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 010209 CCA
AFDSJU

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
1009 PM AST THU JUL 31 2014

.UPDATE...TUTT LOW JUST NORTH AND WEST OF THE REGION AIDED IN
ENHANCING AFTERNOON CONVECTION ACROSS PARTS OF THE ISLANDS AND
ACROSS THE COASTAL WATERS DURING THE AFTERNOON AND EARLY EVENING
HOURS. SINCE THEN MOST OF THE ACTIVITY OVER LAND HAD MOVED OFF
SHORE OR DIMINISHED...EXCEPT FOR THE EAST COASTAL SECTIONS OF
PUERTO RICO AND JUST EAST OF SAINT CROIX WHERE A FEW SHOWERS
CONTINUED TO STEER TOWARDS THE COASTAL AREAS. LATEST SATELLITE
IMAGERY SHOWED LESSER ACTIVITY APPROACHING FROM THE EAST WITH A
SLOT OF DRIER AIR NOW CROSSING THE NORTHERN LEEWARDS IN ADVANCE OF
THE PREVIOUSLY MENTIONED LOW PRESSURE SYSTEM AND ASSOCIATED
TROPICAL WAVE QUICKLY APPROACHING THE LESSER ANTILLES. ONLY MINOR
ADJUSTMENT MADE TO THE INHERITED SHORT TERM FORECAST PACKAGE INCLUDING
THE MARINE WAVE HEIGHTS FOR NOW BASED ON THE PRESENT WEATHER SCENARIO
AND LATEST MODEL GUIDANCE.

BASED ON THE 8 PM AST TROPICAL WEATHER OUTLOOK FROM THE NATIONAL
HURRICANE CENTER...THE AIR FORCE RECON AIRCRAFT EARLIER THIS EVENING
DID FIND THE WELL DEFINED LOW PRESSURE SYSTEM NOW LOCATED SOME 350
MILES EAST SOUTHEAST OF THE ISLAND OF BARBADOS. SURFACE WINDS OF
40 TO 45 MPH WERE FOUND ACROSS THE NORTHERN AND EASTERN PORTIONS
OF THE CIRCULATION BUT HAD LACKED SIGNIFICANT CONVECTION EARLIER.
SINCE THEN HOWEVER...SHOWERS AND THUNDERSTORMS HAVE ONCE AGAIN
INCREASED EAST OF THE CENTER DURING THE PAST COUPLE OF HOURS AND
IF THIS DEVELOPMENT TREND CONTINUES...A TROPICAL STORM COULD FORM
OVERNIGHT OR EARLY FRIDAY AS THIS DISTURBANCE MOVES WEST NORTHWEST
NEAR 20 MPH. STAY TUNED FOR FURTHER UPDATES ON THIS SYSTEM.

&&

.AVIATION UPDATE...VFR CONDS WILL CONT AT ALL TAF SITES THRU 02/00Z
XCP FOR SHRA AND MTN OBSCURATIONS OVER NE PR TIL 01/12Z AND BTW
TJMZ AND TJBQ AFT 01/17Z WHERE AREAS OF +SHRA/TSRA WILL DEVELOP
WITH MVFR CIGS AND MVFR/IFR VSBYS. WINDS ALF E TO SE 5 TO 15 KTS
INCRG TO 10 TO 20 KT AFT 01/14Z.

&&

.MARINE UPDATE...NO CHANGES TO THE OVERNIGHT MARINE CONDITIONS
WITH WINDS AND SEAS 19 KNOTS OR LESS AND 4 FEET OR LESS RESPECTIVELY.
SMALL CRAFT OPERATORS SHOULD EXERCISE CAUTION ACROSS MOST OF THE
COASTAL WATERS DUE TO MODERATE TO LOCALLY FRESH TRADE WINDS OVERNIGHT.
CONDITIONS ARE STILL FORECAST TO RAPIDLY DETERORIRATE OVER THE UPCOMING
WEEKEND AS THE AFOREMENTIONED TROPICAL DISTURBANCE IS APPROACHS THE
REGIONAL WATERS. PLEASE REFER TO THE LATEST COASTAL WATERS FORECAST
ISSUED BY THE NATIONAL WEATEHR SERVICE WFO SAN JUAN PR.

&&

.FIRE WEATHER UPDATE...NO CHANGE TO THE PREVIOUS FIRE WEATHER
DISCUSSION AT THIS TIME...A FIRE WEATHER WATCH WILL BE IN EFFECT
FROM FRIDAY MORNING THROUGH FRIDAY AFTERNOON FOR VIEQUES AND SAINT
CROIX DUE TO INCREASING SUBSIDENCE AND MUCH DRIER AIR...LOWER
RELATIVE HUMIDITIES AND STRONGER SOUTHEAST WINDS.

&&

.PREV DISCUSSION... /ISSUED 306 PM AST THU JUL 31 2014/

SYNOPSIS...TUTT LOW NORTH OF THE AREA WILL RETROGRESS TOWARD THE
BAHAMAS OVER THE NEXT FEW DAYS. STRONG TROPICAL WAVE WILL AFFECT
THE LOCAL AREA SATURDAY INTO SUNDAY.

DISCUSSION...HEAVY SHOWERS WITH STRONG THUNDERSTORMS DEVELOPED
THIS AFTERNOON OVER THE NORTH CENTRAL PUERTO RICO. THE HEAVIEST
RAINFALL AFFECTED THE MUNICIPALITIES BETWEEN VEGA BAJA WEST
THROUGH ARECIBO. RADAR ESTIMATES WERE BETWEEN 1 TO 2 INCHES OF
RAINFALL. THIS ACTIVITY WAS PRIMARILY ASSOCIATED WITH THE
COMBINATION OF AN UPPER LEVEL TROUGH AND DAYTIME HEATING. THESE
SHOWERS ARE EXPECTED TO DISSIPATED NEAR SUNSET.

FOR TOMORROW...A DRIER AIR MASS WILL MOVE ACROSS THE
REGION...AHEAD OF A STRONG TROPICAL WAVE WHICH IS LOCATED NEAR 750
MILES SOUTHEAST OF PUERTO RICO LATE THIS AFTERNOON. PER LATEST
TROPICAL WEATHER OUTLOOK FROM THE NATIONAL HURRICANE CENTER INDICATE
THAT THE ASSOCIATED SHOWERS AND THUNDERSTORMS HAVE DIMINISHED
SIGNIFICANTLY SINCE THIS MORNING. THEREFORE THE LOW CURRENTLY DOES
NOT MEET THE CRITERIA TO DESIGNATE IT AS A TROPICAL CYCLONE.
SHOWERS AND THUNDERSTORMS COULD REDEVELOP LATER TODAY OR TONIGHT,
WHICH COULD RESULT IN TROPICAL CYCLONE FORMATION. RESIDENTS AND
VISITOR IN PUERTO RICO AND THE U.S VIRGIN ISLANDS SHOULD CLOSELY
MONITOR THE PROGRESS OF THIS SYSTEM AS PERIODS OF HEAVY RAIN ARE
EXPECTED TO OCCUR FROM SATURDAY MORNING OVER THE U.S. VIRGIN
ISLANDS AND PUERTO RICO THROUGH SUNDAY MORNING. STAY TUNED FOR
LATEST INFORMATION ON THE WEATHER CONDITIONS.

AVIATION...SHRA/ISOLD TSRA FM 31/16-31/22Z W/BRIEF MVFR CIGS WILL
LIKELY CONTINUE ACROSS THE CENTRAL INTERIOR AND NORTHWESTERN
SECTIONS OF PR AFFECTING MAINLY TJBQ AND TJMZ...WILL KEEP VCTS AT
THE REST OF THE TERMINALS. LOW LEVEL WINDS FM THE SE AT 5-15 KTS.

MARINE...SEAS UP TO 5 FEET AND WINDS UP TO 19 KNOTS ARE EXPECTED
OVER THE COASTAL WATERS TONIGHT. SMALL CRAFT SHOULD EXERCISE
CAUTION ACROSS THE ATLANTIC WATERS.

FIRE WEATHER...FIRE WEATHER WATCH WILL BE IN EFFECT FROM FRIDAY
MORNING THROUGH FRIDAY AFTERNOON FOR LOW HUMIDITIES AND STRONG
WINDS FOR VIEQUES AND SAINT CROIX.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  79  90  80  82 /  20  10  10  70
STT  81  88  81  81 /  20  10  30  70

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...FIRE WEATHER WATCH FROM 9 AM AST FRIDAY THROUGH FRIDAY AFTERNOON
     FOR CULEBRA.

VI...FIRE WEATHER WATCH FROM 9 AM AST FRIDAY THROUGH FRIDAY AFTERNOON
     FOR ST CROIX.

COASTAL WATERS...NONE.
&&

$$

12/09





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