APCEDI ALERT 09F #2, 2005: Gale Watches for Samoa and American Samoa

Tropical Depression 09F continues slow moving about 220 nm (407 km) eastnortheast of Pago Pago, American Samoa. Gale watches and small craft advisories have now been raised for both Samoa and American Samoa. Both the Joint Typhoon Warning Center and the Fiji Meteorological Service are currently tracking the system. Models are somewhat mixed over the trend of system 09F given the complex interaction with the competing system 08F which has also formed to the west.

People in Samoa, American Samoa, Tokelau, Cook Islands and Niue should monitor the progress of both tropical systems 09F and 08F over the next 24-48 hours. Authorities in the Cook Islands should pay close attention as several main islands have already sustained damage from Cyclone Meena and are thus currently more vulnerable even to a small system.

FROM SAMOA METEOROLOGICAL SERVICE
http://www.meteorology.gov.ws/forecast.htm

SPECIAL WEATHER BULLETIN NUMBER FOUR (4) FOR SAMOA ISSUED BY SAMOA METEOROLOGY SERVICES AT 112300.UTC OR 12:00 P.M. FRIDAY 11th FEBRUARY 2005

..... A GALE WATCH REMAINS IN FORCE FOR SAMOA FOR THE NEXT 24 TO 48 HOURS…

A TROPICAL DEPRESSION WAS LOCATED 13.5 SOUTH 168.4 WEST OR ABOUT 194 NAUTICAL MILES NORTHEAST OF APIA AT 111800Z OR 7:00 AM THIS MORNING. THE DEPRESSION IS MOVING SOUTHSOUTHEAST AT 05 MPH AND EXPECTED TO INTENSIFY TO TROPICAL CYCLONE STRENGTH WITHIN THE NEXT 24 TO 36 HOURS. WINDS OF 25 TO 30 KNOTS OR 30 TO 35 MPH CLOSE TO THE CENTRE.

FOR SAMOA: Variable winds of 10 to 15 mph and may increase to 30 to 40 mph within the next 24 to 48 hours. Cloudy with isolated showers, becoming frequent tomorrow with isolated thunderstorms. Seas moderate but rough in open waters with high swell of 4 to 6 feet developing.

FROM WEATHER SERVICE OFFICE, AMERICAN SAMOA
http://www.prh.noaa.gov/pr/samoa/

NARRATIVE SYNOPTIC DISCUSSION FOR AMERICAN SAMOA AND THE INDEPENDENT STATE OF SAMOA

NATIONAL WEATHER SERVICE PAGO PAGO AS

2 PM SST FRI FEB 11 2005

SHORT TERM

TONIGHT THROUGH SUNDAY...

TROPICAL DEPRESSION 09F IS LOCATED IN THE EAST TO NORTHEAST VICINITY OF TUTUILA AND MANUA THIS AFTERNOON. VISIBLE IMAGERY SHOWS A LARGE AREA OF EMBEDDED CLOUDS LINKED TO T.D. 09F, AS WELL AS ISOLATED TO SCATTERED SHOWERY BANDS AND CUMULONIMBUS MOVING ACROSS MANUA WATERS AT 1330 PM LOCAL TIME. NUMERICAL MODELS ARE DOWNPLAYING THE EXPOSURE OF T.D. 09F THROUGH SATURDAY AND SUNDAY. HOWEVER, AN INCREASE IN WINDS ARE EXPECTED TO IMPACT LOCAL CONDITIONS OVER EASTERN ISLANDS BY SUNDAY, WITH A MORE PRONOUNCED EFFECT OVER MANUA AS THE DEVELOPING SYSTEM LIES WITHIN 40 TO 60 MILES EAST TO SOUTHEAST OF MANUA. ANTICIPATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH THE FORECAST PERIOD. T.D. 09F WILL GENERATE SWELLS OF 5 TO 7 FEET BY SUNDAY.

LONG TERM

OUTLOOK FOR MONDAY THROUGH WEDNESDAY...

IMPACT OF STRONGER WINDS ASSOCIATED WITH THE DEVELOPING STORM FROM AN EARLIER PERIOD ARE EXPECTED TO REMAIN OVER THE REGION THROUGH WEDNESDAY. MODELS ARE DELAYING THE MOVEMENT OF THE STORM UNTIL TUESDAY DUE TO A STRONG AREA OF HIGH PRESSURE FARTHER SOUTHEAST OF RAROTONGA. AS THE STORM INTENSIFY AND EXPAND IN SIZE, A SURFACE RIDGE OBSCURING THE MOVEMENT OF THE STORM WILL DISSIPATE. STORM GENERATED SWELLS OF 8 TO 12 FEET WILL GENERATE SURF OF 16 TO 24 FEET ALONG SOUTH SEMICIRCLE AREA OF ALL ISLANDS.

&&

.PPG WATCHES/WARNINGS/ADVISORIES...

GALE WATCH AND SCA FOR AMERICAN SAMOA.

&&

THIS PRODUCT WILL BE UPDATED AT 2 PM SST SATURDAY BY WSO PAGO PAGO OR SOONER IF CONDITION WARRANT.

CMB

FROM FIJI METEOROLOGICAL SERVICE
http://www.met.gov.fj/

Tropical Disturbance Advisory Number A7 issued from RSMC NADI
Feb 12/1349 UTC 2005 UTC.

TROPICAL DEPRESSION 09F CENTRE [997hPa] WAS LOCATED NEAR 13.3S 166.7W AT 121200 UTC MOVING EAST ABOUT 05 KNOTS. POSITION POOR BASED ON GOES9 EIR IMAGERY WITH ANIMATION. 10-MINUTE AVERAGE WINDS 30 KNOTS CLOSE TO THE CENTRE, INCREASING TO 35 KNOTS WITHIN 120 MILES OF CENTRE IN SECTORS FROM NORTH THROUGH EAST TO SOUTH AND WITHIN 50 MILES OF CENTRE ELSEWHERE IN THE NEXT 12 HOURS.

A SMALL CDO HAS APPEARED JUST EAST OF THE LLCC RECENTLY. CONVECTION WRAPS 0.55 ON LOG10 SPIRAL, YIELDING T2.5/2.5/D1.0/24HRS. DT, MET AND PT AGREE AT 2.5. 09F REMAINS IN A REGION OF STRONG DIFFLUENCE. OUTFLOW IS GOOD IN THE EASTERN SEMICIRCLE. AN APPROACHING TROUGH FROM THE SOUTHWEST IS PROVIDING AN INCREASE IN SHEAR AND THIS HAS RETARDED THE DEVELOPMENT OF THE SYSTEM SOFAR. A MID-LEVEL RIDGE FROM THE EAST IS EXPECTED TO STEER 09F SOUTHWARDS. GLOBAL MODELS HAVE STARTED TO DIFFER IN OPINION ABOUT 09F. BRACKNELL AND NOGAPS FAVOUR INTENSIFICATION OF DEPRESSION 08F LOCATED TO THE NORTHWEST OF 09F. ECMWF, GFS AND GFDL SUPPORT 09F AT THE EXPENSE OF 08F.

THE NEXT TROPICAL DISTURBANCE ADVISORY ON 09F WILL BE ISSUED AROUND 122030 UTC.

APCEDI will continue to monitor the progress of this tropical system.

Kevin Vang
APCEDI Coordinator
http://www.afap.org/apcedi/