Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Sat, 25 Dec 2010 13:34:00 -0600

494 
FXPQ60 PGUM 251933
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
533 AM CHST SUN DEC 26 2010

.SYNOPSIS...
SHALLOW TRADE-WIND CLOUDINESS IS SEEN IN IR SATELLITE IMAGERY
UPSTREAM FROM THE FORECAST ZONES TO THE DATE LINE. RADAR SHOWS
ISOLATED SHOWERS IN CONJUNCTION WITH THE CLOUDS. WATER VAPOR
SATELLITE IMAGERY REVEALS IN INDRAFT UPPER-LEVEL ANTICYCLONE
CENTERED JUST EAST OF THE MARIANAS.

&&

.DISCUSSION...
NO CHANGES TO FORECAST REASONING. FORECAST GRIDS REQUIRED ONLY A
FEW MINOR COSMETIC ADJUSTMENTS. MODEL GUIDANCE KEEPS THE
RELATIVELY DRY WEATHER PATTERN IN PLACE THROUGH THE FORECAST
PERIOD. GFS BRINGS A FAIRLY VIGOROUS SHEAR LINE INTO THE CNMI
EARLY NEXT WEEK...BUT THERE IS PLENTY OF TIME TO MONITOR MODEL
SOLUTIONS FOR ANY TRENDS WITH THIS FEATURE.

&&

.MARINE...
TRADE-WIND SWELL HAVE BEEN HOLDING STEADY AT AROUND 5 FEET AT THE
IPAN BUOY DURING THE PAST COUPLE OF DAYS...WITH LITTLE CHANGE IN
HEIGHT EXPECTED THROUGH MONDAY. SURF HEIGHT DECLINES ON WEST AND
NORTH FACING REEFS ARE EXPECTED BY MONDAY AS SECONDARY NORTH-
NORTHWEST SWELL BACK TO NORTH AND DECREASE IN HEIGHT. OVERALL...
MODERATE RIP RISK SHOULD PREVAIL THROUGH AT LEAST MID WEEK.

&&

.EASTERN MICRONESIA...
A WEAK TRADE-WIND DISTURBANCE WILL MOVE ACROSS THE MARSHALL
ISLANDS THRU THIS EVENING AND BRING PERIODS OF SHOWERS. BASED ON
THE RADAR IMAGERY FROM KWAJALEIN...SHOWER COVERAGE NEAR MAJURO
APPEARS TO BE WIDELY SCATTERED. HOWEVER...IR SATELLITE IMAGERY
INDICATES A MORE CONCENTRATED BAND OF SHOWERS LINING UP EAST OF
MAJURO TOWARD THE DATE LINE. THEREFORE...DECIDED TO GIVE
SCATTERED COVERAGE TO MAJURO FOR TODAY WHICH COULD EXTEND INTO
THIS EVENING. THIS DISTURBANCE IS PROGGED BY THE MODELS TO
PROGRESS WESTWARD TO KOSRAE LATER TONIGHT AND EVENTUALLY REACH
POHNPEI EARLY MONDAY MORNING. NARROWNESS OF THIS FEATURE ARGUES
FOR A CONSERVATIVE FORECAST APPROACH FOR THESE TWO LOCATIONS.
FUTURE SHIFTS MAY NEED TO INCREASE SHOWER COVERAGE FOR KOSRAE AND
POHNPEI DURING THIS TIME FRAME IF THIS SYSTEM TRACKS DIRECTLY
TOWARD THEM. ANOTHER SIMILAR DISTURBANCE IS ALREADY QUEUED UP JUST
EAST OF THE DATE LINE. THIS SYSTEM WILL PROBABLY BE THE NEXT
WEATHER MAKER FOR THE REGION NEXT WEEK.

EASTERLY TRADE-WIND SWELLS AND WIND WAVES WILL MAINTAIN HIGH SURF
ON KOSRAE UNTIL MONDAY.

&&

.WESTERN MICRONESIA...
CONVERGENCE ALONG THE LEADING EDGE OF STRONGER TRADES IS GOING TO
TEAM UP WITH AN UPPER-LEVEL TROUGH TO PRODUCE SHOWERS AND POSSIBLE
THUNDERSTORMS OVER CHUUK INTO THIS EVENING. AFTER A PERIOD OF
FAIRER WEATHER ON MONDAY...A SERIES OF TRADE-WIND DISTURBANCES
MIGRATING WESTWARD FROM EASTERN MICRONESIA WILL BRING BACK SHOWERY
CONDITIONS THRU MIDWEEK. A WEAK SURFACE TROUGH WILL FOCUS A FEW
SHOWERS IN THE VICINITY OF YAP THIS MORNING...AND NEAR KOROR
UNTIL THIS EVENING. AFTERWARD...DRIER TRADES FILTERING DOWN FROM
THE MARIANAS SHOULD PROMOTE PLEASANT WEATHER FOR THE EARLY PART OF
NEXT WEEK. BY MIDWEEK...THE CONVERGENT LOW-LEVEL WINDS CURRENTLY
OVER CHUUK WILL BRING MORE UNSETTLED WEATHER TO YAP AND KOROR.

&&

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

$$

MCELROY/CHAN

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