Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 230201
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1001 PM AST TUE JUL 22 2014

.UPDATE...DOPPLER WEATHER RADAR THIS EVENING DEPICTED ONLY LIGHT
ISOLATED SHOWER ACTIVITY ACROSS THE COASTAL WATERS...EASTERN
SECTIONS OF PUERTO RICO...VIEQUES...CULEBRA AND ACROSS THE U.S.
VIRGIN ISLANDS. A GENERALLY DRY AND STABLE AIR MASS WILL CONTINUE TO
ENCOMPASS THE REGION TONIGHT. SAHARAN DUST IS EXPECTED TO MOVE IN
TONIGHT UNTIL THURSDAY CAUSING HAZY SKIES AND KEEPING SHOWERS
ISOLATED WITH A SLIGHT CHANCE OF THUNDERSTORMS ACROSS WESTERN PR IN
THE AFTERNOON HOURS ON WEDNESDAY AND THURSDAY. FOR THE OVERNIGHT
AND EARLY MORNING HOURS...FEW AREAS OF MOISTURE EMBEDDED IN THE
TRADES WILL ALSO CAUSE PERIODS OF CLOUDINESS WITH LIGHT ISOLATED
PASSING SHOWERS ACROSS EASTERN PUERTO RICO AND THE U.S. VIRGIN
ISLANDS.

TROPICAL DEPRESSION TWO...BASED ON THE LATEST PUBLIC ADVISORY FROM
THE NATIONAL HURRICANE CENTER...AT 5 PM AST...WAS LOCATED NEAR
LATITUDE 12.9 N...LONGITUDE 49.6 WEST...MOVING WEST NEAR 18 MPH.
THE ENVIRONMENT AROUND THE DEPRESSION WILL 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. SHOWERS AND THUNDERSTORMS
ASSOCIATED WITH THIS SYSTEM ARE EXPECTED ACROSS THE LOCAL ISLANDS
LATE THURSDAY NIGHT AND FRIDAY. STAY TUNED.

&&

.AVIATION...VFR CONDITIONS EXPECTED AT ALL TERMINALS WITH BRIEF SHRA
IN AND AROUND JSJ/IST AND NCM THROUGH THE MORNING HOURS. SHRA/TSRA
POSSIBLE ACROSS WESTERN PR AFTER 23/17Z...THIS MAY RESULT IN BRIEF
MVFR CONDS AT TJMZ AND TJBQ. WINDS WILL BE FROM THE EAST TO E-SE AT
ABOUT 15 KTS.

&&

.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.

&&

.PREV DISCUSSION... /ISSUED 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.
&&

$$

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