Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Sun, 24 Oct 2010 22:20:09 -0500

929 
FXPQ60 PGUM 250320 AAA
AFDPQ 

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TIYAN GU
120 PM CHST MON OCT 25 2010

.UPDATE...UPDATED SURF FORECAST BASED ON YPAO BEACH REPORT OF 5
TO 6 FEET WAVES AND HIGH RISK OF RIP CURRENTS. LIKELIHOOD OF LARGE
WEST WAVES FROM TS CHABA (17N131E) IS SMALL. ADJUSTED GRIDS ENOUGH
TO CALCULATE MODERATE RIP CURRENT RISK FROM TRADE-WIND WAVES AND
OTHER SLIGHT ADJUSTMENTS TO SURF FORECAST.

&&

.PREV DISCUSSION... /ISSUED 716 AM CHST MON OCT 25 2010/ 

SYNOPSIS...
AN INVERTED SURFACE TROUGH IS CURRENTLY PASSING TO THE SOUTH OF
GUAM. ANIMATED SATELLITE AND RADAR IMAGERY SUGGEST THE NORTHERN
EDGE OF THE ATTENDANT DEEP CONVECTION WILL BE PASSING JUST TO THE
SOUTH OF THE GUAM MARINE ZONES. A TUTT CELL IS CENTERED NEAR
ANATAHAN...AND IS DRIFTING SLOWLY WESTWARD.

DISCUSSION...
PROXIMITY OF THE AFOREMENTIONED TUTT CELL AND SURFACE TROUGH ARGUE
FOR MOSTLY CLOUDY SKIES THROUGH TONIGHT. KEPT SHOWER COVERAGE
ISOLATED THROUGH THE FORECAST PERIOD. IF SHOWERS ASSOCIATED WITH
THE SURFACE TROUGH SPREAD NORTHWARD...AN UPDATE TO THE AM
FORECAST PACKAGE WILL BE NEEDED TO INCREASE CLOUD COVER/POPS. MOST
LIKELY UPDATE SCENARIO WOULD BE TO INCREASE POPS FOR GUAM TO
SCATTERED AND SPLIT THE FORECAST ZONES. AFTER TONIGHT...WEATHER
LOOKS RELATIVELY DRY. NEXT POSSIBLE WEATHER MAKER APPEARS TO BE
THE TRADE-WIND TROUGH IN THE MARSHALLS. GFS BRINGS THIS SYSTEM
SOUTH OF GUAM AS WELL FRIDAY AND FRIDAY NIGHT.

EASTERN MICRONESIA...
THE LEADING EDGE OF CONVECTION ASSOCIATED WITH A TROUGH CROSSING
THE DATELINE INTO THE MARSHALL ISLANDS HAS PASSED OVER MAJURO.
SCATTERED SHOWERS MOVED OVER MAJURO EARLIER THIS MORNING...BUT
HAVE TAPERED OFF FOR THE TIME BEING. MUCH MORE CONVECTION IS
LINED UP TO THE NORTHEAST AND EAST OF MAJURO. THIS ACTIVITY WILL
SLIDE TOWARD THE WEST...RETURNING SCATTERED SHOWERS TO MAJURO
TONIGHT. MODEL DATA CONTINUES TO ADVECT MUCH OF THIS WEATHER
NORTH OF KOSRAE...BUT POHNPEI SHOULD SEE SHOWERS LATE TUESDAY
NIGHT AND WEDNESDAY.

WESTERN MICRONESIA...
SKY CONDITIONS CLEARED RAPIDLY IN THE HOURS BEFORE SUNRISE NEAR
YAP AND PALAU. PARTLY CLOUDY SKIES WERE ADDED TO THE FORECAST FOR
BOTH LOCATIONS FOR TODAY. HOWEVER...DEVELOPING CONVECTION JUST
SOUTHEAST OF YAP COULD BE THE CAUSE FOR AN AMENDMENT SHOULD THIS
WEATHER ENCROACH. OTHERWISE...LIGHT SHOWERS ARE BEING ENHANCED BY
UPPER-LEVEL DIVERGENCE. LATEST SATELLITE IMAGERY INDICATES
SOUTHWARD BUILDING OF CONVECTION...WITH A VERY GRADUAL WESTWARD
DRIFT. CURRENT COURSE SUGGESTS A NEAR TERM PASSAGE JUST SOUTH OF
YAP. MOVING EAST...SCATTERED SHOWERS AND THUNDERSTORMS RESIDE
BETWEEN YAP AND CHUUK. CHUUK REMAINS ON THE EASTERN EDGE OF AN
AREA OF SHOWERS THAT HAS BEEN STRUGGLING TO CLEAR OUT. SHOWERS
ARE DEVELOPING ONCE AGAIN NEAR AND EAST OF CHUUK. MOSTLY CLOUDY
SKIES WERE ADDED FOR TODAY...BUT KEPT SHOWER COVERAGE ISOLATED.

&&

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

$$

SIMPSON/CHAN

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