Area Forecast Discussion
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FXPQ60 PGUM 171849
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
449 AM CHST THU SEP 18 2014

.MARIANAS SYNOPSIS...
RADAR SHOWS PATCHY AREAS OF LIGHT RAIN ACROSS THE COVERAGE AREA.
SATELLITE INDICATES MAINLY MID-LEVEL CLOUDS OVER THE LOCAL REGION
WITH A FEW AREAS OF DEEPER CONVECTION EAST OF GUAM TOWARD 150E.
VAD GRADIENT WINDS ARE LIGHT AND VARIABLE. BUOYS SHOW COMBINED
SEAS OF 3 TO 4 FEET WITH DIRECTIONS FROM SOUTHWEST AND RANGING
FROM NORTHEAST TO SOUTH.

&&

.DISCUSSION...
ONLY MINOR CHANGES WERE MADE TO THE FORECAST AT THIS TIME. WEAK HIGH
PRESSURE HAS MOVED IN OVER THE LOCAL AREA TODAY. THE AIRMASS REMAINS
RELATIVELY MOIST AND SKIES ARE CLOUDY ACROSS THE REGION. MOST MODELS
INDICATE A SLIGHTLY DRIER FLOW OF NORTHEAST WINDS WILL DEVELOP TODAY
AND FRIDAY. BUT...OUR WEATHER WILL LIKELY BECOME MORE UNSTABLE AGAIN
BY NEXT WEEK WHEN MODELS INDICATE THAT ANOTHER MONSOON TROUGH COULD
DEVELOP ACROSS THE MARIANA ISLANDS.

&&

.MARINE...
MIXED SEA CONDITIONS WILL PERSIST NEXT FEW DAYS WITH MODERATE RIP
CURRENT RISK ALONG SOME OF THE REEFS AT LEAST. MINOR ADJUSTMENTS
WERE MADE TO WAVE GRIDS BASED ON WW3 MODEL DATA AND REFRESHED WIND
GRIDS WITH LATEST GFS DATA.

&&

.EASTERN MICRONESIA...
A WEAK CIRCULATION LOCATED TO THE NORTHWEST OF MAJURO AND AN
ASSOCIATED BROAD TROUGH CONTINUE TO PRODUCE ISOLATED SHOWERS OVER
THE MARSHALL ISLANDS THIS MORNING. SHOWERS ARE EXPECTED TO REMAIN
ISOLATED WITHIN AN OVERALL UNSTABLE PATTERN THROUGH THE NEXT COUPLE
OF DAYS. THE TROUGH WILL DRIFT WESTWARD...AFFECTING KOSRAE AND
POHNPEI FRIDAY. THE TROUGH WILL BE FAIRLY BENIGN WHEN IT REACHES
POHNPEI AND KOSRAE...WITH ONLY MOSTLY CLOUDY SKIES AND ISOLATED
CONVECTION. FRIDAY...MODELS CONTINUE TO INDICATE A MONSOON-LIKE
PATTERN NEAR 10N. THIS WILL USHER IN A MORE MOIST AND UNSTABLE
PATTERN FOR THE WEEKEND INTO THE BEGINNING OF NEXT WEEK THOUGH THE
HEAVIEST ACTIVITY LOOKS TO REMAIN NORTH OF 10N.

&&

.WESTERN MICRONESIA...
A FAIRLY BENIGN PATTERN IS IN PLACE OVER YAP AND KOROR AS A HIGH
PRESSURE RIDGE BUILDS IN BEHIND NEWLY FORMED TROPICAL DEPRESSION
16W. THE RIDGE IS CURRENTLY LOCATED JUST EAST OF YAP AND EXTENDS
NORTHWARD FROM NEAR THE EQUATOR ACROSS GUAM AND THE CNMI. A SMALL
BAND OF CONVERGENCE BETWEEN THE RIDGE AND TD 16W WILL BRING A SLIGHT
CHANCE OF THUNDERSTORMS TO YAP TODAY. AS THE RIDGE CONTINUES TO
DRIFT WESTWARD...MORE STABLE CONDITIONS WILL PUSH IN TO YAP AND
REMAIN OVER YAP AND KOROR THROUGH EARLY NEXT WEEK.

LOW-LEVEL CONVERGENCE AHEAD OF A LARGE BUT WEAK TROUGH IS
TRIGGERING ISOLATED SHOWERS AND THUNDERSTORMS OVER CHUUK STATE.
THESE SHOWERS WILL TAPER OFF LATE TONIGHT OR EARLY FRIDAY MORNING AS
THE TROUGH DRIFTS WESTWARD AND WEAKENS OVER THE NEXT 24 HOURS. EARLY
IN THE WEEKEND...MODELS INDICATE THAT THE MONSOON-LIKE PATTERN
DEVELOPING OVER EASTERN MICRONESIA NEAR 10N WILL EXTEND WESTWARD
OVER CHUUK DURING THE WEEKEND. LATEST MODEL RUN SHOWS MOST OF THE
CONVECTION ASSOCIATED WITH THIS PATTERN WILL REMAIN NORTH OF CHUUK.
WILL KEEP AN EYE ON THE SITUATION FOR POSSIBLE INCREASE IN MOISTURE
OVER THE STATE LATE IN THE WEEKEND OR EARLY NEXT WEEK.

&&

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

$$

SIMPSON/KLEESCHULTE





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