FXCA62 TJSJ 260929
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
529 AM AST FRI OCT 26 2007
.SYNOPSIS...MID OCEANIC TROUGH ALIGNED NE TO SW AND EXTENDS SW TO
JUST NORTH OF THE LOCAL AREA THIS MORNING...AND CONTINUES TO DIG
SW. THIS HAS FORCED THE OLD LINGERING TUTT SEGMENT SW ACROSS THE
LOCAL AREA OVERNIGHT. A RATHER VIGOROUS LLVL LOW EVIDENT IN STLT
IMAGERY HAS ALSO BEEN FORCED WSW OVERNIGHT...AND WAS ACROSS ERN PR
AT 08Z WITH A NE TO SW ALIGNED WIND ENVELOPE. SAN JUAN 88D RADAR
HOWEVER HAS SHOWN THAT CENTER OF THIS LLVL CIRCULATION HAS PASSED
JUST S OF VIEQUES OVERNIGHT AND WAS ALONG THE SE COAST OF PR
MOVING WSW AT 7 KT...BUT LOOKS TO BE MOVING MORE W IN THE PAST
HOUR OR SO.
&&
.DISCUSSION...PRESSURE GRADIENT ACROSS THE REGION AND VIGOROUS
TURNING OF LLVL LOW HAS SPREAD STRONG NELY WINDS INTO THE LOCAL
ATLC WATERS OVERNIGHT...AND ACROSS N AND NE HALF OF PR. TJUA
SHOWED VWP WINDS AS HIGH AS 40KT AT 4K FT OVERNIGHT...WITH
SUSTAINED WINDS 20 KT AT TJBQ...AND GUSTS IN THE UPPER 20S
ELSEWHERE. DUE TO INTERACTION OF UPPER LOW AND LLVL CIRC AND
INDUCED VERTICAL SHEAR...DEEPEST CNVTN AND MOST WIDESPREAD WEATHER
IS EXPECTED TO REMAIN ON E AND SE QUADS OF THIS LOW AS IT
CONTINUES TO MOVE W OR WSW TODAY AND TONIGHT. SPEED DIVERGENCE
ALOFT WILL AID IN POTENTIAL FOR CONTINUED MCC DEVELOPMENT ACROSS
THE NE CARIB...INCLUDING LEEWARD AND VIRGIN ISLANDS...WITH BRIEF
BURSTS LIKELY ACROSS E HALF OF PR. HEAVY RAIN POTENTIAL THUS
EXISTS AND HAVE ISSUED A FLASH FLOOD WATCH FOR ALL BUT W SECTIONS
OF PR. ST CROIX WAS HIT WITH TRAINING ECHOS IN A SW TO NE ALIGNED
RAINBAND OVERNIGHT...AND LIKELY SAW 2-4 INCH TOTALS IN ABOUT 2
HOURS...AND A FLASH FLOOD WARNING WAS ISSUED.
MODEL GUIDANCE SUGGESTS THAT ABUNDANT TROPICAL MOISTURE WILL
SPREAD W AND NW ACROSS THE LOCAL AREA THROUGH THE WEEKEND...AND
THEN MORE SHALLOW MOISTURE THROUGH TUESDAY...TO MAINTAIN GOOD RAIN
CHANCES. THE COMPLEX UPPER TROUGHING WILL ALSO SHIFT SW AND
REORGANIZE ACROSS THE REGION TO MAINTAIN UNSTABLE CONDITOINS ALOFT.
&&
.AVIATION...SHOWERS WILL CONTINUE TO AFFECT TNCM...TKPK...TJSJ...
TIST AND TISX DURING THE REST OF THE MORNING HOURS. LATER IN THE
MORNING WILL SPREAD TO THE WEST ACROSS TJPS AND EARLY IN THE
AFTERNOON ACROSS TJMZ AND TJBQ. EXPECT MOSTLY MVFR CONDITIONS WITH
THESE SHOWERS...WITH OCCASIONAL VFR CONDITIONS IN BETWEEN SHOWERS.
IN ADDITION...ISOLATED PASSING THUNDERSTORMS MAY RESULT IN BRIEF
IFR CONDITIONS...ESPECIALLY ACROSS TIST...TISX...AND TSJU THROUGH
THE EARLY MORNING HOURS...WITH WIND GUSTS ASSOCIATED WITH THESE
THUNDERSTORMS AS HIGH AS 35 KNOTS. WITH LINGERING MOISTURE AND
INSTABILITY EXPECTED ACROSS THE REGION TODAY...EXPECT CONTINUED
PERIODS OF MVFR CONDITIONS WITH PASSING SHOWERS FOR ALL THE TAF
SITES THROUGH THE AFTERNOON HOURS...WITH DECREASING WINDS LATE
THIS EVENING AND OVERNIGHT.
&&
.MARINE...U.S.C.G. RELAYED A SHIP REPORT NEAR THE N BOUNDARY OF
OUR ATLC WATERS OF 30 KT AND 10 FT SEAS OVERNIGHT...WHILE SHIP
ZCDG8 REPORTED 40 AND 45 KTS WHILE PASSING JUST NORTH OF PR
EARLIER TONIGHT...WITH THOSE OBS LIKELY WELL ABOUT THE STANDARD
10M OBS. A 01Z ASCAT PASS SHOWED A BROAD ZONE OF 20-25KT WINDS
ACROSS THE LOCAL ATLC...WITH UPPER 20S NORTH OF THE VIRGIN
ISLANDS. HAVE THUS KEPT ATLC WINDS 24-30 KT THROUGH THIS MORNING
AND SEAS MAXED AT 10 FT. THESE ROUGH AND DANGEROUS SEAS WILL
CONTINUE THROUGHOUT THE DAY BEFORE BEGINNING TO SUBSIDE
TONIGHT...AND THEN BE OVERTAKEN BY LONGER PERIOD NELY SWELL FROM
THE SURFACE REFLECTION OF MID OCEANIC TROF. THIS WILL MAINTAIN HIGH
SEAS ACROSS THE REGIONAL WATERS THROUGH THE BEGINNING OF THE
UPCOMING WEEK. STRONG LLVL FLOW IN NW AND N QUADS OF THIS LOW WILL
BE CAPABLE OF INDUCING GUSTS IN SQUALLS TO 45 KT AND HAVE INCLUDED
THIS IN OVERNIGHT STATEMENTS AND LATEST FORECAST.
&&
.HYDROLOGY...WITH RECENT RAINS PRODUCING SOILS AT OR NEAR
SATURATION ACROSS LARGE AREAS OF THE INTERIOR AND WEST OF PR...
FLASH FLOODING AND MUDSLIDES ARE A GOOD POSSIBILITY TODAY FOR THE
E TWO-THIRDS OF THE ISLAND. THE VIRGIN ISLANDS...CULEBRA AND
VIEQUES... WILL CONTINUE TO BE HIT WITH DEEP CNVTV CELLS TODAY AS
WELL...AND THEY ARE ALSO UNDER THE FLASH FLOOD WATCH. MUDSLIDES
HAVE BEEN REPORTED ACROSS PR THE PAST TWO DAYS. IF HEAVY RAINFALL
CONTINUES TO AFFECT PR THRU SATURDAY...AND THEN IN MORE ISOLATED
AREAS SUN THROUGH TUE...THEN MUDSLIDE...NOT TO MENTION FLASH
FLOODING PROBLEMS COULD PERSIST. IF THESE HIGH TOPPED TSTORM
CLUSTERS OCCURRING OVER THE NE CARIB THIS MORNING SHIFT W AND NW
INTO THE LOCAL ISLANDS...ISOLATED AREAS OF 3-5 INCH RAINS WILL BE
SEEN IN 3-6 HR PERIODS.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 84 77 87 77 / 70 80 70 30
STT 82 78 84 78 / 70 70 70 50
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR CENTRAL INTERIOR-
CULEBRA-EASTERN INTERIOR-NORTH CENTRAL-NORTHEAST-PONCE AND
VICINITY-SAN JUAN AND VICINITY-SOUTHEAST-VIEQUES-WESTERN
INTERIOR.
WIND ADVISORY UNTIL 10 AM AST THIS MORNING FOR CENTRAL INTERIOR-
EASTERN INTERIOR-MAYAGUEZ AND VICINITY-NORTH CENTRAL-
NORTHEAST-NORTHWEST-PONCE AND VICINITY-SAN JUAN AND
VICINITY-SOUTHEAST-WESTERN INTERIOR.
VI...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR ST CROIX-ST. THOMAS
ST. JOHN AND ADJACENT ISLANDS.
&&
$$
72/70
Woww there's maybe some action in store given this forecast...hope you're safe Cycloneye
and all the residents in vicinity of Puerto Rico, i've heard that there's numerous muslides in your island...so keep watching this system closely 
.Whereas , us in Guadeloupe have overcast moist and grey weather with light showers this morning at 8AM but given the latest forecasts we should experience some moderate to strong showers with scattered thunderstorms in the next few hours for Guadeloupe but much more for the NE Leewards...and Meteo France have put an yellow alert for a moderate risk of strong showers and moderate
thunderstorms expected today for St Marteen and St Barth...
lool but moist 94%.
until 4am with south wind and from East at 4am.
We have a thread at the top of forum for all of us who live in the Caribbean to post the observations. 
