Area Forecast Discussion
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000
FXPQ60 PGUM 232246
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
846 AM CHST THU APR 24 2014

.MARIANAS SYNOPSIS...
PGUA WSR-88D SHOWS ISOLATED SHOWERS MOVING THROUGH THE MARIANAS
WATERS...MAINLY IN THE GUAM WATERS. SATELLITE SHOWS A TROPICAL
DISTURBANCE TO THE SOUTHEAST NEAR CHUUK WHICH COULD AFFECT THE
MARIANAS WEATHER STARTING FRIDAY. THE VAD WIND PROFILE REVEALS
WINDS OF 13 TO 20 KNOTS WITHIN THE LOWEST 6 THOUSAND FEET OF THE
AIR. DIRECTION TURNS FROM EAST-NORTHEAST NEAR THE SURFACE TO EAST-
SOUTHEAST ALOFT.

&&

.DISCUSSION...
ALOT OF UNCERTAINTY TODAY...ESPECIALLY IN THE DAY 3 AND BEYOND
FORECAST. GFS40 MODEL SPLITS THE TROPICAL DISTURBANCE NEAR CHUUK
INTO TWO PIECES. THE FIRST STAYS TOO FAR SOUTH TO HAVE ANY MORE
THAN JUST A MINIMAL AFFECT ON THE MARIANAS. THE OTHER MOVES
NORTHWARD TO THE EAST OF THE ISLANDS. THIS RESULTS IN A MUCH LESS
HAWKISH RAINFALL FORECAST. SINCE THE SHOWERS NORTH OF 10N ALSO
DISSOLVED OVER THE PAST 24 HOURS...DECIDED NOT TO UP THE SHOWERS
SO PREVIOUS FORECAST WAS ALMOST UNTOUCHED OTHER THAN SOME MINOR
TWEAKS TO THE COMBINED SEAS AND SWELLS.

&&

.MARINE...
GIVEN THE UNCERTAINTY OF THE EVOLUTION OF THE CURRENT PATTERN...
TENDED TOWARD THE LOWER OF THE TWO SEA HEIGHTS OUT OF THE LATEST
GLOBAL WAVE RUN OR THE CURRENT WAVE HEIGHT GRIDS. IF THE
CIRCULATION TO OUR NORTHEAST IS WEAKER THAN PROGGED BY THE GFS40
/OR FAILS TO FORM ENTIRELY/ WAVES WILL BE SUBSTANTIALLY LOWER.
THEREFORE...ATTEMPTED TO FACTOR THIS POSSIBILITY IN TO AT LEAST A
LIMITED DEGREE. A SMALL CRAFT ADVISORY IS UNLIKELY...HOWEVER A
HIGH SURF ADVISORY MAY STILL BE NECESSARY.

&&

.EASTERN MICRONESIA...
THE EASTERN END OF A NEAR-EQUATORIAL TROUGH REACHES SOUTHEASTWARD
FROM A BROAD CIRCULATION CENTERED JUST SOUTHEAST OF WENO ISLAND IN
CHUUK STATE AT 7N154E TO END SOUTHEAST OF KOSRAE AT EQ165E. MODEST
CONVERGING SOUTHEAST WINDS EAST OF THE CIRCULATION CAN STILL TRIGGER
A FEW THUNDERSTORMS NEAR POHNPEI TODAY. OTHERWISE WEAK RIDGING NORTH
OF THE TROUGH SHOULD MAINTAIN RELATIVELY DRY CONDITIONS FOR POHNPEI
UNTIL FRIDAY AFTERNOON...AND NEAR KOSRAE THRU THIS MORNING. FARTHER
EAST...A TRADE-WIND DISTURBANCE IS MOVING WESTWARD ACROSS THE
MARSHALL ISLANDS THIS MORNING. THEREFORE ANTICIPATE PERIODIC SHOWERS
WITH THE POSSIBILITY OF THUNDERSTORMS NEAR MAJURO UNTIL EARLY THIS
EVENING. BY LATE TONIGHT...DRYER NORTHEASTERLY TRADES SHOULD PROMOTE
PARTLY CLOUDY SKIES FOR THE ATOLL. AS THE DISTURBANCE PULLS WEST OF
THE MARSHALLS...IT WILL ALSO BRING WET WEATHER TO KOSRAE THIS
AFTERNOON AND POHNPEI BY FRIDAY NIGHT. LATEST ASCAT SATELLITE
IMAGERY REVEALS CONVERGING TRADES BETWEEN 4N AND 8N STRETCHING
EASTWARD FROM THE DATE LINE TO BEYOND 155W. THIS FEATURE COULD
RESUME SHOWERY WEATHER NEAR MAJURO BY SATURDAY EVENING...AND PROLONG
WETNESS FOR KOSRAE AND POHNPEI INTO NEXT WEEK.

&&

.WESTERN MICRONESIA...
DIFFLUENT LOW-LEVEL FLOW WEST OF A BROAD CIRCULATION CENTERED JUST
SOUTHEAST OF WENO ISLAND IN CHUUK STATE SHOULD ALLOW MAINLY ISOLATED
SHOWERS NEAR THE ISLAND THIS MORNING. THIS CIRCULATION IS EXPECTED
TO GRADUALLY DRIFT NORTHWESTWARD TODAY AND TONIGHT. AS A RESULT...
CONVERGING SURFACE WINDS NEAR AND EAST OF ITS CENTER WILL INCREASE
SHOWER COVERAGE NEAR CHUUK BY LATER THIS AFTERNOON. AFTERWARD A
TRADE DISTURBANCE FROM UPSTREAM NEAR THE MARSHALL ISLANDS MIGHT
GENERATE MORE SHOWERS THIS WEEKEND.

WITH THE WESTERN PORTION OF THE NEAR-EQUATORIAL TROUGH REMAINING
SOUTH OF KOROR AND YAP INTO THIS WEEKEND...MAINLY DRY WEATHER SHOULD
PREVAIL FOR BOTH LOCALES. THE ONLY EXCEPTION WILL BE A FEW SHOWERS
ASSOCIATED WITH A WEAK SURFACE TROUGH NEAR YAP TODAY AND KOROR ON
EARLY FRIDAY. FOR EARLY NEXT WEEK...THE FUTURE STATUS OF THE BROAD
CIRCULATION CURRENTLY NEAR CHUUK COULD PLAY A ROLE IN THE WEATHER OF
YAP AND KOROR.

&&

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

$$

STANKO/CHAN






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