Flash Flood Warning 2, NWS Guam

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
553 PM CHST THU SEP 19 2013

.MARIANAS SYNOPSIS...
PGUA WSR-88D SHOWS SCATTERED SHOWERS IN THE ROTA WATERS WITH
LOCALLY HEAVY SHOWERS TRAINING REPEATEDLY THROUGH THE GUAM WATERS.
ONLY ISOLATED SHOWERS ARE FOUND IN THE TINIAN AND SAIPAN WATERS.
THE VAD WIND PROFILE REVEALS GALE FORCE WEST-NORTHWEST WINDS
THROUGH THE LOWEST 8 THOUSAND FEET OF THE AIR. NOT QUITE ALL OF
THIS IS MIXING DOWN TO THE SURFACE THOUGH.

&&

.DISCUSSION...
MONSOON RAIN BAND FEEDING INTO THE DEVELOPING CIRCULATION EAST OF
THE MARIANAS IS TRAINING LOCALLY HEAVY SHOWERS OVER GUAM
REPEATEDLY. MORE THAN 7 INCHES OF RAIN HAVE FALLEN AT THE AIRPORT
SO FAR TODAY. THE HIGH WINDS AND SEAS SHOULD GRADUALLY BE PULLED
NORTH ALONG WITH THE CIRCULATION. WHETHER IT MOVES NORTHWEST OR
NORTHEAST...AND THE MODELS DISAGREE ON THIS...WILL MAKE ALL THE
DIFFERENCE. NO CHANGES TO THE LONG TERM AS THE SHORT TERM HAS A
FLASH FLOOD WARNING AND ALL KINDS OF OTHER ADVISORIES GOING ON.

&&

.MARINE...
HIGHER WINDS AND SEAS SHOULD GRADUALLY EXPAND NORTH...SO ADDED
SMALL CRAFT ADVISORY TO TINIAN AND SAIPAN WATERS. RITIDIAN BUOY
WAS RECENTLY READING 11.5 FEET. APRA HARBOR HANDAR RECENTLY HAD A
GUST TO 40 KNOTS. ASSUMING THESE GUSTS ARE MERELY OCCASIONAL...
HAVE LEFT THE SMALL CRAFT ADVISORY ALONE. IF THESE ARE DETERMINED
TO BE FREQUENT...WE MAY NEED TO UPGRADE TO A GALE WARNING. IT IS
AWFULLY CLOSE ALREADY AND WINDS WOULD NOT NEED TO GET MUCH
STRONGER.

&&

.EASTERN MICRONESIA...
A TRADE-WIND SURGE IS MOVING WESTWARD INTO THE MARSHALLS THIS
AFTERNOON WITH SIGNIFICANT CONVERGENCE ASSOCIATED WITH IT. THIS WILL
REPLACE FAIRLY DRY CONDITIONS AT MAJURO WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS BY MIDNIGHT WITH GUSTY WINDS LIKELY THROUGH
TONIGHT. SCATTERED SHOWERS WILL CONTINUE THROUGH FRIDAY NIGHT BEFORE
THE CONVERGENCE ZONE MOVES WESTWARD PAST MAJURO AND KWAJALEIN. AS
THIS SURGE APPROACHES KOSRAE FRIDAY AND POHNPEI FRIDAY
NIGHT...EXPECT AN INCREASE IN CLOUD COVER AND CONVECTION FOR BOTH
STATES AS WELL. WILL CONTINUE WITH ISOLATED WORDING FOR NOW...BUT AN
INCREASE TO SCATTERED SHOWERS IS VERY POSSIBLE FOR KOSRAE FRIDAY
NIGHT AND SATURDAY AND FOR POHNPEI SATURDAY NIGHT AND SUNDAY.
SHOWERS WILL QUICKLY DRY OUT AT MAJURO SATURDAY...AT KOSRAE MONDAY
AND POHNPEI TUESDAY. MODELS DEPICT ANOTHER DISTURBANCE NEAR THE
MARSHALL ISLANDS TO START OFF THE NEW WEEK.

&&

.WESTERN MICRONESIA...
TYPHOON USAGI...LOCATED WELL TO THE NORTHWEST OF YAP...AND JTWC
INVEST AREA 98W...CENTERED EAST OF SAIPAN...CONTINUE TO DOMINATE THE
OVERALL WEATHER PATTERN FOR WESTERN MICRONESIA. MODELS CONTINUE
TO INDICATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN
IN PLACE AT CHUUK THROUGH TONIGHT. MODELS ARE IN FAIRLY GOOD
AGREEMENT THAT WEAK RIDGING WILL BUILD INTO CHUUK BY FRIDAY MORNING
AND USHER IN DRIER CONDITIONS FOR THE STATE THROUGH THE TUESDAY.
SHOWERS WILL PUSH INTO YAP TONIGHT AND FRIDAY WITH SCATTERED SHOWERS
EXPECTED BY SATURDAY AS THE MONSOON TROUGH DRIFTS OVER THE STATE AND
REMAINS IN PLACE THROUGH THE WEEKEND. NOT QUITE AS WET AT KOROR...
WITH ISOLATED SHOWERS AND THUNDERSTORMS THROUGH SATURDAY NIGHT. THE
MAIN CONCERN FOR KOROR WILL BE WHERE THE MONSOON TROUGH ACTUALLY
DECIDES TO BECOME ENTRENCHED. IF THE TROUGH DRIFTS A LITTLE FURTHER
SOUTH...KOROR COULD POSSIBLY SEE THE SAME SHOWER ACTIVITY AS YAP.

THE HIGH SURF ADVISORY FOR YAP HAS BEEN EXTENDED TO INCLUDE NORTH
FACING REEFS AS WELL AS WEST FACING. WAVEWATCH MODELS ARE PREDICTING
LARGE...LONG PERIOD NORTHWEST SWELLS FROM TYPHOON USAGI WILL
CONTINUE TO EFFECT YAP. SURF WILL PEAK AT 10 TO 12 FEET FRIDAY BUT
WILL REMAIN ABOVE HAZARDOUS LEVELS FOR THE NEXT SEVERAL DAYS. THE
LARGE SWELL WILL ALSO PUSH INTO PALAU THIS AFTERNOON RESULTING IN
HAZARDOUS SURF ON WEST FACING REEFS ON KOROR. SURF WILL PEAK AT 10
TO 12 FEET FRIDAY EVENING AT KOROR BUT WILL REMAIN ABOVE HAZARDOUS
LEVELS FOR THE NEXT SEVERAL DAYS.

&&

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

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

&&

STANKO/KLEESCHULTE