Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Sat, 4 Dec 2010 15:05:35 -0600

648 
FXPQ60 PGUM 042105
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
705 AM CHST SUN DEC 5 2010

.SYNOPSIS...
AN OLD SHEAR LINE CURVES EAST-NORTHEASTWARD FROM SOUTH OF GUAM TO 
SOUTH OF WAKE ISLAND. A TUTT EXTENDS WESTWARD FROM THE DATE LINE
ALONG 10N TO NEAR 130E. UPPER-LEVEL CONVERGENCE PREVAILS OVER
MICRONESIA TO THE NORTH OF 10N.

&&

.DISCUSSION...
ONLY CHANGES TO THE FORECAST GRIDS WERE TO REFRESH THE WINDS AND DEW 
POINTS. SATELLITE IMAGERY AND NEAR TERM MODEL GUIDANCE CONSENSUS 
CALL FOR WHAT IS LEFT OF THE SHEAR LINE TO SHIFT FARTHER TO THE 
SOUTHWEST OF GUAM AS UPPER-LEVEL CONVERGENCE STRENGTHENS OVERHEAD. 
HOWEVER...UKMET AND GFS BOTH CALL FOR THE SHEAR LINE TO CRACK BACK 
TO THE NORTH ON TUESDAY AND TUESDAY NIGHT AS THE UPPER-LEVEL 
ENVIRONMENT BECOMES MORE FAVORABLE. ECMWF IS NOT AS BULLISH WITH 
THIS FORECAST SCENARIO. IF MODEL GUIDANCE AND SATELLITE IMAGERY 
CONVERGE TOWARD THIS SCENARIO...CLOUD COVER AND POPS MAY NEED TO BE 
INCREASED OVER ALL OR PART OF THE FORECAST DOMAIN DURING THIS TIME 
FRAME. NO OTHER SIGNIFICANT WEATHER MAKERS ARE FORESEEN THROUGH THE 
REMAINDER OF THE FORECAST PERIOD. A NORTHEAST SWELL COULD BRING SURF 
ON RESPECTIVE EXPOSURES CLOSE TO ADVISORY LEVELS ON MONDAY NIGHT OR 
TUESDAY...BUT THE FETCH GENERATION AREA LOOKS TO BE LOCATED TOO FAR 
AWAY FROM FORECAST DOMAIN. LATEST ASCAT IMAGERY SHOWED AN AREA OF
GALES FROM THE NORTHEAST EAST OF WAKE ISLAND AND TO THE NORTH OF
30N.

&&

.EASTERN MICRONESIA...
A WEAK SURFACE TROUGH WILL PASS OVER MAJURO TODAY...BRINGING
INCREASING CLOUD COVER. HOWEVER...SHOWER COVERAGE WILL REMAIN
LIMITED AS A GENERAL DRY SEASON PATTERN CONTINUES. DRY CONDITIONS
CONTINUE OVER KOSRAE AND POHNPEI AS WELL. LOW-LEVEL CONVERGENCE
AND CLOUD COVER ARE EXPECTED TO INCREASE ACROSS THE ENTIRE REGION
AROUND MIDWEEK BUT SPECIFIC AREAS OF INCREASED CONVECTION ARE
DIFFICULT TO ASCERTAIN IN MODEL GUIDANCE.

&&

.WESTERN MICRONESIA...
DRY CONDITIONS ARE EXPECTED TO CONTINUE FOR CHUUK AT LEAST UNTIL 
MONDAY. MODELS INDICATE INCREASING LOW-LEVEL CONVERGENCE AND
CLOUD COVER BY MIDWEEK. A SLOW MOVING SURFACE TROUGH OVER THE
REPUBLIC OF PALAU WILL BE A FOCUSING MECHANISM FOR CONVECTION
TODAY OVER KOROR. MODELS SHOW PERSISTENT TROUGHING SOUTHWEST OF
KOROR WHICH MAY ALLOW FOR A PROLONGED PERIOD OF SCATTERED SHOWERS
THROUGH THE LONG TERM BUT CONFIDENCE IS STILL RATHER LOW WITH THIS
SCENARIO. MODELS DO AGREE IN KEEPING MUCH OF THE ACTIVITY
ASSOCIATED WITH THE TROUGH WELL TO THE SOUTH OF YAP THROUGH NEXT
WEEK.

&&

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

$$

MCELROY/WILLIAMS

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