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000
FXPQ60 PGUM 220726
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
526 PM CHST WED MAY 22 2013

.SYNOPSIS...
RADAR AND SATELLITE INDICATE ISOLATED SHOWERS ARE EVIDENT IN OR
JUST EAST OF THE MARIANAS MARINE ZONES. ADDITIONALLY...VISIBLE AND
IR SATELLITE INDICATES A NORTH TO SOUTH 150 MILE WIDE BAND OF
SHOWERS EAST OF THE MARIANAS MARINE ZONES AT ABOUT 152E.

&&

.DISCUSSION...
MODELS ARE IN GENERAL AGREEMENT WITH SATELLITE IMAGERY. MODELS
INDICATE TRADE WIND FLOW OVER THE MARIANAS FORECAST ZONES WITH A
FEW EMBEDDED WEAK TROUGHS THE NEXT SEVERAL DAYS. THE NEXT WEAK
TROUGH DESCRIBED IN THE SYNOPSIS IS EXPECTED OVER THE MARIANAS
THURSDAY GIVING A SHORT PERIOD OF ISOLATED SHOWERS OR AROUND 0.10
OR 0.15 INCHES OF SPOTTY RAIN. LIGHTNING DETECTION PROGRAM ON
AWIPS INDICATED A FEW LIGHTNING HITS ASSOCIATED WITH THIS TROUGH
THIS AFTERNOON...SO ADDED A SLIGHT CHANCE OF THUNDER THURSDAY AND
THURSDAY NIGHT. EXCEPT FOR THE SLIGHTLY WETTER CONDITIONS FROM THE
WEAK TROUGHS...EXPECT GENERALLY DRY CONDITIONS FOR THE MARIANAS
THE NEXT SEVERAL DAYS.

MARINE WEATHER PATTERN LOOKS BENIGN FOR THE MARIANAS WITH 3 TO 5
FOOT COMBINED SEAS FOR THE NEXT SEVERAL DAYS.

&&

.EASTERN MICRONESIA...
TUTT AXIS LIES TO THE NORTH OF ALL OF THE FORECAST POINTS IN THE
VICINITY OF 14N. THIS IS FAR ENOUGH TO THE SOUTH TO PRODUCE SHEARING
FLOW AND SUBSIDENCE TO THE NORTH OF 6N. BASED ON THIS...KEPT DRY
BIAS IN THE FORECAST FOR MAJURO AND POHNPEI. DID KEEP SLIGHT
CHANCE THUNDER IN THE FORECAST FOR POHNPEI THROUGH THURSDAY NIGHT
DUE TO PROXIMITY OF DEEP CONVECTION TO THE SOUTH. TRADE-WIND
CONVECTION HAS BEEN BACK BUILDING TOWARD THE EAST...FAR ENOUGH TO
ENVELOP KOSRAE. MODELS CONFIRM THIS TREND SO HAVE INTRODUCED
SCATTERED SHOWERS TO THE KOSRAE FORECAST FOR TONIGHT THROUGH
THURSDAY NIGHT. OTHERWISE...INCREASED NEAR TERM WIND SPEEDS 5 KNOTS
FOR ALL FORECAST LOCALES BASED ON THE LATEST ASCAT ANALYSIS WHICH
DEPICTS AN UPTICK IN TRADE WINDS FEEDING INTO THE BAND OF TRADE-
WIND CONVECTION BETWEEN 2N AND 6N.

&&

.WESTERN MICRONESIA...
ANIMATED VISIBLE SATELLITE IMAGERY AND THE LATEST ASCAT ANALYSIS
REVEAL THAT A WEAK CIRCULATION HAS FORMED TO THE SOUTHWEST OF CHUUK
NEAR 4N144E. A WEAK TRADE-WIND DISTURBANCE IS DEPARTING TO THE WEST
OF KOROR TOWARD MINDANAO...TAKING THE ATTENDANT CONVECTION WITH IT.
FORECAST PHILOSOPHY FOR ENTIRE REGION REVOLVES AROUND THE FUTURE
TRACK AND EVOLUTION OF THE SYSTEM CENTERED SOUTHWEST OF CHUUK. ECMWF
MODEL QUICKLY LOSES IT OVER THE NEXT 24 HOURS. UKMET HANGS ON TO
THE SYSTEM AND SLOWLY ADVECTS IT TOWARD THE WEST-NORTHWEST. GFS40
SEEMS TO COMPROMISE BETWEEN THE ECMWF AND UKMET AND BRINGS THE
DISTURBANCE OVER YAP AND CHUUK AS A DIFFUSE/STRUNG OUT SYSTEM DURING
FRIDAY AND FRIDAY NIGHT. BASED UPON THIS ELECTED TO COMPROMISE AS
WELL FOR NOW AND BRING MOSTLY CLOUDY SKIES AND SLIGHT CHANCE THUNDER
INTO THE CHUUK AND YAP FORECASTS THROUGH FRIDAY NIGHT. WEATHER
PATTERN STILL LOOKS QUIET FOR KOROR...ALTHOUGH DEEP LAYER WINDS OVER
KOROR MAY BECOME LIGHT ENOUGH TO SUPPORT AFTERNOON ISLAND CONVECTION
BY EARLY NEXT WEEK IF PWAT INCREASES AS MODEL TIME HEIGHT CROSS
SECTIONS SUGGEST.

MARINE WEATHER PATTERN LOOKS BENIGN THROUGH THE FORECAST PERIOD WITH
COMBINED SEAS RANGING FROM ABOUT 3 FEET IN WESTERN MICRONESIA TO
AROUND 5 FEET IN EASTERN MICRONESIA.

&&

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

$$

DEVITA/MCELROY