Area Forecast Discussion
Issued by NWS San Juan, PR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXCA62 TJSJ 031543
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1143 AM AST THU SEP 3 2015

.SYNOPSIS...
WARM TEMPERATURES AND MOSTLY SUNNY SKIES PREVAILED THIS MORNING
ACROSS THE LOCAL ISLANDS. THE DOPPLER WEATHER RADAR NOT DETECTED
SHOWER ACTIVITY OVER LAND LATE THIS MORNING. TJSJ SOUNDING DATA
OBSERVED STEEP LAPSE RATE AT THE 850-700MB LAYER...TODAYS VALUES
ARE AROUND THE PERCENTILE 75TH FOR THE CURRENT MONTH. MID LEVEL
TEMPERATURES...AT 500MB...HAVE VALUES AROUND -8 DEGREES
CELSIUS. ANOTHER FACT IS THAT THE CURRENT SOUNDING DOES NOT HAVE
ANY INVERSION. THE PROXIMITY OF AN UPPER LEVEL TROUGH WILL COMBINE
WITH THE AVAILABLE MOISTURE TO PRODUCE POSSIBLE ISOLATED TO
SCATTERED SHOWERS WITH MODERATE TO STRONG TSTORM OVER THE
INTERIOR...NORTH AND WEST SECTIONS OF PUERTO RICO. IN
ADDITION...UNDER THE PREVAILING SOUTHERLY WIND FLOW...THE
DEVELOPMENT OF SHOWERS ARE POSSIBLE IN THE WAKE OF THE US VIRGIN
ISLANDS. MINOR CHANGES WERE INTRODUCE TO THE PREVIOUS FORECAST
BUT THE FORECAST DISCUSSION STILL IN GOOD AGREEMENT WITH THE NEW
DATA.

&&

.AVIATION...MAINLY VFR CONDS ACROSS ALL TAF SITE. MOUNTAIN OBSC
WITH TSTORM ARE POSSIBLE OVER THE CORDILLERA CENTRAL...SOME OF
OF THIS SHRA/TSRA ARE POSSIBLE OVER TJBQ/TJMZ/TJSJ AFT 03/18Z.
AFT 0323Z...LIGHT PASSING SHOWERS MAY BE POSSIBLE OVER
TIST/TISX/TJSJ/TNCM/TKPK FROM TIME TO TIME. WINDS FROM THE EAST-
SOUTHEAST AT 10 TO 15 MPH WITH SEA BREEZE VARIATIONS...AND LOCALLY
HIGHER IN/NEAR TSRA/SHRA. FOLLOWED BY CALM TO LIGHT AND VARIABLE
WINDS AND LAND BREEZE VARIATIONS ALONG THE COASTAL SECTIONS AFT
0323Z.

&&

.MARINE...SEAS ARE EXPECTED TO CONTINUE BELOW 4 FEET WITH EAST TO
SOUTHEAST WINDS BETWEEN 10 TO 15 KNOTS. INCLEMENT WEATHER ARE
POSSIBLE NEAR SHOWERS AND THUNDERSTORM THIS AFTERNOON. THE
PREVIOUS MARINE FORECAST STILL IN EFFECT...REFER TO THE PREVIOUS
DISCUSSION.

&&

.PREV DISCUSSION... /ISSUED 429 AM AST THU SEP 3 2015/

SYNOPSIS...TUTT WILL MEANDER OVER AND NORTH OF THE FORECAST AREA
THROUGH SUNDAY. BUILDING MID TO UPPER LEVEL RIDGE FROM THE EAST WILL
BE THE DOMINANT WEATHER FEATURE FOR THE NEXT SEVERAL DAYS. LOW LEVEL
PERTURBATIONS EXPECTED TO INCREASE MOISTURE ON LATE SATURDAY/SUNDAY
AND BY MID-WEEK.

DISCUSSION...MOSTLY CLEAR SKIES PREVAILED OVER LAND AREAS OVERNIGHT.
A FEW SHOWERS WERE NOTED OVER THE MONA PASSAGE AND ACROSS THE
OFFSHORE ATLANTIC WATERS. IN GENERAL...FOR THE NEXT SEVERAL DAYS
EXPECT SHOWERS WITH ISOLATED THUNDERSTORMS TO DEVELOP MAINLY OVER
THE INTERIOR AND WESTERN SECTIONS OF PR EACH AFTERNOON.
ELSEWHERE...MOSTLY DRY AND FAIR WEATHER CONDITIONS ARE EXPECTED.
MODEL GUIDANCE SUGGEST THAT BETWEEN SATURDAY/SUNDAY MOISTURE WILL
INCREASE GRADUALLY...AND PASSING SHOWERS SHOULD BE MORE FREQUENT
ON SATURDAY NIGHT ACROSS THE USVI AND EASTERN PR...WITH USUAL
CONVECTION ALONG THE CORDILLERA CENTRAL AND WESTERN PR IN THE
AFTERNOON HOURS. THEN...DRY AND FAIR WEATHER CONDITIONS WILL
RETURN THROUGH AT LEAST MID-WEEK WHEN THE NEXT TROPICAL WAVE IS
FORECAST TO BE NEAR THE LOCAL AREA.

AVIATION...VFR XPCTD XCP MVFR IN ISOLD/SCT SHRA/TSRA INTERIOR/WEST
PR DURING THU/FRI AFT WI FEW OBSCD MTNS. WIND BLW FL150 VRBL 10 KT
OR LESS BCMG E TO NE UP TO 10 KT LATE TDY THRU FRI.

MARINE...SEAS MAINLY BELOW 3 FEET AND EAST TO SOUTHEAST WINDS
BETWEEN 10 TO 15 KNOTS EXPECTED THRU FRIDAY. SEAS EXPECTED TO
INCREASE UP TO 4 FEET WITH GENTLE TO MODERATE TRADES BY EARLY
NEXT WEEK. THERE IS A MODERATE RISK OF RIP CURRENTS TODAY ACROSS
SOME BEACHES OF NORTHERN PR DUE TO A WEAK NORTHERLY GROUND SWELL.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  78  90  78  91 /  10  10  30  30
STT  78  88  79  88 /  10  10  30  30

&&

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

$$

27/23


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.