000
FXCA62 TJSJ 010921 AAA
AFDSJU
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
521 AM AST SUN MAY 1 2011
.UPDATE...TO ADD CLIMATE SECTION.
&&
.PREV DISCUSSION... /ISSUED 413 AM AST SUN MAY 1 2011/
.SYNOPSIS...MID-UPPER LEVEL TROF ACROSS THE BAHAMAS WILL CONTINUE TO
AMPLIFY ACROSS CUBA AND INTO THE WRN CARIBBEAN OVR THE NEXT 36 HRS
THEN BEGIN TO WEAKEN AS IT MOVES SLOWLY EAST ACROSS THE GREATER
ANTILLES MID WEEK.
&&
.DISCUSSION...GLOBAL MODELS CONTINUE TO TREND DEEPER WITH TROF
FCST TO AMPLIFY ACROSS CUBA INTO THE WRN CARIBBEAN. THIS WILL
ALLOW FOR DEEPER TROPICAL MOISTURE TO ADVECT FARTHER NORTHWARD
THAN PREVIOUSLY FCST. THIS RESULTS IN HIGHER RAINFALL
ACCUMULATIONS ACROSS THE AREA AND THUS INCREASES THE CHANCES FOR
SIGNIFICANT FLOODING. WHILE THE GENERAL THEME REMAINS THE SAME AS
YESTERDAY OF UNSETTLED WX CONDITIONS THRU MID WEEK DUE BROAD
TROFINESS AND ABUNDANT MOISTURE...EXACT DETAILS OF WHEN AND WHERE
THE HEAVIEST RAINFALL WILL OCCUR REMAIN SOMEWHAT UNCERTAIN.
CLOSE EXAMINATION OF LATEST MODEL GUIDANCE SUGGESTS THAT THE BEST
CHANCE FOR THE MOST SIGNIFICANT RAINFALL TO OCCUR WILL BE TONIGHT
THRU EARLY TUE MORNING WHEN THE AREA WILL BE UNDER A STRONG
DIVERGENT FLOW ASSOCIATED WITH A RIGHT ENTRANCE REGION OF A 70-KT
SUBTROPICAL JET STREAK. THIS ALSO COINCIDES WITH THE BEST PW
VALUES...K AND SHOWALTER INDICES. THIS TIMING COULD CHANGE IF
TROUGH EJECTS SLOWER THAN FORECAST. HI RES LOCAL MODELS SHOW THE
HIGHEST RAINFALL ACCUMULATIONS ACROSS THE ERN HALF OF PR AND ALL
OF THE ADJACENT ISLANDS TO THE EAST INCLUDING ALL OF THE USVI.
GIVEN INCREASED CONFIDENCE IN SIGNIFICANT RAINFALL WILL ISSUE A
FFA FOR TONIGHT THRU TUE MORNING. AS ALWAYS THE CASE PRECIP AMTS
IN TROPICAL REGIONS VERY DIFFICULT TO FCST BUT SHOULD EXPECT AMTS
TO EXCEED SIX INCHES IN A FEW PLACES.
H25 TROUGH WILL BEGIN TO WEAKEN TUE WITH AXIS FCST TO MOVE ACROSS
PR LATE WED. EXPECT IMPROVING CONDITIONS AFTER MID WEEK.
&&
.AVIATION...MOSTLY VFR CONDITIONS ARE EXPECTED ACROSS ALL TAF
SITES... HOWEVER BRIEF MVFR CONDITIONS WILL REMAIN POSSIBLE IN
ISOLATED TO SCATTERED PASSING SHOWERS ACROSS TIST/TISX AND
TJSJ/TJPS DURING THE EARLY MORNING HOURS...SPREADING ACROSS TJBQ
AND TJMZ AFT 01/17Z. LLVL WINDS E-ESE 10 TO 20 KTS BELOW 8 KFT.
MVFR TO IFR CONDITIONS MON-MON NIGHT IN +TSRA.
&&
.MARINE...SCEC ATLC WATERS DUE TO WINDS AND SIX FOOT SEAS. NMRS
TSRA TODAY THRU EARLY TUE ALL WATERS.
&&
.CLIMATE...APRIL 2011 WAS THE 7TH COOLEST APRIL ON RECORD AT THE
CHRISTIANSTED ARPT IN ST. CROIX WITH AN AVG TEMP OF 78.7F. AT THE
CYRIL E KING ARPT IN CHARLOTTE AMALIE ST. THOMAS APRIL 2011 WAS
THE 10TH WETTEST ON RECORD WITH 3.50 INCHES OF RAIN RECORDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 84 75 85 75 / 60 70 70 70
STT 84 76 85 77 / 60 60 70 60
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...FLASH FLOOD WATCH FROM THIS EVENING THROUGH LATE MONDAY NIGHT
FOR CENTRAL INTERIOR-CULEBRA-EASTERN INTERIOR-NORTH CENTRAL-
NORTHEAST-SAN JUAN AND VICINITY-SOUTHEAST-VIEQUES.
VI...FLASH FLOOD WATCH FROM THIS EVENING THROUGH LATE MONDAY NIGHT
FOR ST CROIX-ST. THOMAS/ST. JOHN/ADJACENT ISLANDS.
&&
$$
23/64
The Pacific TWD mentions this winds in the Gulf of Tehuantepec and Papagayo but the models show the winds blowing across most of the region.
