Funnel Cloud in Puerto Rico, September 21, 2004

PUERTO RICO AND U.S. VIRGIN ISLANDS FORECAST DISCUSSION NATIONAL
WEATHER SERVICE SAN JUAN PR
253 PM AST TUE SEP 21 2004

.SYNOPSIS...AT UPPER LEVELS HIGH PRESSURE REMAINS ORIENTED EAST TO
WEST. STRONG HIGH PRESSURE WILL BUILD JUST NORTHEAST OF THE LEEWARD
ISLANDS ON THURSDAY AND AND EVER SO GRADUALLY RETREAT THROUGH THE
FOLLOWING WEDNESDAY. AFTER WHICH WEAK TROUGHING IS EXPECTED WEST OF
THE AREA.

AT MID LEVELS...HIGH PRESSURE WILL SIT JUST SOUTH OF THE AREA FOR
MOST OF THE NEXT TEN DAYS. HURRICANE JEANNE WILL SLOWLY DRIFT EAST
OR SOUTHEAST BEING PULLED BY A LONG WAVE TROUGH.

AT LOWER LEVELS...MANY LOW PRESSURE SYSTEMS INCLUDING
JEANNE...KARL...LISA...A DISTURBANCE SOUTHEAST OF LISA AND SYSTEMS
MOVING OFF THE AFRICAN CONTINENT WILL BE AT PLAY IN THE WEATHER
SCENARIO THIS WEEK. FORECASTS DO NOT SHOW ANY OF THE SYSTEMS MOVING
CLOSE TO THE CARIBBEAN WITHIN THE NEXT 5 DAYS. NO WAVE PASSAGES ARE
EXPECTED DURING THIS TIME EITHER. WIND GRADIENTS BETWEEN THE SYSTEMS
ARE LIGHT AS WILL BE WINDS DURING THE NEXT WEEK. BECAUSE JEANNE WILL
BE NORTH OF THE AREA WIND FLOW OVER PUERTO RICO AND THE U.S. VIRGIN
ISLANDS WILL HAVE AN UNCHARACTERISTIC WESTERLY COMPONENT.

&&

.DISCUSSION...THE AIR OVER THE AREA WAS SUFFICIENTLY DRY TO INHIBIT
ALMOST ALL CONVECTION OVER THE ISLANDS TODAY AS OF 3 PM. SOME
SHOWERS WERE DEVELOPING SOUTH OF SOUTHWEST PUERTO RICO AND WERE
MOVING SLOWLY NORTH...BUT WILL LIKELY NOT MAKE IT OVER PUERTO RICO
THIS AFTERNOON. LATE DEVELOPING SHOWERS ARE MOST LIKELY TO OCCUR IN
THE NORTHEAST AND NEAR SAN JUAN...BUT SHOULD NOT LAST MUCH PAST
SUNSET. AS WINDS REMAIN SOUTHERLY FOR THE NEXT 4 TO 5 DAYS...MAXIMUM
SHOWER FORMATION WILL BE ALONG THE NORTH COAST DURING THE DAY AND
ALONG THE SOUTH COAST DURING THE LATE NIGHT PERIODS...PROVIDING
WINDS ARE STRONG ENOUGH TO OVERCOME LAND BREEZES OFF THE CORDILLERA
CENTRAL. SINCE THE ATMOSPHERE IS RELATIVELY DRY...SHOWERS WILL BE
SLOW TO FORM AND FAR LESS NUMEROUS THAN ON A TYPICAL DAY. SHOWERS
THAT DO FORM HOWEVER WILL BE CAPABLE OF LEAVING UP TO 2 TO 3 INCHES
IN ISOLATED SPOTS.

MODEL RUNS SHOW LITTLE TO TRIGGER WIDESPREAD CONVECTION EXCEPT LOCAL
EFFECTS WHICH WILL BE FOCUSED MAINLY IN THE NORTHEAST FOR THE NEXT
SEVERAL AFTERNOONS. THUS SHOWERS SHOULD REMAIN ISOLATED TO SCATTERED
OVER MUCH OF THE AREA THROUGH SATURDAY.

MODELS ARE CONTINUING TO DEVELOP LOW PRESSURE SYSTEMS EXITING THE
AFRICAN CONTINENT DURING THE COMING WEEK. ALTHOUGH LISA IS NOT
EXPECTED TO REACH THE CARIBBEAN AND THE DISTURBANCE SOUTHEAST OF HER
LIKEWISE...OTHER SYSTEMS LATER IN THE TEN DAY MODEL FORECAST PERIOD
ARE BROUGHT FURTHER WEST BECAUSE HIGH PRESSURE IS FORECAST TO
REBUILD INTO THE ATLANTIC. NEVERTHELESS THE EARLIEST THAT THESE
STORMS COULD BEGIN TO AFFECT THE LOCAL AREA IS THE WEEK OF 3
OCTOBER.

&&

.MARINE...EFFECTS FROM JEANNE AND KARL ARE NOT AS DRAMATIC AS
PREVIOUSLY EXPECTED. MODELS DO NOT BRING JEANNE QUITE AS FAR SOUTH
AS EARLIER FORECAST SO SWELL HEIGHTS REACHING LOCAL AND OUTER WATERS
ARE NOW BEING FORECAST LOWER IN THE WAVEWATCH MODEL. HAVE LOWERED
EXPECTATIONS SOMEWHAT TO 7 TO 8 FEET TO MATCH THE MODEL. SEAS SHOULD
PEAK ON THURSDAY AND SLOWLY SUBSIDE TO 3 TO 4 FEET BY NEXT WEEK.

&&

.AVIATION...HAZY CONDITIONS HAVE DEVELOPED...BUT IMPAIRMENT TO
VISIBILITY HAS NOT BEEN SIGNIFICANT. CONVECTION AROUND THE AIRPORT
IN SAN JUAN DURING THE AFTERNOONS WILL BE OF MORE CONCERN TO
AVIATORS. LOCAL AND BRIEF WIND SHEAR AND DOWN DRAFTS MAY ALSO OCCUR
IN THE VICINITY OF THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  78  90  78  90 /   0  40   0  40
STT  78  91  78  91 /  20  20  20  20

&&

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

&&

SNELL

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN JUAN PR
630 AM AST TUE SEP 21 2004

PRZ001>013-AMZ710>750-221000-
630 AM AST TUE SEP 21 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO.

.TODAY AND TONIGHT...
HIGH PRESSURE WILL PREVAIL OVER OUR LOCAL REGION THROUGH THE
WEEKEND. THEREFORE SHOWER ACTIVITY WILL BE VERY LIMITED. IF ANY
SHOWERS DEVELOP...THESE WILL AFFECT THE NORTHERN COAST OF PUERTO
RICO DUE TO SOUTH WINDS.

.SPOTTER CALL TO ACTION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED.

.DAYS TWO THROUGH SEVEN...
WEDNESDAY...MODERATE EASTERLY SWELLS FROM HURRICANE KARL WILL MOVE
INTO THE LOCAL WATERS...AND EVENTUALLY COMBINE WITH NORTHWEST SWELLS
THAT ARE NOW BEING GENERATED BY HURRICANE JEANNE. THESE MERGING
SWELLS WILL CREATE HAZARDOUS MARINE CONDITIONS WEDNESDAY AFTERNOON
THROUGH FRIDAY.

VIZ001-002-AMZ710>730-221000-
630 AM AST TUE SEP 21 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE U.S. VIRGIN ISLANDS.

.TODAY AND TONIGHT...
HIGH PRESSURE WILL PREVAIL ACROSS OUR LOCAL AREA. THEREFORE SHOWERS
WILL BE VERY LIMITED.

.SPOTTER CALL TO ACTION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED.

.DAYS TWO THROUGH SEVEN...
WEDNESDAY...MODERATE EASTERLY SWELLS FROM HURRICANE KARL WILL MOVE
INTO THE LOCAL WATERS...AND EVENTUALLY COMBINE WITH NORTHWEST SWELLS
THAT ARE NOW BEING GENERATED BY HURRICANE JEANNE. THESE MERGING
SWELLS WILL CREATE HAZARDOUS MARINE CONDITIONS WEDNESDAY AFTERNOON
THROUGH FRIDAY.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

FOR ADDITIONAL INFORMATION...VISIT THE NATIONAL WEATHER SERVICE WEB
SITE FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS AT (ALL LOWERCASE
LETTERS): HTTP://WWW.SRH.NOAA.GOV/SJU.