Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Fri, 15 Feb 2008 02:03:10 -0600

067 
FXPQ60 PGUM 150803
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
603 PM CHST FRI FEB 15 2008

.SYNOPSIS...VISUAL SATELLITE IMAGERY AND THE RADAR THIS AFTERNOON
SHOW A LINE OF WEAK SHOWERS BETWEEN GUAM AND ROTA. THIS
REPRESENTS THE APPROXIMATE EXTENT OF THE SHEAR ZONE. OTHERWISE...
LITTLE WEATHER IS APPARENT IN OUR AREA. TRADE-WINDS REMAIN AT 15
TO 20 KT AS SEEN IN THE QUIKSCAT DATA.

&&

.DISCUSSION...LITTLE CHANGE MADE FROM THE PREVIOUS FORECAST.
EXCEPT FOR A DIRECT HIT BY THE MEANDERING...AND WEAKENING...SHEAR
LINE LITTLE WEATHER IS FORECAST UNTIL NEXT MONDAY OR TUESDAY. WIND
FORECAST FOLLOWED THE GFS40 AS THE UKMET AND ECMWF APPEAR TO BE
ABOUT 5 KTS HIGH. NOGAPS WINDS ARE APPROXIMATELY THE SAME AS THE
GFS UNTIL NEXT WEDNESDAY WHEN THERE IS AN INDICATION OF A NEW
TRADE-WIND SURGE. THIS IS SEEN IN ALL OF THE MODELS BUT THE WIND
INTENSITY REMAINS LIGHTER IN THE GFS THAN IN THE OTHER MODELS.
ONLY A SLIGHT BIAS IN THIS DIRECTION WAS MADE ON THIS RUN AS
THERE IS PLENTY OF TIME TO WAIT FOR AN AGREEMENT WITH THE GFS.

&&

.MARINE...LEFT THE FORECAST AS IS. SMALL CRAFT ADVISORY WILL
LIKELY RUN OUT BY TOMORROW MORNING AS WW3 AND AVAILABLE ALTIMETRY
INDICATE THAT WE ARE BORDERLINE AS IS...PROBABLY AROUND 10 FEET TO
THE NORTH...BUT MORE LIKELY 8 TO 9 FEET IN THE VICINITY OF GUAM
AND ROTA. LIKEWISE...THE HIGH SURF CRITERIA IS LIKELY MORE
CONSISTENTLY MET FOR THE NORTHERN ISLANDS THAN FOR THE SOUTHERN
ISLANDS. LATEST MODELS SUGGEST THAT THE SURF MAY DROP BELOW
HAZARDOUS LEVEL EARLIER ON SUNDAY THAN PREVIOUSLY FORECAST...BUT I
LEFT THIS FOR NOW AS WE HAVE ANOTHER 24 HOURS TO DECIDE WHAT TO DO
ABOUT SUNDAY'S FORECAST.

&&

.EASTERN MICRONESIA...
SATELLITE IMAGERY DISPLAYS AN ELONGATED...BROAD BAND OF CLOUDINESS 
SOUTH OF POHNPEI...KOSRAE AND MAJURO LATE THIS AFTERNOON. 
TRADE-WIND CONVERGENCE SOUTH OF 5N IS GENERATING SCATTERED SHOWERS
AND A FEW THUNDERSTORMS. GFS MODEL DEVELOPS TWO SEPARATE TRADE-
WIND DISTURBANCES OVER MAJURO IN THE NEXT 4 TO 12 HOURS AND OVER
KOSRAE IN THE NEXT 24 HOURS. FORECAST REFLECTS BOTH EVENTS FOR THE
FIRST AND SECOND PERIOD. FRESH...DRY TRADES NORTH OF POHNPEI WILL
KEEP THE ISLAND UNDER FAVORABLE WEATHER OVER THE NEXT SEVERAL
DAYS.

LARGE NNW SWELLS UP TO 6 TO 7 FEET ARE EXPECTED TO ARRIVE ACROSS 
POHNPEI...KOSRAE AND MAJURO. EXPECT POHNPEI AND KOSRAE TO RECEIVE HAZARDOUS
SURF HEIGHTS AT 9 TO 10 FEET MONDAY THROUGH WEDNESDAY.  SURF OVER
MAJURO...HOWEVER...WILL REMAIN BELOW ADVISORY CRITERIA. IN ANY
CASE...LOCAL OFFICES SHOULD CONTINUE TO MONITOR THESE EVENTS CLOSELY
AS THEY MAY IMPACT LOCAL SHORES EARLY NEXT WEEK.

&&

.WESTERN MICRONESIA...
SATELLITE IMAGERY SHOWS A NORTHWEST TO SOUTHEAST ORIENTED TRADE-WIND 
DISTURBANCE LOCATED ABOUT 100 MILES NORTHEAST OF YAP LATE THIS 
AFTERNOON...AND THIS ACTIVITY IS EXPECTED TO REACH YAP AROUND 12 TO 
14Z. GFS...UKMET AND ECMWF KEEP SHOWERS AT A MINIMAL BUT CLOSE 
MONITORING OF THIS EVENT WILL AID FORECAST VERIFICATION OVER YAP. 
RAOB DATA FROM THE MORNING RUN REPORTED ALMOST 2 INCHES OF 
PRECIPITABLE WATER. FOR THE REST OF THE ISLANDS...ANTICIPATE MOSTLY 
PLEASANT CONDITIONS DURING THE FORECAST PERIOD.

LARGE NNW SWELL OF 7 FEET WILL REACH CHUUK BY SATURDAY NIGHT.
KOROR AND YAP MAY OBSERVE NNE SWELLS UP TO 7 FEET BY EARLY NEXT
WEEK. ANTICIPATED SWELLS WILL REQUIRED ADVISORIES FOR ALL ISLANDS.

&&

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

MARIANAS WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM CHST SATURDAY 
     FOR PMZ151>154.

&&

$$

EDSON/BAQUI

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