Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Thu, 14 Oct 2010 16:34:54 -0500

231 
FXPQ60 PGUM 142134
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
734 AM CHST FRI OCT 15 2010

.SYNOPSIS...
PGUA WSR-88D SHOWS A LINE OF SHOWERS ASSOCIATED WITH $ MEGI MOVING
THROUGH THE MARIANAS WATERS. THESE SHOWERS SHOULD MOVE WESTWARD
AWAY FROM THE MARIANAS ALONG WITH MEGI. AN UPPER-LEVEL LOW AND A
SURFACE TROUGH ARE CREATING A BROAD AREA OF SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS THAT STRETCHES FROM KOSRAE TO MAJURO TO
WAKE ISLAND AND BEYOND.

&&

.DISCUSSION...GFS40 JUST KEEPS MOVING TRADE-WIND SHOWERS THROUGH
THE MARIANAS FOR THE NEXT WEEK...AND NOT ALL THAT MANY OF THOSE.
ECMWF-HIRES AGREES THAT QPF WILL BE BETWEEN 1 AND 2 INCHES. WHILE
THESE ARE NOT HARD AND FAST FIGURES...THEY DO INDICATE SOMEWHAT
DRIER TIMES AHEAD. CURRENT GRIDS SHOW THIS WELL SO NO CHANGES WERE
NEEDED.

&&

.MARINE...
PREVIOUS SHIFT ADDED WEST SWELL FROM MEGI...WHICH SEEMS LIKE A
REALLY GOOD IDEA. NOT SURE IT WILL WAIT UNTIL MONDAY TO START
COMING IN. IF WE GET A GOOD SCAT PASS TODAY THE DAY SHIFT WILL
HAVE TO DIG OUT THE NOMOGRAMS AND FORECAST THE SWELLS THE OLD
FASHIONED BUT TRIED AND TRUE WAY. THE EFFECT ON THE COMBINED SEAS
WILL BE RATHER MUTED AS THEY WILL REMAIN AROUND 5 FEET.

&&

.EASTERN MICRONESIA...
A TRADE-WIND DISTURBANCE EMBEDDED WITHIN LIGHT TO GENTLE FLOW 
REMAINS TO BE THE ONLY MAJOR FEATURE ACROSS EASTERN MICRONESIA. IT 
WILL MAINTAIN SOME SHOWER ACTIVITY OVER POHNPEI THRU SATURDAY...AND 
KOSRAE THRU TONIGHT. AN UPPER-LEVEL TROUGH OVER THE REGION IS GOING 
TO KEEP A SLIGHT THREAT FOR THUNDERSTORMS AS WELL. AS THE 
DISTURBANCE PULLS FARTHER WEST OF MAJURO LATER TODAY...LIGHT 
EASTERLY TRADES FROM THE DATE LINE SHOULD PROMOTE A PERIOD OF DRIER 
WEATHER INTO SATURDAY NIGHT. THIS LIGHT WIND REGIME WILL ALSO 
MIGRATE WESTWARD AND PROVIDE SIMILAR WEATHER FOR KOSRAE AND POHNPEI 
OVER THE WEEKEND AND EARLY NEXT WEEK. LATEST ASCAT SATELLITE DATA 
REVEAL A MODERATE ITCZ EXTENDING NORTHEASTWARD FROM THE DATE LINE 
TO SOUTH OF HAWAII. THIS CONVERGENT ZONE MIGHT AFFECT THE MARSHALL 
ISLANDS BY MONDAY.

&&

.WESTERN MICRONESIA...
DRIER LIGHT TO GENTLE TRADES ARE ANTICIPATED TO SUPPORT FAIR WEATHER 
FOR CHUUK MOST OF THE FORECAST PERIOD. THE ONLY EXCEPTION WILL BE A 
PERIOD OF SHOWERY CONDITIONS SATURDAY EVENING AND SUNDAY...CAUSED BY 
THE AFOREMENTIONED DISTURBANCE FROM THE EAST. THE IR SATELLITE LOOP 
THIS MORNING SHOWS TYPHOON MEGI BEGINNING TO MOVE NORTHWESTWARD
PASSING NORTH OF YAP. A DISTINCTIVE BAND OF CONVERGING SOUTH WINDS
EXTENDING S-SE FROM MEGI WILL CONTINUE TO FLARE UP CONVECTION OVER
YAP THRU AT LEAST TONIGHT. SOME OF THIS CONVECTION COULD IMPACT
KOROR AS WELL BY SATURDAY MORNING. DURING THE LATTER PART OF THE
WEEKEND...THE SURFACE RIDGE SOUTHEAST OF MEGI IS EXPECTED TO DRIFT
OVER THE AREA. HOWEVER...A TUTT CELL NEAR THE MARIANAS WILL
INTRODUCE DIVERGENT WINDS ALOFT AND SUSTAIN MODERATE INSTABILITY
INTO NEXT WEEK.

&&

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

$$

STANKO/CHAN

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