Area Forecast Discussion
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000
FXPQ60 PGUM 280759
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
559 PM CHST SAT MAR 28 2015

.SYNOPSIS...EAST WINDS AND A FEW SHOWERS PREVAIL ACROSS THE
MARIANAS THIS AFTERNOON. A SHEAR LINE WAS LOCATED NEAR TINIAN AND
SAIPAN. TROPICAL STORM MAYSAK WILL PASS SOUTH OF THE MARIANAS
MONDAY.

&&

.DISCUSSION...
UPDATED WINDS AT VARIOUS PLACES IN THE FORECAST. THE PRESSURE
GRADIENT BETWEEN HIGH PRESSURE TO THE NORTH AND MAYSAK WILL CAUSE
WINDS TO INCREASE SUNDAY ACROSS THE LOCAL AREA AND REMAIN ELEVATED
ON MONDAY. MODELS SHOW LOW-LEVEL CONVERGENCE NORTH OF MAYSAK WHICH
WILL CAUSE A GOOD CHANCE OF SHOWERS MONDAY THROUGH TUESDAY NIGHT.
SCATTERED SHOWERS ARE EXPECTED ACROSS THE MARIANAS AT THAT TIME.
ISOLATED SHOWERS SHOULD RETURN WEDNESDAY.

&&

.MARINE...
SCATTEROMETER DATA SHOWED STRONGER WINDS ACROSS TINIAN AND SAIPAN
WATERS IN ASSOCIATION WITH THE SHEAR LINE. ISSUED A SMALL CRAFT
ADVISORY FOR TONIGHT FOR THIS AREA. WINDS WILL INCREASE ACROSS
ALL THE MARIANAS WATERS SUNDAY AS THE PRESSURE GRADIENT BETWEEN
HIGH PRESSURE TO THE NORTH AND MAYSAK INCREASES. EXPECT SMALL
CRAFT CONDITIONS FOR ALL THE MARIANAS WATERS SUNDAY THROUGH
TUESDAY MORNING.

WAVE WATCH DATA SHOWERS A SOUTHWEST SWELL ENTERING THE AREA BY
MIDWEEK. SINCE MAYSAK IS EXPECTED TO BECOME A TYPHOON IT SHOULD
SEND AT LEAST A FEW SWELL TOWARDS THE MARIANAS. BROUGHT IN A TWO
FOOT SWELL FROM THE SOUTHWEST ON WEDNESDAY AND CONTINUED IT
THROUGH AT LEAST FRIDAY.

&&

.EASTERN MICRONESIA...
TROPICAL STORM MAYSAK IS MOVING ACROSS WESTERN MICRONESIA. A
NEAR- EQUATORIAL TROUGH EXTENDS SOUTHEASTWARD FROM MAYSAK PASSING
JUST SOUTH OF KOSRAE TO END NEAR TARAWA ATOLL. CONVERGING SURFACE
WINDS NEAR THIS TROUGH WILL CONTINUE TO SPARK OFF CONVECTION NEAR
POHNPEI AND KOSRAE THRU TONIGHT. AS MAYSAK AND THE NEAR-EQUATORIAL
TROUGH DRIFT WESTWARD ON SUNDAY...IT WILL ALLOW A SURFACE RIDGE TO
SHIFT FROM THE MARSHALL ISLANDS TO OVER KOSRAE AND POHNPEI.
THEREFORE EXPECT QUIETER WEATHER FOR BOTH PLACES SUNDAY NIGHT AND
MONDAY. A TRADE-WIND DISTURBANCE IS PROGRESSING WESTWARD FROM THE
DATE LINE THIS AFTERNOON. IT WILL ARRIVE AT THE MARSHALL ISLANDS
LATER THIS EVENING. ANTICIPATE INCREASING SHOWER COVERAGE NEAR
MAJURO BY MIDNIGHT WITH ISOLATED THUNDERSTORMS. AFTER THE PASSAGE
OF THIS DISTURBANCE ON MONDAY NIGHT...MUCH DRYER NORTHEAST TRADES
SHOULD DOMINATE THE MARSHALLS THRU MIDWEEK. FOR KOSRAE AND
POHNPEI...THIS SAME DISTURBANCE WILL ALSO BRING SHOWERY CONDITIONS
BY TUESDAY.

A TRADE-WIND SURGE EXPECTED TO DEVELOP EAST OF THE DATE LINE EARLY
NEXT WEEK SHOULD CAUSE TRADE-WIND WAVES AND SWELL TO BUILD ACROSS
KOSRAE AND THE MARSHALL ISLANDS. NEED TO MONITOR FOR POSSIBLE HIGH
SURF AND HAZARDOUS SEAS FOR SMALL CRAFT.


&&

.WESTERN MICRONESIA...
TROPICAL STORM MAYSAK IS EXPECTED TO MOVE CLOSE TO AND NORTH OF
CHUUK. THE CLOSEST POINT OF APPROACH WILL BE LATE TONIGHT OR
EARLY SUNDAY MORNING. A TYPHOON WARNING IS IN EFFECT FOR CHUUK AS
MAYSAK INTENSIFIES TO POSSIBLY A TYPHOON LATE TONIGHT. 4 TO 6
INCHES OF RAIN ARE PROBABLE BY SUNDAY EVENING. INCREASING WIND
WAVES WILL COMBINE WITH EXISTING TRADE-WIND SWELL TO CAUSE SEAS TO
BUILD ABOVE 12 FEET TONIGHT THRU SUNDAY MORNING AS MAYSAK MOVES
THRU. THINGS SHOULD GRADUALLY IMPROVE SUNDAY AFTERNOON AND EVENING
AS MAYSAK DEPARTS THE CHUUK AREA. HOWEVER CONVERGING SOUTHEAST
WINDS WILL KEEP PERIODIC SHOWERS AROUND THRU MONDAY BEFORE SURFACE
RIDGING FROM THE EAST FINALLY INTRODUCES FAIRER WEATHER ON
TUESDAY. SHOWERS MIGHT RETURN NEAR MIDWEEK AS A TRADE DISTURBANCE
APPROACHES FROM NEAR POHNPEI.

A SURFACE TROUGH IS COUPLING WITH A SHEAR LINE TO GENERATE ISOLATED
CONVECTION OVER YAP. THIS CONVECTION IS EXPECTED TO REACH KOROR
SUNDAY MORNING. AS TROPICAL STORM MAYSAK MOVES TOWARD THE REGION ON
MONDAY...SUBSIDENCE ALONG WITH DIVERGENT SURFACE WINDS TO THE WEST
OF THE STORM MIGHT PROVIDE A BRIEF PERIOD OF DRIER CONDITIONS FOR
KOROR AND YAP. FOR TUESDAY AND WEDNESDAY...STORMY CONDITIONS ARE
EXPECTED NEAR YAP FROM MAYSAK.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 6 AM CHST TUESDAY FOR PMZ153-154.

     SMALL CRAFT ADVISORY FROM 6 AM SUNDAY TO 6 AM CHST TUESDAY FOR
     PMZ151-152.

&&

$$

ZIOBRO/DEVITA



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