Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Wed, 22 Dec 2010 02:17:24 -0600

343 
FXPQ60 PGUM 220817
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
617 PM CHST WED DEC 22 2010

SYNOPSIS...
VISIBLE SATELLITE IMAGERY SHOWS A WEAK SHEAR LINE SOUTH OF
GUAM...WITH LIGHT NORTH TO NORTHEAST WINDS AND ISOLATED SHOWERS
NORTH OF THAT LINE. AFTER ALL THE ISLAND SHOWERS OVER GUAM ON
TUESDAY...IT HAS BEEN MUCH QUIETER THIS AFTERNOON...WITH ONLY
ISOLATED ISLAND SHOWERS IN LIMITED MOISTURE. MEANWHILE...SEA LEVEL
PRESSURE AT THE GUAM AIRPORT IS CURRENTLY 1003 MB...UNUSUALLY LOW
FOR DECEMBER IN THE ABSENCE OF ANY TROPICAL SYSTEMS.

DISCUSSION...
GFS/UKMET STILL SHOWING DISJOINTED SHEAR LINE FRAGMENTS NEAR THE
MARIANAS OVER THE NEXT FEW DAYS...POSSIBLY COALESCING INTO A
SINGLE STRONGER SHEAR LINE OVER THE WEEKEND. QUITE A BIT OF
UNCERTAINTY IN THE DETAILS...SO FOR NOW GO WITH MOSTLY CLOUDY
THURSDAY THROUGH FRIDAY NIGHT WITH ISOLATED SHOWERS. COULD SEE
MORE SHOWERS OVER THE HOLIDAY WEEKEND THAN CURRENTLY FORECAST BUT
WOULD LIKE TO SEE MORE DEFINITE INDICATIONS IN THE NEXT FEW MODELS
RUNS BEFORE PUTTING THAT INTO THE FORECAST. 

EASTERN MICRONESIA...
LIGHT SOUTHERLY AND WESTERLY WINDS REMAIN IN PLACE ACROSS THE
REGION. ASCAT ANALYSIS AND MODELS SHOW SOUTHEAST WINDS CREEPING
IN ACROSS THE SOUTHERN MARSHALLS. AS THE LARGE WIND FIELD AROUND A
RIDGE IN IN EASTERN MICRONESIA LIFTS NORTHWARD...WINDS WILL SHIFT
TO EAST THROUGHOUT THE REGION. DRY CONDITIONS ARE EXPECTED TO
PERSIST THROUGH THE WEEK WITH A GRADUAL INCREASE IN LOW-LEVEL
MOISTURE BY THE WEEKEND.

WESTERN MICRONESIA...
LITTLE CHANGE TO WESTERN MICRONESIA FORECASTS EXCEPT FOR FIRST
PERIOD OF KOROR FORECAST. ASCAT...MODEL ANALYSIS AND SATELLITE
INDICATE A SURFACE TROUGH JUST SOUTH OF KOROR. LIGHT RAIN HAS BEEN
FALLING AT KOROR AMOUNTING TO 0.12 INCHES IN THE LAST SIX OR 7
HOURS. SATELLITE IMAGERY SHOWS SCATTERED SHOWERS AND A FEW
THUNDERSTORMS FARTHER SOUTH...AND MODELS KEEP KOROR NORTH OF THE
SURFACE TROUGH. FOR THESE REASONS OPTED TO CHANGE KOROR FORECAST
FOR TONIGHT FROM PARTLY CLOUDY TO MOSTLY CLOUDY AND ISOLATED
SHOWERS. IN THE LONGER TERM...MODELS KEEP KOROR...YAP AND CHUUK
RELATIVELY DRY THROUGH MOST OF THE FORECAST PERIOD. GFS DOES MOVE
A SURFACE TROUGH ACROSS YAP EARLY IN THE WEEKEND WITH A SMALL
INCREASE IN SHOWERS POSSIBLE.

&&

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

$$

MIDDLEBROOKE/DEVITA

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