Puerto Rico dodged the worse of the big rain event (Edited)

[cycloneye]

000
FXCA62 TJSJ 210950
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
530 AM AST THU APR 21 2005

.DISCUSSION...
TODAY PROMISES TO BE ANOTHER ACTIVE DAY. NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS CAN BE EXPECTED...PARTICULARLY ALONG THE
INTERIOR AND NORTH SECTORS OF PUERTO RICO DUE TO A PERSISTENT SOUTH
SOUTHEASTERLY WIND FLOW. RIVERS AND CREEKS ALONG THE NORTHERN
PORTIONS OF PUERTO RICO REMAINED AT ABOVE NORMAL LEVELS...AND AS A
RESULT WILL BE QUICK TO REACT TO ANY ADDITIONAL RAINFALL TODAY.

WEATHER CONDITIONS ACROSS PUERTO RICO...THE U.S. VIRGIN ISLANDS AND
THE ADJACENT COASTAL WATERS WILL NOT CHANGE MUCH DURING THE NEXT
SEVERAL DAYS AND IN FACT THEY WILL DETERIORATE EVEN MORE DURING THE
UPCOMING WEEKEND. MODEL GUIDANCES CONTINUE TO SHOW A TREMENDOUS
INCREASE IN LOW LEVEL MOISTURE ACROSS THE LOCAL ISLANDS LATE FRIDAY
THROUGH SUNDAY. A STRONG MIDDLE TO UPPER TROUGH LOCATED FROM THE
WESTERN ATLANTIC...SOUTHWARD ACROSS THE BAHAMAS AND INTO THE NORTH
CENTRAL CARIBBEAN WILL INDUCE A SURGE OF MOISTURE FROM THE ITCZ
ACROSS NORTHERN SOUTH AMERICA AND THEN INTO THE EASTERN CARIBBEAN.
MOISTURE WILL RAPIDLY SPREAD NORTH INTO PUERTO RICO AND THE VIRGIN
ISLANDS BEGINNING LATE FRIDAY. DEEP MOISTURE...STRONG SOUTHWESTERLY
WINDS AT UPPER LEVELS...GOOD OMEGA VALUES AND A NEARLY STATIONARY
FRONTAL BOUNDARY WILL TEAM UP TO PRODUCE HEAVY RAIN AND THE
POTENTIAL FOR WIDESPREAD FLASH FLOODING NOT ONLY OVER PUERTO RICO
BUT ALSO ACROSS THE U.S. VIRGIN ISLANDS THIS WEEKEND. ALL LOCAL
RESIDENTS AND VISITORS ARE URGED TO REMAIN ALERT FOR THREATENING
WEATHER AND FLOODING CONDITIONS THROUGH THE UPCOMING WEEKEND.

&&

.MARINE...MODERATE NORTHERLY SWELLS WILL PERSIST ACROSS THE LOCAL
ATLANTIC WATERS TODAY. DANGEROUS THUNDERSTORMS WILL AFFECT THE LOCAL
COASTAL WATERS TODAY AND TONIGHT...BUT ESPECIALLY ACROSS THE
ATLANTIC OFFSHORE WATERS...PRODUCING LOW VISIBILITIES...STRONG GUSTY
WINDS AND CLOUD TO WATER LIGHTNING.

&&

.HYDROLOGY...FLASH FLOOD WATCH REMAINS IN EFFECT FOR THE ENTIRE
ISLAND OF PUERTO RICO THROUGH THIS MORNING...BUT IT MAY BE EXTENDED
THROUGH THE WEEKEND. RAINFALL ACCUMULATIONS OF BETWEEN 2 AND 5
INCHES PER DAY ARE LIKELY OVER THE NEXT FEW DAYS...ESPECIALLY FRIDAY
NIGHT THROUGH SUNDAY...WITH LOCALLY HIGHER AMOUNTS POSSIBLE DURING
THE WEEKEND.

&&
[b]

Much more rain is expected thru sunday.With the orografic effects of the mountains if this event of the weekend come thru many mudslides will occur and a massive flood event like the 1996 one that Hurricane Hortense brought may happen but I hope that the strong trough that the models show forming south of Puerto Rico dont materialize.

[cycloneye]

000
FXCA62 TJSJ 212008
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
406 PM AST THU APR 21 2005

.DISCUSSION...

...SIGNIFICANT WEATHER EVENT SHAPING UP ACROSS PUERTO
RICO...CULEBRA...VIEQUES AND ALL THE VIRGIN ISLANDS...

FORECAST...THE GOOD...THE BAD AND THE REALLY UGLY.

THE GOOD...FOR THE MOST PART SHOWERS AND THUNDERSTORMS WILL DIMINISH
THIS EVENING ACROSS THE NORTHERN COAST OF PUERTO RICO...EXCEPT FOR
ISOLATED TO SCATTERED SHOWERS ACROSS THE SOUTH-SOUTHEAST-EAST
COASTAL WATERS....A FEW WHICH WILL MOVE ON SHORE.

THE BAD...LOCAL AREA SHOULD SEE ABOUT THE SAME WEATHER AS WAS SEEN
THIS AFTERNOON WITH SCATTERED TO NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORM DEVELOPING MAINLY ACROSS THE NORTHERN HALF OF PUERTO
RICO THEN MOVING NORTHWARD INTO THE ATLANTIC.

THE REALLY UGLY...AS WE HAVE BEEN FORECASTING THE PAST SEVERAL DAYS
A STRONG MID/UPPER TROUGH WILL START TO AFFECT THE LOCAL AREA FRIDAY
EVENING THROUGH SUNDAY. WE HAVE THE DYNAMICS FOR A MAJOR FLOOD EVENT
ACROSS PORTIONS OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS. WITH A
SURGE OF DEEP ITCZ MOISTURE EXPECTED TO MOVE NORTHWARD ACROSS THE
LOCAL AREA...HIGH OMEGA VALUES...VERY GOOD DIFFLUENCE ALOFT AND
BEING IN THE RIGHT REAR QUADRANT OF THE JET...AND THIS ALL IN THE
MID/UPPER LEVELS. TO AGGRAVATE THE SITUATION AT LOW LEVELS A
SOUTHERLY LOW LEVEL "JET" OF 15 TO 20 KNOTS IS EXPECTED TO COME UP
FROM THE SOUTH WHICH WILL TRIGGER GOOD LOW LEVEL CONVERGENCE ACROSS
SOUTHERN FACING COAST WHICH WILL PROPAGATE NORTH TO THE NORTHERN
COASTS AS WELL. BASED ON THE PAST 2 RUNS OF THE GFS...THE MAX LOW
LEVEL CONVERGENCE APPEARS TO OCCUR ACROSS THE EASTERN SECTION OF
PUERTO RICO...OVER CULEBRA...VIEQUES AND THE USVI...ESPECIALLY THE
NORTHERN USVI LATE FRIDAY NIGHT THROUGH SUNDAY. HOWEVER...THE POOL
OF MOISTURE THAT WILL BE ADVECTED FROM THE SOUTH WILL LIKELY BE
ENOUGH FOR WIDESPREAD SHOWERS AREA WIDE.

THIS IS A DANGEROUS SITUATION!!! THE BULK OF THE EVENT IS FORECAST
TO BEGIN DURING THE EVENING OR NIGHT HOURS...YOU ARE URGED TO KEEP
ABREAST OF THIS DEVELOPING WEATHER PATTERN.


Look how the folks at the NWS In San Juan typed the discussion.

On my I hope that this event dont materilize.

[depotoo]

wow - luis sounds like you guys could use a break about now! stay safe!

[msbee]

and I say "WOW" again
I hope it doesn't materialize either.
good luck to all of you in PR!

[cycloneye]

and I say "WOW" again
I hope it doesn't materialize either.
good luck to all of you in PR!

And in march we were in a drought but look now how the weather extremes go to work.

[TS Zack]

I feel your pain Luis.

Not much in the way of relief on the way either. Especially over the course of the next 3-5 days. A persistent ULL over the Bahamas is pumping some deep Low-level Moisture into the area. Now looking at the Long Range Models, you may see this slacken off in about a week or so as a ridge of high pressure builds back into the area from the East.

The East Coast Trough will not help you either being on the front south quadrant of the ULL.

Good Luck Down There,

[x-y-no]

Wow ... what a difference a couple of days make, eh? What started out as good news about the breaking of your drought now looks like real trouble.

Stay safe.

Jan

[cycloneye]

http://www.meteo.psu.edu/~arnottj/cgi-b ... hour=036hr

12z GFS

http://www.meteo.psu.edu/~arnottj/cgi-b ... hour=036hr

12z Nogaps

Those two models above dont show nothing good for Puerto Rico in the next 36 hours as copius amounts of rain are forecasted with this event.All is combining for a significant event of rainfall such as a jet stream,upper troughs and surface boundary.

[cycloneye]

HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE SAN JUAN PR
400 PM AST THU APR 21 2005

...POTENTIAL FOR WIDESPREAD TORRENTIAL RAINFALL FOR THE ENTIRE AREA
THIS WEEKEND...

THE MONTH OF APRIL HAS BROUGHT A QUICK TRANSITION FROM A ABNORMALLY
DRY CONDITIONS ACROSS MUCH OF THE LOCAL AREA...TO VERY WET
CONDITIONS IN THE PAST SEVERAL DAYS. THE LOCAL REGION HAS COME UNDER
THE INFLUENCE OF A STRONG UPPER LEVEL TROUGH WHICH HAS ACTED TO
CREATE A VERY UNSTABLE ATMOSPHERE...LEADING TO HEAVY RAINS ACROSS
THE WEST AND NORTHERN HALF OF PUERTO RICO IN THE PAST FEW DAYS.

NATIONAL WEATHER SERVICE COMPUTER MODEL GUIDANCE IS SUGGESTING THAT
THIS TROUGH WILL FURTHER INTENSIFY THURSDAY NIGHT THROUGH SUNDAY TO
CREATE A POTENTIALLY EXPLOSIVE WEATHER SCENARIO ACROSS THE NORTHEAST
CARIBBEAN. AN OLD COLD FRONTAL BOUNDARY LINGERING FROM THE MONA
PASSAGE NORTHEASTWARD INTO THE CENTRAL ATLANTIC THE PAST FEW DAYS
HAS PROVIDED AMPLE LOW LEVEL MOISTURE FOR THE ACTIVE WEATHER OF
RECENT. THE COMBINATION OF THE INTENSIFYING UPPER LEVEL TROUGH AND A
DEVELOPING LOW LEVEL CYCLONIC CIRCULATION ALONG THIS LINGERING
FRONTAL BOUNDARY TO OUR NORTHWEST...IS FORECAST TO GRADUALLY ENHANCE
THE SOUTHERLY FLOW OF TROPICAL MOISTURE FROM SOUTH AMERICA INTO THE
LOCAL CARIBBEAN WATERS FRIDAY AFTERNOON...THEN SPREAD NORTH AND
NORTHEAST ACROSS PUERTO RICO SATURDAY THROUGH SATURDAY NIGHT...AND
SHIFT SLOWLY EASTWARD INTO THE VIRGIN ISLANDS ON SUNDAY. THE
ELONGATED LOW PRESSURE ACROSS THE AREA...ABUNDANT TROPICAL
MOISTURE...AND A VERY STRONG AND ENERGETIC UPPER LEVEL TROUGH ACROSS
THE REGION ARE THUS EXPECTED TO COMBINE THIS WEEKEND TO GENERATE
PERSISTING CLUSTERS OF INTENSE SHOWERS AND THUNDERSTORMS ACROSS THE
REGION...AFFECTING THE LOCAL ISLANDS EARLY SATURDAY THROUGH SUNDAY
NIGHT.

THIS TYPE OF INTENSE SHOWER AND THUNDERSTORM ACTIVITY WILL BE
CAPABLE OF PRODUCING 24 HOUR RAIN TOTALS OF 4 TO 8 INCHES...WITH
ISOLATED HIGHER AMOUNTS POSSIBLE OVER MOUNTAINOUS TERRAIN. RECENT
RAINS HAVE WETTED THE LOCAL SOILS...AND ARE KEEPING RIVER AND STREAM
LEVELS AT ELEVATED LEVELS. RIVER AND STREAMS WILL THUS REACT TO
HEAVY RAINFALL AT FASTER RATES EACH DAY AS WE APPROACH THE WEEKEND.
FLASH FLOODING POTENTIAL WILL REMAIN HIGH TONIGHT AND FRIDAY...AND
COULD BECOME LIKELY OVER THE WEEKEND.

LOCAL RESIDENTS AND VISITORS ARE ADVISED TO KEEP ABREAST OF THIS
DEVELOPING AND POTENTIALLY LIFE THREATENING WEATHER EVENT.

ADDITIONAL INFORMATION CAN BE OBTAINED AT THE FOLLOWING WEBSITE:
(ALL LOWER CASE).

NWS SAN JUAN HOME PAGE: HTTP://WWW.SRH.NOAA.GOV/SJU

[*StOrmsPr*]

000
FXCA62 TJSJ 212008
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
406 PM AST THU APR 21 2005

.DISCUSSION...

...SIGNIFICANT WEATHER EVENT SHAPING UP ACROSS PUERTO
RICO...CULEBRA...VIEQUES AND ALL THE VIRGIN ISLANDS...

FORECAST...THE GOOD...THE BAD AND THE REALLY UGLY.

THE GOOD...FOR THE MOST PART SHOWERS AND THUNDERSTORMS WILL DIMINISH
THIS EVENING ACROSS THE NORTHERN COAST OF PUERTO RICO...EXCEPT FOR
ISOLATED TO SCATTERED SHOWERS ACROSS THE SOUTH-SOUTHEAST-EAST
COASTAL WATERS....A FEW WHICH WILL MOVE ON SHORE.

THE BAD...LOCAL AREA SHOULD SEE ABOUT THE SAME WEATHER AS WAS SEEN
THIS AFTERNOON WITH SCATTERED TO NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORM DEVELOPING MAINLY ACROSS THE NORTHERN HALF OF PUERTO
RICO THEN MOVING NORTHWARD INTO THE ATLANTIC.

THE REALLY UGLY...AS WE HAVE BEEN FORECASTING THE PAST SEVERAL DAYS
A STRONG MID/UPPER TROUGH WILL START TO AFFECT THE LOCAL AREA FRIDAY
EVENING THROUGH SUNDAY. WE HAVE THE DYNAMICS FOR A MAJOR FLOOD EVENT
ACROSS PORTIONS OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS. WITH A
SURGE OF DEEP ITCZ MOISTURE EXPECTED TO MOVE NORTHWARD ACROSS THE
LOCAL AREA...HIGH OMEGA VALUES...VERY GOOD DIFFLUENCE ALOFT AND
BEING IN THE RIGHT REAR QUADRANT OF THE JET...AND THIS ALL IN THE
MID/UPPER LEVELS. TO AGGRAVATE THE SITUATION AT LOW LEVELS A
SOUTHERLY LOW LEVEL "JET" OF 15 TO 20 KNOTS IS EXPECTED TO COME UP
FROM THE SOUTH WHICH WILL TRIGGER GOOD LOW LEVEL CONVERGENCE ACROSS
SOUTHERN FACING COAST WHICH WILL PROPAGATE NORTH TO THE NORTHERN
COASTS AS WELL. BASED ON THE PAST 2 RUNS OF THE GFS...THE MAX LOW
LEVEL CONVERGENCE APPEARS TO OCCUR ACROSS THE EASTERN SECTION OF
PUERTO RICO...OVER CULEBRA...VIEQUES AND THE USVI...ESPECIALLY THE
NORTHERN USVI LATE FRIDAY NIGHT THROUGH SUNDAY. HOWEVER...THE POOL
OF MOISTURE THAT WILL BE ADVECTED FROM THE SOUTH WILL LIKELY BE
ENOUGH FOR WIDESPREAD SHOWERS AREA WIDE.

THIS IS A DANGEROUS SITUATION!!! THE BULK OF THE EVENT IS FORECAST
TO BEGIN DURING THE EVENING OR NIGHT HOURS...YOU ARE URGED TO KEEP
ABREAST OF THIS DEVELOPING WEATHER PATTERN.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 73 85 76 84 / 20 50 70 70
STT 73 82 77 81 / 20 40 70 90

&&

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

[cycloneye]

000
FXCA62 TJSJ 212008
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
406 PM AST THU APR 21 2005

.DISCUSSION...

...SIGNIFICANT WEATHER EVENT SHAPING UP ACROSS PUERTO
RICO...CULEBRA...VIEQUES AND ALL THE VIRGIN ISLANDS...

FORECAST...THE GOOD...THE BAD AND THE REALLY UGLY.

THE GOOD...FOR THE MOST PART SHOWERS AND THUNDERSTORMS WILL DIMINISH
THIS EVENING ACROSS THE NORTHERN COAST OF PUERTO RICO...EXCEPT FOR
ISOLATED TO SCATTERED SHOWERS ACROSS THE SOUTH-SOUTHEAST-EAST
COASTAL WATERS....A FEW WHICH WILL MOVE ON SHORE.

THE BAD...LOCAL AREA SHOULD SEE ABOUT THE SAME WEATHER AS WAS SEEN
THIS AFTERNOON WITH SCATTERED TO NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORM DEVELOPING MAINLY ACROSS THE NORTHERN HALF OF PUERTO
RICO THEN MOVING NORTHWARD INTO THE ATLANTIC.

THE REALLY UGLY...AS WE HAVE BEEN FORECASTING THE PAST SEVERAL DAYS
A STRONG MID/UPPER TROUGH WILL START TO AFFECT THE LOCAL AREA FRIDAY
EVENING THROUGH SUNDAY. WE HAVE THE DYNAMICS FOR A MAJOR FLOOD EVENT
ACROSS PORTIONS OF PUERTO RICO AND THE U.S. VIRGIN ISLANDS. WITH A
SURGE OF DEEP ITCZ MOISTURE EXPECTED TO MOVE NORTHWARD ACROSS THE
LOCAL AREA...HIGH OMEGA VALUES...VERY GOOD DIFFLUENCE ALOFT AND
BEING IN THE RIGHT REAR QUADRANT OF THE JET...AND THIS ALL IN THE
MID/UPPER LEVELS. TO AGGRAVATE THE SITUATION AT LOW LEVELS A
SOUTHERLY LOW LEVEL "JET" OF 15 TO 20 KNOTS IS EXPECTED TO COME UP
FROM THE SOUTH WHICH WILL TRIGGER GOOD LOW LEVEL CONVERGENCE ACROSS
SOUTHERN FACING COAST WHICH WILL PROPAGATE NORTH TO THE NORTHERN
COASTS AS WELL. BASED ON THE PAST 2 RUNS OF THE GFS...THE MAX LOW
LEVEL CONVERGENCE APPEARS TO OCCUR ACROSS THE EASTERN SECTION OF
PUERTO RICO...OVER CULEBRA...VIEQUES AND THE USVI...ESPECIALLY THE
NORTHERN USVI LATE FRIDAY NIGHT THROUGH SUNDAY. HOWEVER...THE POOL
OF MOISTURE THAT WILL BE ADVECTED FROM THE SOUTH WILL LIKELY BE
ENOUGH FOR WIDESPREAD SHOWERS AREA WIDE.

THIS IS A DANGEROUS SITUATION!!! THE BULK OF THE EVENT IS FORECAST
TO BEGIN DURING THE EVENING OR NIGHT HOURS...YOU ARE URGED TO KEEP
ABREAST OF THIS DEVELOPING WEATHER PATTERN.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 73 85 76 84 / 20 50 70 70
STT 73 82 77 81 / 20 40 70 90

&&

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

I posted this same discussion at above posts.

[cycloneye]

CARIBBEAN FORECAST DISCUSSION

--------------------------------------------------------------------------------
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
221 PM EDT THU APR 21 2005

A BROAD MID/UPPER LEVEL TROUGH DOMINATES THE WESTERN
ATLANTIC-CENTRAL/EASTERN CARIBBEAN. SHORT WAVE PERTURBATIONS
ARE EJECTING OVER THE CONTINENTAL RIDGE AND FEEDING INTO THE
BASE OF THE TROUGH. THIS IN-TURN WILL SUPPORT THE WESTWARD
RETROGRESSION OF THIS AXIS ACROSS CUBA INTO HONDURAS/
NICARAGUA BY 36-48 HRS. AT 72 HRS THE TROUGH WILL MOVE AGAIN
ACROSS EASTERN CUBA-PANAMA/COSTA RICA INTO THE EASTERN
PACIFIC. AT 250 HPA...A SUBTROPICAL JET WILL REMAIN JUST
NORTH OF THE EASTERN CARIBBEAN ISLANDS...WITH A CORE OF 90-
110KT TO PERSIST THROUGH 60-72 HRS. THE CORE THEN EJECTS TO
THE NORTHEAST BY 84-96 HRS. MEANWHILE...THIS JET WILL
SUPPORT A DIVERGENT PATTERN ALOFT THAT IS TO PROVIDE
VENTILATION FOR DEEP CONVECTION ACROSS HISPANIOLA-PUERTO
RICO-VIRGIN ISLES (VI). THE TROUGH SUPPORTS A FRONT NORTH OF
THE ISLANDS THAT IS BECOMING DIFFUSE OVER THE SOUTHEAST
BAHAMAS.

AT 850 HPA...THE DEEP UPPER TROUGH SUPPORTS A FRONTAL TROUGH
NORTH OF THE ISLANDS WITH AXIS TO THE WEST/SOUTHWEST INTO
THE SOUTHEAST BAHAMAS/CUBA. THIS IS ALSO FAVORING THE
NORTHWARD AMPLIFICATION OF AN INVERTED TROUGH FROM NORTHWEST
VENEZUELA TO HISPANIOLA...AND THE INTENSIFICATION OF THE
CLIMATOLOGICAL TROUGH OVER PANAMA/WESTERN COLOMBIA. THIS
TROUGH...COUPLED WITH A LOW LEVEL RIDGE EAST OF THE
ISLANDS...WILL FAVOR A SOUTH/SOUTHEASTERLY FLOW INTO THE
EASTERN CARIBBEAN...THAT TAKES A MORE SOUTHERLY COMPONENT
EARLY THIS CYCLE. THE TROUGH/RIDGE IS INDUCING A SURGE OF
ITCZ/NEAR EQUATORIAL TROUGH MOISTURE ACROSS VENEZUELA INTO
THE ABC ISLES... WITH MOISTURE TO RAPIDLY SPREAD NORTH INTO
PUERTO RICO-THE VIRGIN ISLES BY 42-48 HRS...TO ENVELOP THE
ISLAND CHAIN BY 48-54 HRS. IN THIS PATTERN THE GFS IS
CONSISTENT ON ITS FORECAST OF AN MCS/MCC OVER NORTHWEST
VENEZUELA BY 24-36 HRS...THAT EJECTS NORTH ACROSS PUERTO
RICO/VIRGIN ISLES BY 48-60 HRS...WHERE IT INTENSIFIES. THE
GFS HAS MAINTAINED GOOD TEMPORAL AND CYCLE-TO-CYCLE
CONSISTENCY ON THE DEVELOPMENT OF THIS EVENT. IT IS ALSO
WELL SUPPORTED BY THE NCEP ENSEMBLE MODELS. ACROSS PUERTO
RICO IT WILL RESULT IN RAINFALL AMOUNTS OF 35-70MM...WITH
MAXIMA TO PEAK AROUND 125-250MM (05-10 INCHES). ACROSS THE
VIRGIN ISLES EXPECT SIMILAR AMOUNTS...WITH MAXIMA OF 75-
125MM. BY 54-84 HRS CONVECTION IS TO AFFECT THE NORTHERN
LEEWARD ISLES...WITH ACCUMULATION OF 10-20MM/DAY AND MAXIMA
OF 40-50 MM.



The above from HPC discussion about Caribbean.

[cycloneye]

000
FXCA62 TJSJ 221109 RRA
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
600 AM AST FRI APR 22 2005

.DISCUSSION...

...VERY SIGNIFICANT WEATHER EVENT STILL ON TAP FOR PUERTO RICO...
CULEBRA...VIEQUES AND ALL OF THE U.S. VIRGIN ISLANDS...

FOR TODAY...SHOULD BE BASICALLY A DITTO OF THE PAST COUPLE OF
DAYS...WITH THE VERY MOIST AND UNSTABLE AIR MASS...COMBINING WITH
MID TO UPPER LEVEL TROUGH AND LOCAL EFFECTS...TO MAKE FOR SCATTERED
TO NUMEROUS SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS...SOME
WITH VERY HEAVY TO TORRENTIAL RAINFALL ACROSS THE LOCAL ISLANDS...
BUT ESPECIALLY OVER THE INTERIOR AND NORTH SECTIONS OF PUERTO RICO.
ONCE AGAIN...THIS AFTERNOON WE EXPECT AT LEAST LOCALIZED FLASH AND
RIVER FLOODING AND THE LIKELIHOOD OF MORE MUDSLIDES DEVELOPING.

FOR TONIGHT THROUGH SUNDAY...THIS PREVIOUS DISCUSSION WAS
EXCELLENT...SO HERE IT IS AGAIN WITH A COUPLE OF MINOR TWEAKINGS. AS
WE HAVE BEEN FORECASTING THE PAST SEVERAL DAYS...A STRONG MID TO
UPPER LEVEL TROUGH WILL BEGIN TO ASSERT MORE INFLUENCE ON LOCAL AREA
TODAY AND TONIGHT AND THIS SHOULD CONTINUE THROUGH SUNDAY. WE HAVE
THE DYNAMICS FOR A MAJOR FLOOD EVENT ACROSS PORTIONS OF PUERTO RICO
AND THE U.S. VIRGIN ISLANDS. A SURGE OF DEEP ITCZ MOISTURE WILL MOVE
NORTHWARD ACROSS THE CARIBBEAN TODAY AND THEN ACROSS THE LOCAL
ISLANDS LATE THIS AFTERNOON AND TONIGHT THROUGH AT LEAST SATURDAY OR
SATURDAY NIGHT. ALSO...WE WILL HAVE HIGH OMEGA VALUES...VERY GOOD
DIFFLUENCE ALOFT AND WILL BE IN THE RIGHT REAR QUADRANT OF THE
JET...AND THIS ALL IN THE MID AND UPPER LEVELS. TO AGGRAVATE THE
SITUATION AT LOW LEVELS A SOUTHERLY LOW LEVEL "JET" OF 15 TO 20+
KNOTS IS EXPECTED TO COME UP FROM THE SOUTH WHICH WILL TRIGGER GOOD
LOW LEVEL CONVERGENCE ACROSS THE SOUTHERN FACING COASTS WHICH WILL
PROPAGATE NORTH THROUGH THE INTERIOR MOUNTAINS AND TO THE NORTHERN
COASTS AS WELL. BASED ON THE PAST FEW RUNS OF THE GFS...THE MAX LOW
LEVEL CONVERGENCE STILL LOOKS LIKE IT WILL OCCUR ACROSS THE EASTERN
SECTIONS OF PUERTO RICO...OVER CULEBRA...VIEQUES AND THE U.S. VIRGIN
ISLANDS...ESPECIALLY THE NORTHERN ISLANDS LATE TONIGHT THROUGH
SUNDAY. HOWEVER...THE POOL OF MOISTURE THAT WILL BE ADVECTED FROM
THE SOUTH WILL LIKELY BE ENOUGH FOR NUMEROUS TO WIDESPREAD SHOWERS
AND MANY THUNDERSTORMS IN BANDS AND CLUSTERS...ACROSS THE LOCAL
ISLANDS TONIGHT THROUGH AT LEAST SATURDAY NIGHT.

THIS UPCOMING WEATHER EVENT HAS A GOOD POTENTIAL TO DEVELOP INTO A
DANGEROUS AND POSSIBLY LIFE THREATENING SITUATION FOR PARTS OR ALL
OF PUERTO RICO...CULEBRA AND VIEQUES AND THE U.S. VIRGIN ISLANDS.
ALL LOCAL RESIDENTS AND VISITORS SHOULD CLOSELY MONITOR THE WEATHER
DURING THE NEXT FEW DAYS...AND STAY OUT OF AND AWAY FROM ALL LOCAL
RIVERS AND STREAMS.

BASED ON WEATHER TRENDS OVERNIGHT AND ANTECEDENT AND FORECAST
CONDITIONS...WE DECIDED TO ISSUE A FLASH FLOOD WATCH FOR ALL OF
PUERTO RICO EFFECTIVE UNTIL 445 AM SATURDAY MORNING. UNDOUBTEDLY...
THIS WATCH WILL NEED TO BE EXPANDED TO INCLUDE CULEBRA AND VIEQUES
AND THE U.S. VIRGIN ISLANDS...AND EXTENDED IN TIME LATER TODAY OR
TONIGHT.

&&

.MARINE...FAIRLY TRANQUIL CONDITIONS EXPECTED ON THE COASTAL WATERS
FOR THE NEXT FEW DAYS WATER-WISE...BUT NOT A GOOD PLACE TO BE GIVEN
AMOUNT OF SHOWER AND THUNDERSTORM ACTIVITY THAT IS EXPECTED. HAVE
MENTIONED THE CAVEAT FOR WINDS AND SEAS HIGHER AND VISIBILITIES
LOCALLY 1 NAUTICAL MILE OR LESS IN AND NEAR THUNDERSTORMS IN CWF FOR
TODAY AND THIS WILL NEED TO BE EXTENDED TO OTHER PERIODS LATER ON.
ALSO...AFOREMENTIONED SOUTHERLY JET OF 15 TO 20+ KNOTS WILL MAKE FOR
A PERIOD OF LOCALLY HAZARDOUS WINDS AND ASSOCIATED SEA CONDITIONS AS
IT TRANSITIONS NORTHWARD ACROSS THE LOCAL WATERS.

&&

.HYDROLOGY...AFTER THE DRIEST MARCH EVER ON RECORD WITH ONLY A TRACE
OF RAINFALL RECORDED AT THE LUIS MUNOZ MARIN INTERNATIONAL AIRPORT
IN SAN JUAN...APRIL HAS CERTAINLY BROUGHT A SIGNIFICANT CHANGE IN
THE WEATHER PATTERN. IN FACT...SO FAR THIS MONTH...11.60 INCHES OF
RAIN HAS BEEN MEASURED AT THE AIRPORT AND THIS VALUE HAS ALREADY
BROKEN THE PREVIOUS APRIL RECORD OF 10.37 INCHES OF RAIN SET BACK IN
1988. SO...THIS MONTH IS ALREADY THE WETTEST APRIL ON RECORD...AND
MORE RAIN IS EXPECTED DURING THE NEXT FEW DAYS.

ON TOP OF THE LOCALIZED HEAVY RAIN THAT HAS ALREADY FALLEN THE PAST
FEW DAYS...FOR THE UPCOMING EVENT...ALTHOUGH IT IS TOO EARLY TO
PINPOINT EXACTLY WHERE THE HEAVIEST RAINFALL WILL OCCUR TONIGHT
THROUGH SATURDAY AND SUNDAY...PAST WEATHER SCENARIOS OF THIS KIND
HAVE RESULTED IN WIDESPREAD TOTAL RAINFALL ACCUMULATIONS OF 4 TO 8
INCHES ACROSS MOST OF THE LOCAL ISLANDS...WITH LOCALLY HIGHER
AMOUNTS OVER THE HIGHER TERRAIN AND WHERE BEST LOW LEVEL CONVERGENCE
AND DYNAMICS COME TOGETHER. SIGNIFICANT FLASH AND RIVER FLOODING AND
MUDSLIDES APPEAR LIKELY FOR THE NEXT FEW DAYS.


Nothing different this morning from the discussions of yesterday as the big event will take place.For those who may be worried about my safety I am in a very safe place high and dry in a 5th floor condo.

[msbee]

still sounds ominous Luis.
I am glad you are safe, and I hope others will be safe too.
and I still offer to take some of that rainfall up for you.
we still need it here.
Barbara

[cycloneye]

still sounds ominous Luis.
I am glad you are safe, and I hope others will be safe too.
and I still offer to take some of that rainfall up for you.
we still need it here.
Barbara

Omminous this morning is that in San Juan it is sunny with almost no clouds in the sky but this brief weather will not last too long.

[msbee]

the calm before the storm, right?

[cycloneye]

A STRONG THUNDERSTORM WITH ROTATION...VERY HEAVY RAIN...FREQUENT
LIGHTNING AND SMALL HAIL CONTINUES TO DEVELOP ACROSS THE
MUNICIPALITIES OF VEGA BAJA...VEGA ALTA...DORADO AND TOA BAJA.
STRONG GUSTY WINDS HAVE BEEN REPORTED NEAR 40 TO 50 MPH. ROTATION
HAS ALSO BEEN REPORTED IN DORADO AND TOA BAJA. SMALL HAIL HAS ALSO
BEEN REPORTED. THE STORM IS MOVING RAPIDLY TO THE EAST NORTHEAST AND
COULD SPAWN WATERSPOUTS OVER THE NEAR SHORE COASTAL WATERS.


A big complex of thunderstorms formed in northern Puerto Rico producing some hail and some rotation.I got it where I am but it has weakened a bit with only a brief heavy downpour.But I fear that this is only the start of the big event.

[cycloneye]

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH
NATIONAL WEATHER SERVICE SAN JUAN PR
1130 AM AST FRI APR 22 2005


...THE FLASH FLOOD WATCH ISSUED EARLIER BY THE NATIONAL WEATHER
SERVICE IN SAN JUAN HAS BEEN EXPANDED IN AREAL COVERAGE AND TIME...

IN PUERTO RICO...
ALL OF PUERTO RICO INCLUDING VIEQUES AND CULEBRA.

IN THE U.S. VIRGIN ISLANDS...
ST CROIX AND ST. THOMAS...ST. JOHN... AND ADJACENT ISLANDS.

...THE FLASH FLOOD WATCH HAS BEEN EXPANDED IN AREAL COVERAGE...

...THE NATIONAL WEATHER SERVICE IN SAN JUAN HAS EXPANDED THE FLASH
FLOOD WATCH UNTIL 1100 AM SATURDAY MORNING. THE WATCH INCLUDES ALL
OF PUERTO RICO...VIEQUES AND CULEBRA AND ALL OF THE U.S. VIRGIN
ISLANDS...

A LARGE AREA OF DEEP TROPICAL MOISTURE WILL SPREAD NORTH ACROSS THE
CARIBBEAN TODAY...INTO PUERTO RICO THIS EVENING AND THEN FURTHER
EAST INTO CULEBRA AND VIEQUES AND THE U.S. VIRGIN ISLANDS LATER
TONIGHT INTO SATURDAY. THIS ABUNDANT TROPICAL MOISTURE WILL COMBINE
WITH AN ENERGETIC...MID TO UPPER LEVEL TROUGH LOCATED JUST TO THE
WEST OF THE LOCAL ISLANDS...A BROAD SURFACE TROUGH ACROSS THE
NORTHEAST CARIBBEAN AND LOCAL ISLAND EFFECTS...TO PRODUCE ADDITIONAL
SHOWERS AND THUNDERSTORMS...SOME WITH TORRENTIAL RAINFALL...OVER
PUERTO RICO BY LATE THIS AFTERNOON OR EARLY TONIGHT AND THEY WILL
GRADUALLY SPREAD EASTWARD LATE TONIGHT AND SATURDAY. ALTHOUGH IT IS
TOO EARLY TO PINPOINT EXACTLY WHERE THE HEAVIEST RAINFALL WILL OCCUR
TONIGHT THROUGH SATURDAY...PAST WEATHER SCENARIOS OF THIS KIND HAVE
RESULTED IN WIDESPREAD TOTAL RAINFALL ACCUMULATIONS OF 4 TO 8 INCHES
ACROSS MOST OF PUERTO RICO...AND PORTIONS OF VIEQUES...CULEBRA AND
THE U.S. VIRGIN ISLANDS...WITH LOCALLY HIGHER AMOUNTS OVER THE
HIGHER TERRAIN.

THIS UPCOMING WEATHER EVENT HAS THE POTENTIAL TO DEVELOP INTO A
DANGEROUS AND POSSIBLY LIFE THREATENING SITUATION FOR PUERTO RICO
AND THE U.S. VIRGIN ISLANDS. ALL LOCAL RESIDENTS AND VISITORS SHOULD
CLOSELY MONITOR THE WEATHER DURING THE NEXT FEW DAYS...AND STAY OUT
OF AND AWAY FROM ALL LOCAL RIVERS AND STREAMS.

A FLASH FLOOD WATCH MEANS THAT CONDITIONS ARE FAVORABLE FOR HEAVY
RAIN ACROSS THE WATCH AREA...WHICH MAY LEAD TO FLOODING. IF YOU ARE
IN THE WATCH AREA...CHECK YOUR PREPAREDNESS REQUIREMENTS...ESPECIALLY
IF YOU HAVE INTERESTS ALONG AREA RIVERS. KEEP INFORMED...AND BE READY
FOR QUICK ACTION IF FLOODING IS OBSERVED OR IF A FLASH FLOOD WARNING
IS ISSUED.

PEOPLE IN THE WATCH AREA SHOULD CONTINUE TO BE AWARE OF THE
POSSIBILITY FOR HEAVY RAINFALL. AVOID LOW LYING AREAS...AND BE
CAREFUL WHEN APPROACHING HIGHWAY DIPS AND UNDERPASSES. THE HEAVY RAIN
COULD ALSO CAUSE MUDSLIDES IN AREAS OF STEEP TERRAIN.

STAY TUNED TO NOAA WEATHER RADIO...LOCAL TV...RADIO OR YOUR CABLE
TELEVISION PROVIDER FOR LATER STATEMENTS AND POSSIBLE WARNINGS.

[cycloneye]

THE CONTINENTAL RIDGE IS FEEDING COLD/POLAR ENERGY INTO THE
BASE OF A BROAD MID/UPPER LEVEL TROUGH ON THE WESTERN
ATLANTIC-CENTRAL CARIBBEAN. THE INFLOW OF ENERGY IS ALLOWING
THE TROUGH TO AMPLIFY SOUTH WHILE RETROGRESSING ACROSS THE
BASIN. AT 24 HRS THE 500 HPA TROUGH WILL LIE ACROSS THE
CENTRAL BAHAMAS-CENTRAL CUBA TO NICARAGUA/CENTRAL CARIBBEAN.
THROUGH 48 HRS THE TROUGH WILL AMPLIFY ACROSS THE WINDWARD
PASSAGE-GULF OF URABA TO WESTERN COLOMBIA. AT 60-72 HRS THE
TROUGH STARTS TO LIFT OVER A BROAD RIDGE EAST OF THE
ISLANDS...WITH A SHORT WAVE TROUGH MEANDERING OVER THE
CENTRAL CARIBBEAN. CONSISTENT WITH THE PREVIOUS MODEL
RUNS...AT 250 HPA...A SUBTROPICAL JET WILL LIE JUST NORTH OF
THE EASTERN CARIBBEAN ISLANDS...WITH A CORE OF 90-110KT TO
PERSIST THROUGH 48 HRS. THE CORE THEN EJECTS TO THE
NORTHEAST BY 60-72 HRS...LEADING TO THE DAMPENING OF THE
LONG WAVE TROUGH. THE RIGHT ENTRANCE REGION OF THIS JET WILL
FAVOR A DIVERGENT PATTERN ALOFT THAT IS TO PROVIDE
VENTILATION FOR DEEP CONVECTION ACROSS HISPANIOLA-PUERTO
RICO-VIRGIN ISLES (VI) THROUGH 48 HRS. THE TROUGH SUPPORTS A
FRONT NORTH OF THE ISLANDS...TRAILING TO THE SOUTHEAST
BAHAMAS.

AT 850 HPA...THE DEEP UPPER TROUGH SUPPORTS A FRONTAL TROUGH
NORTH OF THE ISLANDS WITH AXIS TO THE WEST/SOUTHWEST INTO
THE SOUTHEAST BAHAMAS/CUBA. IT ALSO SUPPORTS A TROUGH SOUTH
ACROSS THE CARIBBEAN TO COLOMBIA/NORTHWEST VENEZUELA. AS THE
AFOREMENTIONED NEW POLAR TROUGH/FRONT AMPLIFIES ACROSS THE
EASTERN USA...IT WILL FORCE THE CARIBBEAN TROUGH TO EJECT TO
THE EAST-NORTHEAST BY 48-72 HRS. FARTHER EAST...THE MODELS
RESOLVE A RIDGE...WITH 850 HPA HIGH NEAR 32N 35W. THIS
RIDGE...AND THE TROUGH ON THE CENTRAL CARIBBEAN...FAVOR A
DEEP SOUTHERLY FLOW ACROSS VENEZUELA/EASTERN CARIBBEAN. THIS
FLOW FAVORS THE ADVECTION OF DEEP EQUATORIAL TROUGH MOISTURE
NORTHWARD INTO THE EASTERN CARIBBEAN...WITH MOISTURE TO
REACH PUERTO RICO/USVI IN THE NEXT 06-12 HOURS. DEEP
MOISTURE IS TO ENVELOP THE ISLAND CHAIN BY 24-30 HRS. THE
GFS MAINTAINS CONSISTENCY ON ITS FORECAST OF AN MCS FORMING
OVER PUERTO RICO/VIRGIN ISLES LATER THIS AFTERNOON/EARLY
THIS EVENING...AND TO PEAK THROUGH 36 HRS. THIS IS SUPPORTED
BY THE SATELLITE IMAGERY...AS IT SHOWS A MOIST SURGE/AREA OF
CONVECTION ABOUT 100NM SOUTH OF THE ISLAND. THIS IS TO
CONVERGE OVER PUERTO RICO/VIRGIN ISLES AT THE SAME TIME AS A
MID LEVEL SHORT WAVE VORTEX EJECTS ACROSS THE MONA PASSAGE.
THE GFS HAS GOOD TEMPORAL AND CYCLE-TO-CYCLE CONSISTENCY ON
THE DEVELOPMENT OF THIS EVENT. IT IS ALSO WELL SUPPORTED BY
THE NCEP ENSEMBLE MODELS. ACROSS PUERTO RICO IT WILL RESULT
IN RAINFALL AMOUNTS OF 35-70MM...WITH MAXIMA TO PEAK AROUND
125-250MM (05-10 INCHES) BY 36-42 HRS. ACROSS THE VIRGIN
ISLES EXPECT SIMILAR AMOUNTS...WITH MAXIMA OF 75-125MM. BY
42-66 HRS CONVECTION IS TO AFFECT THE LEEWARD ISLES WITH
ACCUMULATION OF 15-25 MM/DAY...AND MAXIMA OF 75-100 MM TO
CONCENTRATE BETWEEN ST. MARTIN AND GUADELOUPE.


The above is the HPC discussion for the Caribbean.

Hey msbee (Barbara) it looks like where you are in ST Marteen will get some of this.

I say to all of you to say a prayer to us here to see if this big rain event doesn't come thru and if it comes no tragic things occur.

[cycloneye]

OMG it's comming.Look at all the moistere in the Caribbean Sea that is moving northward.