Caribbean - Central America Weather

[cycloneye]

Midday discussion by NWS San Juan

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1206 PM AST WED APR 21 2010

.UPDATE...A LIGHT SOUTHERLY WIND FLOW ALONG WITH MOIST AND
UNSTABLE ATMOSPHERIC CONDITIONS WILL PREVAIL ACROSS PUERTO RICO
AND THE U.S. VIRGIN ISLANDS TODAY. THIS WILL RESULT IN HOT AND
HUMID CONDITIONS ACROSS THE REGION...WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS EXPECTED ACROSS THE USVI...AND MORE
NUMEROUS SHOWER AND THUNDERSTORM ACTIVITY EXPECTED OVER THE
CORDILLERA CENTRAL OF PUERTO RICO AND THE NORTHERN SECTIONS OF THE
ISLAND. WENT AHEAD AND INCREASED SHOWER AND THUNDERSTORM COVERAGE
A BIT FOR THIS AFTERNOON AND EVENING...WITH NO OTHER CHANGES
NECESSARY TO THE INHERITED FORECAST AT THIS TIME.

&&

.AVIATION...A VCSH AND BRIEF MVFR CONDITIONS WILL BE POSSIBLE
ACROSS ALL THE TAF SITES TODAY. MORE FREQUENT MVFR CONDITIONS
EXPECTED ACROSS TJSJ AFT 21/18Z...AS A SHRA OR TSRA WILL LIKELY
RESULT IN TEMPORARY MVFR AND POSSIBLY IFR CIGS AND VSBYS THROUGH
21/00Z. IN ADDITION...DUE TO WIDESPREAD SHOWER AND THUNDERSTORM
DEVELOPMENT EXPECTED ACROSS PUERTO RICO AFT 21/16Z...MOUNTAIN
OBSCRUATIONS WILL BE LIKELY. WIND FLOW WILL REMAIN LIGHT AND
GENERALLY SOUTHERLY AT LESS THAN 10 KTS FOR THE NEXT 24 HOURS.

[cycloneye]

Afternoon discussion by NWS San Juan


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
246 PM AST WED APR 21 2010

.SYNOPSIS...BROAD TROUGH ACROSS THE WESTERN ATLANTIC WILL PREVAIL
THROUGH THE END OF THE WEEK. A SURFACE TROUGH OR SHEARLINE WILL
MOVE THROUGH PUERTO RICO THURSDAY FOLLOWED BY A COLD FRONT SAT
NIGHT.

&&

.DISCUSSION...ISOLATED TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS DEVELOPED ALONG THE CORDILLERA CENTRAL AND THEN
SLOWLY DRIFTED TOWARD THE NNE...AFFECTING THE NORTHERN PORTIONS OF
PUERTO RICO INCLUDING THE SAN JUAN METROPOLITAN AREA. THE FIRST
FEW SHOWERS AS QUICKLY AS THEY DEVELOP THEY DISSIPATED. MORE
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE
NORTHERN PORTIONS OF PUERTO RICO THROUGH THE EVENING HOURS.

THE MID TO UPPER LEVEL CONDITIONS WILL CONTINUE TO ENHANCED
AFTERNOON SHOWERS ACTIVITY ON THURSDAY WITH STEERING WINDS PUSHING
THE SHOWERS OVER THE EASTERN AND NORTHEASTERN PORTIONS OF PUERTO
RICO. AN EVEN MORE UNSTABLE CONDITIONS ARE EXPECTED FOR FRIDAY AS
A SERIES OF MID LEVEL SHORT WAVES ARE EXPECTED TO MOVE ACROSS THE
REGION ROM FRIDAY THROUGH SATURDAY. DEEPER EASTERLIES WILL STEER
AFTERNOON CONVECTION TOWARD THE WEST AND SOUTHWEST PORTIONS OF
PUERTO RICO ON FRIDAY AND SATURDAY.

&&

.AVIATION...A VCSH/SHRA ALONG WITH BRIEF MVFR CONDITIONS WILL BE POSSIBLE
ACROSS ALL THE LOCAL TAF SITES THROUGH 22/00Z. MORE FREQUENT MVFR OR
EVEN IFR CONDITIONS WILL BE POSSIBLE ACROSS TJSJ AND TJBQ THROUGH
22/00Z...AS A SHRA OR TSRA WILL BE POSSIBLE THROUGH 22/00Z. IN
ADDITION...DUE TO WIDESPREAD SHOWER AND THUNDERSTORM DEVELOPMENT
EXPECTED ACROSS PUERTO RICO...MOUNTAIN OBSCRUATIONS WILL ALSO BE
LIKELY. WIND FLOW WILL REMAIN LIGHT AND GENERALLY SOUTHERLY AT LESS
THAN 10 KTS FOR THE NEXT 24 HOURS...WITH PREVAILING VFR CONDITIONS
EXPECTED FROM 22/00Z THROUGH 22/16Z.


&&

.MARINE...ALTHOUGH TRANQUIL MARINE CONDITIONS ARE EXPECTED ACROSS
ALL LOCAL WATERS THROUGH SATURDAY...MARINERS SHOULD BE IN THE
LOOKOUT FOR STRONG THUNDERSTORMS MOVING ACROSS OUR LOCAL WATERS.

[cycloneye]

Updated discussion by NWS San Juan


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
913 PM AST WED APR 21 2010

.UPDATE...ONCE AGAIN...SHOWERS DEVELOPED LATE THIS AFTERNOON
ACROSS THE CORDILLERA CENTRAL...AND MOST ACTIVITY MOVED ACROSS THE
NORTHERN MUNICIPALITIES OF PUERTO RICO. THIS TIME...THE HEAVIEST
RAINFALL WAS OBSERVED ACROSS THE MUNICIPALITIES OF
QUEBRADILLAS...CAMUY AND HATILLO. FEW OF THESE SHOWERS ALSO
AFFECTED THE SAN JUAN METROPOLITAN AREA LIKE YESTERDAY...BUT
RAINFALL AMOUNTS WERE LESS IMPRESSIVE.

COMPUTER MODELS SUGGEST BETTER MOISTURE THAT WE WILL HAVE DURING
THE NEXT DAYS...IS ALREADY HAPPENING. A DRYING TREND IN MOISTURE
IS EXPECTED ACROSS THE LOCAL AREA. THEREFORE...CONDITIONS ACROSS
THE LOCAL AREA SHOULD REMAIN UNCHANGED...WITH AFTERNOON SHOWERS
DEVELOPING ACROSS THE CORDILLERA CENTRAL...EXCEPT FOR FRIDAY...
WHEN A FRONTAL BOUNDARY...OR ITS REMNANTS AFFECT THE LOCAL
AREA...AND WINDS ARE EXPECTED TO SHIFT FROM THE NORTH AND
NORTHEAST. MADE CHANGES TO FORECAST GRIDS...TO BE IN A BETTER
AGREEMENT WITH MODELS...AND WITH CONTINUITY WITH WHAT WE HAVE SEEN
THE LAST TWO DAYS. ALTHOUGH SOME SHOWERS COULD PRODUCE HEAVY RAINFALL
AT TIMES IN ISOLATED SPOTS...NO WIDESPREAD FLOODING IS EXPECTED.

&&

.AVIATION...WHILE MOST SHOWERS HAVE CLEARED OFF OF LAND...SHOWERS
CONTINUE OFF THE NORTHWEST COAST OF PUERTO RICO AND ARE LIKELY TO
PERSIST BEYOND 22/02Z...THIS WILL KEEP TJBQ VULNERABLE TO MVFR
CONDS. SHOWERS OVER LAND WILL CONTINUE TO DIMINISH HOWEVER. SHOWERS
ARE EXPECTED TO RE-DEVELOP OVER PUERTO RICO AND TO A LESSER EXTENT
THE U.S. VIRGIN ISLANDS AFT 22/15Z WITH MOUNTAIN OBSCURATIONS
INTERIOR PR AND...AFT 22/17Z PROBABLY MVFR CONDS AT TJMZ AND TJBQ
TIL 22/23Z. SOUTHWEST FLOW AT LOWER LEVELS WILL BEGIN TO VEER
DRAMATICALLY AFT 23/00Z AND MAY SEEM QUITE VARIABLE THROUGH 24/06Z.

[cycloneye]

Good morning to all. A rainy day mainly in the afternoon hours here.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
534 AM AST THU APR 22 2010


.SYNOPSIS...BROAD MID TO UPPER LEVEL TROUGH ACROSS THE WESTERN
ATLANTIC WILL SLOWLY SHIFT EASTWARDS OVER THE NEXT FEW DAYS...TO
MAINTAIN A SOUTHWEST TO WEST WIND FLOW ACROSS THE REGION. A MID
LEVEL PERTURBATION NOW ACROSS HISPANIOLA WILL MOVE THROUGH BASE OF
THIS TROUGH LATER TODAY THOUGH FRIDAY TO AID IN ENHANCING
CONVECTIVE ACTIVITY ACROSS THE REGION. A SURFACE TROUGH AND
ASSOCIATED CONVERGENCE ZONE NOW ACROSS THE MONA PASSAGE WILL
SHIFT FURTHER EASTWARDS ACROSS PUERTO RICO AND LINGER ACROSS THE
NORTHEAST CARIBBEAN THROUGH FRIDAY...AND THEN GRADUALLY WEAKEN
OVER THE UPCOMING WEEKEND... AS AN AREA OF HIGH PRESSURE BUILDS
AND SPREADS EAST ACROSS THE SOUTHWEST ATLANTIC.

&&

.DISCUSSION.. THE PRESENCE OF THE SURFACE TROUGH WILL MAINTAIN THE
WARM...MOIST AND UNSTABLE WEATHER PATTERN ACROSS THE ISLANDS FOR
THE REST OF THE WEEK AND INTO THE WEEKEND. LOW LEVEL CONVERGENCE
AND LIGHT WINDS...AIDED BY GOOD DAYTIME HEATING AND FAVORABLE
UPPER LEVEL CONDITIONS WILL LEAD TO FAIR AMOUNTS OF AFTERNOON
CONVECTION ACROSS THE INTERIOR SECTIONS OF PUERTO RICO TODAY.
WITH THE LIGHT SURFACE WINDS...EXPECT LOW TO MID WIND FLOW TO
EVENTUALLY STEER THE SHOWERS AND ISOLATED THUNDERSTORM ACTIVITY
EAST NORTHEAST ACROSS OVER THE NORTH CENTRAL AND EAST SECTIONS OF
PUERTO RICO DURING THE AFTERNOON HOURS. THIS WILL RESULT IN
SHOWERS AND POSSIBLY ISOLATED THUNDERSTORMS ONCE AGAIN ACROSS
PARTS OF THE SAN JUAN METRO AREA.

BY LATE FRIDAY AND OVER THE WEEKEND HOWEVER EXPECT THIS PATTERN TO
CHANGE AS HIGH PRESSURE BUILDS NORTH OF THE AREA AND THE PREVAILING
EASTERLY WIND FLOW WILL ONCE AGAIN STEER AFTERNOON CONVECTION TOWARD
THE WEST AND SOUTHWEST PORTIONS OF THE ISLAND. UNTIL THEN...THE
OVERALL LIGHT AND VARIABLE WINDS WILL FOCUS MOST OF SHOWERS AND
THUNDERSTORMS ACROSS THE CENTRAL INTERIOR SECTIONS OF THE PUERTO
RICO...TO BE LATER STEERED EASTWARD ACROSS THE ISLAND DURING THE
AFTERNOON. EXPECT ONLY ISOLATED SHOWERS ACROSS THE VIRGIN ISLANDS
AT THIS TIME...AS MOST OF THE ACTIVITY IS EXPECTED TO REMAIN
OFFSHORE. SOME OF THE SHOWERS AND STORMS THAT DEVELOP ACROSS
PUERTO RICO WILL HOWEVER PRODUCE PERIODS OF MODERATE TO LOCALLY
HEAVY DOWNPOURS... WHICH MAY LEAD TO PONDING OF WATER ON ROADWAYS...
AS WELL AS LOCALIZED FLOODING DURING THE DAYTIME. HOWEVER NO MAJOR
EVENT OR WIDESPREAD RAINFALL IS EXPECTED FOR THE NEXT SEVERAL DAYS.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS ALL TAF SITES
DURING THE NEXT 24 HOURS. BRIEF PERIODS OF MVFR OR EVEN IFR ARE
POSSIBLE ACROSS TJSJ...TJMZ AND TJBQ AFT 22/17Z...DUE TO SHOWERS
AND POSSIBLE THUNDERSTORMS. MOST SHOWERS AND TSTMS WILL DISSIPATE BY
23/00Z. IN ADDITION...DUE TO THE SHOWER ACTIVITY MOUNTAIN OBSCURATIONS
WILL ALSO BE LIKELY. SOUTHWEST FLOW AT LOWER LEVELS WILL BEGIN TO
VEER DRAMATICALLY AFT 23/00Z AND MAY SEEM QUITE VARIABLE THROUGH
24/06Z.

[cycloneye]

Midday discussion by NWS San Juan

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
1153 AM AST THU APR 22 2010

.UPDATE...EXPECT A MIXTURE OF CLOUDINESS AND A BIT OF SUNSHINE
ACROSS THE LOCAL ISLANDS THIS AFTERNOON. SCATTERED TO NUMEROUS
SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO DEVELOP...
ESPECIALLY OVER THE INTERIOR AND NORTH SECTIONS OF PUERTO RICO.
PERIODS OF HEAVY RAINFALL AND SOME MINOR LOW LYING FLOODING WILL
OCCUR IN A FEW LOCATIONS. INHERITED SHORT TERM GRIDS AND ZFP HAD
A GOOD HANDLE ON EXPECTED CONDITIONS FOR THIS AFTERNOON...BUT
SENT A QUICK UPDATE TO BOTH TO EXTEND THE AFTERNOON CONVECTION
A COUPLE OF EXTRA HOURS. FOR THE COASTAL WATERS...MADE A COUPLE
OF MINOR ALTERATIONS TO THE PREVIOUS CWF...OTHERWISE NO CHANGES.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS TO CONTINUE ACROSS
THE LOCAL ISLANDS AND AT MOST LOCAL TAF SITES THROUGH THE NEXT 24
HOURS. HOWEVER...EXPECT DEVELOPING MVFR CONDITIONS AND LOCAL
MOUNTAIN OBSCURATIONS OVER THE INTERIOR AND NORTH SECTIONS OF
PUERTO RICO BETWEEN 22/16Z AND 23/00Z IN SCATTERED TO NUMEROUS
SHOWERS AND ISOLATED THUNDERSTORMS.

[cycloneye]

Afternoon discussion by NWS San Juan


AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
318 PM AST THU APR 22 2010

.SYNOPSIS...LIGHT WINDS AND HUMID CONDITIONS ARE EXPECTED TO
PERSIST ACROSS THE LOCAL ISLANDS THROUGH FRIDAY. WINDS WILL
GRADUALLY SHIFT TO NORTHEAST AS HIGH PRESSURE BEGINS TO BUILD
ACROSS THE WESTERN ATLANTIC TOMORROW...SHIFTING THE FOCUS OF
AFTERNOON SHOWER AND THUNDERSTORM ACTIVITY TOWARDS THE INTERIOR
AND SOUTHWESTERN SECTIONS OF PUERTO RICO.

&&

.DISCUSSION...DEEP TROPICAL MOISTURE IN A LIGHT SOUTHERLY FLOW
CONTINUED TO MAINTAIN UNSEASONABLE WARM AND HUMID CONDITIONS
ACROSS THE LOCAL ISLANDS TODAY. A LOW LEVEL TROUGH NORTH OF THE
LOCAL ISLANDS HAS HELPED ENHANCE SOME OF TODAYS SHOWER
ACTIVITY...AND IS EXPECTED TO REMAIN DRAPED ACROSS PUERTO RICO ON
FRIDAY...HELPING TO INITIATE ANOTHER DAY OF SCATTERED AFTERNOON
CONVECTION OVER THE INTERIOR AND SOUTHWESTERN SECTIONS OF THE
ISLAND. LATEST GFS CONTINUES TO HANG ONTO GOOD LOW LEVEL MOISTURE
ACROSS THE LOCAL AREA OVER THE UPCOMING WEEKEND AS A FRONT APPROACHES
THE REGION FROM THE NORTHWEST...BUT STABILIZING CONDITIONS IN THE MID
TO UPPER LEVELS OF THE ATMOSPHERE WILL HELP TO LIMIT SHOWER ACTIVITY
SOMEWHAT OVER THE UPCOMING WEEKEND. A SHIFT IN THE POSITION OF THE
HIGH NORTH OF THE LOCAL ISLANDS EARLY NEXT WEEK WILL LIKELY RESULT
IN A RETURN TO SOUTHEASTERLY FLOW AND WARM TEMPERATURES ACROSS
NORTHERN PUERTO RICO FOR MUCH OF NEXT WEEK.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS TO CONTINUE ACROSS THE
LOCAL ISLANDS AND AT MOST LOCAL TAF SITES THROUGH THE NEXT 24 HOURS.
HOWEVER...BRIEF MVFR CONDITIONS AND LOCAL MOUNTAIN OBSCURATIONS ARE
EXPECTED TO CONTINUE...ESPECIALLY OVER THE INTERIOR AND NORTH
SECTIONS OF PUERTO RICO THROUGH ABOUT 23/00Z...IN SCATTERED TO
NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS.

[cycloneye]

Updated discussion by NWS San Juan


AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
1040 PM AST THU APR 22 2010

.UPDATE...WIND FLOW HAS SHIFTED TO THE NORTHEAST OVER MOST OF
PUERTO RICO EXCEPT NEAR SHOWERS AND AREAS OF STRONG OPPOSING LAND
BREEZES. THE BOUNDARY WHICH HAS BEEN VISIBLE BETWEEN SAINT THOMAS
AND SAINT CROIX...REFORMED CLOSER TO SAINT THOMAS EARLY THIS
EVENING...BUT IS NOW MOVING SOUTHWEST WITH THE FLOW. SHOWERS ARE
STILL SCARCE OVER THE ATLANTIC WATERS...BUT WITH FLOW DEFINITIVELY
CHANGED...CANNOT RULE OUT SHOWERS ON THE NORTHEAST COAST WITH
OROGRAPHIC LIFTING IN VERY MOIST AIR. THE PRECIPITABLE WATER VALUE
YIELDED BY THE SOUNDING AT 00Z OF 2.34 INCHES WAS PROBABLY TOO
HIGH. THE SOUNDER AND MIMIC PRODUCTS SUGGEST THAT IT IS CLOSER TO
2.00 INCHES AS IT WAS 24 HOURS AGO.

&&

.DISCUSSION...MODELS CONTINUE TO SHOW A PERSISTENT BOUNDARY WITH
GOOD LOW LEVEL CONVERGENCE OVER OR NEAR PUERTO RICO TRAILING
BEHIND A MIGRATING LOW NOW IN THE NORTHERN ATLANTIC. THIS
BOUNDARY WILL PERSIST THROUGH EARLY NEXT WEEK ONLY TO BE REPLACED
BY ANOTHER BOUNDARY LATER NEXT WEEK. DURING THE NEXT 10 DAYS
PRECIPITABLE WATER VALUES OF 1.5 TO 2.0 INCHES WILL CONTINUE OVER
THE AREA. THIS WILL KEEP THE AREA IN A WET PATTERN WITH HEAVY
SHOWERS IN AFTERNOON THUNDERSTORMS AND NOCTURNAL CONVECTION OVER
THE LOCAL WATERS THAT OCCASIONALLY MOVE ONSHORE WITH THE
PREVAILING FLOW. DURING A BREAK BETWEEN THE CURRENT BOUNDARY WHICH
FADES IN-SITU AND THE ONE THAT FOLLOWS IT MID-WEEK NEXT WEEK SOUTHEAST
FLOW COULD DRIVE TEMPERATURES BACK INTO THE LOWER 90S ON THE NORTH
EAST AND NORTH CENTRAL COASTS AND COASTAL PLAINS. THIS WOULD ALSO FUEL
CONVECTION IN THE INTERIOR AND NORTHWEST THOUGH SHOWER ACTIVITY
OVER OTHER AREAS INCLUDING VIEQUES...CULEBRA AND THE U.S. VIRGIN
ISLANDS SHOULD DECREASE. AMOUNTS EXPECTED AT THIS TIME SHOULD NOT
BE EXCESSIVE...BUT THUNDERSTORMS COULD BE SUFFICIENTLY INTENSE TO
GENERATE LOCAL URBAN AND SMALL STREAM FLOODING DURING THE
AFTERNOONS ANY TIME DURING THE NEXT 10 DAYS...FIRST IN THE
SOUTHWEST QUARTER OF PUERTO RICO THEN BEGINNING ON
MONDAY...SHIFTING MORE TOWARD THE NORTHWEST QUADRANT OF THE ISLAND.


&&

.AVIATION...
LIGHT TO MODERATE SHOWERS WILL CONTINUE ACROSS TJPS AT
LEAST THROUGH 23/04Z...PRODUCING BRIEF PERIODS OF MVFR CONDITIONS.
VFR CONDITIONS WILL PREVAIL ACROSS ALL TAF SITES THROUGH AT LEAST
23/16Z. BETWEEN 23/16Z AND 24/00 BRIEF PERIODS OF MVFR CONDITIONS
ARE EXPECTED ACROSS TJPS...TJMZ...TJBQ WITH MOUNTAIN OBSCURATIONS IN
SHOWERS WITH ISOLATED THUNDERSTORMS. WINDS HAVE SHIFT LATE THIS
EVENING TO THE NORTHEAST AT 5 TO 10 KTS AT THE SURFACE. LATEST 00Z
TJSJ SOUNDING SHOWED WINDS SHIFTING NORTH BETWEEN 5K TO 8K
FEET...AND BECOMING WESTERLY AND STRONGER ABOVE.

[cycloneye]

Good morning to all.

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
440 AM AST FRI APR 23 2010


.SYNOPSIS...SURFACE HIGH PRESSURE WILL BUILD ACROSS THE WEST AND
SOUTHWEST ATLANTIC...THEN SPREAD FURTHER EASTWARD INTO THE WEST
CENTRAL ATLANTIC OVER THE UPCOMING WEEKEND. THIS WILL TIGHTEN THE
SURFACE PRESSURE GRADIENT...RESULTING IN A MODERATE EAST NORTHEAST
TRADE WIND FLOW ACROSS THE REGION FOR THE REST OF THE WEEK AND
THROUGH THE WEEKEND. IN THE MID TO UPPER LEVELS...SUBTROPICAL RIDGE
IS SPREAD ACROSS THE CARIBBEAN BASIN AND EXTENDS NORTHWARD ACROSS
THE NORTHEAST CARIBBEAN...WHILE A BROAD TROUGH REMAINS IN PLACE
ACROSS THE ATLANTIC. THIS WILL MAINTAIN PREVAILING WESTERLIES ACROSS
THE REGION TODAY...THEN BECOME MORE NORTHWESTERLY BY LATE SATURDAY
AND INTO SUNDAY...AS TROUGH BECOMES SLIGHTLY AMPLIFIED ACROSS THE
REGION.

&&

.DISCUSSION...FRAGMENTS OF LOW LEVEL MOISTURE ALONG FRONTAL
TROUGH/CONVERGENCE ZONE WHICH REMAINED DRAPED ACROSS THE NORTHEAST
CARIBBEAN...WILL BE BROUGHT IN ACROSS THE REGION IN THE PREVAILING
EASTERLIES FROM TIME TO TIME OVER THE NEXT FEW DAYS. AS A RESULT
EXPECT INTERVALS OF CLOUDINESS AND PASSING SHOWERS ALONG THE
THE NORTH AND EAST COASTAL SECTIONS OF PUERTO RICO...AS WELL AS
PARTS OF THE VIRGIN ISLANDS ESPECIALLY DURING THE EARLY MORNING
HOURS. DURING THE REST OF THE DAY...AVAILABLE MOISTURE WILL COMBINE
WITH LOCAL AND DIURNAL EFFECTS TO INDUCE AFTERNOON SHOWER
DEVELOPMENT MAINLY ACROSS PARTS OF THE WEST AND SOUTHWEST SECTION OF
PUERTO RICO. A FEW AFTERNOON SHOWERS MAY ALSO DEVELOP ACROSS ONE OR
TWO OF THE VIRGIN ISLANDS...BUT NO WIDESPREAD PRECIPITATION IS
FORECAST FOR THE NEXT SEVERAL DAYS. AFTERNOON CONVECTION ACROSS
PUERTO RICO MAY BE EXPLOSIVE AT TIMES TODAY AND SATURDAY AS MID
LEVEL PERTURBATION IS EXPECTED TO MOVE ACROSS THE REGION DURING THE
NEXT 24 HOURS OR SO. THIS WILL LEAD TO AREAS OF MODERATE TO LOCALLY
HEAVY RAINFALL CAUSING PONDING OF WATER ON ROADWAYS.. AS WELL AS
POSSIBLE URBAN AND SMALL STREAM FLOODING IN ISOLATED SPOTS ACROSS
PUERTO RICO DURING THE AFTERNOON HOURS.


&&

.AVIATION...LIGHT SHOWERS WILL CONTINUE ACROSS TISX AT LEAST THROUGH
23/10Z...PRODUCING BRIEF PERIODS OF MVFR CONDITIONS. VFR CONDITIONS
WILL PREVAIL ACROSS THE REST OF THE LOCAL TAF SITES THROUGH AT LEAST
23/16Z. BETWEEN 23/16Z AND 24/00 BRIEF PERIODS OF MVFR CONDITIONS
ARE EXPECTED ACROSS TJPS...TJMZ...TJBQ WITH MOUNTAIN OBSCURATIONS IN
SHOWERS WITH ISOLATED THUNDERSTORMS. WINDS HAVE SHIFT TO THE
NORTHEAST AT 5 TO 10 KTS AT THE SURFACE. TJSJ 23/00Z SOUNDING SHOWED
WINDS SHIFTING NORTH BETWEEN 5K TO 8K FEET...AND BECOMING WESTERLY
AND STRONGER ABOVE.

&&

.CLIMATE...
THE RECORD WARMEST MINIMUM TEMPERATURE OF 78 DEGREES WAS TIED AT THE
LUIS MUNOZ MARIN AIRPORT IN SAN JUAN PUERTO RICO ON 22 APRIL 2010.
THE OLD WARMEST MINIMUM RECORD WAS SET IN 1987. AT THE CYRIL E KING
AIRPORT IN SAINT THOMAS... THE RECORD WARMEST MINIMUM TEMPERATURE
OF 79 DEGREES WAS ALSO TIED YESTERDAY 22 APRIL 2010. THIS PREVIOUS
RECORD WAS FIRST SET IN 1987 AND TIED AGAIN IN 2006.

&&

[msbee]

good morning Luis
thanks once again for your updates.
I see it is hot there.
we are steaming here too.
there is very little wind and it is boiling hot!

[cycloneye]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE SAN JUAN PR
104 PM AST FRI APR 23 2010

VIC020-030-232000-
/O.NEW.TJSJ.FA.Y.0064.100423T1704Z-100423T2000Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAINT JOHN VI-SAINT THOMAS VI-
104 PM AST FRI APR 23 2010

THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED AN

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

IN THE U.S. VIRGIN ISLANDS
SAINT JOHN AND SAINT THOMAS

* UNTIL 400 PM AST

* AT 103 PM AST NATIONAL WEATHER SERVICE DOPPLER RADAR DETECTED
HEAVY RAINFALL ACROSS SECTIONS OF THE U.S. VIRGIN ISLANDS. THIS
SHOWER ACTIVITY WILL HAVE THE CAPABILITY OF PRODUCING RAPID RISES IN
SMALL STREAMS AND CREEKS...AS WELL AS MINOR FLOODING ALONG
ROADWAYS...THROUGH AT LEAST 4:00 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]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE SAN JUAN PR
157 PM AST FRI APR 23 2010

PRC009-019-025-035-039-041-043-045-057-107-109-123-149-232100-
/O.NEW.TJSJ.FA.Y.0065.100423T1757Z-100423T2100Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CIALES PR-CAGUAS PR-CIDRA PR-COAMO PR-CAYEY PR-COMERIO PR-AIBONITO
PR-BARRANQUITAS PR-OROCOVIS PR-VILLALBA PR-PATILLAS PR-GUAYAMA
PR-SALINAS PR-
157 PM AST FRI APR 23 2010

THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED AN

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

IN PUERTO RICO
CIALES...CAGUAS...CIDRA...COAMO...CAYEY...COMERIO...AIBONITO...
BARRANQUITAS...OROCOVIS...VILLALBA...PATILLAS...GUAYAMA AND
SALINAS

* UNTIL 500 PM AST

* AT 156 PM AST...NATIONAL WEATHER SERVICE DOPPLER RADAR DETECTED
HEAVY RAINFALL ACROSS THESE AREAS. THIS SHOWER ACTIVITY WILL HAVE
THE CAPABILITY OF PRODUCING RAPID RISES IN SMALL STREAMS AND
CREEKS...AS WELL AS MINOR FLOODING ALONG ROADWAYS...THROUGH AT LEAST
5:00 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]

Afternoon discussion by NWS San Juan

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
312 PM AST FRI APR 23 2010

.SYNOPSIS...MID TO UPPER LEVEL DISTURBANCE WILL MOVE ACROSS OR
JUST NORTH OF THE LOCAL AREA LATE TONIGHT THROUGH THE FIRST PART
OF SATURDAY...BEFORE LIFTING SLOWLY OUT TO THE NORTHEAST LATER
SATURDAY AND SATURDAY NIGHT. BEHIND THIS FEATURE...A MID TO UPPER
LEVEL RIDGE WILL GRADUALLY BUILD ACROSS THE LOCAL AREA SUNDAY AND
MONDAY AND SHOULD LINGER THROUGH AT LEAST THE MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...OLD FRONTAL TROUGH/CONVERGENCE ZONE AND ASSOCIATED
MOIST AND UNSTABLE AIR MASS WILL LINGER ACROSS THE LOCAL AREA
TONIGHT THROUGH AT LEAST SATURDAY AND PROBABLY SUNDAY AS WELL...
BEFORE A GRADUAL...OVERALL AIR MASS DRYING TAKES PLACE EARLY NEXT
WEEK. FOR TONIGHT AND SATURDAY...MOISTURE AND INSTABILITY SHOULD
COMBINE WITH AFOREMENTIONED MID TO UPPER LEVEL DISTURBANCE AND
LOCAL EFFECTS TO MAINTAIN A GOOD DEAL OF CLOUDINESS...SHOWERS AND
ISOLATED THUNDERSTORMS OVER PARTS OF THE LOCAL ISLANDS. FOR
SATURDAY NIGHT AND ESPECIALLY SUNDAY...BUILDING HIGH PRESSURE
SHOULD BEGIN TO CAP CONVECTION A BIT...BUT STILL SHOULD BE ENOUGH
MOISTURE IN COMBINATION WITH LOCAL EFFECTS...TO PRODUCE AT LEAST
LOCALIZED CLOUDINESS...SHOWERS AND POSSIBLY A COUPLE OF
THUNDERSTORMS. LOOKING AHEAD...FOR MONDAY AND TUESDAY AND PROBABLY
WEDNESDAY ALSO...COMBINATION OF MID TO UPPER LEVEL RIDGE AND AN
OVERALL DRIER AND MORE STABLE AIR MASS...SHOULD ALLOW FOR A
GENERALLY FAIR AND MAINLY DRY WEATHER PATTERN ACROSS THE FA.
HOWEVER...LOCAL EFFECTS WILL STILL BE ABLE TO PRODUCE SOME LIMITED
AND LOCALIZED CONVECTION EACH DAY. ADDITIONALLY...THE SURFACE WIND
FLOW IS EXPECTED TO BECOME SOUTHEAST DURING THIS TIME AND IF
ENOUGH SUNSHINE OCCURS...NORTH COASTAL TEMPERATURES MAY ONCE AGAIN
REACH THE LOWER 90S...AS INDICATED BY 12Z MEXJSJ GUIDANCE.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS ALL TAF SITES
DURING THE NEXT 24 HOURS. BRIEF PERIODS OF MVFR OR EVEN IFR
CONDITIONS AND MOUNTAIN OBSCURATIONS ARE EXPECTED...ESPECIALLY
ACROSS TJPS...TJMZ...TJBQ...AND TIST DUE TO SHOWERS AND ISOLATED
THUNDERSTORMS. MOST SHOWERS AND THUNDERSTORMS WILL DISSIPATE BY
24/00Z. ALSO...BASED ON VISIBLE SATELLITE DATA DURING THE PAST
COUPLE OF HOURS...A SMALL PLUME OF VOLCANIC ASH OR STEAM IS MOVING
NORTHWEST FROM MONTSERRAT AND IS EXPECTED TO REMAIN CLOSE TO...BUT
JUST TO THE WEST OF TKPK FOR AT LEAST THE NEXT FEW HOURS.

&&

.MARINE...GENERALLY EXPECT WINDS OF 18 KNOTS OR LESS AND SEAS OF
6 FEET OR LESS ACROSS THE REGIONAL WATERS THROUGH SUNDAY.

[cycloneye]

FLOOD ADVISORY
NATIONAL WEATHER SERVICE SAN JUAN PR
508 PM AST FRI APR 23 2010

PRC107-232300-
/O.NEW.TJSJ.FA.Y.0068.100423T2108Z-100423T2300Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
OROCOVIS PR-
508 PM AST FRI APR 23 2010

THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED AN

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

IN PUERTO RICO
OROCOVIS

* UNTIL 700 PM AST

* AT 506 PM AST DOPPLER RADAR ESTIMATED VERY HEAVY RAIN CONTINUING
IN THE ADVISORY AREA.

ADDITIONAL RAINFALL AMOUNTS OF ANOTHER INCH ARE POSSIBLE IN THE
ADVISORY AREA. THE RIO BAUTA IS STILL RISING AND AT 5 PM WAS NEARLY
ONE FOOT FROM FLOOD STAGE.

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]

Flash Flood Warning

FLASH FLOOD WARNING
PRC001-141-240015-
/O.NEW.TJSJ.FF.W.0011.100423T2146Z-100424T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN JUAN PR
546 PM AST FRI APR 23 2010

THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED A

* FLASH FLOOD WARNING FOR...
THE FOLLOWING MUNICIPALITIES

IN PUERTO RICO
ADJUNTAS
UTUADO

* UNTIL 815 PM AST

* AT 541 PM AST...HEAVY RAINFALL ACROSS THE RIO GRANDE DE ARECIBO
RIVER BASIN IS LEADING TO RAPID RISES AND FLASH FLOODING ALONG THE
RIVER AND MANY OF ITS TRIBUTARIES. AT 540 PM...A U.S.G.S. RIVER
SENSOR NEAR THE HEADWATERS OF THE RIO GRANDE DE ARECIBO INDICATED
THAT THE RIVER HAD RISEN ABOVE FLOOD STAGE...AND WAS CONTINUING TO
RISE. LOCAL RESIDENTS AND MOTORISTS SHOULD TAKE EXTREME CAUTION NEAR
THE RIO GRANDE DE ARECIBO AS THIS SURGE OF WATER MAKES ITS WAY
TOWARDS THE DOS BOCAS RESERVOIR OVER THE NEXT FEW HOURS.

DO NOT UNDERESTIMATE THE POWER OF FLOOD WATERS. ONLY A FEW INCHES OF
RAPIDLY FLOWING WATER CAN QUICKLY CARRY AWAY YOUR VEHICLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 1832 6666 1826 6669 1821 6671 1813 6672
1813 6676 1824 6675 1832 6670

$$

SR/WS

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

[cycloneye]

Plenty of diurnal action today triggered by a nearby trough as you can see by the flood advisorys and warnings.This is expected to weaken as the temperatures go down.

[Gustywind]

[cycloneye]

FLASH FLOOD WARNING
PRC039-091-101-240100-
/O.NEW.TJSJ.FF.W.0012.100423T2158Z-100424T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN JUAN PR
558 PM AST FRI APR 23 2010

THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED A

* FLASH FLOOD WARNING FOR...
THE FOLLOWING MUNICIPALITIES

IN PUERTO RICO
CIALES
MOROVIS
MANATI

* UNTIL 900 PM AST

* AT 553 PM AST...THE RIO GRANDE DE MANATI NEAR CIALES WAS RAPIDLY
APPROACHING FLOOD STAGE...AND DUE TO HEAVY RAINFALL CONTINUING
ACROSS THIS AREA...FLASH FLOODING IS EXPECTED ALONG THE RIO GRANDE
DE MANATI AND MANY OF ITS TRIBUTARIES THROUGH THE EVENING HOURS.

FOR THE RIO GRANDE DE MANATI NEAR CIALES - CIAP4
FLOOD STAGE - 10 FEET.
MODERATE FLOODING IS FORECAST WITH A CREST BETWEEN 13 AND 14
FEET.

DO NOT UNDERESTIMATE THE POWER OF FLOOD WATERS. ONLY A FEW INCHES OF
RAPIDLY FLOWING WATER CAN QUICKLY CARRY AWAY YOUR VEHICLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 1843 6649 1836 6645 1830 6644 1830 6647
1841 6652

$$

SR/WS

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

[Gustywind]

[cycloneye]

FLASH FLOOD WARNING
PRC121-125-240430-
/O.NEW.TJSJ.FF.W.0013.100423T2239Z-100424T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN JUAN PR
639 PM AST FRI APR 23 2010

THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED A

* FLASH FLOOD WARNING FOR...
THE FOLLOWING MUNICIPALITIES

IN PUERTO RICO
SABANA GRANDE
SAN GERMAN

* UNTIL 1230 AM AST

* AT 6:30 PM AST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
VERY HEAVY RAIN IN THE UPPER REACHES OF THE RIO GUANAJIBO AND ITS
TRIBUTARIES. NWS DOPPLER WEATHER RADAR INDICATED AT LEAST 4 TO 6
INCHES HAVE FALLEN IN THE NORTHERN PORTION OF SABANA GRANDE AND THIS
WATER WILL WORK ITS WAY DOWN THROUGH THE RIVER DURING THE NEXT
SEVERAL HOURS.

THE RIVER GAGE ON THE RIO GUANAJIBO HAS NOT YET BEGUN RISING...BUT
IS EXPECTED TO CREST OVER FLOOD STAGE OF 13 FEET DURING THE NEXT
SEVERAL HOURS. THIS WATER WILL EVENTUALLY REACH HORMIGUEROS.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN SAN
JUAN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 1809 6701 1815 6697 1815 6694 1804 6693
1806 6699 1810 6709 1814 6707

$$

SNELL

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

[cycloneye]

FLASH FLOOD WARNING
PRC013-141-240045-
/O.NEW.TJSJ.FF.W.0014.100423T2254Z-100424T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN JUAN PR
654 PM AST FRI APR 23 2010

THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS ISSUED A

* FLASH FLOOD WARNING FOR...
THE FOLLOWING MUNICIPALITIES

IN PUERTO RICO
UTUADO
ARECIBO

* UNTIL 845 PM AST

* AT 641 PM AST...VERY HEAVY RAINFALL ACROSS THE UPPER PORTIONS OF
THE RIO GRANDE DE ARECIBO RIVER BASIN IS RESULTING IN AREAS OF FLASH
FLOODING ALONG THE RIO GRANDE DE ARECIBO AND MANY OF ITS TRIBUTARIES
ACROSS UTUADO AND ARECIBO...INCLUDING THE RIO LIMON. FLASH FLOODING
AND POSSIBLE MUDSLIDES IN AREAS OF STEEP TERRAIN IS EXPECTED TO
CONTINUE THROUGH AT LEAST 845 PM AST THIS EVENING.

DO NOT UNDERESTIMATE THE POWER OF FLOOD WATERS. ONLY A FEW INCHES OF
RAPIDLY FLOWING WATER CAN QUICKLY CARRY AWAY YOUR VEHICLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 1834 6658 1822 6664 1826 6668 1834 6665

$$

SR/WS

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