Tropical Storm FITOW Advisory Mon Sep 30

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 22W (TWENTY-TWO)
WARNING NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 22W (TWENTY-TWO), LOCATED APPROXIMATELY 336
NM NORTHWARD OF KOROR, PALAU HAS TRACKED NORTHWARD AT 07 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
DEPICTS A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH
IMPORVED FORMATIVE BANDING ALONG THE NORTHERN AND SOUTHERN
PERIPHERIES WRAPPING INTO A MORE DEFINED LLCC. A 300519Z TRMM
37GHZ MICROWAVE IMAGE ALSO SHOWS IMPROVED CONVECTIVE BANDING
WRAPPING INTO AN INCREASINGLY DEFINED CENTER. A 300312Z OSCAT PASS
ADDITIONALLY SHOWS CONSOLIDATION AS THE LLCC HAS BECOME MORE
DEFINED. THE INITIAL POSITION IS BASED UPON THE MSI LOOP AND THE
MICROWAVE IMAGE WITH FAIR CONFIDENCE. THE INITIAL INTENSITY IS
ASSESSED AT 25 KNOTS BASED UPON THE OSCAT PASS AND DVORAK INTENSITY
ESTIMATES FROM RJTD AND KNES. UPPER-LEVEL ANALYSIS INDICATES A
FAVORABLE ENVIRONMENT WITH GOOD EQUATORWARD OUTFLOW AND LOW TO
MODERATE (10-20 KNOTS) VERTICAL WIND SHEAR. TD 22W IS CURRENTLY
TRACKING NORTH ALONG THE WESTERN PERIPHERY OF THE NEAR-EQUATORIAL
RIDGE (NER) LOCATED EAST OF THE SYSTEM.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST
PHILOSOPHY.
   B. TD 22W IS EXPECTED TO TRACK GENERALLY NORTH ALONG THE NER
THROUGH THE NEXT 72 HOURS. FAVORABLE ENVIRONMENTAL CONDITIONS OF
GOOD OUTFLOW, LOW VWS, AND WARM SEA SURFACE TEMPERATURES WILL ALLOW
FOR GENERAL INTENSIFICATION, REACHING TYPHOON STRENGTH BY TAU 48,
THROUGH THE NEXT 96 HOURS.
   C. AFTER TAU 72, A MID-LATITUDE TROUGH WILL BE PROPAGATING OVER
JAPAN, WHICH WILL ALLOW A LOBE OF THE SUBTROPICAL RIDGE TO BUILD IN
SOUTH OF JAPAN AND BECOME THE DOMINATE STEERING INFLUNCE OF TD 22W.
THIS SHIFT OF STEERING INFLUENCE WILL CAUSE TD 22W TO BEGIN TO TRACK
TO THE NORTHWEST. AFTER REACHING A PEAK INTENSITY OF 85 KNOTS AT TAU
96, TD 22W WILL SLOWLY BEGIN TO WEAKEN AS SEA SURFACE TEMPERATURES
START TO DECREASE AND VWS BEGINS TO INCREASE IN RESPONSE TO THE
TROUGH OVER JAPAN. DYNAMIC MODEL GUIDANCE IS WIDELY SPREAD THROUGH
THE FORECAST WITH LARGE VARIANCES IN THE NORTHWEST TURN AND TRACK
SPEEDS. DUE TO THIS, THE JTWC FORECAST IS LAID CLOSE TO MULTI-MODEL
CONSENSUS WITH LOW CONFIDENCE.//
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