FXPQ60 PGUM 250600
AFDPQ 
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
400 PM CHST WED NOV 25 2009
.SYNOPSIS...TYPHOON NIDA LOCATED ABOUT 150 NM SOUTHWEST OF GUAM IS
SKIRTING PAST THE SOUTHERN MARIANAS AS A VERY INTENSE TROPICAL
CYCLONE. A WELL DEFINED EYE IS EVIDENT ON BOTH SATELLITE AND RADAR.
WINDS IN THE SOUTHERN MARIANAS ARE 20 TO 30 KT AND NEAR-GALE FORCE
WINDS ARE LIKELY IN THE GUAM COASTAL WATERS SOUTHWEST OF GUAM. THE
MARINE CONDITIONS HAVE BEEN INITIALIZED FROM THE IPAN BUOY...WHICH
SHOWED A MARKED INCREASE IN SEA HEIGHTS AROUND 1 PM TO AROUND 15
FEET WITH A 10-11 SECOND PERIOD. THIS PROMPTED US TO UPGRADE THE
HIGH SURF ADVISORY TO A HIGH SURF WARNING FOR GUAM AND ROTA. THE
POTENTIAL FOR COASTAL INUNDATION FROM POUNDING SURF IS MODERATE ON
SOUTHEASTERN EXPOSURES TONIGHT.
&&
.DISCUSSION...TYPHOON NIDA IS ACTING WELL-BEHAVED AS IT PASSES THE
SOUTHERN MARIANAS. NO SIGNIFICANT WOBBLES OR ERRATIC MOVEMENT HAS
BEEN OBSERVED ON RADAR TODAY. THE TYPHOON IS MOVING AS EXPECTED BY
THE VARIOUS GLOBAL MODELS. WE HAVE A HIGH DEGREE OF CONFIDENCE IN
THE POSITION...MOVEMENT AND THE JTWC FORECAST TRACK. THIS MEANS IT
WILL CONTINUE MOVING TANGENTIALLY TO THE MARIANA ISLANDS TONIGHT
WITH CLOSEST APPROACH STAYING AROUND 150 NM. FORECAST CONTINUES TO
BE BASED ON THIS SCENARIO...AND APPEARS TO BE ON TRACK...EXCEPT FOR
THE UNEXPECTED JUMP IN SEA HEIGHTS FROM THE IPAN BUOY. WE EXPECT
WINDS TO REMAIN STRONG AND GUSTY THROUGH THE THANKSGIVING HOLIDAY
THEN GRADUALLY DIMINISH THURSDAY NIGHT. SHOWER ACTIVITY WILL BE
HIGHLY VARIABLE THE NEXT COUPLE OF DAYS DEPENDING ON WHETHER RAIN
BANDS FORM NEAR THE ISLANDS OR NOT. SO FAR TODAY RAIN HAS STAYED
CLEAR AS THE SHOWERS REMAIN CONCENTRATED NEAR THE TYPHOON CENTER.
&&
.MARINE...WINDS AND SEAS WILL REMAIN STRONG AND GUSTY THE NEXT 24
TO 36 HOURS AS TYPHOON NIDA PASSES NEAR THE SOUTHERN MARIANAS.
CONDITIONS WILL BE HAZARDOUS FOR SMALL VESSELS AND INEXPERIENCED
SAILORS. A SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL FRIDAY.
&&
.EASTERN MICRONESIA...CONT PREV FORECAST TRENDS. SATELLITE SHOWS
THAT SCATTERED SHOWERS AND A FEW THUNDERSTORMS ASSOCIATED WITH A
TRADE-WIND DISTURBANCE OVER THE WESTERN MARSHALL ISLANDS HAVE
MOVED INTO THE KOSRAE AREA THIS AFTERNOON. THIS SYSTEM HAS BEEN
MOVING SLOWLY WESTWARD AND WILL LIKELY AFFECT KOSRAE THROUGH
FRIDAY...AND AFFECT POHNPEI LATE THURSDAY THROUGH SATURDAY. IN THE
LONGER TERM...MODEL GUIDANCE INDICATES LIGHT EASTERLY WINDS AND
ISOLATED SHOWERS ACROSS THE AREA.
&&
.WESTERN MICRONESIA...RE-ISSUED HIGH SURF ADVSY TO INCLUDE PALAU
FOR ALL COASTAL EXPOSURES. SWELLS AND WIND WAVES WILL ARRIVE FROM
SEVERAL DIRECTIONS AND MOST SHORELINES WILL BECOME HAZARDOUS.
TYPHOON NIDA IS NEAR 11N143E...AND HAS BEEN MOVING NW MORE
PREDICTABLY THAN YESTERDAY. A MOTE AREA CONTINUES ACROSS YAP THIS
AFTN...BUT W-SW SURFACE WINDS WILL DOMINATE AT BOTH PALAU AND YAP
THE NEXT FEW DAYS. PERIODS OF SCATTERED SHOWERS ARE EXPECTED TO
DEVELOP TONIGHT THROUGH FRIDAY NIGHT AT KOROR AND PROBABLY LONGER
AT YAP. A SURFACE RIDGE OF HIGH PRES LINGERS BETWEEN CHUUK AND
POHNPEI TODAY. THE RIDGE WILL DRIFT WESTWARD ACROSS CHUUK THE NEXT
COUPLE OF DAYS...BUT WEATHER WILL LIKELY DETERIORATE AFTERWARD.
GFS INDICATES THE DISTURBANCE APPROACHING KOSRAE MAY BECOMING A
WEAK CIRCULATION AND MOVE TOWARD CHUUK BY THIS WEEKEND.
&&
.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF WARNING UNTIL NOON CHST THURSDAY FOR GUZ001-002.
     HIGH SURF ADVISORY UNTIL 6 PM CHST FRIDAY FOR GUZ003-004.
MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 10 AM CHST FRIDAY FOR
PMZ151>154. 
&&
$$
MUNDELL/SIMPSON