Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Tue, 21 Sep 2010 15:48:18 -0500

841 
FXPQ60 PGUM 212048
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
545 AM CHST WED SEP 22 2010

.SYNOPSIS...
TROPICAL STORM MALAKAS CONTINUES DEVELOPING AS IT MOVES 
NORTHWESTWARD AWAY FROM THE MARIANAS. CIRRUS CLOUDS ASSOCIATED WITH 
TROPICAL STORM MALAKAS (13W) BLANKET THE MARIANAS. RADAR SHOWS ONLY 
ISOLATED SHOWERS MOVING THROUGH THE MARIANAS WATERS WITH SCATTERED 
SHOWERS WEST AND NORTHWEST OF SAIPAN WATERS.  

&&

.DISCUSSION...
AMSR-E IMAGERY SHOWS THE EXPOSED LOW-LEVEL CIRCULATION CENTER OF 
MALAKAS NEAR 19N143E. FOR FURTHER DETAILS AND UPDATES... REFER TO 
PUBLIC ADVISORIES ISSUED BY WFO GUAM UNDER WMO HEADER WTPQ32 PGUM OR 
JTWC WARNINGS UNDER WMO HEADER WTPN32 PGTW. SATELLITE IMAGERY SHOW 
THE ACTIVE CONVECTION TO THE SOUTHWEST OF THE STORM. EXPECT THIS 
AREA TO REMAIN WEST AND NORTHWEST OF THE MARIANAS. AS THE DAY 
PROGRESSES AND THE TROPICAL STORM MOVES FARTHER NORTHWEST..THE 
CIRRUS CLOUD SHIELD WILL THIN OUT AND GIVE WAY TO PARTLY CLOUDY 
SKIES. WITH LIGHT WINDS PREVAILING..WE MAY SEE SOME INTERIOR SHOWERS 
DEVELOP FROM AFTERNOON HEATING.  

&&

.MARINE...
MAINTAINED THE SWELL GRIDS INHERITED FROM THE PREVIOUS SHIFT WHICH 
SHOW THE NORTHWEST SWELL RESULTING FROM TYPHOON FANAPI WHEN IT WAS 
NEAR TAIWAN. YESTERDAYS OBS PICKED UP ON THIS SWELL BUT IT IS 
EXPECTED TO GRADUALLY DIMINISH BY THURSDAY.

&&
.EASTERN MICRONESIA...
SATELLITE IMAGERY SHOWS A LINE OF DEEP CONVECTION AHEAD OF STRONGER 
EASTERLY TRADE WINDS APPROACHING THE MARSHALLS. WINDS WILL BE SLOW 
TO INCREASE AT MAJURO SINCE A WSW-ENE ORIENTED TROUGH JUST CROSSING 
THE DATE LINE WILL KEEP WIND SPEEDS SUPPRESSED THROUGH THURSDAY. THE 
TROUGH WILL ALSO KEEP SCATTERED SHOWERS AROUND MAJURO THROUGH 
THURSDAY. FOR KOSRAE AND POHNPEI...MOST OF THE SHOWERS IN THE AREA 
WILL REMAIN TO THE NORTH THROUGH THE WEEKEND. GFS SEEMS TO BRING IN 
SOUTHEAST WINDS TO POHNPEI A BIT PREMATURELY COMPARED TO THE LATEST 
ASCAT ANALYSIS SO HAVE KEPT WINDS FROM THE EAST. ALTIMETRY DATA 
SHOWS INCREASING SEAS NORTHEAST OF MAJURO IN ASSOCIATING WITH 
INCREASED TRADE WINDS...BUT THE WAVEWATCH MODEL FORECAST OF 6 TO 7 
FT FOR THE NEXT 3 DAYS STILL LOOKS GOOD FOR MAJURO.

.WESTERN MICRONESIA...
LOW-LEVEL CONVERGENCE CONTINUES TO GENERATE SCATTERED SHOWERS NEAR 
CHUUK...BUT MODELS GUIDANCE AND DECREASED CONVECTION TO THE EAST 
SUGGEST THAT SHOWERS WILL BECOME ISOLATED BY TONIGHT. AFTERWARDS... 
DRY CONDITIONS AFFECTING MUCH OF EASTERN MICRONESIA WILL SPREAD TO 
CHUUK. SURFACE RIDGING FARTHER TO THE WEST...COURTESY OF TROPICAL 
STORM MALAKAS FAR TO THE NORTH...WILL KEEP YAP AND PALAU FAIRLY DRY 
THE NEXT COUPLE OF DAYS. HOWEVER...SHOWERS SOUTHEAST OF YAP WILL 
EVENTUALLY ARRIVE A PALAU BY THURSDAY NIGHT. MODELS KEEP YAP NORTH 
OF MOST ACTIVITY WHILE PALAU CAN EXPECT TO SEE SCATTERED SHOWERS 
THURSDAY NIGHT AND FRIDAY. GFS BRINGS NORTHEAST WINDS TO YAP AND 
PALAU LATER TODAY AND FOR THE REST OF THE WEEK...BUT ASCAT DATA DOES 
NOT CURRENTLY SUPPORT THAT...NOR DO ECMWF AND UKMET AGREE...SO HAVE 
LEFT WIND FORECASTS GENERALLY UNTOUCHED FROM PREVIOUS FORECAST.

&&

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

$$

MILLER/W. AYDLETT

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