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396
FXPQ60 PGUM 010919
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
719 PM CHST MON SEP 1 2014

.MARIANAS SYNOPSIS...
PGUA WSR-88D SHOWS ISOLATED SHOWERS AND THUNDERSTORMS MOVING
THROUGH THE MARIANAS WATERS. THE VAD WIND PROFILE REVEALS MONSOON
FLOW...MAINLY FROM THE WEST-SOUTHWEST...AT 10 TO 15 KNOTS THROUGH
THE LOWEST 20 THOUSAND FEET OF THE AIR.

&&

.DISCUSSION...
MONSOON TROUGH IS NOW NORTH OF SAIPAN AND WILL BE THE STRONGEST
INFLUENCE ON OUR WEATHER THE NEXT COUPLE OF DAYS.CLIMATE
PREDICTION CENTER MJO UPDATE SHOWS THE MADDEN-JULIAN OSCILLATION
IS CURRENTLY WEAK AND INCOHERENT...SO THE MONSOON TROUGH IS NOT
EXPECTED TO STRENGTHEN SIGNIFICANTLY. EVEN THE GFS40 DOES NO MORE
THAN BRING A SURGE OF 25 TO 30 KNOTS CREATING A TROPICAL
DEPRESSION NORTHWEST OF KOROR WHICH DOES NOT DO MUCH MORE THAN
THAT. COMBINED SEAS REMAIN NEAR 2 TO 4 FEET ALL THIS WEEK...WITH
POSSIBLY A SPARSE 5 FOOT READING THROWN IN FOR VARIETY. THESE ARE
ALL WELL BELOW ADVISORY CRITERIA...SO NO ADVISORIES ARE FORESEEN.

&&

.EASTERN MICRONESIA...
LIGHT TO GENTLE TRADE WINDS ARE GRADUALLY FILTERING WESTWARD
ACROSS THE REGION FROM NEAR THE DATE LINE. LATEST VISIBLE AND
ASCAT SATELLITE IMAGERY REVEAL A SERIES OF SURFACE IMPULSES
EMBEDDED WITHIN THESE TRADES. THE FIRST ONE IS JUST WEST OF
KWAJALEIN NEAR 167E AND THE SECOND ONE NEAR MAJURO THIS EVENING.
THE FIRST ONE IS MOVING MUCH SLOWER DUE TO A SURFACE RIDGE OVER
POHNPEI BLOCKING ITS PROGRESSION. THEREFORE FAIR WEATHER WILL
LINGER NEAR POHNPEI THRU TUESDAY EVENING. ON THE OTHER HAND...THE
SECOND IMPULSE WILL MAINTAIN WETNESS FOR MAJURO THRU TUESDAY
MORNING AND SPREAD IT INTO KOSRAE BY TUESDAY AFTERNOON. IT IS
EXPECTED TO MERGE TOGETHER WITH THE FIRST IMPULSE ON TUESDAY AND
THEN APPROACH POHNPEI ON TUESDAY NIGHT. AFTER THE PASSAGE OF THIS
COMBINED SYSTEM...A BRIEF PERIOD OF DRIER WEATHER IS POSSIBLE FOR
KOSRAE AND POHNPEI AFTER MIDWEEK. FOR MAJURO...MORE SURFACE
IMPULSES FROM UPSTREAM EAST OF THE DATE LINE WILL KEEP SHOWERS
AROUND UNTIL THIS WEEKEND. THESE SAME IMPULSES WILL ALSO AFFECT
KOSRAE AND POHNPEI BY THIS WEEKEND.

&&

.WESTERN MICRONESIA...
AN AREA OF DIVERGENT WINDS ASSOCIATED WITH AN UPPER-LEVEL HIGH
CENTERED OVER THE PHILIPPINE SEA COULD STILL TRIGGER A FEW
THUNDERSTORMS NEAR CHUUK THIS EVENING. LATEST WV SATELLITE AND
MODEL GUIDANCE IMAGERY INDICATE A POOL OF MID-LEVEL DRY AIR
MIGRATING WESTWARD FROM NEAR POHNPEI. THIS DRY AIR MASS SHOULD
STABILIZE THINGS OVER CHUUK BY TUESDAY MORNING. BY THURSDAY...THE
FIRST OF A SERIES OF TRADE DISTURBANCES CURRENTLY OVER EASTERN
MICRONESIA WILL BEGIN TO IMPACT CHUUK WITH PERIODIC SHOWERS.

THE BROAD MONSOONAL CIRCULATION CENTERED JUST NORTH OF KOROR AT
11N135E IS SHOWING SIGNS OF STRENGTHENING THIS AFTERNOON.
MODERATE TO FRESH WINDS ARE APPEARING BOTH WEST AND SOUTH OF THE
CENTER. SOUNDING DATA FROM WSO KOROR ALSO DISPLAY A DEEP LAYER OF
10 TO 20-KNOT SOUTHWEST WINDS FROM THE SURFACE TO ABOUT 550MB.
THESE CONVERGING SOUTHWEST WINDS ALONG WITH NORTHEAST WINDS ABOVE
500MB WILL ENHANCE VERTICAL DEVELOPMENT. THEREFORE ANTICIPATE
SPORADIC DEEP CONVECTION TO FLARE UP OVER KOROR AND YAP THRU AT
LEAST WEDNESDAY AFTERNOON. IF THE CIRCULATION DEVELOP INTO A
MONSOON DEPRESSION BY WEDNESDAY...INCLEMENT WEATHER COULD PROLONG
BEYOND WEDNESDAY ACROSS KOROR AND YAP. AS THE CIRCULATION FINALLY
LIFTS NORTHWARD AFTER MIDWEEK...CONDITIONS SHOULD START TO
IMPROVE TOWARD THE WEEKEND.

SOUTHWEST SWELL AND WIND WAVES ASSOCIATED WITH THE MONSOON WINDS
WILL BEGIN TO BUILD ACROSS PALAU AND WESTERN YAP STATE TONIGHT
AND TUESDAY. THIS COULD CAUSE SURF TO REACH HAZARDOUS LEVELS BY
TUESDAY NIGHT...NEED TO CLOSELY MONITOR THIS SITUATION.

&&

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

$$

STANKO/CHAN








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