Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Thu, 7 Oct 2010 02:44:41 -0500

451 
FXPQ60 PGUM 070744
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
544 PM CHST THU OCT 7 2010

.SYNOPSIS...AN UPPER-LEVEL TROUGH WEST OF THE MARIANAS IS HELPING
TO GENERATE MID TO UPPER-LEVEL CLOUDINESS HOWEVER LATEST RADAR
AND SATELLITE IMAGERY SHOW MOST OF THE HEAVIEST SHOWER ACTIVITY
IS REMAINING SOUTH OF THE ISLANDS. WITH THE STRONGEST ACTIVITY IN
THE ITCZ POSITIONED NEAR 10N THIS WEEK...ANY PASSING DISTURBANCES
WILL HAVE TO BE MONITORED CLOSELY FOR THE NEXT COUPLE OF DAYS AS
THEY TRAVEL JUST SOUTH OF THE GUAM COASTAL WATERS.

&&

.DISCUSSION...MODELS ARE SOMEWHAT IN AGREEMENT WITH KEEPING MOST
OF THE STRONGEST CONVECTIVE ACTIVITY SOUTH AND WEST OF THE
MARIANAS OVER THE NEXT COUPLE OF DAYS. HOWEVER AS MENTIONED IN THE
ABOVE SYNOPSIS...ANY SLIGHT SHIFT TO THE NORTH WILL QUICKLY BRING
WEATHER OVER THE MARIANAS...ESPECIALLY GUAM AND ROTA. I HAVE ALSO
ADJUSTED THE WINDS AND WEATHER SO THAT THE NEXT SIGNIFICANT DISTURBANCE
PASSES CLOSEST TO THE MARIANAS ON SUNDAY VERSUS SATURDAY. OF
INTEREST IS THE TENDENCY FOR SEVERAL NWP MODELS TO GIN UP A GOOD
SIZE TROPICAL CYCLONE FROM THIS ITCZ DISTURBANCE ABOUT 200 TO 300
MILES TO OUR WEST BY NEXT TUESDAY. THIS COULD HAVE AN AFFECT OF
MAINTAINING SOUTHEAST WINDS OVER OUR AREA AS WELL AS MORE
EXTENSIVE CLOUD COVER...EVEN IF IT DOES NOT DEVELOP NEAR US. OF
COURSE...ANY DEVELOPMENT IS YET TO BE SEEN AS THE SHEAR IS STILL
QUITE STRONG EVERYWHERE IN THE WESTERN PACIFIC OUTSIDE OF THE SOUTH
CHINA SEA AND PERHAPS THE PHILIPPINE COASTAL WATERS.

&&

.EASTERN MICRONESIA...
A SURFACE TROUGH COUPLED WITH UPPER-LEVEL DIVERGENCE SHOULD BRING 
SCATTERED SHOWERS TO  MAJURO STARTING TONIGHT AND LASTING THROUGH 
FRIDAY NIGHT. THE TROUGH SHOULD PROGRESS WESTWARD BUT MOST OF THE
ASSOCIATED CONVECTION IS EXPECTED TO REMAIN NORTH OF KOSRAE. AN
ACTIVE TRADE-WIND CONVERGENCE PATTERN WILL PERSIST AT POHNPEI
THROUGH TONIGHT BUT EFFECTS FROM THE SURFACE TROUGH OVER THE
MARSHALLS IS QUESTIONABLE GIVEN THAT MODELS TEND TO WASH OUT THE
FEATURE AS THE WEEKEND APPROACHES. THE ITCZ IS PROGGED TO SLOWLY
MOVE NORTHWARD OVER THE NEXT FEW DAYS ALLOWING DRIER CONDITIONS TO
MOVE BACK OVER MAJURO AND KOSRAE BY THE WEEKEND.

&&

.WESTERN MICRONESIA...
A SURFACE TROUGH OVER YAP AND AN UPPER-LEVEL LOW SITUATED NORTH 
OF THE ISLAND SHOULD MAINTAIN WET CONDITIONS OVER THE AREA TONIGHT. 
THUNDERSTORMS ARE ALSO POSSIBLE FOR YAP TONIGHT GIVEN THE PROXIMITY 
TO THE UPPER-LOW. MODELS INDICATE THE SUBTROPICAL RIDGE WILL
WEAKEN AND IN RESPONSE...REDUCE GRADIENT WINDS ACROSS MOST OF
MICRONESIA INCLUDING OVER YAP AND KOROR. CONVECTION ASSOCIATED
WITH THE ITCZ SHOULD PERSIST OVER CHUUK THROUGH AT LEAST TONIGHT
BEFORE SLOWLY MOVING TO THE NORTH AND WEST BY SATURDAY.

&&

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

$$

EDSON/DEVITA

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