Area Forecast Discussion
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FXPQ60 PGUM 270755 AAA
AFDPQ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TIYAN GU
555 PM CHST SAT DEC 27 2014

ADDED MICRONESIAN DISCUSSION

.MARIANAS SYNOPSIS...EAST TRADE-WINDS AND ISOLATED SHOWERS
PREVAILED ACROSS THE MARIANAS THIS AFTERNOON.

&&

.DISCUSSION...
A WEAK TRADE-WIND DISTURBANCE COULD BE SEEN ON SATELLITE IMAGERY TO
THE EAST OF THE MARIANAS. PROJECTING THIS AREA WEST SHOWS IT SHOULD
START TO PUSH ACROSS THE MARIANAS BETWEEN 9 AND 10Z TONIGHT.
PROJECTING THE MOTION OF THE BACK EDGE OF THE DISTURBANCE KEEPS
CLOUDS ACROSS THE LOCAL AREA THROUGH SUNDAY MORNING. COMPUTER MODELS
DO SHOW THIS FEATURE. THE DISTURBANCE SHOULD BRING A FEW CLOUDS TO
THE MARIANAS BUT EXPECT SHOWER COVERAGE TO REMAIN ISOLATED.

MODELS SHOW A SIMILAR DISTURBANCE PASSING ACROSS THE MARIANAS
TUESDAY NIGHT. DID NOT ADD TO THIS TO FORECAST YET. GFS AND GFS
ENSEMBLE HAVE THE DISTURBANCE... ECMWF DOES NOT. WILL WAIT FOR
BETTER MODEL AGREEMENT BEFORE ADDING TO FORECAST. IF IT DID OCCUR
IT WOULD PROBABLY RESULT IN SIMILAR WEATHER TO THE DISTURBANCE
EXPECTED TONIGHT.

MODELS KEEP THE WEATHER RELATIVELY QUIET THROUGH THE FORECAST WITH
EAST WINDS BETWEEN 10 TO 20 MPH AND ONLY ISOLATED SHOWERS AT MOST.

&&

.MARINE...
AN EAST TRADE-WIND SWELL AND A NORTH SWELL WILL PERSIST THROUGH
THE FORECAST. BUOY DATA INDICATE SEAS NEAR GUAM AND SAIPAN AROUND
8 TO 9 FEET. FEEL SEAS HAVE DECREASED ENOUGH TO ALLOW THE SMALL
CRAFT ADVISORY TO BE CANCELLED. LITTLE CHANGE IS EXPECTED THE
NEXT FEW DAYS.

&&

.EASTERN MICRONESIA...
LATEST SOUNDING FROM WSO CHUUK REVEALS DRIER AIR BETWEEN 750 AND 300
MB. THIS AIR MASS ALONG WITH FRESH TRADE WINDS WILL DOMINATE CHUUK
AND POHNPEI FOR THE NEXT COUPLE OF DAYS...AND KOSRAE THRU TONIGHT. A
TRADE-WIND DISTURBANCE WILL SLOWLY SLIDE WESTWARD PASSING SOUTH OF
ALL THREE LOCATIONS IN THE NEXT FEW DAYS. EVEN THOUGH THE STRONGEST
CONVERGENCE IS EXPECTED TO STAY SOUTH OF 5N...IT COULD STILL BE
CLOSE ENOUGH TO TRIGGER A FEW SHOWERS NEAR CHUUK AND POHNPEI FROM
MONDAY TO TUESDAY AND NEAR KOSRAE SUNDAY NIGHT AND MONDAY. WATER
VAPOR SATELLITE LOOP THIS EVENING INDICATES STRONG SUBSIDENCE ALOFT
OVER THE MARSHALL ISLANDS. THIS WILL ALSO WORK WITH FRESH TRADES TO
SUPPORT FAIR WEATHER OVER MAJURO THRU MONDAY NIGHT. BASED ON THE
ASCAT IMAGERY...A BETTER-ORGANIZED TRADE DISTURBANCE IS UPSTREAM
EAST OF THE DATE LINE AT 168W. THIS SYSTEM WILL INCREASE THE CHANCE
OF SHOWERS FOR MAJURO AND KOSRAE NEAR MIDWEEK...AND POSSIBLY NEAR
POHNPEI AND CHUUK AFTER MIDWEEK.

TRADE-WIND SWELL HAS DECLINED FURTHER AND ALLOWED SURF ACROSS THE
MARSHALL ISLANDS TO DROP BELOW ADVISORY LEVELS THIS EVENING.
HOWEVER...IT WILL REMAIN HIGH ENOUGH TO MAINTAIN HAZARDOUS SURF ON
KOSRAE THRU THE FIRST HALF OF NEXT WEEK. COUPLING WITH PERSISTENT
LARGE WIND WAVES...SEAS WILL STAY HAZARDOUS FOR SMALL CRAFT FROM
CHUUK STATE EASTWARD TO THE MARSHALL ISLANDS OVER THE NEXT SEVERAL
DAYS.

&&

.WESTERN MICRONESIA...
A TROPICAL DISTURBANCE IS GRADUALLY PULLING WESTWARD AWAY FROM
PALAU. MODEST CONVERGING SOUTHEAST WINDS FLOWING TOWARD THE
DISTURBANCE WILL KEEP A FEW THUNDERSTORMS FOR KOROR UNTIL MONDAY
AFTERNOON...AND NEAR YAP THRU TONIGHT. AFTERWARD...A BROAD SURFACE
RIDGE MOVING WESTWARD FROM NEAR CHUUK IS GOING TO BRING PLEASANT
CONDITIONS TO YAP ON SUNDAY AND KOROR BY MONDAY EVENING. BY MIDWEEK
NEXT WEEK...WEAK DISTURBANCES EMBEDDED WITHIN NORTHEASTERLY TRADES
WILL BRING BACK A SLIGHTLY WETTER PATTERN FOR BOTH PLACES.

&&

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

$$

ZIOBRO/CHAN








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