Area Forecast Discussion
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000
FXPQ60 PGUM 032038 AAA
AFDPQ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TIYAN GU
620 AM CHST SAT JUL 4 2015

UPDATED TO INCLUDE MICRONESIA DISCUSSION

.SYNOPSIS...NORTHEAST WINDS AND SCATTERED SHOWERS AND ISOLATED
THUNDERSTORM WILL PREVAIL TODAY.

&&

.DISCUSSION...
CHAN-HOM REMAINS A TROPICAL STORM THIS MORNING. AGAIN THE TRACK IS
THE BIG QUESTION. PREVIOUS FORECAST TRACKS HAD CHAN-HOM PASSING
CLOSE TO GUAM THEN THROUGH THE TINIAN CHANNEL. THE LATEST TRACK
FORECAST SHOWS CHAN-HOM PASSING NORTH OF SAIPAN.

FORECAST REFLECTS THE CHANGE WITH GUAM AND ROTA PROBABLY ONLY
GETTING TROPICAL STORM FORCE WINDS BRIEFLY AT BEST. TINIAN AND
SAIPAN MAY BRIEFLY SEE TYPHOON FORCE WINDS SUNDAY NIGHT. GUAM AND
ROTA ARE STILL UNDER A TYPHOON WATCH THIS MORNING. AS IS APPARENT
FROM WATCHING THIS SYSTEM OVER THE LAST FEW DAYS IS THAT THE TRACK
FORECAST HAS CHANGED OFTEN. WILL LEAVE GUAM AND ROTA IN THE WATCH
UNTIL THE FORECAST TRACK IS BETTER BEHAVED.

THE INTENSITY FORECAST IS NOT SO CERTAIN EITHER AS CHAN-HOM IS
VERY DISORGANIZED THIS MORNING. WILL IT REGAIN TYPHOON INTENSITY
AS PREDICTED IS A BIG QUESTION. AGAIN BECAUSE OF THE BIG
UNCERTAINTY TYPHOON CONDITIONS ARE POSSIBLE AT SOME POINT THROUGH
SUNDAY NIGHT.

AFTER CHAN-HOM PASSAGE THE MARIANAS WILL BE IN SOUTHWEST WINDS
AS THE STORM WILL DRAG THE MONSOON TROUGH NORTH OF THE LOCAL AREA.

&&

.MARINE...
BUOY DATA SHOWED AN EAST SWELL OVER THE MARIANAS THIS MORNING.
THERE IS WINDS GENERATED ALONG THE MONSOON TROUGH SOUTH OF THE
MARIANAS IS PUSHING WAVES IN THIS DIRECTION GENERATING A SOUTHWEST
SWELL. THE BUOY DATA INDICATED SEAS OF 8 TO 11 FEET THIS MORNING.
EXPECT LITTLE CHANGE IN THE COMBINED SEAS THROUGH TONIGHT. SEAS
PROBABLY WILL NOT CHANGE VERY MUCH ACROSS GUAM AND ROTA THROUGH
THE FORECAST. IF CHAN-HOM PASSES BY TINIAN AND SAIPAN SEAS THERE
MAY BRIEFLY REACH 15 TO 20 FEET SUNDAY NIGHT.

&&

.EASTERN MICRONESIA...
TROPICAL STORM CHAN-HOM CENTERED EAST-SOUTHEAST OF GUAM NEAR 11N149E
IS BEHAVING MORE LIKE A MONSOONAL SYSTEM WITH A VAST WIND FIELD
BETWEEN THE EQUATOR AND 20N. THE STRONGEST WINDS ARE CONCENTRATED
NORTH AND SOUTH OF THE CENTER WITH WEAKER WINDS NEAR THE CENTER.
FRESH TO STRONG MONSOON WINDS SOUTH OF CHAN-HOM ARE GOING TO
MAINTAIN UNSTABLE WEATHER NEAR CHUUK AND POHNPEI THRU SUNDAY.
FARTHER EAST...NEWLY FORMED TROPICAL DEPRESSION 11W CENTERED NEAR
10N171E IS DRIFTING NORTHWESTWARD OVER THE NORTHERN MARSHALL ISLANDS
WITH DEEP CONVECTION FLARING UP NEAR THE CENTER. DESPITE FRESH
SOUTHWEST WINDS FEEDING INTO 11W...SUBSIDENT AIR JUST SOUTH OF 11W
IS GOING TO PROMOTE DRIER WEATHER NEAR MAJURO THRU THIS EVENING.
BEING FARTHER AWAY FROM THE CONVECTION...THESE SAME WINDS SHOULD
KEEP A FEW THUNDERSTORMS NEAR KOSRAE THRU TONIGHT.

ONCE CHAN-HOM HAS DRIFTED FARTHER NORTHWEST OF CHUUK AND POHNPEI
SUNDAY AFTERNOON...11W WILL BEGIN TO HAVE A BIGGER INFLUENCE ACROSS
CHUUK...POHNPEI AND KOSRAE. THIS WILL PROLONG SHOWERY WEATHER NEAR
THESE THREE LOCALES THRU MONDAY. ONCE 11W HAS PASSED NORTH OF THESE
LOCALES...MODERATE SOUTH WINDS SHOULD ALLOW LESS SHOWER COVERAGE BY
MONDAY. FOR MAJURO...MODERATE TRADE WINDS SHOULD BEGIN TO USHER IN
FAIR WEATHER FROM SUNDAY ON.

HIGH SURF AND HAZARDOUS SEAS FOR SMALL CRAFT WILL LINGER NEAR MAJURO
AND KOSRAE UNTIL SUNDAY...POHNPEI AND CHUUK THRU MONDAY. MINOR
COASTAL INUNDATIONS ARE STILL POSSIBLE NEAR MAJURO THRU THIS
EVENING. BOTH SURF AND SEAS ACROSS ALL LOCATIONS ARE EXPECTED TO
SUBSIDE BELOW HAZARDOUS LEVELS BY TUESDAY.

&&

.WESTERN MICRONESIA...
DISCUSSION FOR THE CHUUK FORECAST IS INCLUDED UNDER THE EASTERN
MICRONESIA SECTION ABOVE DUE TO SIMILAR SYNOPTIC FEATURES.

THE LARGE MONSOONAL WIND FIELD OF TROPICAL STORM CHAN-HOM WILL
SUSTAIN FRESH TO OCCASIONAL STRONG SOUTHWEST TO WEST WINDS ACROSS
THE REPUBLIC OF PALAU AND YAP STATE OVER THE NEXT FEW DAYS.
ANTICIPATE SCATTERED HEAVY SHOWERS NEAR YAP...AND WIDELY SCATTERED
SHOWERS NEAR KOROR THRU MONDAY. AS CHAN-HOM FINALLY PULLS
NORTHWESTWARD OVER THE PHILIPPINE SEA EARLY NEXT WEEK...MONSOONAL
WINDS MIGHT BEGIN TO DECREASE OVER THE AREA.

SOUTHWEST SWELL AND WIND WAVES ARE GOING TO MAINTAIN HAZARDOUS SURF
AND SEAS FOR SMALL CRAFT ACROSS PALAU AND YAP THRU AT LEAST MONDAY.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...TYPHOON WATCH FOR GUZ001>004.

MARIANAS WATERS...TYPHOON WATCH FOR PMZ151>154.

&&

$$

ZIOBRO/CHAN



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