Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 030820
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
420 AM AST TUE MAR 3 2015

.SYNOPSIS...SHORT WAVE TROUGH IS TO GRADUALLY FILL AND MOVE FARTHER
EAST OF THE FORECAST AREA TODAY...AS RIDGE ALOFT WILL BUILD ACROSS
THE REGION BY WEDNESDAY AND DURING THE REMAINDER OF THE WEEK. THIS
IN TURN WILL REINFORCE THE TRADE WIND CAP INVERSION...AND THEREFORE
MAINTAIN MODERATE TO STRONG EASTERLY TRADE WINDS FOR THE NEXT SEVERAL
DAYS. SURFACE HIGH PRESSURE WILL ALSO BUILD ACROSS THE WEST AND SOUTHWESTERN
ATLANTIC DURING THE REST OF THE WEEK AND REINFORCE THE ATLANTIC HIGH
NOW ACROSS THE CENTRAL AND EAST ATLANTIC. THE MODERATE TO STRONG EASTERLY
TRADE WIND WILL THEREFORE PERSIST AND CONTINUE TO BE THE DOMINANT FEATURE
ACROSS THE REGION. THE PREVAILING EASTERLIES WILL CONTINUE TO TRANSPORT
OCCASIONAL FRAGMENTS/SURGES OF TRADE WIND MOISTURE FROM REMNANTS OF
OLD FRONTAL BOUNDARIES/SHEAR LINES ACROSS THE FORECAST AREAS FROM
TIME TO TIME.

&&

.DISCUSSION...EXPECT SIMILAR WEATHER PATTERN AS RECENT DAYS TODAY
AND AT LEAST UNTIL THURSDAY. THE PREVAILING EAST TO NORTHEAST WIND
FLOW WILL STEER PATCHES OF LOW TO MID LEVEL CLOUDS AND ACCOMPANY
LIGHT TO MODERATE SHOWERS ACROSS THE REGIONAL WATERS AND PORTIONS
OF THE NORTH AND EAST COASTAL SECTION OF THE ISLANDS. SOME SHOWERS
MAY BE LOCALLY HEAVY AT TIMES WITH ACCOMPANYING GUSTY WINDS...BUT
WILL OF SHORT DURATION AND FAST MOVING STREAMER LIKE CONVECTION.
THE AFTERNOON CONVECTION WILL BE SHORT OF SHORT DURATION TODAY AND
DURING THE NEXT SEVERAL DAYS AND WILL BE FOCUSED MAINLY ACROSS PARTS
OF THE INTERIOR AND WEST SECTION OF PUERTO RICO.

SO FAR MODEL GUIDANCE HAS INITIALIZED FAIRLY WELL AND CONTINUED TO
SUGGEST EVEN DRIER CONDITIONS BY FRIDAY AND INTO THE UPCOMING WEEKEND.
STILL HOWEVER LOOKING FOR BRIEF INTERVALS OF PASSING LATE EVENING AND
EARLY MORNING SHOWERS...FOLLOWED BY ISOLATED TO SCATTERED AFTERNOON CONVECTION
MOSTLY ACROSS PARTS OF THE CENTRAL INTERIOR AND WEST SECTIONS OF PUERTO
RICO. FOR MOST OF THE U.S. VIRGIN ISLANDS A FEW SHOWERS WILL REMAIN
POSSIBLE EACH DAY...BUT MOSTLY FAIR WEATHER SKIES SHOULD PREVAIL.

&&

.AVIATION...MOSTLY VFR CONDITIONS EXPECTED WITH BRIEF PASSING VCSH/SHRA
ACROSS THE LOCAL FLYING AREA TIL 03/17Z. SHRA EXPECTED OVER WESTERN
PR AFT 03/17Z WITH AREAS OF MTN TOP OBSCURATIONS DUE TO SHOWER ACTIVITY
AND SOME QUICK PASSING LOW RAGGED CLDS. PREVIOUS TJSJ 03/00Z SOUNDING
AS WELL AS FCST UPPER AIR SOUNDING CONTINUE TO SUGGEST EAST TO EAST
NORTHEAST WIND FLOW 20-25 KNOTS FROM THE SFC- FL200...BECOMING NORTH
NORTHWESTERLY AND INCR W/HT ALOFT TO MAX OF AROUND 45KTS NR FL450.
NO SIG OPERATIONAL IMPACTS ATTM.

&&

.MARINE...SMALL CRAFT ADVISORY CONTINUE IN EFFECT FOR MOST OF THE
LOCAL WATERS. LATEST GUIDANCE SUGGESTS SEAS OF 7 TO 8 FEET ACROSS
MOST OF THE SURROUNDING WATERS THROUGH THIS WEEK DUE TO THE FAIRLY
STRONG AND PERSISTENT EASTERLY TRADE WINDS. THE LATEST MODEL GUIDANCE
CONTINUES TO INITIALIZE FAIRLY WELL AND REMAIN NEARLY CONSISTENT
WITH THE PRESENT MARINE CONDITIONS. FOR THAT REASON THE SMALL
CRAFT ADVISORIES WILL REMAIN IN EFFECT AT LEAST UNTIL LATE
THURSDAY NIGHT. PLEASE REFER TO THE LATEST COASTAL WATERS FORECAST
AND MARINE WEATHER MESSAGE ISSUED BY THE NATIONAL WEATHER SERVICE
WFO SAN JUAN PR.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  84  74  86  74 /  40  40  40  10
STT  85  73  85  73 /  40  40  40  20

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 6 AM AST FRIDAY FOR ANEGADA PASSAGE
     SOUTHWARD TO 17N-ATLC WATERS OF PUERTO RICO AND USVI FROM
     10NM TO 19.5N-CARIBBEAN WATERS OF PUERTO RICO FROM 10 NM TO
     17N-COASTAL WATERS OF NORTHERN PUERTO RICO OUT 10 NM-
     COASTAL WATERS OF NORTHERN USVI AND CULEBRA OUT 10 NM-
     COASTAL WATERS OF SOUTHERN USVI VIEQUES AND EASTERN PUERTO
     RICO OUT 10 NM-MONA PASSAGE SOUTHWARD TO 17N.

&&

$$

72/09




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