Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Sat, 30 Oct 2010 03:49:28 -0500

914 
FXPQ60 PGUM 300849
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
649 PM CHST SAT OCT 30 2010

.SYNOPSIS...
RADAR...IR IMAGERY AND VISIBLE IMAGERY INDICATE ISOLATED SHOWERS
IN THE MARIANAS MARINE ZONES. WV IMAGERY SHOWS AN UPPER LOW 
CENTERED AT 19N154E APPROACHING THE NORTHERN MARIANAS. 

&&

.DISCUSSION...
THE FORECASTS MAY BE IN A STATE OF TRANSITION THE NEXT FEW DAYS
WITH AN INCREASE OF MOISTURE AND THE APPROACH OF AN UPPER LOW. THE
MODELS STILL INDICATE PARTLY TO MOSTLY CLOUDY SKIES WITH ISOLATED
SHOWERS. MODELS GENERALLY DO NOT HANDLE UPPER-LEVEL SYSTEMS WELL.
THE EXACT POSITIONING AND TIMING OF THE UPPER LOW IS THE FORECAST
PROBLEM THE NEXT TWO DAYS. OPTED TO GO WITH A CONTINUATION OF THE
PREVIOUS FORECAST REASONING WITH THE UPPER LOW JUST MISSING
GUAM...ROTA...TINIAN AND SAIPAN TO THE NORTH...AND THE LONGER
TERM MODEL SOLUTIONS INDICATING LIGHT TO MODERATE EAST WINDS AND
ISOLATED SHOWERS THROUGH TUESDAY.

&&

MARINE...
SURF OBSERVATIONS SHOW THAT THE NORTHWEST SWELL FROM FORMER TYPHOON
CHABA HAS ARRIVED. A HIGH SURF ADVISORY HAS BEEN ISSUED FOR NORTH
AND WEST FACING EXPOSURES OF THE MARIANAS THROUGH SUNDAY. SURF OF
8 TO 10 FEET SATURDAY NIGHT SHOULD DIMINISH BELOW HAZARDOUS LEVELS
SUNDAY NIGHT. MODERATE RISK OF RIP CURRENTS CONTINUES ON EAST
FACING EXPOSURES.

&&

.EASTERN MICRONESIA...
TRADE-WIND TROUGHS ARE COMBINING WITH UPPER-LEVEL DIVERGENCE TO 
FOCUS CONVECTION OVER CHUUK STATE AND ALSO EASTWARD FROM KOSRAE. 
FORECAST PACKAGE PRODUCED BY PREVIOUS SHIFT REQUIRED ONLY MINOR 
ADJUSTMENTS. LULL IN THE WEATHER OVER POHNPEI IS COMING TO AN END AS 
SHOWERS CLOSE IN ONCE AGAIN FROM THE EAST. AGREE IN KEEPING THUNDER 
IN THE FORECAST FOR ALL THREE FORECAST LOCATIONS. UPPER-LEVEL LOWS 
CENTERED JUST SOUTHWEST OF MIDWAY ISLAND AND JUST SOUTH OF MINAMI 
TORI SHIMA ARE PRODUCING A BROAD AREA OF UPPER-LEVEL DIVERGENCE FROM 
CHUUK EASTWARD. MODEL GUIDANCE STILL CALLS FOR SCATTERED SHOWERS TO 
WIND DOWN OVER ALL THREE LOCATIONS BY SUNDAY NIGHT AS THE TRADE-WIND 
CONVERGENCE ZONE LIFTS NORTHWARD.

&&

.WESTERN MICRONESIA...
TRADE-WIND TROUGH IS CURRENTLY TRANSITING CHUUK STATE. INHERITED 
FORECAST CALLS FOR ASSOCIATED SCATTERED SHOWERS AND SLIGHT CHANCE 
THUNDER TO WIND DOWN BY TOMORROW MORNING OVER WENO ISLAND. REMAINDER 
OF FORECAST FOR CHUUK LOOKS DRY AS THE AFOREMENTIONED TRADE-WIND 
CONVERGENCE ZONE OVER EASTERN MICRONESIA LIFTS NORTHWARD. LATEST 
SATELLITE IMAGERY STILL SUPPORTS THIS TIMING FOR CHUUK. TUTT CELL 
NORTH OF KOROR CONTINUES TO SLIDE OFF TO THE WEST. THIS IS ALLOWING 
UPPER-LEVEL DIVERGENCE OVER YAP AND KOROR TO SUBSIDE. HAVE MADE 
SHORT-TERM ADJUSTMENTS AT THESE LOCATIONS TO DROP MENTION OF THUNDER 
AND REDUCE SHOWER COVERAGE TO ISOLATED. LATEST ALTIMETRY AND WAVE 
WATCH TABULAR DATA SHOWS CURRENT HIGH SURF EVENT ON NORTH FACING 
EXPOSURES IS PEAKING AND SHOULD SUBSIDE BY SUNDAY EVENING.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 6 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

DEVITA/MCELROY

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
To unsubscribe from WX-TROPL send e-mail to [email-masked] with
"unsub wx-tropl" in the body of your message. For help with WX-TROPL
write to [email-masked]. For more information on tropical weather products, see the NHC Homepage at http://www.nhc.noaa.gov.