE ACROSS THE LOCAL AREA LATE NEXT WEEK. WITH THIS IN
MIND...URBAN AND SMALL STREAMS FLOODING ARE POSSIBLE FOR THE
FORESEEABLE FUTURE. STAY TUNED.

&&

.AVIATION...ALTHOUGH A WIDE AREA OF CLOUDS AND SHOWERS WILL PREVAIL
OVER THE LOCAL AREA...CONDITIONS WILL GENERALLY BE VFR UNTIL 13/16Z.
NEVERTHELESS...MOUNTAIN OBSCURATIONS WILL CONTINUE...ESPECIALLY OVER
THE CORDILLERA CENTRAL OF PUERTO RICO AND BRIEF PERIODS OF MVFR ARE
POSSIBLE AT ALL TAF SITES. AFTER 16Z...TJMZ AND TJBQ WILL HAVE
OCCASIONAL PERIODS OF MVFR...MAINLY FOR CEILINGS. BRIEF IFR
CONDITIONS WILL BE POSSIBLE IN HEAVY RAIN TILL 14/02Z...MAINLY AT
TJSJ...TJBQ...TJMZ. CONDITIONS WILL IMPROVE SOMEWHAT AFTER 14/02Z.

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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
228 PM AST THU MAY 14 2009

.DISCUSSION...SATELLITE IMAGERY SHOWING U/L LOW OVER EASTERN CUBA
WITH LOW LEVEL EASTERLY DISTURBANCES OVER HISPANIOLA AND THE
LEEWARD ISLANDS. FA CURRENTLY WEDGED IN BETWEEN THESE TWO LOW
LEVEL FEATURES WITH SOME 700 LAYER DRIER AIR EVIDENT ON MORNING
TJSJ SOUNDING. AMPLE CIRRUS DECK THIS MORNING HAS HELPED TO HOLD
CONVECTION AT BAY UNTIL LATER THAN EXPECTED THIS AFTERNOON...AND
TO A MORE LOCALIZED EXTENT. STILL TRYING TO DECIDE WHAT TO DO WITH
THE FLASH FLOOD WATCH...AS CONDITIONS HAVE NOT PANNED OUT FOR
WIDESPREAD ACTIVITY...BUT MORE MOISTURE IS ON THE WAY IN FROM THE
EAST.

12Z NAM12 RUN SHOWING STRONG LOW LEVEL MOISTURE ADVECTION RIDING
ALONG THE TOP EDGE OF NEXT LOW LEVEL DISTURBANCE TO MOVE OVER
NORTHERN COASTAL WATERS AND N COAST OF THE ISLANDS OVERNIGHT.
SHOULD PROVIDE FOR AT LEAST NUMEROUS SHOWER ACTIVITY...BUT DOUBT
ANYTHING MORE THAN MINOR FLOODING SHOULD RESULT. MAY LET THE WATCH
GO WITH THE AFTERNOON PACKAGE. HOWEVER...WERE NOT OUT OF THE WOODS
YET AS MODELS SHOWING GOOD LOW LEVEL ADVECTION IN SELY FLOW
TOMORROW WITH U/L SHIFTING SLIGHTLY EAST AND PLACING REGION UNDER
GOOD DIFFLUENT FLOW ALOFT. TOMORROW STILL ON TRACK FOR HEAVY RAIN
EVENT. WEEKEND FORECAST IS TRICKY WITH AREA ON THE BOUNDARY OF
SHARP U/L DRYING TO OUR NORTH TO BE RIGHT ON THE NORTHERN EDGE OF
THE ISLAND. DECIDED TO KEEP THE SCATTERED RANGE POPS...BUT NEXT
SHIFTS MAY NEED TO BUMP THAT UP A BIT. SUNDAY LOOKS THE SAME WITH
DIURNAL CONVECTION OVER THE INTERIOR AND WESTERN PORTIONS OF THE
ISLAND.

LOOKING AHEAD TO NEXT WEEK...ANOTHER U/L LOW TO MOVE OVER THE GULF
OF MEXICO AND OVER THE GREATER ANTILLES WITH LOWER LEVEL TROUGHING
TO FORM DEEP SOUTHERLY LOW LEVEL FLOW FOR THE FIRST HALF OF THE
WEEK. WITH UPPER LEVEL CONDITIONS STILL FAVORABLE AND AMPLE
TROPICAL MOISTURE IN PLACE...NO END IN SIGHT FOR HEAVY RAINFALL
THREAT AS OF NEXT WEEK. SOILS ARE FULLY SATURATED IN MOST
LOCATIONS...WITH SOME RIVERS STILL NEAR ACTION STAGE...SHOULD BE A
DECENT CHANCE OF FLOODING AND HIGH CHANCE OF MUDSLIDES THROUGH THE
FIRST HALF OF THE WEEK.


&&

.AVIATION...MOSTLY PREVAILING VFR FOR THE NEXT 6 TO 12
HOURS...WITH SOME TEMPO MVFR AT TJMZ AMD TISX. MORE MOISTURE TO
COME OVERNIGHT...LIKELY LEADING TO MORE MVFR CONDITIONS OVER MOST
EASTERN AIRPORTS.


&&

.MARINE...BUOY 41403 NOW SHOWING 8 FOOT SEAS...ALTHOUGH THOSE
HEIGHTS MAY BE CONFINED TO WATERS TO THE NORTH OF OUR LOCAL AREA.
WILL INTRODUCE SOME 7 FOOT SEAS AND SCA TO OFFSHORE ATLC ZONE 710
FOR THE NEXT FEW PERIODS. ALL OTHER AREAS AT 6 FEET OR LESS
THROUGH THE 7 DAY FORECAST.

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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
210 PM AST FRI MAY 15 2009

.DISCUSSION...SATELLITE PICS CONTINUE TO SHOW U/L LOW OVER EASTERN
CUBA WITH WEAK EASTERLY DISTURBANCES NEARLY UNDERNEATH IT AND
ANOTHER OVER THE VI ATTM. THE LATTER OF THESE TWO FEATURES IS
HELPING TO TRIGGER SOME CONVECTION...FOCUSED ON THE WESTERN
PORTION OF THE ISLAND...THANKS TO PLENTIFUL SUNSHINE THIS MORNING
ISLAND WIDE. AS THIS WEAK DISTURBANCE MOVES BY COMPLETELY THIS
EVENING...LOOKS LIKE SOME DRYING IS IN STORE ESPECIALLY OVER THE
NORTHERN AND EASTERN SECTIONS OF THE CWA.

SUNDAY LOOKS DRIER THAN ANY DAY SEEN RECENTLY WITH SHARP 700 LAYER
DRY SLOT AND WEAKER U/L MOISTURE...HOPEFULLY WILL ALLOW FOR SOME
SUNSHINE. AFTER THAT...THE FAUCET TURNS ON AGAIN AS DEEP LAYER
SOUTHERLY FLOW ADVECTS MORE TROPICAL MOISTURE INTO THE REGION.
BOTH NAM12 AND GFS SPINNING UP A LOWER LEVEL LOW...BUT DIFFER ON
TIMING AND PLACEMENT MONDAY INTO TUESDAY. U/L DIFFLUENCE MONDAY
AFTERNOON SHOULD HELP THUNDERSTORM ACTIVITY. REMAINDER OF THE
WEEK LOOKS FAIRLY MOIST...WITH GFS SHOWING SOUTHERLY FLOW AND
DEEP MOISTURE TO PREVAIL THROUGH MID WEEK.


&&

.AVIATION...TSRA AT JMZ WITH MVFR/IFR CIGS THRU 21Z...OTHERWISE VFR
CONDITIONS AT ALL OTHER AIRPORTS WITH VCSH.


&&

.MARINE...WILL CANCEL THE SCA FOR OFFSHORE ATLC WATERS FOR 4 PM
PACKAGE AS BUOY SHOWING WAVE HEIGHTS UNDER 6 FEET AND WWIII DATA
COMING DOWN FOR THE NEXT DAY OR SO. SEAS ARE PROGGED TO RISE A BIT
LATER THIS WEEKEND AS SOME WEAK TO MODERATE NELY SWELL ENERGY
COMES IN AT AROUND 6 FEET AT 10 SECONDS.

[cycloneye]

Area Forecast Discussion
Issued by NWS San Juan, PR


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000
FXCA62 TJSJ 161037
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
637 AM AST SAT MAY 16 2009

.SYNOPSIS...AT UPPER LEVELS...PUERTO RICO AND THE U.S. VIRGIN
ISLANDS WILL REMAIN ON THE EAST SIDE OF A TROUGH CURRENTLY OVER
THE CENTRAL CARIBBEAN UNTIL ITS PASSAGE TUESDAY EVENING. A LOCAL
JET MAXIMUM WILL REMAIN JUST SOUTHEAST OF PUERTO RICO AND THE U.S.
VIRGIN ISLANDS...BUT WILL RETURN TO THE AREA SUNDAY NIGHT AND
MONDAY. FLOW WILL SHIFT FROM SOUTHWEST TO NORTHWEST TUESDAY NIGHT
AND A RIDGE WILL APPROACH ON WEDNESDAY AND THURSDAY. FRIDAY
THROUGH MONDAY OF NEXT WEEK THE LOCAL AREA WILL REMAIN NEAR OR
UNDER AN UPPER LEVEL RIDGE.

AT MID LEVELS...DESPITE THE STRENGTH AND SIZE OF A STRONG LOW
PRESSURE ABOUT 1200 MILES NORTHEAST OF SAN JUAN...THE LOCAL AREA
WILL REMAIN UNDER THE INFLUENCE OF WEAK RIDGING OUT OF SOUTH
AMERICA. THIS RIDGE WILL DRIFT SLOWLY WEST DURING THE UPCOMING
WEEK AND THEN RETURN AS CLOSE AS HISPANIOLA BY MONDAY OF THE
FOLLOWING WEEK. THE STRONGEST INFLUENCE OF THE MID LEVEL TROUGH
ASSOCIATED WITH THE LOW WILL REMAIN JUST NORTH OF THE AREA.

AT LOWER LEVELS...ALTHOUGH HIGH PRESSURE CURRENTLY DOMINATES THE
WESTERN ATLANTIC...IT WILL WEAKEN DURING THE WEEKEND AND A TROUGH
WILL BE ABLE TO DEEPEN FROM SOUTH AMERICA...ACROSS THE LOCAL AREA...TO
A STRONG LOW ABOUT 1200 MILES NORTHEAST OF THE LOCAL AREA...NEAR 32
NORTH 53 WEST. THIS TROUGH WILL MOVE FROM THE SOUTHEAST ACROSS THE
FORECAST AREA WITH COPIOUS MOISTURE MONDAY. ALTHOUGH HIGH PRESSURE TRIES
TO RETURN TO THE WESTERN ATLANTIC...SOUTH TO SOUTHEASTERLY FLOW
REMAINS OVER THE LOCAL AREA THROUGH THE END OF THE WEEK GENERATING
ANOTHER WET WEEK FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS.

&&

.DISCUSSION...CURRENT RADAR SHOWED SCATTERED SHOWERS GENERATING
JUST OFFSHORE AND THEN MOVING INLAND ON EAST NORTHEAST FLOW. MUCH
OF THE NORTH CENTRAL AND NORTHEASTERN COAST AND FOOTHILLS HAVE
RECEIVED RAIN THAT RANGED FROM A TRACE TO ALMOST ONE HALF INCH.
MODELS ARE INDICATING A LITTLE LESS CLOUD COVER AND RAIN DURING
THE WEEKEND AND THE DRIEST PERIOD MAY BE TONIGHT. STILL EXPECT
LOCALLY HEAVY RAIN IN THE FAVORED AREAS OF WESTERN AND
SOUTHWESTERN PUERTO RICO TODAY...PERHAPS LESS TOMORROW...SUNDAY.

BOTH THE NAM AND GFS SHOW A TROUGH ENTERING THE SOUTHEAST CORNER
OF THE FORECAST AREA SUNDAY EVENING. THAT TROUGH CURRENTLY APPEARS
AS A CLOUD ENHANCEMENT THAT STRETCHES ACROSS THE SOUTHERN WINDWARD
ISLANDS...ROUGHLY FROM 10 NORTH 64 WEST TO 19 NORTH 54 WEST.
MODELS HAVE BEEN HARPING ON THIS SYSTEM FOR THE PAST SEVERAL DAYS
ALTHOUGH THE GFS AND NAM DIFFER CONSIDERABLY ON THE LOCAL DETAILS.
THE GFS FAVORS MORE WIDESPREAD RAIN THAT MOVES IN FROM THE
SOUTHEAST SUNDAY NIGHT INTO MONDAY MORNING AND BUILDING TO OUR
NORTH IN SEVERAL...LIKELY SPURIOUS...BULLS EYES OF PRECIPITATION.
ALTHOUGH RELATIVE HUMIDITIES AT 850 MB FADE FROM THEIR HIGHS
MONDAY AFTERNOON OVER THE AREA...THEY SHOW AREAS OF 80 PLUS
PERCENT RELATIVE HUMIDITY TUESDAY THROUGH SUNDAY MAY 24. THE NAM
BRINGS IN VERY DRY AIR TONIGHT AT 850 MB...LESS THAN 50 PERCENT RH
OVER SAN JUAN...AND THEN ADVANCES RELATIVE HUMIDITIES OF 95 PLUS
PERCENT THROUGH THE FORECAST AREA...BEGINNING 18Z SUNDAY AND
PASSING OUT OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS TO THE
NORTH BY 12Z MONDAY. A SECOND WAVE OF MOISTURE ROLLS THROUGH
MONDAY NIGHT AND AGAIN TUESDAY EVENING.

AT THE MOMENT FAVOR THE GFS INTERPRETATION MOST. THE NAM SEEMS TO
HAVE ARRIVED AT ITS SOLUTION OF STRONG BANDED PRECIPITATION
THROUGH THE FORMATION OF A STRONGER WAVE AROUND THE TROUGH THAN IS
ACTUALLY LIKELY AND HAS BEEN OVER AMPLIFYING ALL FEATURES IN THE
SAME MANNER DURING THE LAST SEVERAL DAYS. ON THE OTHER HAND...THE
NAM SHOWS MORE MOISTURE FOLLOWING THE TROUGH PASSAGE ON MONDAY
THAN THE GFS AND DUE TO THE PERSISTING WET CONDITIONS IN THE
ENTIRE EASTERN CARIBBEAN WOULD TEND TO AGREE THAT THIS IS THE MORE
LIKELY SCENARIO.

THEREFORE EXPECT INCREASING SHOWERS FROM THE SOUTHEAST ON SUNDAY
NIGHT WITH CONSIDERABLE RAIN AND ISOLATED EMBEDDED THUNDERSTORMS
ON MONDAY FOLLOWED BY SCATTERED SHOWERS MONDAY NIGHT AND ANOTHER
ROUND OF SHOWERS AND GENERALLY WET WEATHER TUESDAY AND POSSIBLY
EVEN WEDNESDAY DURING THE DAYLIGHT HOURS. ALTHOUGH THE TROUGH WILL
BE QUITE WET...DO NOT BELIEVE THE UPPER LEVEL DYNAMICS ARE QUITE
STRONG ENOUGH TO GENERATE VERY HEAVY RAIN. NEVERTHELESS WITH
PRECIPITABLE WATER VALUES FROM 1.8 TO 2.1 INCHES OVER A WIDE AREA
OF THE EASTERN CARIBBEAN...THE UPPER LEVEL JET IN THE VICINITY AND
THE TROUGH HOLDING TO THE WEST UNTIL LATE TUESDAY...CONDITIONS ARE
QUITE FAVORABLE TO WIDESPREAD MODERATE TO HEAVY RAINFALL AMOUNTS
THAT WILL EVENTUALLY GENERATE SOME FLOODING OF SMALL STREAMS AND
MAIN STEM RIVERS AND ANOTHER ROUND OF MUDSLIDES ACROSS A FAIRLY
WIDE AREA OF PUERTO RICO. AMOUNTS ACROSS THE U.S. VIRGIN ISLANDS
HAVE TYPICALLY BEEN LIGHTER THAN OVER PUERTO RICO THIS
MONTH...BUT THIS PATTERN WILL EXTEND THE PERIOD OF WELL-ABOVE
NORMAL RAINFALL THERE...EVEN THOUGH FLOODING IS NOT PARTICULARLY
LIKELY. WET CONDITIONS WILL CONTINUE BUT WILL BE MORE DIFFICULT TO
PREDICT...BECAUSE THE GFS IS TRYING TO DEVELOP LOW PRESSURE TO THE
NORTH WHICH WILL CAUSE FLOW TO BECOME SOUTHERLY OVER THE AREA.
THIS IN TURN WILL BRING CONSIDERABLE RAINFALL TO THE SOUTHERN
SLOPES AND MAY ALSO GENERATE THUNDERSTORMS ON THE NORTH HALF OF
THE ISLAND SHOULD SUFFICIENT SUN BE SEEN. THAT SAID THOUGH...MODELS HAVE
BEEN SHOWING MOSTLY CLOUDY SKIES FOR MUCH OF THE WEEK AND EXPECT
THAT THIS WILL BE THE CASE. WILL ISSUE AN ESF FOR UPCOMING RAIN
SITUATION SHORTLY.

&&

.AVIATION...MAINLY VFR CONDITIONS ARE EXPECTED ACROSS MOST TAF SITES
DURING THE MORNING HOURS. BETWEEN 10-16Z...SOME VCSH ARE POSSIBLE
ACROSS TNCM...TKPK...TIST...TISX...TJSJ AND TJPS. AFTER 16Z...EXPECT
AFTERNOON SHOWER AND THUNDERSTORM DEVELOPMENT OVER THE INTERIOR OF
PUERTO RICO TO BRING TEMPORARY MVFR CONDITIONS ACROSS TJMZ FROM
16-22Z. WINDS WILL BE MAINLY FROM THE EAST AT 10 TO 15 KTS...WITH
GUSTS BETWEEN 20-25 KTS NEAR SHOWERS. MOUNTAIN OBSCURATIONS SHOULD
BE EXPECTED ACROSS SOUTHWEST PUERTO RICO AFTER ABOUT 17Z.

&&

.MARINE...MODERATE TO FRESH WINDS ACROSS THE ATLANTIC AND
CARIBBEAN WATERS HAVE BROUGHT SEAS OF 4 TO 6 FEET ACROSS MOST
AREAS EXPOSED TO EASTERLY WINDS. ALTHOUGH SEAS ARE TO SUBSIDE DUE
TO WINDS...A STRONG LOW PRESSURE NEAR 32.5 NORTH 53.1 WEST
HAS GALE FORCE WINDS IN ITS NORTHWEST QUADRANT WHICH WILL
GENERATE OF 4 TO 6 FOOT SWELL FOR PUERTO RICO AND THE NORTHERN
U.S. VIRGIN ISLANDS BEGINNING TONIGHT AND CONTINUING THROUGH
TUESDAY. THIS WILL BRING ROUGH AND CONFUSED CONDITIONS TO ALL
AREAS NOT IN THE SHADOW OF THE NORTH NORTHEASTERLY SWELL.
CONDITIONS WILL SUBSIDE SLOWLY TUESDAY THROUGH THE END OF THE WEEK.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
549 AM AST SUN MAY 17 2009

.SYNOPSIS...AT UPPER LEVELS...A TROUGH WILL DIG THROUGH THE WINDWARD
PASSAGE OVER THE WEEKEND AND THEN MOVE EAST...PASSING PUERTO RICO
AND THE U.S. VIRGIN ISLANDS ON TUESDAY. A RIDGE WILL BUILD BEHIND
IT ON WEDNESDAY OVER THE DOMINICAN REPUBLIC AND THEN SLOWLY DRIFT
THROUGH THE LOCAL AREA FRIDAY AND SATURDAY. A SECOND TROUGH WILL
PASS THROUGH THE FOLLOWING MONDAY FOLLOWED BY INCREASED JET
ACTIVITY.

AT MID LEVELS...HIGH PRESSURE EXTENDS ACROSS PUERTO RICO FROM THE
SOUTHEAST CARIBBEAN TO A HIGH NORTH OF THE BAHAMAS. HIGH PRESSURE
THEN RE-GROUPS ALONG 70 WEST THURSDAY WITH TWO LOW SYSTEMS...ONE
STRENGTHENING OVER THE GULF AND A MATURE LOW OVER THE CENTRAL
ATLANTIC...FORMING A HARD-TO-MOVE BLOCK.

AT LOWER LEVELS...HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL
PULL NORTH WHILE A LOW NEAR 32 NORTH AND 53 WEST IN THE CENTRAL
ATLANTIC SLOWLY DECAYS IN PLACE. ON THURSDAY THE LOW MOVES SOUTH
OF 30 WEST. SURFACE FLOW IS MORE SOUTHEASTERLY AND GENERALLY
MOIST.


&&

.DISCUSSION...LOWER LEVEL FLOW CONTINUES TO BE EAST NORTHEAST AND
MOISTURE IS FAIRLY CONSTANT. VERY LIGHT SHOWERS HAVE CROSSED THE
ISLANDS OF SAINT JOHN AND SAINT THOMAS AND A FEW SHOWERS PUSHED
ONSHORE IN NORTHEAST PUERTO RICO. THE SOUNDER IN SAN JUAN
CONTINUES TO SHOW FALLING PRECIPITABLE WATER VALUES AS A DRY SLOT
MOVES THROUGH THE AREA AHEAD OF A TROUGH.

THIS NEGATIVELY TILTED TROUGH OVER THE WINDWARD ISLANDS
IS STILL FORECAST TO MOVE NORTHWEST INTO THE SOUTHEAST CORNER OF
THE FORECAST AREA LATE THIS AFTERNOON AND CONTINUE ACROSS PUERTO
RICO ON MONDAY MORNING. BOTH THE NAM AND THE GFS ARE RELATIVELY IN
LINE WITH THE TIMING AND THE BEST MOISTURE SHOULD PASS THROUGH THE
AREA BETWEEN 12 AND 18Z. THE NAM APPEARS TO INDICATE A STRONGER AND
MORE DEFINED LINE OF CONVECTION THAT MOVES THROUGH EASTERN PUERTO
RICO AND THE U.S. VIRGIN ISLANDS AROUND 15Z. MOISTURE CONTENT IS
NOT QUITE AS HIGH AS PREVIOUS RUNS INDICATED 24 HOURS AGO...BUT
PRECIPITABLE WATER STILL PEAKS ABOVE 2 INCHES AND EXPECT
WIDESPREAD RAINFALL WITH ISOLATED TO SCATTERED THUNDERSTORMS
DURING THE DAY. RAINFALL MAY ALSO AFFECT NORTHWEST PUERTO RICO AS
CONVECTION SHIFTS WITH THE WINDS BEHIND THE TROUGH. SOUTHEAST FLOW
CONTINUES DURING THE WEEK AND THIS WILL ENHANCE THE HIGH
TEMPERATURES FOR NORTHEAST AND NORTH CENTRAL PUERTO RICO BY
SEVERAL DEGREES MID WEEK. MOISTURE MODERATES AT THE SAME TIME BUT
BY NO MEANS BECOMES DRY AND AFTERNOON THUNDERSTORMS IN NORTHWEST
AND WESTERN INTERIOR PUERTO RICO WILL BE REGULARS. ANOTHER BAND OF
MOISTURE IN THE SOUTHEAST FLOW FORMS OVER AND SOUTHEAST OF THE
ISLANDS ON SATURDAY AS WET WEATHER CONTINUES IN THE REGION.

&&

.AVIATION...MAINLY VFR CONDITIONS ARE EXPECTED ACROSS MOST TAF SITES
DURING THE MORNING HOURS. BETWEEN 10-16Z...PATCHES OF MOISTURE WILL
BRING SCATTERED SHOWERS ACROSS TNCM...TKPK...TIST...TISX AND TJSJ.
AFTER 16Z...EXPECT AFTERNOON SHOWER AND THUNDERSTORM DEVELOPMENT
OVER THE INTERIOR OF PUERTO RICO TO BRING TEMPORARY MVFR CONDITIONS
ACROSS TJMZ FROM 16-22Z. WINDS WILL BE MAINLY FROM THE EAST AT 10 TO
15 KTS...WITH GUSTS BETWEEN 20-25 KTS NEAR SHOWERS. MOUNTAIN
OBSCURATIONS SHOULD BE EXPECTED ACROSS SOUTHWEST PUERTO RICO AFTER
ABOUT 17Z.

&&

.MARINE...SWELL FROM A PERSISTENT LOW IN THE CENTRAL ATLANTIC ARE
BEGINNING TO AFFECT THE WATERS NORTH OF THE FORECAST AREA. SEAS AS
HIGH AS 8.5 FEET WERE NOTED IN THE ATLANTIC AT BUOY 41043. SEAS IN
THE FORECAST AREA ARE BEGINNING TO FEEL THE EFFECT OF THESE SWELL
FROM THE NORTH NORTHEAST...AND THIS WILL HOLD ATLANTIC WATERS AND
PASSAGES JUST ABOVE SMALL CRAFT ADVISORY CONDITIONS THROUGH AROUND
TUESDAY NOON. SEAS IN THE CARIBBEAN ARE EXPECTED TO TO SLOWLY
DIMINISH AS WINDS GENERATED BY HIGH PRESSURE IN THE WESTERN
ATLANTIC ALSO DIMINISH.

&&

.HYDROLOGY...MODELS HAVE BEEN VERY CONSISTENT ABOUT BRINGING A WET
TROUGH ACROSS THE AREA ON MONDAY AND THEN KEEPING THE AREA
RELATIVELY MOIST. THIS WILL SPREAD RAIN ACROSS MUCH OF THE ISLAND
ON MONDAY WITH SOME AREAS RECEIVING UPWARDS OF 6 INCHES IN THE
PERIOD FROM SUNDAY NIGHT THROUGH WEDNESDAY NIGHT. EXPECT MANY
AREAS TO RECEIVE 1 TO 3 INCHES ON MONDAY WHICH WOULD LIKELY
TRIGGER URBAN AND SMALL STREAM FLOODING AS WELL AS RISES AND LOCAL
FLOODING IN MAIN STEM RIVERS. WILL HOLD OFF ON ISSUING A FLASH
FLOOD WATCH UNTIL IT IS CLEAR THAT THE SYSTEM WILL DEVELOP A
LITTLE MORE BEFORE PASSING THROUGH AND TIMING IS BETTER KNOWN. BUT
WETTER WEATHER IS DEFINITELY ON THE WAY EVEN THOUGH CURRENT DRIER
CONDITIONS AND SKIES WITH ONLY PARTLY CLOUDY SKIES WOULD SEEM TO
INDICATE OTHERWISE.

IN THE MEANTIME...WITH FLOW CONTINUING FROM THE NORTHEAST...
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WITH HEAVY RAIN IS
EXPECTED IN SOUTHWEST PUERTO RICO WITH THE RIO GUANAJIBO
APPROACHING FLOOD STAGE. AT THIS TIME EXPECT FLOW TO BEGIN
CHANGING SO THAT THE FOCUS OF THE HEAVIEST RAIN IS NOT DIRECTLY
OVER THE BASIN...BUT RAINFALL THERE WILL BE SIGNIFICANT. LOCAL
RAINFALL MAXIMUMS IN THE AREA WILL LIKELY REACH 2 TO 4 INCHES
AGAIN THIS AFTERNOON.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
501 AM AST MON MAY 18 2009

.SYNOPSIS...SURFACE HIGH PRESSURE ACROSS THE WESTERN ATLANTIC WILL HELP
MAINTAIN MODERATE TO FRESH TRADE WINDS ACROSS THE LOCAL AREA THROUGH
TONIGHT. A WEAK SURFACE TROUGH OVER THE LESSER ANTILLES WILL MOVE
SLOWLY NORTHWEST AND SPREAD SHOWERS AND ISOLATED THUNDERSTORMS
ACROSS THE LOCAL WATERS TODAY.

&&

.DISCUSSION...SATELLITE AND RADAR IMAGES ARE SHOWING A LARGE AREA
OF SOWERS OVER THE EXTREME SOUTH PORTION OF OUR LOCAL WATERS, THIS
AREA IS ASSOCIATED TO A WEAK SURFACE TROUGH THAT IS EXPECTED TO
CONTINUE TO MOVE SLOWLY NORTHWARD THROUGH THIS EVENING. THIS
WEATHER FEATURE PROMISE A SIGNIFICANT INCREASE ON CLOUD AND
SHOWER COVERAGE ACROSS THE LOCAL REGION THROUGH MI WEEK.

TODAY...EXPECT SHOWERS AND THUNDERSTORMS TO AFFECT THE SOUTHERN
HALF OF PUERTO RICO DURING THE MORNING HOURS. THESE SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO SLOWLY SPREAD NORTHWARD ACROSS THE
REST OF THE ISLAND BEFORE THE EVENING HOURS. SOILS REMAIN
SATURATED ACROSS THE LOCAL ISLANDS TODAY AND MORE RAIN WILL
INCREASE THE POTENTIAL FOR FLOODING AND LANDSLIDES.

&&

.AVIATION...MVFR CIGS OVER TISX...TNCM AND TKPK THROUGH 12Z AS DEEP
TROPICAL MOISTURE APPROACHES THE REGION. WINDS WILL BE SELY AT MOST
SITES...WITH TSRA AND TEMPO IFR POSSIBLE OVER TISX...TJSJ...TJMZ AND
TJBQ THIS AFTERNOON.

&&

.MARINE...THE BUOY 41043 HAS BEEN CONSTANT ON THE SWELL REPORT...
SWELL BETWEEN 5.5 TO 6.5 FEET AND WITH A PERIOD OF AROUND 11
SECONDS. THEREFORE EXPECT SIMILAR CONDITIONS TO YESTERDAY...TODAY
WITH THE EXCEPTION OF LESS WIND WAVES AS WINDS HAVE DECREASE
SLIGHTLY. THE NAM AND GFS ARE SUGGESTING A MORE SE COMPONENT ON
THE WINDS BEGINNING LATE TODAY AND EARLY TUESDAY.

[cycloneye]

000
FXCA62 TJSJ 190902
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
502 AM AST TUE MAY 19 2009

.SYNOPSIS...A DEVELOPING AREA OF LOW PRESSURE ACROSS CUBA AND THE CENTRAL
BAHAMAS...WILL HELP TO PRODUCE AN EAST SOUTHEAST WIND FLOW ACROSS
THE REGION FOR THE NEXT SEVERAL DAYS. THIS MODERATE TO FRESH WIND
FLOW WILL BRING SHOWERS AND ISOLATED THUNDERSTORMS WITH AREAS OF
LOCALLY HEAVY RAINFALL OVER THE INTERIOR AND NORTHWEST SECTIONS OF
PUERTO RICO THROUGH AT LEAST WEDNESDAY.

&&

.DISCUSSION...LIMITED WEATHER ACTIVITY HAS BEEN REPORTED BY THE
DOPPLER RADAR...ONLY SHOWING A FEW SHOWERS MOVING ACROSS THE LOCAL
CARIBBEAN WATERS.

ENOUGH MOISTURE WILL COMBINE WITH LOCAL EFFECTS TO PRODUCE SHOWERS
AND THUNDERSTORMS ACROSS THE INTERIOR AND NORTHWEST PORTIONS OF
PUERTO RICO. UPPER LEVEL WINDS CONTINUE TO BE FAVORABLE FOR
THUNDERSTORM DEVELOPMENT THIS AFTERNOON. THIS WEATHER SCENARIO IS
EXPECTED TO CONTINUE THROUGH FRIDAY.

&&

.AVIATION...VFR EXPECTED NEXT 24 HOURS ALL SITES EXCEPT TJMZ AND
TJBQ WHERE AFTERNOON TSRA WITH TEMPO IFR CONDITIONS POSSIBLE 19Z/21Z.


&&

.MARINE...NORTH NORTHEAST SWELLS ASSOCIATED WITH A LOW PRESSURE SYSTEM
ACROSS THE CENTRAL ATLANTIC...WILL CONTINUE TO SLOWLY SUBSIDE
THROUGH THIS EVENING. AT THIS MOMENT THE BUOYS 41043 AND 41049 ARE
REPORTING SWELLS AT 6 FEET OR LESS.

[cycloneye]

FXCA62 TJSJ 200908
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
508 AM AST WED MAY 20 2009

.SYNOPSIS...AN AREA OF LOW PRESSURE ACROSS CUBA AND THE CENTRAL
BAHAMAS AND HIGH PRESSURE BUILDING ACROSS THE NORTHWEST
ATLANTIC...WILL RESULT IN A MAINLY MODERATE TRADE WIND FLOW ACROSS
THE LOCAL FORECAST AREA FOR THE NEXT SEVERAL DAYS.

&&

.DISCUSSION...THE DOPPLER RADAR IS SHOWING ISOLATED SHOWERS MOVING
ACROSS THE EASTERN CARIBBEAN AND ATLANTIC WATERS. EXPECT A FEW
SHOWERS TO AFFECT THE EASTERN PORTIONS OF PUERTO RICO THROUGH MID
MORNING. THIS AFTERNOON ISOLATED TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL DEVELOP ALONG THE CORDILLERA CENTRAL AND LATER
ON THE NORTHWEST SECTIONS OF PUERTO RICO.

ON THURSDAY...INCREASING MOISTURE AND A MORE UNSTABLE ATMOSPHERE
WILL PRODUCE ACTIVE WEATHER AFTERNOONS THROUGH SATURDAY.

&&

.AVIATION...VFR CONDITIONS AT ALL SITES NEXT 24 HOURS EXCEPT TJBQ
WHERE MVFR CIGS IN A PASSING SHRA ARE EXPECTED 19Z/21Z./RA

&&

.MARINE...SEAS AND WINDS WILL CONTINUE TO RELAX THROUGH THE
INCOMING WEEKEND.

[cycloneye]

FXCA62 TJSJ 210855
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
455 AM AST THU MAY 21 2009

.DISCUSSION...THE DOPPLER RADAR IS SHOWING SCATTERED SHOWERS MOVING
ACROSS THE LOCAL WATERS...SOME OF THESE SHOWERS AFFECTED THE
EASTERN PORTIONS OF PUERTO RICO PRODUCING RAINFALL ACCUMULATIONS
OF OF BETWEEN 1 TO2 INCHES ESPECIALLY OVER THE MUNICIPALITIES OF
YABUCOA AND SAN LORENZO. IN THE LAST HOUR MORE SHOWERS HAVE
DEVELOPED OVER THE SOUTHEAST SECTIONS OF PUERTO RICO.

VERY MOIST AND UNSTABLE ATMOSPHERE WILL PREVAIL ACROSS THE LOCAL
REGION TODAY. THIS WEATHER SCENARIO IS ASSOCIATED TO A DEEP LAYER
TROUGH...NOW LOCATED OVER THE HISPANIOLA. THIS TROUGH IS FORECAST
TO MOVE EASTWARD ACROSS THE MONA PASSAGE TODAY AND LATER TONIGHT
OVER PUERTO RICO. AT THIS MOMENT THIS WEATHER FEATURE IS
GENERATING OVERCAST SKIES OVER PUERTO RICO...THIS COULD RETARD THE
SHOWER AND THUNDERSTORM DEVELOPMENT OVER THE ISLAND THIS
AFTERNOON. THEREFORE EXPECT MOSTLY CLOUDY SKIES WITH SCATTERED
SHOWERS AND THUNDERSTORM DEVELOPING OVER THE INTERIOR AND NORTHERN
PORTIONS OF PUERTO RICO. MOST OF THIS SHOWERS WILL BE SLOW MOVERS
DUE TO LIGHT WINDS...THEREFORE EXPECTED MODERATE TO LARGE RAINFALL
ACCUMULATIONS AMOUNTS IN SOME LOCALIZE AREAS.

&&

.AVIATION...MVFR CIGS WITH A PASSING -SHRA LIKELY THROUGH 10 TO 12Z
OVER TIST AND TJSJ. LATER THIS AFTERNOON BKN TO OVC CEILINGS
EXPECTED OVER MOST OF THE REGION ASSOCIATED WITH DEEP CONVECTION
OVER HISPANIOLA. MVFR CIGS AND A SHRA EXPECTED LATER TODAY (19Z)
OVER TJBQ. TSRA SHOULD STAY WELL WEST OF THE LOCAL SITES.


&&

.MARINE...SEAS AND WINDS WILL REMAIN CALM FOR THE NEXT 48 HOURS
BUT SEAS COULD BECOME DANGEROUS NEAR THUNDERSTORMS ALONG THE MONA
PASSAGE AS A DEEP LAYER TROUGH MOVE ACROSS THE LOCAL WATERS.

[cycloneye]

000
FXCA62 TJSJ 220856
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
456 AM AST FRI MAY 22 2009

.DISCUSSION...A LARGE AREA OF SHOWERS AND THUNDERSTORMS THAT
DEVELOPED OVER THE DOMINICAN REPUBLIC THURSDAY AFTERNOON IS
SPREADING THICK CLOUD COVER ACROSS PUERTO RICO THIS MORNING...AS
WELL AS BRINGING NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS TO
THE MONA PASSAGES AND EXTREME PORTIONS OF WESTERN PUERTO RICO.
IN ADDITION...WITH A GENERAL EAST SOUTHEASTERLY FLOW ACROSS THE
REGION BEING FUNNELED TOWARDS AND AREA OF LOW PRESSURE ACROSS THE
GULF OF MEXICO...NUMEROUS SHOWERS HAVE DEVELOPED ACROSS
SOUTHEASTERN PUERTO RICO AS THIS MOIST TROPICAL AIRFLOW HAS BEEN
INTERACTING WITH THE LAND BREEZE THERE. EXPECT THIS HEAVY SHOWER
ACTIVITY ACROSS SOUTHEASTERN PUERTO RICO TO DIMINISH DURING THE
EARLY MORNING HOURS...WITH AFTERNOON SHOWER ACTIVITY EXPECTED TO
DEVELOP OVER THE INTERIOR OF PUERTO RICO...SPREADING NORTHWEST
DURING THE AFTERNOON HOURS. SOME UNCERTAINTY WITH HOW MUCH AFFECT
ALL THE CLOUD COVER OVER THE ISLAND THIS MORNING WILL HAVE ON
SUPPRESSING AFTERNOON SHOWER DEVELOPMENT...SO HAVE DECIDED AGAINST
ISSUING A FLASH FLOOD WATCH FOR WIDESPREAD HEAVY PRECIPITATION
THIS AFTERNOON. HOWEVER...STILL EXPECT SIGNIFICANT SHOWER
DEVELOPMENT AND THE POSSIBILITY FOR LOCALIZED FLOODING ACROSS
SECTIONS OF THE INTERIOR AND NORTHERN PUERTO RICO LATE IN THE
AFTERNOON.

EXPECT THIS MOIST AND GENERALLY EAST SOUTHEASTERLY WIND FLOW TO
CONTINUE ACROSS THE LOCAL ISLANDS THROUGH THE UPCOMING WEEKEND AND
INTO NEXT WEEK...WITH AMPLE INSTABILITY IN PLACE FOR AT LEAST
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EACH DAY.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS MOST OF THE
LOCAL ISLANDS AND TAF SITES TODAY AND TONIGHT. HOWEVER...DO EXPECT
MORE PREVALENT THAN NORMAL MVFR OR EVEN IFR CONDITIONS...MOUNTAIN
OBSCURATIONS AND BRIEF SURFACE WIND GUSTS...ESPECIALLY NEAR TJBQ...
TJMZ AND TJSJ LATE THIS MORNING THROUGH LATE THIS AFTERNOON/EARLY
THIS EVENING...IN SHRA AND ISOLATED TSRA.

[cycloneye]

000
FXCA62 TJSJ 230942
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
542 AM AST SAT MAY 23 2009

.DISCUSSION...ANOTHER NICE CONVECTIVE BLOWUP WAS OBSERVED
OVERNIGHT JUST SOUTH OF THE DOMINICAN REPUBLIC...ENHANCED BY AN
UPPER LEVEL SHORTWAVE TROUGH...PARTIALLY EVIDENT IN WATER VAPOR
IMAGERY. WITH THE UPPER LEVEL SUPPORT FOR THIS AREA OF CONVECTION
CONTINUING TO PROGRESS AWAY FROM THE AREA...EXPECT THIS CLUSTER OF
SHOWERS AND THUNDERSTORMS TO DECREASE AS IT TRIES TO APPROACH
WESTERN PUERTO RICO LATER THIS MORNING...WITH ONLY SOME SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED TO ACTUALLY REACH THE
WESTERN EDGE OF THE ISLAND.

ONCE AGAIN...EXPECT THE THICK CONVECTIVE BLOW OFF FROM THIS SHOWER
ACTIVITY TO ACT TO INHIBIT LOCALLY INDUCED CONVECTIVE ACTIVITY
ACROSS PUERTO RICO TODAY...BUT LIKELY ONLY DELAYING SHOWER AND
THUNDERSTORM DEVELOPMENT TO THE LATE AFTERNOON HOURS...AS AMPLE
MOISTURE...ALBEIT STILL ON THE DECREASE IN LATEST PROFILER
DATA...AND INSTABILITY...REMAIN IN PLACE. THEREFORE...PUSHED
DIURNALLY INDUCED CONVECTION...FROM SAINT CROIX NORTHEASTWARD
ACROSS THE NORTHERN HALF OF PUERTO RICO...TO THE AFTERNOON HOURS
ALONG WITH REDUCING THE OVERALL COVERAGE A TOUCH.

LATEST COMPUTER MODELS ARE INDICATING MID TO UPPER LEVEL RIDGING
ACROSS THE REGION FOR THE FIRST HALF OF NEXT WEEK WITH VARYING
AMOUNTS OF MOISTURE IN A GENERALLY SOUTHEASTERLY WIND FLOW...WHICH
SHOULD KEEP WIDESPREAD SHOWER AND THUNDERSTORM DEVELOPMENT AT
BAY...WITH MAINLY SCATTERED DIURNALLY INDUCED CONVECTION EXPECTED
EACH AFTERNOON. AN UPPER LEVEL LOW MAY DEVELOP ACROSS THE WESTERN
ATLANTIC LATE IN THE PERIOD AS THE LOW LEVEL FLOW SHIFTS MORE
EASTERLY IN RESPONSE TO AN AREA OF HIGH PRESSURE BUILDING ACROSS
THE CENTRAL ATLANTIC. IF THIS VERIFIES...WE CAN EXPECT A SLIGHT
INCREASE IN SHOWER COVERAGE TOWARDS THE LATER HALF OF NEXT WEEK.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS MOST OF THE
LOCAL ISLANDS AND TAF SITES TODAY AND TONIGHT. HOWEVER...EXPECT
BRIEF MVFR OR POSSIBLY EVEN IFR CONDITIONS AND LOCAL MOUNTAIN
OBSCURATIONS...ESPECIALLY NEAR TJBQ...TJMZ AND TJSJ LATE THIS
MORNING THROUGH LATE THIS AFTERNOON/EARLY THIS EVENING...IN SHRA AND
ISOLATED TSRA. IN ADDITION...MULTI-LAYERED CLOUDINESS WILL CONTINUE
ACROSS THE LOCAL AREA THROUGH TODAY.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
444 AM AST SUN MAY 24 2009

.DISCUSSION...DECREASED CLOUD COVER ACROSS THE REGION THIS MORNING
WILL LIKELY AID IN THE DEVELOPMENT OF SHOWER ACTIVITY ACROSS THE
INTERIOR OF PUERTO RICO BY LATE MORNING. WITH A GENERAL EAST
SOUTHEASTERLY STEERING FLOW...EXPECT THESE DIURNALLY INDUCED
SHOWERS AND THUNDERSTORMS TO MOVE ACROSS MUCH OF THE NORTHERN HALF
OF THE ISLAND...INCLUDING THE POSSIBILITY OF A STREAMER COMING OFF
EL YUNQUE AFFECTING PORTIONS OF THE METRO AREA DURING THE
AFTERNOON HOURS. HOWEVER...A SLIGHT DRYING TREND IN THE LOWEST
LEVELS OF THE ATMOSPHERE ALONG WITH STABILIZING CONDITIONS IN THE
UPPER LEVELS...WILL HELP TO COMBAT WIDESPREAD PRECIPITATION ACROSS
THE ISLAND. FOR THE NEXT SEVERAL DAYS...EXPECT A GENERALLY EAST TO
SOUTHEASTERLY WIND FLOW WITH VARIABLE AMOUNTS OF LOW LEVEL MOISTURE TO
CONTINUE...ALLOWING FOR AT LEAST SCATTERED DIURNAL CONVECTION TO
DEVELOP EACH AFTERNOON ACROSS THE INTERIOR AND NORTHERN SECTIONS OF
PUERTO RICO. A RETURN TO A MORE EASTERLY WIND FLOW AND COOLER
TEMPERATURES ACROSS THE NORTHERN HALF OF THE ISLAND IS EXPECTED BY
THE END OF THE WEEK AS AN AREA OF SURFACE HIGH PRESSURE BUILDS
ACROSS THE NORTH CENTRAL ATLANTIC.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS THE LOCAL
ISLANDS AND AT ALL LOCAL TAF SITES TODAY AND TONIGHT. HOWEVER...
EXPECT BRIEF MVFR OR EVEN IFR CONDITIONS AND LOCAL MOUNTAIN
OBSCURATIONS...ESPECIALLY NEAR TJBQ...TJMZ AND TJSJ LATE THIS
MORNING THROUGH LATE THIS AFTERNOON/EARLY THIS EVENING...IN SHRA AND
ISOLATED TSRA. IN ADDITION...MULTI-LAYERED CLOUDINESS WILL CONTINUE
ACROSS THE LOCAL AREA THROUGH TODAY.

&&

.MARINE...RELATIVELY TRANQUIL MARINE CONDITIONS ARE EXPECTED TO
PERSIST THROUGH THE END OF THE WEEK.

[cycloneye]

AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
539 AM AST MON MAY 25 2009

.DISCUSSION...MID LEVEL RIDGING EXPECTED ACROSS THE LOCAL AREA
DURING THE NEXT FEW DAYS AND THIS SHOULD HELP TO KEEP MOST
CONVECTION FROM REALLY EXPLODING OR BECOMING WIDESPREAD...BUT WILL
STILL HAVE SOME UPPER LEVEL VENTILATION. DIURNAL AND NOCTURNAL
PROCESSES WILL GENERALLY DICTATE SENSIBLE WEATHER THE NEXT FEW
DAYS. FOR TODAY AND TONIGHT...A "DRIER" AIR MASS WILL CONTINUE
ADVECTING ACROSS THE LOCAL AREA AND A GIVEN ABOVE MENTIONED
RIDGING...THIS SHOULD ALLOW FOR ONLY LIMITED ACTIVITY TODAY AND IN
FACT...MAY HAVE A TAD TOO MUCH ACTIVITY IN GRIDS AND ZFP...BUT
ALL IN ALL SHOULD BE OKAY. FOR TUESDAY AND TUESDAY NIGHT...AN AREA
OF BETTER MOISTURE IS PROGGED TO MOVE ACROSS THE LOCAL ISLANDS AND
THIS SHOULD RESULT IN A BIT MORE SHOWER AND THUNDERSTORM ACTIVITY
THAN TODAY. THEN FOR WEDNESDAY THROUGH FRIDAY...MOISTURE APPEARS
LIMITED AGAIN...SO EXPECT NOTHING MORE THAN SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS OVER PARTS OF THEN LOCAL ISLANDS...MAINLY
EACH AFTERNOON.

&&

.AVIATION...PREVAILING VFR CONDITIONS ARE EXPECTED ACROSS ALL THE
LOCAL TAF SITES THROUGH AT LEAST 15Z. THEREAFTER...DIURNALLY INDUCED
SHOWERS AND A THUNDERSTORM OR TWO CAN BE EXPECTED OVER THE INTERIOR
OF PR...SLOWLY MOVING NORTHWEST. THIS WILL LIKELY RESULT IN
TEMPORARY MVFR CONDITIONS ACROSS TJBQ BETWEEN 17-22Z...WITH VCNTY
SHWRS EXPECTED NEAR TJSJ AND TJMZ...ALONG WITH POSSIBLE BRIEF MVFR
CONDITIONS THERE. VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS
THE USVI...TKPK...TNCM AND TJPS ALL DAY.

&&

.MARINE...GENERALLY EXPECT WINDS OF 16 KNOTS OR LESS AND SEAS OF 5
FEET OR LESS ACROSS THE REGIONAL WATERS THROUGH AT LEAST
WEDNESDAY.

[cycloneye]

FXCA62 TJSJ 260929
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
529 AM AST TUE MAY 26 2009

.DISCUSSION...ELONGATED MID TO UPPER LEVEL RIDGE WILL CONTINUE
OVER THE LOCAL AREA DURING THE NEXT FEW DAYS AND THIS SHOULD HELP
TO KEEP MOST CONVECTION FROM REALLY EXPLODING OR BECOMING
WIDESPREAD. STILL EXPECT DIURNAL AND NOCTURNAL PROCESSES TO
GENERALLY DICTATE SENSIBLE WEATHER FOR THE NEXT FEW DAYS. FOR
TODAY AND TONIGHT...PER SATELLITE AND GFS MODEL DATA...STILL
EXPECT AN INCREASE IN LOW LEVEL MOISTURE ALBEIT LESS THAN
INDICATED YESTERDAY. THIS MOISTURE ADVECTION...ESPECIALLY
OCCURRING DURING THE TIME OF MAX HEATING...SHOULD ALLOW FOR A
SIMILAR DAY TO MONDAY...WITH SCATTERED TO LOCALLY NUMEROUS
SHOWERS AND ISOLATED THUNDERSTORMS...ESPECIALLY OVER THE INTERIOR
AND NORTH SECTIONS OF PUERTO RICO THIS AFTERNOON. FOR WEDNESDAY
THROUGH FRIDAY...MOISTURE APPEARS LIMITED AGAIN...SO EXPECT
NOTHING MORE THAN SCATTERED SHOWERS AND AN ISOLATED THUNDERSTORM
OR TWO OVER PARTS OF THE LOCAL ISLANDS...MAINLY EACH AFTERNOON.
LOOKING AHEAD...A SLIGHT INCREASE IN MOISTURE IS INDICATED FOR
SATURDAY AND SUNDAY AND IF CORRECT...SHOULD IN TURN RESULT IN
SLIGHTLY MORE ACTIVITY AT THAT TIME.

&&

.AVIATION...PREVAILING VFR CONDITIONS ARE EXPECTED ACROSS ALL THE
LOCAL TAF SITES THROUGH AT LEAST 15Z. THEREAFTER...DIURNALLY INDUCED
SHOWERS AND A THUNDERSTORM OR TWO CAN BE EXPECTED OVER THE INTERIOR
OF PR...SLOWLY MOVING NORTHWESTERLY. THIS WILL LIKELY RESULT IN
TEMPORARY MVFR CONDITIONS ACROSS TJBQ BETWEEN 17Z AND 22Z...WITH
VCNTY SHWRS EXPECTED NEAR TJSJ AND TJMZ...ALONG WITH POSSIBLE
BRIEF MVFR CONDITIONS THERE. VFR CONDITIONS ARE EXPECTED TO
PREVAIL ACROSS THE USVI AND TJPS...WITH A VCNTY SHWR OR TWO
POSSIBLE NEAR TNCM AND TKPK.

&&

.MARINE...GENERALLY EXPECT WINDS OF 17 KNOTS OR LESS AND SEAS OF
5 FEET OR LESS ACROSS THE REGIONAL WATERS THROUGH AT LEAST
THURSDAY.

[cycloneye]

000
FXCA62 TJSJ 261944
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
344 PM AST TUE MAY 26 2009

.SYNOPSIS...AT UPPER LEVELS...A RIDGE WILL PASS OVER THE AREA
WEDNESDAY FOLLOWED BY A TROUGH FRIDAY EVENING. GENERALLY WEST
NORTHWEST FLOW WILL CONTINUE OVER THE WEEKEND. A MODERATE JET WILL
MOVE INTO THE AREA FROM THE WEST NEXT WEEK.

AT MID LEVELS...HIGH PRESSURE WILL DOMINATE THE EASTERN CARIBBEAN
AND THE WESTERN TROPICAL ATLANTIC THROUGHOUT THE FORECAST PERIOD.
A WEAK TROUGH EXTENDING FROM THE NORTHWEST WILL PASS BY LATE IN
THE WEEK.

AT LOWER LEVELS...A WEAK WAVE WILL APPROACH THE AREA TONIGHT AND
TOMORROW TO CONTINUE THE GENERALLY WET PATTERN OVER THE NORTHERN
HALF OF PUERTO RICO. ANOTHER WAVE...THOUGH WEAKENED FROM A LONG
JOURNEY ACROSS THE ATLANTIC...WILL BRING BETTER MOISTURE MID WEEK
NEXT WEEK.


&&

.DISCUSSION...A SOUTHEAST SURFACE FLOW PATTERN CONTINUES DUE TO
HIGH PRESSURE OVER THE WESTERN ATLANTIC. THIS IS BRINGING HEAVY
SHOWERS TO MUCH OF THE NORTHERN COAST AND COASTAL FOOTHILLS OF
PUERTO RICO. ACTIVITY APPEARS TO BE DISSIPATING AT THE MOMENT AND
PRECIPITABLE WATER VALUES IN THE SAN JUAN SOUNDING HAVE PEAKED AT
CLOSE TO 2.3 INCHES. MODELS SHOW A DIP IN THIS MOISTURE
OVERNIGHT...ONLY TO RETURN TO NEARLY THE SAME INTENSITY TOMORROW
FOR ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS OVER THE NORTH HALF
OF PUERTO RICO. HAVE LOWERED MAX TEMPS ACROSS THE AREA DESPITE
SOUTHEAST WINDS SINCE THERE SHOULD BE MORE CLOUDS OVER THE AREA
THAN EARLIER ANTICIPATED. MOS WAS CALLING FOR 88 TOMORROW AS
WELL...BUT STILL HAS 90 FOR WEDNESDAY AND THURSDAY. WILL WAIT
UNTIL CLOUDS HAVE STOPPED STREAMING ACROSS THE AREA FROM ACTIVITY
ASSOCIATED WITH A JET AND TROUGH ALOFT TO OUR WEST BEFORE RAISING
TEMPERATURES ABOVE THE 89 FOR SAN JUAN NOW IN THE FORECAST. NO
SIGNIFICANT FEATURES ARE ON THE HORIZON ALTHOUGH MODELS ARE MAKING
MORE OF A WAVE EXPECTED MID-WEEK NEXT WEEK AND STILL HAVE ONE THAT
SHOULD ARRIVE AROUND 8 JUN. UNTIL MOISTURE SUBSIDES SIGNIFICANTLY...
AND MODELS KEEP PROMISING THIS FOR NO LATER THAN THURSDAY...CLOUDS
SHOULD CONTINUE. STILL SOUTHWEST PUERTO RICO SHOULD REMAIN THE
SUNNIEST AND DRIEST FOR THE NEXT 2 TO 3 DAYS.

&&

.AVIATION...BRIEF PERIODS OF MVFR WILL CONTINUE ACROSS TJMZ AND TJBQ
DURING THE REST OF THE AFTERNOON AND UNTIL AT LEAST 23Z THIS
EVENING. AFTER 23Z MOSTLY VFR CONDITIONS ARE EXPECTED TO PREVAIL
ACROSS ALL THE LOCAL TAF SITES. FOR TOMORROW AFTERNOON...DIURNALLY
INDUCED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED OVER THE INTERIOR
OF PR...SLOWLY MOVING NORTHWESTERLY. THIS WILL LIKELY RESULT IN
TEMPORARY MVFR CONDITIONS ACROSS TJBQ BETWEEN 17-22Z...WITH VCTY
SHWRS EXPECTED NEAR TJSJ AND TJMZ...ALONG WITH POSSIBLE BRIEF MVFR
CONDITIONS THERE. MOUNTAIN OBSCURATIONS CAN ALSO BE EXPECTED
DURING THIS PERIOD. LATEST TJSJ 12Z SOUNDING INDICATED A
SOUTHEASTERLY WIND FLOW UP TO 20 KNOTS FROM THE SURFACE TO AROUND
10K FEET... BECOMING WESTERLY FROM 10-25K FEET AND THEN
NORTHWESTERLY AND STRONGER ABOVE THAT LEVEL.

&&

.MARINE...GENERALLY TRANQUIL CONDITIONS ARE EXPECTED TO CONTINUE
ACROSS LOCAL WATERS WITH EXCEPTION OF GUSTY WINDS AND BRIEFLY
RAISED SEAS IN THE VICINITY OF THUNDERSTORMS.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
444 AM AST WED MAY 27 2009

.SYNOPSIS...HIGH PRES NE OF THE AREA IN THE MID LEVELS OF THE
ATMOSPHERE WITH RIDGE EXTENDING SW INTO THE NORTHEAST CARIBBEAN WILL
HOLD INTO EARLY NEXT WEEK.

&&

.DISCUSSION...LATEST MICROWAVE IMAGERY INDICATES PLUME OF 2.0+ INCH
PWAT AIR REMAINS ACROSS THE AREA EARLY THIS MORNING. SHOWERS STILL
LOOK LIKELY TODAY NORTH OF THE CORDILLERA CENTRAL BUT EXTENSIVE
CLD CVR SHOULD LIMIT TSTM CVRG SOMEWHAT. SHOWERS WILL BE SLOW
MOVERS AND CAPABLE OF PRODUCING TORRENTIAL DOWNPOURS AS MID-LVL
WINDS ARE LESS THAN 10 KTS. MOISTURE REMAINS HIGH THROUGH THE END
OF THE WORK WEEK PER GFS GUIDANCE AND THEN DROPS SHARPLY FOR SAT
AND SUN. A FEW MORE WET DAYS STILL IN STORE FOR THE AREA WITH SIG
IMPROVEMENT EXPECTED FOR THE WEEKEND.

&&

.AVIATION...VARIABLY CLOUDY CONDITIONS WILL PREVAIL ACROSS THE LOCAL
FLYING AREA DURING THE MORNING HOURS...AS CONSIDERABLE AMOUNTS OF
LOW TO MID LEVEL CLOUDS TRANSPORTED ACROSS THE REGION. MOSTLY VFR
CONDITIONS EXPECTED AT LEAST THROUGH 27/12Z. THIS WILL BE FOLLOWED
BY BRIEF MVFR CONDITIONS ENROUTE FROM THE NORTHERN LEEWARDS TO
EASTERN PUERTO RICO...AS WELL AS IN AND AROUND TJNR...TJSJ...TNCM
AND TKPK DUE TO PASSING SHOWERS AND ONE OR TWO ISOLATED TSTMS AT
LEAST THROUGH THE EARLY MORNING HOURS. FOR THIS AFTERNOON...
DIURNALLY INDUCED SHOWERS AND THUNDERSTORMS WILL BE AGAIN
POSSIBLE OVER PARTS OF THE CORDILLERA CENTRAL OF PUERTO RICO WITH
LOCAL TAF SITES TJBQ...TJMZ BEING AFFECTED BTWN 17-22Z AS THE TSTM
ACTIVITY IS EXPECTED TO SLOWLY DRIFT TOWARDS THE NORTHWEST UNDER THE
PREVAILING SOUTHEAST LOW LEVEL WIND FLOW.


&&

.MARINE...RELATIVELY TRANQUIL CONDITIONS EXPECTED THROUGH THE
PERIOD. SCT TSTMS MOVING OFF THE WEST AND NORTHWEST COAST OF PR EACH
AFTERNOON THE MAIN HAZARD.

[cycloneye]

FXCA62 TJSJ 280901
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
501 AM AST THU MAY 28 2009

.SYNOPSIS...RIDGE OF HIGH PRES SFC AND ALOFT WILL HOLD OVER
NORTHEAST CARIBBEAN THROUGH TODAY WITH SOME WEAKENING EXPECTED
THIS WEEKEND AS TROUGH OVER THE BAHAMAS PROGRESSES SLOWLY EAST.

&&

.DISCUSSION...LATEST MICROWAVE IMAGERY SHOWS SIG DRYING HAS TAKEN
PLACE ACROSS THE REGION EARLY THIS MORNING WITH PWAT VALUES AROUND
1.5 INCHES OR ABOUT 85% OF NORMAL FOR THIS TIME OF THE YEAR. THIS
IS ALSO ABOUT HALF INCH LOWER THAN 24 HRS AGO. LOW TO MID LVL
RIDGING OVR THE AREA WILL ALSO LIMIT CONVECTION TODAY WITH ONLY
ISOLD TO POSSIBLY SCT CONVECTION IN NW PR THIS AFTERNOON. HAVE CUT
IN POPS CONSIDERABLY FOR TODAY GIVEN ABOVE FACTORS.

AN INCREASE IN CONVECTION/MOISTURE IS PORTRAYED BY 00Z GFS ON FRI
AFTERNOON AS SOME EROSION OF THE RIDGE OCCURS AS TROUGH OVR THE
BAHAMAS PROGRESSES EAST. GFS SHOWS A DROP IN MOISTURE FOR THE
WEEKEND BUT MID TO UPPER LVL TROF OVR THE AREA MAY ALLOW FOR
BETTER CONDITIONS ALOFT FOR THE DEVELOPMENT OF CONVECTION.

&&

.AVIATION...VFR CONDITIONS TO PREVAIL ACROSS ALL LOCAL TAF SITES FOR
THE NEXT 24 HOURS...WITH THE EXCEPTION OF TJBQ FROM 2818Z/2822Z.
SHOWERS...THUNDERSTORMS...LOW CEILINGS AND REDUCED VISIBILITY IS
ANTICIPATED TO OCCUR AS OF THE RESULT OF LOCAL ISLAND EFFECTS IN
COMBINATION WITH DIURNAL HEATING AND SEA BREEZE CONVERGENCE ALONG
THE NORTHWESTERN COAST OF PR. WINDS ARE EXPECTED TO BE AT 10 TO 15
KNOTS OUT OF THE EAST SOUTHEAST.


&&

.MARINE...RELATIVELY TRANQUIL CONDITIONS EXPECTED THROUGH THE
PERIOD. SCT TSTMS MOVING OFF THE WEST AND NORTHWEST COAST OF PR EACH
AFTERNOON THE MAIN HAZARD.

[cycloneye]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
408 AM AST FRI MAY 29 2009

.SYNOPSIS...LOW LVL RIDGING WILL CONTINUE TO HOLD OVER THE AREA
TODAY. MID LVL TROUGH WITH AXIS OVR THE BAHAMAS WILL CONTINUE TO
WEAKEN WHILE AT THE UPPER LVLS A CLOSED LOW IS EXPECTED TO MEANDER
ACROSS PR OVR THE NEXT FEW DAYS.

&&

.DISCUSSION...MODELS SHOW A SLIGHT INCREASE IN MOISTURE FOR TODAY
HOWEVER THEY HAVE HAD A WET BIAS AS OF LATE. IT CAN`T BE ANY DRIER
THAN IT WAS YESTERDAY SO AM GOING WITH ISOLD POPS OVR NW PR. LOW LVL
RIDGING STILL FORECAST TO HOLD OVR THE AREA TODAY AND ALOFT THE GFS
ACTUALLY SHOWS CONVERGENCE AT H25 SO ALL OF THESE SPEAK AGAINST HIGH
POPS. ANOTHER DRY AND HOT DAY IN STORE.

AMS FCST TO DRY OUT EVEN MORE OVR THE WEEKEND WITH PWAT VALUES FCST
AT LESS THAN 1.5 INCHES WHICH IS QUITE LOW FOR THIS TIME OF THE
YEAR. WE ALSO GET UNDER THE SUBSIDENT SIDE OF MID-UPPER LVL TROUGH.
OVERALL...EXCELLENT WEEKEND TO GO TO THE BEACH JUST MAKE SURE TO
TAKE THE SUNSCREEN WITH YOU AS UVI IS FCST BY NOAA TO BE AT 13 OR
HIGHER.

00Z GFS PORTRAYS WETTER CONDITIONS FOR THE MIDDLE OF NEXT WEEK AS
SUBTROPICAL RIDGE SHIFTS FURTHER EAST.


&&

.AVIATION...VFR CONDITIONS EXPECTED AT ALL AIRPORTS NEXT 24 HRS.