Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 221853
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
253 PM AST TUE JUL 22 2014

.SYNOPSIS...SURFACE HIGH PRESSURE ACROSS THE CENTRAL ATLANTIC
REMAINS STRONG AND EXPECTED TO CONTINUE FOR THE NEXT SEVERAL DAYS.
DRIER AIR IS EXPECTED TO MOVE INTO THE LOCAL AREA TOMORROW AND
THURSDAY. INCREASE IN MOISTURE EXPECTED ON FRIDAY AND SATURDAY DUE
TO THE CURRENT TROPICAL DEPRESSION 2 WHICH IS EXPECTED TO
DISSIPATE BEFORE IT GETS TO THE LOCAL AREA.


&&

.DISCUSSION...ISOLATED TO SCATTERED SHOWERS WERE OBSERVED TODAY
WITH SOME OF THEM PERSISTING OVER SECTIONS OF THE SAN JUAN METRO.
THE DRIER AIR MOVING IN SHOULD KEEP SHOWER ACTIVITY LIGHT AND
ISOLATED FOR THE REST OF THE DAY INTO THE OVERNIGHT HOURS AND EVEN
WEDNESDAY AND THURSDAY. SAHARAN DUST IS EXPECTED TO MOVE IN LATE
TODAY UNTIL THURSDAY CAUSING HAZY SKIES AND KEEPING SHOWERS
ISOLATED TO SCATTERED WITH A SLIGHT CHANCE OF THUNDERSTORMS ACROSS
WESTERN PR IN THE AFTERNOON HOURS ON WEDNESDAY AND
THURSDAY.

TROPICAL DEPRESSION TWO...BASED ON THE LATEST PUBLIC ADVISORY
FROM THE NATIONAL HURRICANE CENTER...AT 1100 AM AST...THE
DEPRESSION WAS LOCATED NEAR LATITUDE 12.6 N...LONGITUDE 48.0
WEST...MOVING WEST NEAR 17 MPH. A SLOW WEST NORTHWESTWARD MOTION
IS EXPECTED OVER THE NEXT FEW DAYS. HOWEVER AT THIS TIME...LITTLE
CHANGE IS EXPECTED IN STRENGTH AS THIS FEATURE WILL ENTER A MORE
HOSTILE ENVIRONMENT AND LESS CONDUCIVE FOR DEVELOPMENT. THIS PRESENT
SCENARIO...SHOULD THEREFORE INHIBIT FURTHER INTENSIFICATION AND THEREFORE
THE DEPRESSION IS STILL EXPECTED TO WEAKEN TO A REMNANT LOW OR
TROPICAL WAVE BY LATE WEDNESDAY...AS IT APPROACHES AND MOVES
ACROSS THE REGION.

EVEN IF IT WEAKENS INTO A TROPICAL WAVE...THE ASSOCIATED MOISTURE
WILL HELP WITH THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS INTO
THE LOCAL AREA. STARTING LATE THURSDAY NIGHT...THE SHOWERS MAY
START AFFECTING THE USVI THEN FRIDAY MORNING STARTING ACROSS PR.
IT IS A BIT EARLY TO HAVE HIGH CONFIDENCE BUT AT THIS TIME THE
LONG RANGE MODELS SHOW MOST OF THE SHOWER ACTIVITY AFFECTING THE
NORTHERN USVI AS WELL AS THE EASTERN AND NORTHERN SECTIONS OF PR
UNTIL EARLY SATURDAY. THIS IS NOT TO SAY THAT IT WILL NOT RAIN
ELSEWHERE...BUT THE HIGHEST POTENTIAL FOR SHOWERS AND THUNDERSTORMS
AT THIS TIME SEEMS TO BE IN THE AFOREMENTIONED AREAS.


&&

.AVIATION...PASSING L/LVL CLD LYRA BTW FL025-FL080 AND ISOLD-SCT SHRA
WILL MOV ACROSS THE FLYING AREA AND AFFECT MOST TAF SITES EXCEPT FOR
TJPS TIL AT LEAST 22/22Z. SCT SHRA/PSBL ISOLD TSRA EXPECTED OVR W PR
DURG AFT TIL 22/22Z WITH BRIEF MTN TOP OBSCR/MVFR DUE TO SHRA/LOW
CIG. WIND BLO FL200 FM SE BTW 15-25 KT BCMG E LATER TONITE AND WED
AM. RECENT LOCAL ASSESSMENT TOOLS SUGGEST PSBL FAIR WX WATERSPOUTS
WITH PREVAILING SE STREAMER WND FLOW TIL AT LEAST 22/23Z...MAINLY
BTW ERN PR AND ADJACENT ISLANDS.


&&

.MARINE...SEAS WERE 3 TO 5 FEET BASED OF THE LATEST OBSERVATIONS
WITH WINDS OF 19 KNOTS OR LESS ACROSS MOST OF THE REGIONAL WATERS.
A SLIGHT INCREASE IN WINDS AND SEAS IS EXPECTED DURING THE LATTER
PART OF THE WEEK AS THE DEPRESSION OR ITS REMNANTS MOVE ACROSS THE
EASTERN CARIBBEAN WATERS. DURING THAT TIME AN INCREASE IN THUNDERSTORM
ACTIVITY WITH AREAS OF LOCALLY HEAVY RAINFALL AND GUSTY WINDS WILL BE
POSSIBLE.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  78  90  79  90 /  20  20  10  10
STT  80  90  80  91 /  30  30  20  20

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
COASTAL WATERS...NONE.
&&

$$

09/25





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