Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Wed, 6 Oct 2010 01:47:11 -0500

397 
FXPQ60 PGUM 060647
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
447 PM CHST WED OCT 6 2010

.SYNOPSIS...SATELLITE IMAGERY AND RADAR SHOW AN EXTENSIVE AREA OF
MID TO UPPER-LEVEL CLOUDINESS COVERING THE MARIANAS THIS
AFTERNOON...PRIMARILY RELATED TO THE POSITIONING OF AN UPPER
TROUGH WEST OF THE ISLANDS. IN ADDITION...INCREASED SHOWER
ACTIVITY ASSOCIATED WITH A WEAK WESTWARD MOVING TRADE-WIND
DISTURBANCE BETWEEN GUAM AND CHUUK IS EXPECTED TO AFFECT THE GUAM
AND ROTA ZONES TONIGHT INTO TOMORROW. LITTLE THUNDERSTORM
ACTIVITY IS SEEN ON THE RADAR BUT THIS MAY CHANGE OVER NIGHT.

&&

.DISCUSSION...KEPT MOST OF THE IMMINENT WEATHER RESTRICTED TO THE
SOUTHERN ZONES AS MODELS ARE UNCLEAR HOW FAR NORTH THE SHOWERS
WILL PUSH. THE WATER VAPOR IMAGERY SHOWS THE EFFECT OF THE UPPER
LEVEL RIDGING OVER THE MARIANAS BY INCREASING THE CLOUD COVER
NORTHWARD OVER THE ISLANDS...HOWEVER THE SHOWER ACTIVITY IN THE
RADAR SEEMS TO BE FOLLOWING WHAT THE NWP MODELS ARE PREDICTING BY
REMAINING PRIMARILY SOUTH OF GUAM. ANOTHER WEATHER MAKER APPEARS
IN THE NOGAPS AND UKMET AND SOMEWHAT WEAKER IN THE ECMWF AND GFS
RUNS TO BE ASSOCIATED WITH THE CONVECTIVE ACTIVITY CURRENTLY
ALONG 160E...JUST SOUTHEAST OF ANOTHER UPPER LEVEL TUTT. THIS
FEATURE IN CONJUNCTION WITH A ITCZ-RELATED
DISTURBANCE...CURRENTLY BETWEEN POHNPEI AND KWAJALEIN...SEEMS
LIKELY TO AFFECT THE MARIANAS BY LATE FRIDAY INTO SUNDAY. WITH
THE UNCERTAINTY IN TIMING AND NORTHWARD PUSH FOR THIS PARTICULAR
FEATURE...I FIGURED IT BEST TO JUST INCREASE THE CLOUDINESS FOR
NOW AND TO ADD THE PHRASE...SLIGHT CHANCE OF
THUNDERSTORMS...UNTIL WE GET A BETTER IDEA WHAT IT WANTS TO DO.

&&

.EASTERN MICRONESIA...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EXTENDED ACROSS MUCH
OF EASTERN MICRONESIA TODAY BUT IS SHOWING GRADUAL SIGNS OF
STRATIFICATION NORTH AND EAST OF KOSRAE AND SOME CLEARING ACROSS
THE MARSHALLS. SHOWERS ARE EXPECTED TO TAPER OVERNIGHT...MOVING
WEST OF POHNPEI WITH ISOLATED SHOWERS REMAINING ACROSS THE
REGION. HOWEVER...ANOTHER LARGE AREA OF SHOWERS IS CROSSING THE
DATELINE AND WILL BRING SCATTERED SHOWERS TO MAJURO TOMORROW
NIGHT. MODELS KEEP MAJURO WET INTO THE WEEKEND BUT INDICATES A
NORTHWARD DRIFT OF THE ITCZ...KEEPING MOST OF THE SHOWERS NORTH
OF KOSRAE AND POHNPEI.

&&

.WESTERN MICRONESIA...
SCATTERED SHOWERS FROM THE EAST ALSO COVERED MUCH OF WESTERN
MICRONESIA FROM PALAU TO CHUUK. CHUUK WILL SEE ISOLATED SHOWERS
OVERNIGHT BEFORE MORE SHOWERS NEAR POHNPEI PASS THROUGH.
SCATTERED SHOWERS WILL REMAIN NEAR KOROR TONIGHT BUT WILL HANG
AROUND YAP THROUGH FRIDAY AS SHOWERS SEEM TO BE FOLLOWING A PATH
BETWEEN YAP AND GUAM.. MOVING INTO THE WEEKEND...THE MODELS TEND
TO BREAK THE CURRENT PATTERN...KILLING THE WINDS ACROSS THE
REGION. GFS HAS A SIMILAR PATTERN EXTENDING TO NEAR KOSRAE. AT
THIS TIME...LIGHT AND VARIABLE WINDS WILL BE IN THE FORECAST
FRIDAY NIGHT FOR YAP AND SATURDAY FOR PALAU.

&&

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

$$

EDSON/M. AYDLETT

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