Tropical Storm SOUDELOR Advisory Tue Aug 04

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 13W (SOUDELOR) WARNING NR 17//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 13W (SOUDELOR), LOCATED APPROXIMATELY 196 NM WEST-
NORTHWEST OF SAIPAN, HAS TRACKED WEST-NORTHWESTWARD AT 13 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) INDICATES A SLIGHT WEAKENING TREND DUE TO LOW TO MODERATE (10
TO 15 KNOTS) EASTERLY VERTICAL WIND SHEAR (VWS); HOWEVER, THE SYSTEM
HAS MAINTAINED A 7-NM PINHOLE EYE, WHICH SUPPORTS THE CURRENT
POSITION WITH GOOD CONFIDENCE. DESPITE THE SLIGHT WEAKENING TREND, A
030451Z SSMI IMAGE SHOWS A SMALL 50 TO 60NM EYEWALL WITH TIGHTLY-
CURVED BANDING WRAPPING INTO THE CENTER. THE SSMI 85GHZ AND 37GHZ
IMAGERY ALSO SHOWS A SLIGHT TILT TO THE EYE, APPROXIMATELY 10NM,
WHICH ALSO MAY BE A SHORT-TERM FACTOR IN THE RECENT WEAKENING TREND.
THE INITIAL INTENSITY HAS BEEN REDUCED SLIGHTLY TO 105 KNOTS BASED
ON AN AVERAGE OF DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM 90
TO 115 KNOTS. ANIMATED WATER VAPOR IMAGERY CONTINUES TO SHOW RADIAL
OUTFLOW, WHICH SHOULD ALLOW THE SYSTEM TO RE-INTENSIFY. IN ADDITION,
SEA SURFACE TEMPERATURES (SSTS) ARE NEAR 31 CELSIUS. TY SOUDELOR IS
CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED
SUB-TROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 13W IS FORECAST TO CONTINUE TRACKING WEST-NORTHWESTWARD
THROUGHOUT THE FORECAST PERIOD UNDER THE STEERING INFLUENCE OF THE
WELL-ESTABLISHED STR. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO
REMAIN CONDUCIVE FOR TY 13W TO RE-INTENSIFY OVER THE NEXT 48 HOURS,
REACHING SUPER TYPHOON INTENSITY BY TAU 36. AFTER TAU 48,
ENVIRONMENTAL CONDITIONS BECOME SLIGHTLY LESS FAVORABLE LEADING TO
GRADUAL WEAKENING.
   C. IN THE EXTENDED TAUS, TY 13W WILL START TO WEAKEN DUE TO
REDUCED OCEAN HEAT CONTENT, LOWER SSTS AND A SLIGHT INCREASE IN VWS
TO MODERATE LEVELS. BY THE END OF THE FORECAST PERIOD, TY SOUDELOR
WILL BEGIN TO MAKE LANDFALL OVER THE NORTHERN COAST OF TAIWAN, WHICH
WILL FURTHER WEAKEN THE TYPHOON DUE TO THE FRICTIONAL EFFECTS OF
LAND INTERACTION. DYNAMIC MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT
THROUGHOUT THE FORECAST PERIOD, WHICH SUPPORTS HIGH CONFIDENCE IN
THE JTWC FORECAST.//
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