Tropical Storm SIX Advisory Mon Aug 10

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (SIX)
WARNING NR 1//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 06W (SIX), LOCATED APPROXIMATELY 350 NM
EAST-NORTHEAST OF IWO TO, HAS TRACKED WESTWARD AT 07 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY DEPICTS A COMPACT, SYMMETRIC SYSTEM OF DEEP CONVECTION
OBSCURING A LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE LOW LEVEL
CIRCULATION (LLC) FEATURE PRESENT IN A 091136Z AMSU COMPOSITE
IMAGE. THE INITIAL INTENSITY OF 35KTS IS PLACED WITH HIGH
CONFIDENCE BASED ON A PARTIAL 091137Z ASCAT-B IMAGE DEPICTING
35 KTS WINDS ALONG THE EASTERN PERIPHERY OF THE LLC AND HEDGED
ABOVE A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T1.5 (25 KTS)
BASED ON THE SCATTEROMETRY DATA. TS 06W IS TRACKING ALONG THE
SOUTHERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) AND THROUGH AN
UNFAVORABLE ENVIRONMENT FOR CONTINUED DEVELOPMENT WITH MODERATE
(15-20) KTS) VERTICAL WIND SHEAR (VWS) AND WEAK UPPER LEVEL
OUTFLOW OFFSET BY WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES.
3. FORECAST REASONING.
   A. THIS IS THE FIRST PROGNOSTIC REASONING MESSAGE AND SETS
THE FORECAST PHILOSOPHY.
   B. TS 06W IS FORECAST TO CONTINUE TRACKING WESTWARD ALONG
THE SOUTHERN EDGE OF THE STR. THE ENVIRONMENT WILL BECOME
INCREASINGLY UNFAVORABLE DUE TO THE ROBUST EASTERLY FLOW ALOFT,
LEADING TO A RISE IN VWS TO 25 KTS BY TAU 12 AND 30 KTS BY TAU
48. DESPITE THE CONTINUED WARM (29-30 CELSIUS) SSTS DURING THIS
TIME, THE SYSTEM IS FORECAST TO WEAKEN TO 30 KTS BY TAU 12 AND
25 KTS BY TAU 24. CONTINUED HIGH (25-30 KTS) VWS AT TAU 36 WILL
CAUSE THE SYSTEM TO BEGIN DISSIPATION OVER WATER AND LEAD TO
DISSIPATION OVER WATER BY TAU 72 AFTER WEAKENING TO 20 KTS.
NUMERICAL MODEL SOLUTIONS ARE IN TIGHT AGREEMENT LENDING HIGH
CONFIDENCE TO THE OVERALL JTWC FORECAST TRACK.//
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