Area Forecast Discussion
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000
FXPQ60 PGUM 010831
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
631 PM CHST SAT AUG 1 2015

.SYNOPSIS...
PGUA DOPPLER WEATHER RADAR SHOWS ISOLATED SHOWERS MOVING THROUGH
THE MARIANAS WATERS. SATELLITE SHOWS TROPICAL STORM SOUDELOR TO
THE EAST WHICH IS GRADUALLY APPROACHING THE MARIANAS. THE VAD WIND
PROFILE REVEALS DEEP NORTHEAST WINDS OF 15 TO 25 KNOTS THROUGH THE
LOWEST 40 THOUSAND FEET OF THE AIR.

&&

.DISCUSSION...
TROPICAL STORM SOUDELOR IS THE BIG FORECAST PROBLEM...WHICH WILL
BE HIGHLIGHTED UNDER THE TROPICAL SYSTEMS SECTION. OTHERWISE...
THE BIG ACTION WILL BE THE APPROACH OF THE MONSOON TROUGH. THIS
HAS THE POTENTIAL TO DUMP 6 TO 10 INCHES OF RAIN NEXT WEEK. THIS
WILL BE ENOUGH TO INDUCE PERIODS OF MINOR FLOODING DURING THE
HEAVIEST SHOWERS. THE CLOUDS AND SHOWERS COULD GO ON A FEW DAYS
LONGER THAN WHAT IS CURRENTLY IN THE FORECAST. MAY HAVE TO EXTEND
THEM...PERHAPS MORE THAN ONCE.

&&

.MARINE...
BUOYS ARE SHOWING 3 TO 4 FEET RIGHT NOW. EXPECT THEM TO INCREASE
DRAMATICALLY OVER THE NEXT 24 HOURS. WINDS WILL ALSO INCREASE...
ESPECIALLY NORTH OF TROPICAL STORM SOUDELOR. AFTER SOUDELOR PASSES
ON MONDAY...MARINE CONDITIONS WILL GRADUALLY IMPROVE. HOWEVER...IT
WILL BE QUITE SOME TIME BEFORE THEY REACH THE BENIGN LEVELS WE
HAVE BEEN ENJOYING RECENTLY.

&&

.TROPICAL SYSTEMS...
TROPICAL STORM SOUDELOR KEEPS GETTING FORECAST TO INTENSIFY AND TO
TURN NORTHWEST. ALL LAST NIGHT AND ALL DAY TODAY IT HAS REMAINED
A LOW-END TROPICAL STORM AND BARRELED ALMOST STRAIGHT WEST. THE
CURRENT JTWC TRACK HAS IT PASSING BETWEEN SAIPAN AND ANATAHAN.
SINCE THE STRONGEST WINDS ARE NORTH OF THE CENTER...THIS WOULD BE
IDEAL FROM THE STANDPOINT OF REDUCING DAMAGE. HOWEVER...THE ECMWF-
HIRES TAKES IT OVER TINIAN AND SAIPAN. THE GFS75 TAKES IT OVER
TINIAN AND SAIPAN. THE UKMET TAKES IT SOUTH OF TINIAN. HOPEFULLY
SOUDELOR WILL NOT STRENGTHEN MUCH UNTIL IT IS WEST OF THE
MARIANAS...BECAUSE IT IS STARTING TO LOOK LIKE TINIAN AND SAIPAN
MAY GET THE WORSE WINDS OF THE NORTH SIDE. THIS IS WHY WE WENT
AHEAD AND UPGRADED THEIR TYPHOON WATCH TO A TYPHOON WARNING.

&&

.EASTERN MICRONESIA...
LITTLE CHANGE TO THE FORECAST PATTERN AND REASONING. TROPICAL
STORM SOUDELOR IS NOW LOCATED NORTH OF CHUUK NEAR 14N153E AND
CONTINUES TO MOVE WEST. THE MONSOON TROUGH EXTENDS SOUTHEASTWARD
FROM SOUDELOR THROUGH A WEAK CIRCULATION NEAR 3N166E TO END AT
EQ176E. CONVERGENT WINDS FLOWING INTO SOUDELOR ARE GENERATING
SCATTERED SHOWERS AND A FEW THUNDERSTORMS OVER CHUUK...
POHNPEI...KWAJALEIN AND KOSRAE. THESE SHOWERS WILL CONTINUE
THROUGH THE NIGHT AS THE STORM CONTINUES TO MOVE TOWARD THE
MARIANAS. ACTIVE CONVECTION CONTINUES ALONG THE MONSOON TROUGH
THROUGH KOSRAE STATE WITH SCATTERED SHOWERS AND A FEW
THUNDERSTORMS. THE CONVECTION ASSOCIATED WITH THE TROUGH IS NOW TO
THE WEST OF MAJURO WITH IMPROVING CONDITIONS AT MAJURO THE NEXT
FEW DAYS. THE CIRCULATION WEST OF MAJURO WILL HELP MAINTAIN A
MONSOON PATTERN OVER KOSRAE THROUGH TONIGHT...WITH A DRIER AND
MORE PLEASANT PATTERN MOVING IN FROM THE MARSHALL ISLANDS SUNDAY
EVENING. DRIER CONDITIONS WILL SPREAD WESTWARD...OVER POHNPEI
MONDAY AND OVER CHUUK LATER IN THE WEEK.

WESTERLY WINDS WILL CAUSE SIGNIFICANT SWELL AND WIND WAVES ALONG THE
WEST COASTS OF MICRONESIA. THE WW3 MODEL AND ALTIMETRY DATA INDICATE
SHORT-PERIOD WAVES WILL BE UP TO 5 OR 6 FEET ACROSS THE AREA IN THE
COMING DAYS. IF THE WEST SWELL BUILDS UP TO AROUND 7 FEET...THEN
HIGH SURF ADVISORIES MAY BE NEEDED.

&&

.WESTERN MICRONESIA...
CHUUK DISCUSSION IS INCLUDED ABOVE WITH THE EASTERN MICRONESIAN
DISCUSSION DUE TO A SIMILAR SYNOPTIC PATTERN.

THE MONSOON TROUGH STRETCHES EASTWARD FROM 10N130E TO ABOUT 10N140E
THEN TURNS NORTHEASTWARD TO TROPICAL STORM SOUDELOR. CONVERGENCE
SOUTH OF THE TROUGH IS GENERATING SCATTERED SHOWERS AND A FEW
THUNDERSTORMS OVER THE REPUBLIC OF PALAU THIS AFTERNOON. MOST OF THE
CONVECTION AND INSTABILITY WILL REMAIN TO THE SOUTH OF YAP BUT THE
MORNING SOUNDING INDICATED CONDITIONS SUITABLE FOR THUNDERSTORMS SO
ADDED ISOLATED THUNDERSTORMS TO TONIGHTS AND SUNDAYS FORECAST.
EXPECT A FEW THUNDERSTORMS OVER THE STATE EARLY NEXT WEEK.

SEAS WILL RESPOND TO THE WESTERLY WINDS WITH COMBINED SEAS BUILDING
ACROSS PALAU AND YAP THIS WEEKEND. THE WEST SURF IN PARTICULAR COULD
BECOME HAZARDOUS BY TUESDAY OR WEDNESDAY.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...TROPICAL STORM WATCH FOR GUZ002.
     TYPHOON WARNING FOR GUZ003-004.

MARIANAS WATERS...TROPICAL STORM WATCH FOR PMZ152.
                  TYPHOON WARNING FOR PMZ153-154.

&&

$$

STANKO/ZIOBRO/DEVITA



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