Area Forecast Discussion
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FXPQ60 PGUM 220554
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
354 PM CHST FRI AUG 22 2014

.MARIANAS SYNOPSIS...
IT HAS BEEN A CLASSIC DAY FOR ISLAND THUNDERSTORMS ON GUAM--LIGHT
WINDS DOWN THE LENGTH OF THE ISLAND...SOME SOLAR HEATING...AND
PLENTY OF MOISTURE. HIT-AND-RUN THUNDERSTORMS HAVE BEEN POPPING
RANDOMLY UP AND DOWN SINCE 1030 AM...AND CURRENTLY WHILE ONE IS
WEAKENING OVER ANDERSEN AFB...ANOTHER IS POPPING UP AROUND
INARAJAN IN SOUTHERN GUAM.

OTHERWISE...RADAR AND SATELLITE SHOW ISOLATED SHOWERS AROUND THE
MARIANAS...WITH A COUPLE OF ISOLATED THUNDERSTORMS WELL SOUTH OF
GUAM.

&&

.DISCUSSION...
ONE MORE ISLAND THUNDERSTORM DAY IS POSSIBLE FOR GUAM SATURDAY AS
WINDS WILL BE VERY LIGHT...BUT LIKELY FROM THE SOUTHEAST WHICH IS
LESS FAVORABLE FOR ISLAND-GENERATED CONVECTION. EVEN SO...HAVE
GONE WITH ISOLATED AFTERNOON THUNDER FOR GUAM FOR SATURDAY. OTHER
THAN THAT...THE REST OF THE FORECAST IS UNCHANGED--PARTLY CLOUDY
WITH ISOLATED SHOWERS AND GENERALLY LIGHT EAST WINDS.

&&

.EASTERN MICRONESIA...
A DIFFUSE SURFACE TROUGH IS PRODUCING CLOUDINESS FROM EAST OF MAJURO
TO BEYOND THE DATE LINE. THE MONSOON TROUGH PASSES TO THE NORTH OF
KOSRAE AND POHNPEI...BUT THE PATTERN OF RIDGING ON THE SOUTH SIDE OF
THE TROUGH IS PROMOTING WEAK MONSOONAL FLOW OVER THESE LOCALES.
FORECAST CLOSELY FOLLOWS PERSISTENCE. MADE SOME MINOR SHORT TERM
WIND ADJUSTMENTS BASED ON THE LATEST ASCAT IMAGERY. STILL EXPECT
WEAK AND CHAOTIC WIND FLOW REGIME TO PERSIST THROUGH THE FORECAST
PERIOD. A WEAK WIND FLOW PATTERN MEANS LOW-LEVEL FORCING WILL BE
WEAK AS WELL...THUS DO NOT EXPECT SCATTERED SHOWERS OVER ANY OF
THE FORECAST LOCALES THROUGH DAY 5.

&&

.WESTERN MICRONESIA...
MONSOON TROUGH PASSES TO THE NORTH OF ALL 3 FORECAST POINTS.
MONSOONAL FLOW HAS BECOME ESTABLISHED FOR THE TIME BEING OVER
CHUUK...YAP AND KOROR. DID MAKE SHORT TERM WIND ADJUSTMENTS TO THE
CHUUK AND YAP FORECASTS TO FACTOR IN THE MONSOONAL FLOW...BUT THEN
WEAKER WIND FLOW REGIME MOVES BACK IN FROM THE EAST. FORECASTS FOR
CHUUK AND YAP REMAIN RELATIVELY QUIET. HOWEVER...MADE SEVERAL
ADJUSTMENTS TO THE KOROR FORECASTS WHERE MONSOONAL FLOW IS MORE
DEEPLY ENTRENCHED. LATEST ASCAT IMAGERY AND METARS FROM KOROR
INDICATE STRONGER WINDS THAN EARLIER FORECAST...SO HAVE INCREASED
WINDS AND SEAS THERE ON DAYS 1 AND 2. COLD CLOUD TOPS WERE SEEN IN
IR SATELLITE IMAGERY TODAY IN THE VICINITY OF KOROR. GFS TIME-HEIGHT
CROSS SECTION SHOWS SIGNIFICANT OMEGA OVER KOROR JUST FOR TONIGHT.
HAVE ACCORDINGLY ADDED THUNDER FOR TONIGHT TO THE KOROR FORECAST.
LONG TERM FORECAST FOR ALL 3 LOCALES REMAINS VIRTUALLY UNCHANGED AND
QUIET AS WEAKER WIND FLOW REGIME TAKES HOLD DAYS 3 THROUGH 5.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...NONE.

&&

$$

MIDDLEBROOKE/MCELROY





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