Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Sat, 19 Jan 2008 13:52:51 -0600

745 
FXPQ60 PGUM 191952
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
552 AM CHST SUN JAN 20 2008

.SYNOPSIS...
SATELLITE IMAGERY AND THE EVENING QUIKSCAT ANALYSIS SHOW TWO SHEAR 
LINE PASSING THROUGH THE MARIANAS AROUND 15N AND 20N. SHOWER 
ACTIVITY APPEARED TO BE IN SHORT SUPPLY IN THE VICINITY OF BOTH 
SHEAR LINES. QUIKSCAT STREAMLINE ANALYSIS SHOWS DIVERGENT LOW-LEVEL 
FLOW IN THE VICINITY OF THE MARIANAS. AGREE WITH PREVIOUS SHIFT IN 
REMOVING MENTION OF SCATTERED SHOWERS FROM THE SHORT-TERM FORECAST.

&&

.DISCUSSION...
PRIMARY FORECAST CONCERN REVOLVES AROUND THE MARINE ARENA. PLEASE 
SEE MARINE DISCUSSION SECTION FOR DETAILS. LEFT WEATHER FORECAST 
GRIDS INTACT WITH SOME COSMETIC CHANGES TO TEMPS. GFS TIME-HEIGHT 
CROSS SECTION SUPPORTS MOSTLY CLOUDY SKIES THROUGH MID DAY TUESDAY. 
REFRESHED WIND AND DEW POINT GRIDS. RAN GUST GRIDS USING A 35 
PERCENT FACTOR THROUGH THE ENTIRE GRID SET.

&&

.EASTERN MICRONESIA...
CONVECTION TO THE SOUTH OF POHNPEI AND SOUTHWEST OF KOSRAE WILL 
CONTINUE TO SPREAD MID TO HIGH LEVEL CLOUDINESS OVER THESE ISLANDS 
TODAY. SCATTERED SHOWERS CAN BE EXPECTED OVER THE MARSHALL ISLANDS 
INTO THIS EVENING AS A WEAK TRADE-WIND DISTURBANCE MOVES THROUGH. 
SIMILAR CONDITIONS WILL THEN AFFECT KOSRAE AND POHNPEI FROM MONDAY 
TO MONDAY NIGHT. FAIR WEATHER FINALLY COMES EARLY NEXT WEEK FOR THE 
ENTIRE AREA INTO MID-WEEK.

SURF HEIGHTS ON KOSRAE REMAIN NEAR ADVISORY LEVELS FOR THE NEXT 12 
TO 24 HOURS BEFORE SUBSIDING GRADUALLY BELOW 8 FT BY SUNDAY EVENING.

&&

.WESTERN MICRONESIA...
A DRY TRADE-WIND PATTERN IS IN STORE FOR PALAU AND YAP THROUGH THE 
PERIOD AS THE NEAR-EQUATORIAL TROUGH REMAINS TO THE SOUTHWEST AND
INACTIVE. A SLOW MOVING CIRCULATION SOUTH OF CHUUK WILL PRODUCE
MORE WET WEATHER OVER THE ISLAND TODAY. AS THE CIRCULATION SLOWLY
DRIFTS WESTWARD SHOWERS AND THUNDERSTORMS WILL SHIFT SOUTHWEST OF
CHUUK BY THIS EVENING. LINGERING CLOUDS ON CHUUK ARE EXPECTED TO
LAST INTO MONDAY NIGHT. A TRADE-WIND REGIME RETURNS TO THE ENTIRE
REGION BY TUESDAY AND LASTS THROUGH MID WEEK.

&&

.MARINE...
MADE A FEW MINOR ADJUSTMENTS TO MARINE GRIDS. LOOKS LIKE A THRESHOLD 
HIGH SURF EVENT FOR TINIAN AND SAIPAN TODAY...AND COMBINED SEAS 
AROUND 10 FEET TODAY AND TONIGHT AND THE BIGGEST NORTH SWELL MOVE 
THROUGH THE MARIANAS. ANOTHER TRADE SURGE COULD RESURRECT THE SMALL 
CRAFT ADVISORY AROUND MID WEEK...WITH WAVE WATCH PROGGING A ROBUST 
NORTH SWELL EVENT NEXT WEEKEND.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY IN EFFECT UNTIL 6 PM CHST THIS AFTERNOON
ALONG NORTH FACING REEFS FOR GUZ003-004.
MARIANAS WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS
UNTIL 6 AM CHST MONDAY FOR PMZ151>154.

&&

$$

MCELROY/CHAN

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