Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Sat, 05 Jan 2008 01:45:51 -0600

685 
FXPQ60 PGUM 050745
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
545 PM CHST SAT JAN 5 2008

.SYNOPSIS...
VISIBLE SATELLITE IMAGERY SHOWS SHEAR LINE NEAR ANATAHAN...CLOSE TO 
WHERE THE GFS PROGGED IT SEVERAL DAYS AGO. SCATTERED SHOWERS AND 
MOSTLY CLOUDY SKIES WERE PRESENTLY CONFINED TO THE NORTH OF THE 
SHEAR LINE. AN INVERTED SURFACE TROUGH EXTENDS NORTHEASTWARD FROM 
POHNPEI STATE TO SOUTH OF WAKE ISLAND. VORTICITY CENTERS WERE 
RESOLVABLE SOUTHEAST OF CHUUK NEAR 5N154E AND NORTHWEST OF 
KWAJALEIN NEAR 11N163E.

&&

.DISCUSSION...
PRIMARY FORECAST CONCERN REMAINS THE POTENTIAL FOR HIGH SURF. SEE 
MARINE DISCUSSION SECTION FOR MORE DETAILS.

ONLY MINOR ADJUSTMENTS TO THE WEATHER FORECAST GRIDS NEEDED. REDUCED 
CLOUDS FOR TINIAN AND SAIPAN BASED UPON RECENT VISIBLE SATELLITE 
IMAGERY. AT PRESENT...LOOKS LIKE MARIANAS WILL BE POSITIONED TOO FAR 
SOUTH TO BE SIGNIFICANTLY AFFECTED BY THE SHEAR LINE...AND TOO FAR 
NORTH TO BE AFFECTED BY THE INVERTED TROUGH OVER EASTERN MICRONESIA. 
MODELS SUGGEST CONVECTION ASSOCIATED WITH THIS TROUGH WILL BE 
STEERED TO THE SOUTH OF GUAM BY STRONG HIGH PRESSURE. LOOKS LIKE 
ISOLATED SHOWERS AND PARTLY CLOUDY SKIES WILL PREVAIL THROUGH DAY 7.

&&

.EASTERN MICRONESIA...
FAIR WEATHER WILL PREVAIL ACROSS KOSRAE AND MAJURO TONIGHT THROUGH 
SUNDAY NIGHT. AN AREA OF SHOWERS INDUCED BY TRADE-WIND CONVERGENCE 
WILL BRING SCATTERED SHOWERS TO MAJURO MONDAY THROUGH TUESDAY.
KOSRAE WEATHER WILL REMAIN FAIR THROUGH THURSDAY.

A TROUGH OF LOW PRESSURE IS LOCATED BETWEEN CHUUK AND POHNPEI 
TONIGHT. SCATTERED SHOWERS ASSOCIATED WITH THE TROUGH WILL
LINGER ACROSS POHNPEI UNTIL MIDNIGHT TONIGHT. FAIR WEATHER WILL 
PREVAIL ACROSS POHNPEI UNTIL THURSDAY.
 
LATEST COMPUTER MODEL SUGGESTS HIGH SURF ADVISORY WILL CONTINUE 
UNTIL SUNDAY MORNING FOR MAJURO...AND INTO MONDAY FOR KOSRAE. 

&&

.WESTERN MICRONESIA...
THE TROUGH OF LOW PRESSURE THAT IS LOCATED BETWEEN CHUUK AND POHNPEI 
WILL BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO CHUUK 
TONIGHT. SCATTERED SHOWERS GENERATED FROM TRADE-WIND CONVERGENCE IN 
THE WAKE OF THE TROUGH WILL REMAIN ACROSS CHUUK THROUGH SUNDAY NIGHT.

SCATTERED SHOWERS GENERATED BY THE NEAR-EQUATORIAL TROUGH WILL
LINGER ACROSS THE REPUBLIC OF PALAU THIS EVENING...WITH ISOLATED
SHOWERS PREVAILING AFTER MIDNIGHT TONIGHT. FAIR WEATHER WILL
CONTINUE ACROSS PALAU THROUGH THURSDAY. NO MAJOR WEATHER SYSTEMS
ARE FORECAST TO AFFECT YAP THROUGH THE FORECAST PERIOD.

COMPUTER GUIDANCE SUGGESTED THAT SURF HEIGHTS HAD DECREASED BELOW 
HIGH SURF ADVISORY CRITERIA FOR YAP AND PALAU. FOR THIS REASON THE 
HIGH SURF ADVISORY WAS DISCONTINUED FOR PALAU AND YAP.

&&

.MARINE...
HAVE REISSUED HIGH SURF ADVISORY FOR THE OVERNIGHT PERIOD TONIGHT 
BASED PRIMARILY ON AN AFTERNOON SURF OBSERVATION CALLED IN FROM 
RITIDIAN POINT. MADE ADJUSTMENTS TO THE MARINE SWELL GRIDS TO 
REFLECT THIS. BELIEVE SURF HAS PEAKED BASED ON WAVE WATCH TABULAR 
DATA AND WEAKENED UPSTREAM FETCH OBSERVED IN THE LATEST QUIKSCAT 
IMAGERY. KEPT COMBINED SEAS AT 9 FEET BASED ON PREVAILING SEAS 
BETWEEN 6 AND 7 FEET AT THE IPAN BUOY.

&&

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

MARIANAS WATERS...NONE.
&&

$$

MCELROY/ZIOBRO

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