Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Fri, 18 Jan 2008 01:57:30 -0600

024 
FXPQ60 PGUM 180757
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
557 PM CHST FRI JAN 18 2008

.SYNOPSIS...
TRADE WINDS CONTINUE TO DOMINATE THE MARIANAS AND MICRONESIA IN
RESPONSE TO THE ON-GOING MATURE MODERATE LA NINA. THIS WILL KEEP
THE MARIANAS IN RELATIVELY GOOD WEATHER...BUT WITH OCCASIONAL
SHORT EPISODES OF TRADE WIND DISTURBANCES AND AN OCCASIONAL SHEAR
LINE PASSAGE. ONE OF THOSE SHEAR LINES IS EXPECTED TO MOVE INTO
THE MARIANAS BY SUNDAY NIGHT. RADAR IS STILL DOWN.

&&

.DISCUSSION...
THE CURRENT GFS RUN IS CONSISTENT WITH THE LAST RUN...SO ONLY
SMALL CHANGES WERE MADE TO THE GRIDS. GFS AND ECMWF DO INDICATE
THE ARRIVAL OF A SHEAR LINE LATE SUNDAY NIGHT FOR SAIPAN AND
MONDAY FOR GUAM. SPLIT THE GRIDS FOR SHEAR LINE TIMING...DURATION
AT GUAM AND SAIPAN AND FOR SURF. GFS INDICATES A LATER ARRIVAL AND
A SHORTER DURATION FOR GUAM. CURRENTLY GFS RAINFALL PREDICTIONS
ARE FOR LESS THAN 0.10 INCHES FOR GUAM AND AROUND 0.25 INCHES FOR
SAIPAN FOR EACH 6 HOUR PERIOD. UKMET INDICATES LESS RAINFALL THAN
GFS. TRADE WINDS ARE EXPECTED TO INCREASE WITH THE ARRIVAL OF THE
SHEAR LINE.

&&

.EASTERN MICRONESIA...
A WEAK WAVE IS TRAVELING THROUGH KOSRAE AND POHNPEI WITH SCATTERED 
SHOWERS TONIGHT INTO SATURDAY EVENING. FRESH TRADES WILL STABILIZE 
THE ATMOSPHERE FOR THE SECOND HALF OF THE WEEKEND. A TRADE-WIND 
DISTURBANCE IS TAKING SHAPE SOUTH AND SOUTHEAST OF 
MAJURO...SPREADING MID TO HIGH-LEVEL CLOUDS OVER THE SOUTHERN 
MARSHALL ISLANDS. SHOWERS ASSOCIATED WITH THIS SYSTEM WILL WET THE 
ISLANDS SUNDAY INTO SUNDAY NIGHT. KOSRAE AND POHNPEI WILL BE THE 
NEXT DESTINATIONS FOR THIS SYSTEM EARLY NEXT WEEK.

HIGH SURF ADVISORIES CONTINUE UNTIL TONIGHT FOR MAJURO AND 
THROUGH THE WEEKEND FOR KOSRAE. A SPECIAL WEATHER STATEMENT FOR COASTAL
INUNDATION EARLY NEXT WEEK WAS ISSUED FOR POHNPEI STATE.

&&

.WESTERN MICRONESIA...
CLOUDS ARE THICKENING OVER CHUUK THIS EVENING AND SHOWERS WILL 
ARRIVE LATER THIS EVENING INTO SATURDAY NIGHT AS SURFACE CONVERGENCE 
INCREASES. DIFLUENT FLOW AT THE UPPER LEVEL MIGHT HELP TO PRODUCE A 
FEW THUNDERSTORMS AS WELL. FAIR WEATHER PATTERN WILL THEN SPREAD 
FROM THE EAST TO CHUUK BY SUNDAY NIGHT. IN RESPONSE TO A TROUGH OF 
LOW PRESSURE DEVELOPING NORTHWEST OF PALAU...LOW-LEVEL CONVERGENCE 
NORTH THE NEAR-EQUATORIAL TROUGH AXIS HAS DECREASED SIGNIFICANTLY 
TODAY. THIS HAS PREVENTED WIDESPREAD CONVECTION TO REFORM OVER 
PALAU. HOWEVER DIURNAL INSTABILITY WILL SPIN UP SOME SHOWERS AND A 
SLIGHT CHANCE OF THUNDER TONIGHT INTO SATURDAY MORNING. THIS TROUGH 
IS EXPECTED TO REMAIN INACTIVE UNTIL MIDWEEK. TYPICAL TRADE-WIND 
REGIME WILL BE IN CONTROL OF YAP THROUGH THE PERIOD.

A SPECIAL WEATHER STATEMENT FOR COASTAL INUNDATION EARLY NEXT WEEK WAS
ISSUED FOR CHUUK STATE.

&&

.MARINE...
THE CURRENT NORTH SWELL WILL LIKELY BE REINFORCED ON
SUNDAY...WHICH SHOULD GENERATE HIGH SURF ON NORTHERN
EXPOSURES. WW3 SUPPORTS THIS AND INDICATED A LONG PERIOD OF 13-16
SECONDS. THIS WILL OCCUR DURING HIGH ASTRONOMICAL TIDES...AND SOME
COASTAL INUNDATION MAY OCCUR ON THE NORTH EXPOSURES OF THE
ISLANDS. A HIGH SURF ADVISORY WILL LIKELY BE NEEDED BY SATURDAY
AFTERNOON. RIP CURRENT RISK WILL ALSO LIKELY RISE TO HIGH ON
NORTHERN EXPOSURES.

&&

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

$$

GUARD/CHAN

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