Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Thu, 21 Oct 2010 17:21:16 -0500

555 
FXPQ60 PGUM 212221
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
821 AM CHST FRI OCT 22 2010

.SYNOPSIS...
TD 16W FORMED OVERNIGHT ABOUT 400 MILES WEST OF THE MARIANAS IN
THE PHILIPPINE SEA...WHILE TD 17W FORMED ABOUT 700 MILES WEST-
NORTHWEST OF WAKE ISLAND. CONVERGENT SOUTH WINDS TO THE EAST OF
16W ALLOWED A NARROW BAND OF HEAVY CONVECTION TO SET UP OVER GUAM
AND ROTA. LATEST RADAR SHOWED THE SHOWERS WERE ALREADY BEGINNING
TO TAPER OFF. UPDATED FORECAST PACKAGE CARRYING SCATTERED POPS FOR
GUAM AND ROTA THROUGH MID MORNING ALREADY REFLECTS THIS FORECAST
SCENARIO. URBAN AND SMALL STREAM FLOOD ADVISORY REMAINS IN EFFECT
UNTIL 930 AM THIS MORNING.

&&

.DISCUSSION...
OTHER THAN THE SHORT TERM FORECAST ADJUSTMENT FOR GUAM AND ROTA
THIS MORNING...FORECAST PHILOSOPHY REMAINS THE SAME. STILL EXPECT
DEEP-LAYER RIDGING TO BUILD IN AS TD16W MOVES OFF TO THE
WEST...WHILE TD 17W IS EXPECTED TO PASS TOO FAR TO THE NORTHEAST
OF THE MARIANAS TO BECOME A SIGNIFICANT WEATHER PLAYER. MARINE
FORECAST GRIDS MERELY REQUIRED A FEW COSMETIC CHANGES. STILL
EXPECT MODERATE RIP CURRENT RISK LEVEL SURF ON NORTH AND EAST
FACING EXPOSURES DURING THE NEXT FEW DAYS.

&&

.EASTERN MICRONESIA...
SHOWERS ASSOCIATED WITH TRADE-WIND CONVERGENCE ZONE OVER THE 
MARSHALLS IS EXPECTED TO REMAIN PRIMARILY TO THE NORTH OF MAJURO 
TODAY...PUSHING EVEN FARTHER TO THE NORTH OVER THE WEEKEND ALLOWING 
DRIER CONDITIONS TO MOVE BACK OVER THE REGION DURING THAT TIME FRAME.
A WEAK TRADE-WIND TROUGH AND ATTENDANT CONVECTION IS ANTICIPATED
TO PASS TO THE NORTH OF KOSRAE THROUGH TONIGHT AS RELATIVELY DRY
SOUTHEAST TRADE-WIND FLOW CONTINUES OVER THE AREA. THIS TROUGH
SHOULD PROPAGATE WESTWARD AND ARRIVE OVER POHNPEI LATE FRIDAY NIGHT
AND SATURDAY BUT MODELS SHOW ONLY A LIMITED IMPACT AT POHNPEI.

&&

.WESTERN MICRONESIA...
CONVERGING SOUTHWEST WINDS IN RESPONSE TO NEWLY-FORMED TD 16W
WEST OF THE MARIANAS SHOULD CAUSE INCREASED CONVECTION OVER YAP
TONIGHT AND SATURDAY...POSSIBLY INTO SUNDAY...DEPENDING ON HOW
FAST 16W MOVES WESTWARD. ALL MODEL SOLUTIONS HAVE BEEN CONSISTENT
IN DEPICTING THIS SCENARIO FOR THE PAST FEW RUNS BUT KEEP THE BULK
OF CONVECTION NORTH AND EAST OF KOROR. AS 16W MOVES WEST...RIDGING
WILL GRADUALLY BUILD BACK OVER YAP AND PALAU ALLOWING WINDS TO
SLOWLY BACK TO THE SOUTHEAST BY NEXT WEEK. CONVECTION REMAINS TO
THE NORTHWEST OF CHUUK WITH RELATIVELY DRY CONDITIONS EXPECTED TO
PERSIST THROUGH AT LEAST LATE SATURDAY. TRADE-WIND TROUGH OVER THE
MARSHALLS MAY MAKE IT AS FAR WEST CHUUK BUT DIFFERING MODEL
SOLUTIONS IN THE LONG-TERM MAKES FOR HIGH FORECAST UNCERTAINTY
WITH THIS FEATURE.

&&

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

$$

MCELROY/WILLIAMS

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