Area Forecast Discussion
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000
FXPQ60 PGUM 242050
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
650 AM CHST SAT OCT 25 2014

.MARIANAS SYNOPSIS...
SCATTERED SHOWERS AND THUNDERSTORMS ASSOCIATED WITH AN UPPER LOW
CENTERED NW OF THE MARIANAS NEAR 20N143E ARE NOW WEST OF THE
ISLANDS AND MOVING WEST. RADAR SHOWS ISOLATED SHOWERS AND
THUNDERSTORMS NEAR AND EAST OF THE ISLANDS...MAINLY UP NEAR SAIPAN
AND TINIAN.

&&

.DISCUSSION...
GFS...ECMWF AND NAVGEM DISAGREE ON SOME DETAILS...BUT ALL THREE
MODELS KEEP THE MARIANAS IN AN UNSETTLED EASTERLY FLOW NORTH OF
WEAK AND ILL-DEFINED TROUGHING TO THE SOUTH FOR SOME TIME. ALL THE
MODELS NOW BRING IN A FAIR AMOUNT OF MOISTURE OVER THE NEXT WEEK
OR MORE WITH POTENTIAL FOR SCATTERED SHOWERS AT TIMES IN THE NEXT
10 DAYS. THE ECMWF IS MOST GENEROUS WITH 0VER 5 INCHES...AND IT
SETS UP THE BEST-ORGANIZED MONSOON PATTERN OF ANY OF THE MODELS.
HAVE EXTENDED MOSTLY CLOUDY WITH ISOLATED SHOWERS AND
THUNDERSTORMS THROUGH AT LEAST WEDNESDAY NIGHT...AND WILL HAVE TO
WATCH OUT FOR THE POSSIBILITY OF MORE THAN ISOLATED AT TIMES.

&&

.MARINE/SURF...
WW3 GUIDANCE FOR SEAS AND SWELL SEEMS A LITTLE ON THE LOW SIDE
COMPARED WITH BUOY OBSERVATIONS...AND HAVE BOOSTED WAVE GRIDS A
FOOT FOR TODAY THROUGH SUNDAY. BUOY SWELL SPECTRA SHOW THAT THE
LONG-PERIOD NORTHEAST SWELL IS FAR AND AWAY THE DOMINANT COMPONENT
AND SHOULD KEEP HIGH SURF GOING THROUGH SUNDAY AFTERNOON ON NORTH-
FACING REEFS. THE SWELL WILL DIMINISH SUNDAY NIGHT AND MONDAY
WITH A MODERATE RIP RISK FOR MOST OF NEXT WEEK.

&&

.EASTERN MICRONESIA...
THE SURFACE TROUGH MOVING WESTWARD FROM THE MARSHALL ISLANDS HAS
MERGED WITH THE CIRCULATION SOUTH OF POHNPEI NEAR 5N158E. THIS
COMBINED SYSTEM WILL KEEP SHOWERS AND A FEW THUNDERSTORMS NEAR
POHNPEI TODAY. AS THEY SLOWLY DRIFT WESTWARD AWAY FROM POHNPEI
THIS EVENING...THIS WILL LET WEAKER SOUTHEASTERLY TRADES ALREADY
OVER KOSRAE REACH POHNPEI. HOWEVER THESE MODEST CONVERGING
SOUTHEAST WINDS CAN STILL TRIGGER ISOLATED CONVECTION NEAR BOTH
POHNPEI AND KOSRAE THRU SUNDAY. FARTHER EAST...A TRADE-WIND
CONVERGENCE ZONE CAN BE SEEN BETWEEN 4N AND 8N STRETCHING EASTWARD
FROM NEAR MAJURO THRU THE DATE LINE TO A TRADE DISTURBANCE NEAR
165W. SPORADIC DEEP CONVECTION ASSOCIATED WITH THE ZONE AND
DISTURBANCE WILL AFFECT MAJURO THRU MONDAY. WITH THESE FEATURES
PUSHING FARTHER WESTWARD INTO THE REGION OVER THE NEXT COUPLE OF
DAYS...INCLEMENT WEATHER WILL ALSO IMPACT KOSRAE AND POHNPEI BY
MONDAY. THINGS FINALLY IMPROVE TOWARD MIDWEEK NEXT WEEK WHEN GENTLE
TRADES RETURN TO THE REGION FROM EAST TO WEST.

LONG-PERIOD NORTH-NORTHEAST SWELL WILL MAINTAIN HAZARDOUS SURF
ACROSS CHUUK AND POHNPEI STATES UNTIL SUNDAY AFTERNOON. LATEST
READINGS FROM THE KALO BUOY AT MAJURO INDICATE THESE SWELLS HAVE
ARRIVED AT THE MARSHALL ISLANDS. BLOCKAGE CAUSED BY THE NORTHERN
MARSHALL ISLANDS HAS REDUCED THE SWELLS TO BETWEEN 3 AND 4 FEET
WITH A PERIOD OF NEAR 11 SECONDS...RESULTING IN SURF HEIGHTS OF 5
TO 6 FEET. COUPLED WITH SPRING HIGH TIDES OF 4 TO 5 FEET AT MAJURO
ATOLL...THE CRITERION FOR COASTAL INUNDATION WILL PROBABLY NOT BE
MET...BUT IT WILL BE CLOSE. WHILE NO INUNDATION IS EXPECTED...THE
RISK OF RIP CURRENTS WILL BE HIGHER DURING HIGH TIDES FROM THIS
AFTERNOON TO MONDAY AFTERNOON. DAY SHIFT MIGHT WANT TO INCLUDE A
HEADLINE MENTIONING THIS IN THE MAJURO FORECAST.

&&

.WESTERN MICRONESIA...
THE CIRCULATION AND ITS RELATED TROUGH NEAR POHNPEI THIS MORNING
WILL APPROACH CHUUK THIS AFTERNOON AND TONIGHT. THEREFORE...EXPECT
INCREASING SHOWERS OVER CHUUK BY THIS EVENING. AFTER THE PASSAGE
OF THESE FEATURES ON SUNDAY NIGHT...WEAK RIDGING FOLLOWING BEHIND
SHOULD USHER IN A QUIETER PERIOD. THEN BY EARLY NEXT WEEK...THE
TRADE CONVERGENCE ZONE CURRENTLY AFFECTING MAJURO SHOULD ARRIVE AT
CHUUK WITH MORE WET WEATHER. REFER TO THE SECOND PARAGRAPH UNDER
THE EASTERN MICRONESIA DISCUSSION ABOVE FOR HAZARDOUS SURF
CONDITIONS THRU SUNDAY MORNING.

THE WEAK MONSOON TROUGH NEAR KOROR AND YAP IS GRADUALLY LIFTING
NORTHWARD THIS MORNING. THIS WILL ALLOW THE THREAT OF THUNDERSTORMS
TO DECREASE ACROSS BOTH LOCATIONS BY TONIGHT. ONCE THE TROUGH AXIS
HAS MOVED FARTHER NORTH INTO THE PHILIPPINE SEA ON SUNDAY...LIGHT
WINDS TO THE SOUTH WILL PROMOTE PARTLY CLOUDY SKIES FOR THE AREA
THRU MONDAY. TOWARD MIDWEEK...THE CHANCE OF SHOWERS WILL INCREASE AS
THE CIRCULATION CURRENTLY NEAR POHNPEI MAKES ITS WAY WESTWARD.
REMNANTS OF THE NORTH-NORTHEAST SWELLS AFFECTING THE MARIANA ISLANDS
ARE SCHEDULED TO ARRIVE AT YAP STATE AND PALAU TONIGHT. SURF HEIGHTS
SHOULD STAY BELOW ADVISORY LEVELS BUT THE RISK OF RIP CURRENTS WILL
BE HIGHER.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

MIDDLEBROOKE/CHAN





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