Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Sat, 25 Dec 2010 02:15:48 -0600

671 
FXPQ60 PGUM 250815
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
615 PM CHST SAT DEC 25 2010

.SYNOPSIS...
RADAR AND SATELLITE SHOWS ONLY A FEW SMALL SHOWERS OVER THE
MARIANAS THIS AFTERNOON. A SHEAR LINE IS DRAPED ACROSS THE FAR
NORTHERN MARIANAS ISLANDS.

&&

.DISCUSSION...
MODELS KEEP BASIC EAST TRADE-WIND FLOW ACROSS THE ISLANDS THROUGH
AT LEAST MONDAY NIGHT. WIND SPEEDS MAY INCREASE A BIT ON SUNDAY
AND REMAIN THAT WAY UNTIL ABOUT TUESDAY BEFORE DECREASING
SLIGHTLY.

RADAR AND SATELLITE IMAGERY SHOW A SMALL BUBBLE OF DRY WEATHER
MOVING ACROSS THE LOCAL AREA. WILL CHANGE FORECAST TO A SLIGHT
CHANCE OF SHOWERS TONIGHT AS A RESULT.

ISOLATED SHOWERS EXPECTED THROUGH REMAINDER OF THE FORECAST.
SATELLITE IMAGERY THIS AFTERNOON SHOWS AN AREA OF CLOUDS BETWEEN
150E AND 160E. GFS...ECMWF AND UKMET BRING THIS AREA OF CLOUDS
ACROSS THE LOCAL AREA MONDAY. MODELS KEEP MOISTURE SHALLOW SO WILL
KEEP SKIES PARTLY CLOUDY AND SHOWERS ISOLATED. A SHEAR LINE WILL
MOVE SOUTHWARD ACROSS THE NORTHWEST PACIFIC...BUT WILL MAKE IT
ONLY DOWN TO 18N BY WEDNESDAY. CONVERGENCE SOUTH OF THE SHEAR LINE
WILL INCREASE MOISTURE A LITTLE BY THE SECOND HALF OF NEXT WEEK.
THIS MAY TRANSLATE INTO A SLIGHTLY BETTER CHANCE OF SHOWERS BUT
COVERAGE WILL PROBABLY REMAIN ISOLATED.

&&

.MARINE...
EAST TRADE-WIND SWELL AND A NORTH-NORTHWEST SWELL WILL PERSIST
THROUGH THE FORECAST. THE NORTH-NORTHWEST SWELL WILL DECREASE
SLIGHTLY ON MONDAY BUT WILL BE RE-ENFORCED BY ANOTHER SET OF
SWELLS WEDNESDAY NIGHT.

&&

.EASTERN MICRONESIA...
SURFACE RIDGING HAS SHIFTED EAST OF THE DATE LINE...ALLOWING
MODERATE TO FRESH TRADE WINDS TO FLOW THROUGH EASTERN MICRONESIA.
BASED ON SATELLITE IMAGERY...THE LEADING EDGE OF THE TRADES IS
JUST WEST OF POHNPEI IN THE FORM OF A SURFACE TROUGH. THIS FEATURE
WILL CAUSE SOME PASSING SHOWERS FOR POHNPEI INTO THIS EVENING.
FARTHER EAST...A TRADE DISTURBANCE IS CROSSING THE DATE LINE
BETWEEN 5N AND 13N. EXPECT THIS DISTURBANCE TO BRING WET WEATHER
FOR MAJURO BY MIDNIGHT TONIGHT...KOSRAE ON SUNDAY AND EVENTUALLY
OVER POHNPEI EARLY NEXT WEEK. CONVERGENT WINDS TRAILING BEHIND THE
DISTURBANCE WILL LIKELY PROLONG SHOWERY CONDITIONS FOR THE ENTIRE
REGION THRU MIDWEEK.

HIGH SURF ADV REMAINS IN EFFECT FOR KOSRAE. ELSEWHERE...NE SWELL
IS GENERATING SURF JUST BELOW ADVISORY CRITERIA ACROSS CHUUK AND
POHNPEI. THIS SURF WILL TEMPORARILY SUBSIDE THIS EVENING...BUT
THEN EASTERLY TRADE-WIND SWELLS AND WIND WAVES WILL KEEP BUILDING
WESTWARD FROM THE MARSHALLS AND REACH CHUUK BY SUNDAY EVENING.

&&

.WESTERN MICRONESIA...
THE AFOREMENTIONED SURFACE TROUGH JUST WEST OF POHNPEI WILL CAUSE
SHALLOW SHOWERS SUNDAY FOR CHUUK. DEEPER MOISTURE WILL BEGIN TO
SPREAD FROM THE EAST ABOUT MIDWEEK...AGAIN INCREASING THE CHANCE
FOR SHOWERS. MOIST SOUTHEAST FLOW ALOFT WILL CONTINUE TO ENHANCE
SHOWER ACTIVITY TRIGGERED BY CONVERGING SURFACE WINDS NEAR KOROR
AND YAP THROUGH SUNDAY. BY MIDDLE OF NEXT WEEK...THE ENVIRONMENT
WILL AGAIN BECOME FAVORABLE FOR SHOWERS AS BOTH TRADE-WIND
CONVERGENCE AND MOISTURE INCREASES.

&&

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

$$

ZIOBRO/DEVITA

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