Area Forecast Discussion
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000
FXPQ60 PGUM 250535
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
335 PM CHST MON MAY 25 2015

.SYNOPSIS...
ONLY A FEW SHOWERS ARE SEEN THIS AFTERNOON WELL SOUTHEAST OF GUAM.
VAD WIND PROFILE SHOWS GENTLE SOUTHEAST WINDS...SLOWLY SHIFTING
TOWARDS THE EAST. A WEAK MONSOON TROUGH ALONG 10N STRETCHES
EASTWARD TO A DISTURBANCE NORTH OF POHNPEI. VIS SATELLITE IMAGERY
SHOWS SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS NEAR THIS
DISTURBANCE.

&&

.DISCUSSION...
THE DISTURBANCE NORTH OF POHNPEI WILL SLOWLY TRACK WEST THE NEXT
COUPLE DAYS. MODELS KEEP THIS DISTURBANCE WEAK...BRINGING MAINLY
AN INCREASE IN CLOUDS AND A BETTER CHANCE OF SHOWERS MID AND LATE
WEEK. WINDS WILL BECOME LIGHT AND VARIABLE THURSDAY AND FRIDAY.
COMBINED SEAS WILL DIMINISH ANOTHER FOOT BY FRIDAY. WILL HAVE TO
KEEP A CLOSE WATCH FOR AFTERNOON ISLAND CONVECTION LATER THIS
WEEK DUE TO THE LIGHT WINDS EXPECTED OVER THE MARIANAS.

&&

.CLIMATE...
LATEST ENSO DIAGNOSTIC UPDATE FROM CLIMATE PREDICTION CENTER
CONFIRMS THAT A WEAK EL NINO CONTINUES. THE MARIANAS HAVE HAD A
WETTER THAN NORMAL DRY SEASON...MICRONESIA IS HAVING A RATHER BUSY
TROPICAL CYCLONE SEASON SO FAR AND PALAU HAS BEEN DRY. PALAU HAS
RECEIVED ABOUT 50 PERCENT OF ITS NORMAL MONTHLY RAINFALL SO
FAR...AND 58 PERCENT ITS NORMAL RAINFALL FOR THE YEAR. IF THE
DEFICIT GROWS MUCH LARGER WE MAY NEED TO START ISSUING DROUGHT
STATEMENTS. THERE APPEARS TO BE LITTLE RELIEF IN THE NEAR-TERM.
THE GFS40 PREDICTS LESS THAN A QUARTER OF AN INCH THE NEXT 10 DAYS
WHILE THE ECMWF-HIRES PREDICTS ABOUT AN INCH. THE LATEST
FORECASTS FROM THE CLIMATE PREDICTION CENTER ARE FOR AN 80 PERCENT
CHANCE THAT THIS EL NINO CONTINUES THROUGH THE END OF THE YEAR.
THE MODEL PLUMES INDICATE IT COULD GROW FROM WEAK TO MODERATE OR
EVEN STRONG IN THAT TIME. THE ECMWF ENSEMBLE PLUME EVEN HINTS AT A
CHANCE THIS COULD BE AN EXTREME TO RECORD EVENT. THIS IS
DEFINITELY A SITUATION TO MONITOR CLOSELY.

&&

.EASTERN MICRONESIA...
VISIBLE SATELLITE IMAGERY SHOWS INCREASING CLOUD COVER AND SHOWERS
EAST AND SOUTHEAST OF THE MARSHALL ISLANDS IN ASSOCIATION WITH TRADE-
WIND CONVERGENCE. MODELS SHOW THE MAIN CONVERGENCE LINE MAINTAINING
AN APPRECIABLE AMOUNT OF CONVECTION JUST NORTH OF MAJURO THROUGH
TUESDAY NIGHT SO OPTED FOR AT LEAST KEEPING MOSTLY CLOUDY WORDING
THROUGH THE TIME PERIOD. IN THE LONG TERM...LIGHT TO GENTLE E-NE
FLOW AND DRY CONDITIONS WILL PREVAIL FROM MIDWEEK TO THE WEEKEND. A
DRY PATTERN WILL PERSIST OVER KOSRAE THROUGH THE WEEKEND. NO MAJOR
WEATHER FEATURES WILL IMPACT THE STATE OVER THE NEXT SEVERAL DAYS.
SATELLITE-DERIVED LIGHTNING DATA REVEALED AT LEAST A FEW STRIKES
NEAR THE POHNPEI AIRPORT THIS AFTERNOON. LIGHT WINDS WILL POSE AN
AFTERNOON THUNDERSTORM THREAT TO POHNPEI OVER THE NEXT COUPLE OF
DAYS. OTHERWISE...MAINLY DRY CONDITIONS WILL PERSIST ACROSS POHNPEI
AND KOSRAE STATES FOR THE NEXT SEVERAL DAYS WITH MODELS DEPICTING
MAIN LINE OF CONVECTION REMAINING NORTH OF BOTH LOCATIONS THROUGH
THE WEEK.

&&

.WESTERN MICRONESIA...
LIGHT WEST WINDS TONIGHT AT CHUUK WILL GRADUALLY SHIFT TO THE
SOUTHEAST BY THURSDAY AS THE EASTERN END OF A DIFFUSE MONSOON
TROUGH RETREATS WESTWARD OVER THE NEXT FEW DAYS. ECMWF AND NAVGEM
BRING INCREASED SHOWER ACTIVITY TO CHUUK WEDNESDAY AND THURSDAY
WITH GFS MAINTAINING A MOSTLY DRY PATTERN ACROSS THE STATE THROUGH
THIS WEEK. CLOUD COVER AND SHOWER ACTIVITY IS POISED TO INCREASE
WED AND THU OVER CHUUK AS LOW-LEVEL CONVERGENCE INCREASES ON THE
EASTERN SIDE OF A BROAD CIRCULATION THAT IS EXPECTED TO DEVELOP
OUT OF THE WEAK MONSOON TROUGH. HOWEVER...MAINTAINED ISOLATED
SHOWER COVERAGE DURING THIS TIME UNTIL MODELS COME INTO BETTER
AGREEMENT IN THIS SCENARIO. CONVECTION ON THE NORTH END OF THE
WEAK MONSOON TROUGH IS DISSIPATING OVER YAP. MODELS ARE IN GOOD
AGREEMENT IN DEVELOPING ANOTHER BAND OF SHOWERS OVERNIGHT BUT WITH
A DISPLACEMENT TO THE NORTH OF YAP. OTHERWISE...QUIET CONDITIONS
WILL PERSIST ACROSS KOROR AND YAP THROUGH THE REMAINDER OF THE
WEEK.

&&

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

$$

M. AYDLETT/WILLIAMS



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