Tropical Storm SANBA Advisory 2月9日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 02W (TWO) WARNING
NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 02W (TWO), LOCATED APPROXIMATELY 243 NM
SOUTHEAST OF ANDERSEN AFB, HAS TRACKED NORTH-NORTHWESTWARD AT 12
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY REVEALS A BROAD ELONGATED LOW LEVEL CIRCULATION
WITH FALRING CONVECTION ALONG ITS AXIS AND A BROAD AREA OF
CONVECTION TO THE NORTHEAST. THE ANIMATION DOES REVEAL SOME MID
LEVEL TURNING IN THE CONVECTIVE MASS TO THE NORTH OF THE INITIAL
POSITION; HOWEVER, THERE IS NOT AN LLC ASSOCIATED WITH THAT
CONVECTION AT THIS TIME. THE INITIAL POSITION IS PLACED WITH LOW
CONFIDENCE BASED ON ANIMATED EIR IMAGERY ALONG WITH A 081647Z SSMI
85 GHZ MICROWAVE SATELLITE IMAGE SHOWING LOW LEVEL CLOUD WRAPPING
INTO AN ELONGATED CENTRAL AREA. THE CURRENT INTENSITY IS ASSESED AT
20 KNOTS BASED ON THE LACK OF CONSISTENT CONVECTION OVER THE LLC AND
SUPPORTED BY A 081005Z OSCAT IMAGE. THE ENVIRONMENT IS FAVORABLE
WITH 5 TO 10 KNOTS OF VWS AND GREATER THAN 28C SSTS. THE SYSTEM IS
CURRENTLY TRACKING NORTHWESTWARD ALONG THE SOUTHERN BOUNDARY OF A
STR TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST
PHILOSOPHY.
   B. TD 02W IS EXPECTED TO TURN TOWARDS THE SOUTHWEST AFTER TAU 12
UNDER THE INFLUENCE OF A STEERING RIDGE TO THE NORTHWEST. IT WILL
THEN TRACK DUE WEST AFTER TAU 48 ALONG THE SOUTHERN PERIPHERY OF THE
STEERING RIDGE. THE SYSTEM IS EXPECTED TO GRADUALLY INTENSIFY UNTIL
TAU 72 AS IT ENCOUNTERS FAVORABLE SSTS AND FAVORABLE TO MARGINAL
WINDSHEAR.
   C. AFTER TAU 72, LAND INTERACTION WITH THE PHILLIPINES IS EXPECTED
TO SPIN DOWN THE SYSTEM. NUMERICAL MODEL GUIDANCE IS IN FAIRLY TIGHT
AGREEMENT; HOWEVER, DUE TO UNCERTAINTY IN THE INITIAL POSITION, THERE
IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST AT THIS TIME.//
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