Area Forecast Discussion
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000
FXPQ60 PGUM 062039
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
639 AM CHST TUE JUL 7 2015

.SYNOPSIS...
TY CHAN-HOM IS ABOUT 500 MILES WNW TO NW OF THE MARIANAS AND TY
NANGKA IS ABOUT 800 MILES EAST OF THE ISLANDS. MAINLY MODERATE
SOUTH TO SOUTHWEST WINDS AND ISOLATED SHOWERS ARE PRESENT IN THE
MARIANAS WATERS. SEAS ARE STILL AT 10-11 FT AT TANAPAG BUOY WITH
THE GREATEST SWELL ENERGY FROM THE WSW TO WEST.

&&

.DISCUSSION...
REFRESHED WINDS FROM THE 12Z GFS...BUT OTHERWISE MADE NO MAJOR
CHANGES TO THE PUBLIC FORECAST GRIDS. INFLUENCE OF TY CHAN-HOM IS
SLOWLY WANING AS IT PULLS AWAY TO THE NORTHWEST...AND WINDS WILL
DROP OFF TO LIGHT THROUGH WEDNESDAY BEFORE PICKING UP FROM THE
WEST TO SOUTHWEST AGAIN WED NIGHT AND THURSDAY AS TY NANGKA
APPROACHES AND MOVES BY WELL NORTH OF SAIPAN ON ITS WAY TO THE
PAGAN-AGRIHAN AREA. LEFT ISOLATED SHOWERS AND THUNDERSTORMS AS
IS...BUT COULD BE SCATTERED AT TIMES LATER IN THE WEEK IF A
MONSOON TAIL DEVELOPS SOUTH OF NANGKA.

&&

.MARINE/SURF...
COMPLETELY RE-DID ALL THE MARINE GRIDS TO ACCOUNT AS BEST WE CAN
FOR SWELL GENERATED BY THE TWO TYPHOONS AS WELL AS THE WESTERLY
MONSOON FLOW. THIS KEEPS COMBINED SEAS AT AROUND 10 FT OR HIGHER
FOR THE NEXT FEW DAYS. VARYING SWELL AS THE TWO MOVING TYPHOONS
RESULTS IN A COMPLICATED SURF FORECAST FOR THE MARIANAS THE REST
OF THE WEEK. HIGH SURF WILL BE ALONG SOUTH AND WEST FACING REEFS
TODAY AND WEDNESDAY DUE TO MONSOON AND CHAN-HOM SWELL...BUT THEN
EAST SWELL COMES IN ABRUPTLY WED NIGHT AND THURSDAY FROM TY
NANGKA. THIS MAY BRING HIGH SURF TO NORTH AND EAST FACING REEFS BY
THURSDAY...WHILE HIGH SURF LINGERS ALONG WEST AND POSSIBLY SOUTH
FACING SHORES AS WELL. THE NANGKA EAST SWELL IS EXPECTED SWING
AROUND TO NE AND NORTH AS THE WEEK PROGRESSES AND NAGKA PASSES
WELL NORTH OF SAIPAN...THEN AROUND TO NORTHWEST BY SATURDAY WHILE
THE WEST SWELL DIMINISHES. THIS IS A COMPLEX SITUATION THAT WILL
LIKELY REQUIRE FREQUENT UPDATING FROM DAY TO DAY AS EVENTS UNFOLD.

&&

.TROPICAL SYSTEMS...
NOW THAT CHAN-HOM IS MOVING AWAY...ATTENTION FOCUSES ON TY NANGKA.
MODELS AGREE WELL ON TAKING NANGKA NW THROUGH THE FAR NORTHERN
MARIANAS NEAR AGRIHAN ON THURSDAY...AND JTWC IS FORECASTING WINDS
AT 125 MPH AT THAT TIME. ITS IMPACTS ON THE MARIANAS WATERS WILL
VARY FROM NORTH TO SOUTH...PROMPTING THE SPLITTING OFF OF TINIAN
AND SAIPAN ZONES...WERE SEAS AND WINDS WILL BE SOMEWHAT HIGHER...
FROM THE GUAM AND ROTA ZONES. SEAS IN PARTICULAR COULD GET QUITE
HIGH...15 FT OR MORE...IN NORTHERN SAIPAN WATERS ON THURSDAY.

&&

.EASTERN MICRONESIA...
TYPHOON NANGKA...CENTERED NORTH-NORTHWEST OF POHNPEI NEAR
12N157E...CONTINUES TO MOVE QUICKLY WEST-NORTHWEST. A FEW SHOWERS
AND THUNDERSTORMS ARE FOUND JUST NORTHWEST OF POHNPEI...
OTHERWISE...THE REST OF THE REGION IS FAIRLY DRY. AS NANGKA PULLS
FARTHER AWAY...SOUTHWEST WINDS WILL TURN TO SOUTH AND DECREASE IN
SPEED. THE REST OF THE WEEK IS EXPECTED TO BE DRY AT ALL THREE
LOCATIONS. A WEAK DISTURBANCE WILL BRING MORE CLOUDS TO MAJURO
LATE IN THE WEEK.

&&

.WESTERN MICRONESIA...
TYPHOON CHAN-HOM CONTINUES TO MOVE WEST-NORTHWEST OVER THE
PHILIPPINE SEA. SOUTHWEST WINDS AT BOTH KOROR AND YAP WILL PERSIST
FOR ANOTHER DAY OR TWO THEN TURN TO THE SOUTH AND GRADUALLY
DECREASE. ISOLATED THUNDERSTORMS AT YAP WILL PULL FARTHER TO THE
NORTH THIS EVENING AS CHAN-HOM MOVES AWAY. THE REST OF THE WEEK IS
EXPECTED TO BE DRY FOR BOTH LOCATIONS.

SATELLITE IMAGERY SHOWS A BAND OF SHOWERS AND THUNDERSTORMS
EXTENDING SOUTHWEST FROM TYPHOON NANGKA NEAR CHUUK THIS MORNING.
MODELS INDICATE SHOWERS AND THUNDERSTORMS WILL DECREASE THROUGH THE
DAY AS NANGKA CONTINUES TO THE WEST-NORTHWEST. SOUTHWEST WINDS WILL
DECREASE AND TURN TO SOUTH AROUND MIDWEEK. DRIER WEATHER IS EXPECTED
FOR THE SECOND HALF OF THE WEEK.

SURF REMAINS HAZARDOUS ALONG SOUTH AND WEST FACING SHORES OF BOTH
YAP AND PALAU. WAVE WATCH MODEL INDICATES SURF WILL BEGIN TO FALL
WEDNESDAY AND COULD FALL BELOW HAZARDOUS LEVELS THAT NIGHT OR
THURSDAY. SEAS WILL REMAIN HAZARDOUS TO SMALL CRAFT A COUPLE MORE
DAYS AT YAP.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 6 PM CHST THURSDAY FOR GUZ001>004.

MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 6 PM CHST THURSDAY
     FOR PMZ151>154.

&&

$$

MIDDLEBROOKE/W. AYDLETT



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