Flash Flood Warning 2, NWS Guam

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
521 AM CHST WED JUL 30 2014

.MARIANAS SYNOPSIS...
RADAR AT 0430L SHOWS THE EYE OF TROPICAL STORM HALONG IS 65 MILES
EAST-SOUTHEAST OF ROTA...MOVING WEST-NORTHWEST ROUGHLY TOWARD ROTA.
HALONG IS GRADUALLY BECOMING MORE INTENSE AND COULD MOVE ACROSS ROTA
BY NOON AS A TYPHOON...WHILE PROBABLY CAUSING TROPICAL STORM FORCE
CONDITIONS FOR SAIPAN...TINIAN AND GUAM.

&&

.DISCUSSION...
MAIN FOCUS OF THE FORECAST PACKAGE IS OF COURSE TROPICAL STORM
HALONG WHICH IS ARRIVING AT THE EXPECTED STRENGTH BUT JUST A
LITTLER EARLIER THAN PREVIOUSLY FORECASTED. ROTA IS UNDER A
TYPHOON WARNING...WHILE GUAM IS UNDER A TYPHOON WATCH/TROPICAL
STORM WARNING...TINIAN AND SAIPAN ARE UNDER TROPICAL STORM
WATCHES. WE ALSO ISSUED A FLASH FLOOD WARNING FOR ROTA AND GUAM
AND SEVERAL OTHER HAZARDOUS WEATHER PRODUCTS HAVE BEEN ISSUED.

&&

.MARINE/TROPICAL SYSTEMS...
SAIPAN AND RITIDIAN BUOYS BOTH SHOW COMBINED SEAS OF 10 TO 11 FEET
MAINLY FOR WSW AND IPAN BUOY SHOWS SEAS AROUND 4 FEET FROM THE EAST.
THE TROPICAL CYCLONE TOOL ALONG WITH FORECAST DATA FROM GFS40 WERE
THE MAIN FORECAST GUIDANCE DATA LOADED INTO WIND GRIDS. THE WW3 DATA
WAS USED AS GUIDANCE FOR WAVE GRIDS BUT WITH GENEROUS ADJUSTMENTS
BASED ON A SIGNIFICANT INCREASE OF HAZARDOUS SEA CONDITIONS WHILE
HALONG MOVES ACROSS THE AREA. HAZARDOUS SEAS AND GUSTY WINDS WILL
LIKELY PERSIST THROUGH THURSDAY AND GRADUALLY DIMINISH FRIDAY.

&&

.EASTERN MICRONESIA...
SURFACE RIDGING WILL KEEP PLEASANT WEATHER IN PLACE AT CHUUK AND
POHNPEI TODAY. A WEAK DISTURBANCE NORTH OF KOSRAE WILL SLOWLY MOVE
WEST BRINGING SHOWERS AND A FEW THUNDERSTORMS TO POHNPEI LATE THIS
EVENING. ISOLATED THUNDERSTORMS REMAIN IN THE FORECAST FOR KOSRAE AND
POHNPEI UNTIL FRIDAY...AND ARE IN THE FORECAST FOR CHUUK ON FRIDAY AS
THE DISTURBANCE APPROACHES THEN. ANOTHER WEAK DISTURBANCE IS PROGGED
TO TAKE SHAPE NEAR MAJURO FRIDAY AND SATURDAY PRODUCING ISOLATED
SHOWERS AND THUNDERSTORMS. SOME MODELS SHOW THIS FEATURE PASSING
JUST TO THE NORTH...BUT WILL STICK WITH THE GFS FOR NOW. GENERALLY
GENTLE WINDS ARE EXPECTED THROUGH THE WEEKEND.

&&

.WESTERN MICRONESIA...
REASONING FOR CHUUK FORECAST CAN BE FOUND ABOVE UNDER THE EASTERN
MICRONESIA SECTION DUE TO A SIMILAR SYNOPTIC PATTERN.

KOROR AND YAP...SATELLITE SHOWS PATCHY DEEP CONVECTION AROUND THE
YAP AREA AND MAINLY FAIR SKIES OVER MOST OF PALAU. ASCAT STREAMLINE
ANALYSIS INDICATES STRONGER MONSOON WIND FLOW IS GRADUALLY LIFTING
NORTHWARD AWAY FROM YAP AND KOROR...BUT LIGHT TO MODERATE SOUTH TO
SOUTHWEST WINDS WILL LIKELY CONTINUE ACROSS KOROR AND YAP THE NEXT
FEW DAYS AT LEAST. A LITTLE STRONGER AND WETTER SOUTHWEST FLOW COULD
RETURN BY THIS WEEKEND.

LINGERING MONSOONAL SWELL WILL MAINTAIN HAZARDOUS SURF FOR THE
REPUBLIC OF PALAU AND YAP STATE THIS MORNING BUT IS EXPECTED TO
SUBSIDE BELOW ADVISORY LEVELS LATER TODAY.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...TROPICAL STORM WARNING FOR GUZ001-003-004.

     TYPHOON WATCH FOR GUZ001.

     FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR GUZ001>004.

     HIGH SURF ADVISORY UNTIL 6 AM CHST SUNDAY FOR GUZ001>004.

     TYPHOON WARNING FOR GUZ002.

MARIANAS WATERS...TROPICAL STORM WARNING FOR PMZ151-153-154.

     TYPHOON WARNING FOR PMZ152.

&&

STANKO/M. AYDLETT/SIMPSON