Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Tue, 28 Sep 2010 00:59:19 -0500

133 
FXPQ60 PGUM 280558
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
358 PM CHST TUE SEP 28 2010

.SYNOPSIS...
AFTER THE SHOWERS OF THIS MORNING...THERE HAS BEEN A BREAK IN THE
ACTION THIS AFTERNOON. BUT RADAR AND SATELLITE SHOW SHOWERS
STARTING TO DEVELOP EAST OF THE ISLANDS. A SURFACE TROUGH ALONG11N
EXTENDS AS FAR EAST AS ABOUT 141E...AS IS EVIDENT FROM LOW CLOUD
MOTIONS ON HI-RES VISIBLE SATELLITE IMAGERY.

&&

.DISCUSSION...
GFS AND UKMET HAVE BACKED OFF SOMEWHAT ON SCATTERED SHOWERS
TONIGHT...BUT STILL SUFFICIENT INDICATIONS OF SOME SHOWERS
DEVELOPING TONIGHT INTO WEDNESDAY. GFS AND UKMET STILL SHOW THE
TROUGH EXTENDING EASTWARD TOWARD THE MARIANAS TONIGHT...WITH A
SEPARATE N-S WESTWARD-MOVING TROUGH PASSING SOUTH OF GUAM WED.
LOW-LEVEL CONVERGENCE EAST OF THE E-W TROUGH SHOULD SET UP ACROSS
THE MARIANAS...TRIGGERING SCATTERED SHOWERS OVERNIGHT. SHOWERS
SHOULD PERSIST WELL INTO WEDNESDAY AS THE SECOND TROUGH PASSES BY
ON WED. NOT NECESSARILY LOOKING FOR A BIG RAIN EVENT...JUST A LOW-
END SCATTERED SITUATION BLENDING BACK INTO ISOLATED SHOWERS/THUNDER
WED NITE THRU THURSDAY NIGHT. BY FRI AND THE WEEKEND...DRYING SETS
IN IN THE MID AND UPPER LEVELS...RESULTING IN PARTLY CLOUDY WITH
ONLY ISOLATED SHOWERS.

&&

.MARINE...
AFTERNOON REPORTS INDICATE SURF STILL HITTING 10 FEET ON NORTH
FACING REEFS OF GUAM...SO HIGH SURF IS CONTINUED UNTIL NOON WED.
SEAS SHOULD FALL STEADILY THRU THE SECOND HALF OF THE WEEK AS THE
NORTH AND EAST SWELL BOTH DIMINISH. 

&&

.EASTERN MICRONESIA...
CONVECTION HAS LARGELY DISSIPATED ACROSS THE REGION FROM POHNPEI TO 
WEST OF THE MARSHALLS WITH ONLY LOW-LEVEL CUMULUS NOTED ON VISIBLE 
SATELLITE IMAGERY. THE MAIN WEATHER FEATURE IN THE AREA IS A TROUGH 
ORIENTED NW-SE AND JUST CROSSING THE RATAK CHAIN OF THE MARSHALLS. 
MODELS CONTINUE TO KEEP SHOWER COVERAGE LOW AT MAJURO SO HAVE 
FOLLOWED SUIT WITH ISOLATED SHOWERS. THE TROUGH TURNS EASTWARD FROM 
NEAR MAJURO AND CROSSES THE DATE LINE HEADING INTO A STATIONARY 
CIRCULATION AT 9N175W. MODELS TEND TO AGREE THAT THE CIRCULATION 
WILL EVENTUALLY PUSH WNW THE NEXT COUPLE DAYS...BYPASSING MAJURO. 
HOWEVER...THIS TROUGH WILL NEED TO BE WATCHED CLOSELY IN CASE
SCATTERED SHOWERS DO DEVELOP IN THE COMING DAYS. WINDS AT MAJURO
WILL REMAIN ON THE LIGHT SIDE BUT WITH VARYING DIRECTION BASED ON
JUST WHERE THE TROUGH AXIS LIES.

&&

.WESTERN MICRONESIA...
AFTER SEEING ANOTHER ROUND OF SCATTERED SHOWERS TODAY...CHUUK WILL 
SEE IMPROVING CONDITIONS FOR THE NEXT SEVERAL DAYS AS DRY WEATHER 
OVER EASTERN MICRONESIA SPREADS WESTWARD AND A TROUGH JUST WEST OF 
CHUUK CONTINUES WESTWARD. 

SHOWERS AND ISOLATED THUNDERSTORMS HAVE PERSISTED OVER A LARGE AREA 
INCLUDING PALAU...YAP AND THE MARIANAS...BETWEEN 5N TO 14N FROM 130E 
TO 148E. A WEAK CIRCULATION WEST OF YAP IS THE PRIMARY FOCUS WHILE 
TRADE-WIND CONVERGENCE CONTRIBUTES NEAR THE MARIANAS. ENHANCED IR 
SATELLITE IMAGERY SHOWS COLDER CLOUD TOPS MIGRATING SOUTHWESTWARD 
FROM YAP TO PALAU WHICH SHOULD END SCATTERED SHOWERS AT YAP THIS 
EVENING WHILE STARTING UP A PALAU. MODELS SLOWLY PUSH THE 
CIRCULATION NORTHWEST DURING THE NEXT 2 DAYS. ADDITIONAL SHOWERS ARE 
EXPECTED TO REDEVELOP AT YAP WEDNESDAY...BUT SHOULD BECOME ISOLATED 
FOR BOTH YAP AND PALAU BY WEDNESDAY NIGHT. NORTH SWELL WILL CONTINUE 
TO AFFECT BOTH LOCATIONS...BUT WAVEWATCH MODEL INDICATES HEIGHTS 
WILL BEGIN TO SUBSIDE BY WEDNESDAY.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL NOON CHST WEDNESDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

MIDDLEBROOKE/W. AYDLETT

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