Tropical Storm SOUDELOR Advisory Mon Aug 03

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 13W (SOUDELOR) WARNING
NR 18//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 13W (SOUDELOR), LOCATED APPROXIMATELY 268 NM
WEST-NORTHWEST OF SAIPAN, HAS TRACKED WEST-NORTHWESTWARD AT 12 KNOTS
OVER THE PAST SIX HOURS. AFTER A BRIEF WEAKENING PERIOD DUE TO AN
EYEWALL REPLACEMENT CYCLE, STY 13W HAS RAPIDLY INTENSIFIED AS
DEPICTED IN ENHANCED INFRARED SATELLITE IMAGERY, WHICH DEPICTS A 20-
NM EYE. OVER THE PAST 24 HOURS, STY 13W HAS INTENSIFIED FROM 90
KNOTS TO THE CURRENT INTENSITY OF 135 KNOTS. DVORAK INTENSITY
ESTIMATES HAVE JUMPED AS HIGH AS T7.0 (140 KNOTS), HOWEVER, THE
CURRENT INTENSITY ASSESSMENT IS CONSERVATIVELY HELD AT AN AVERAGE OF
ESTIMATES RANGING FROM T6.5 (RJTD) TO T7.0 (PGTW). A 031204Z METOP-B
89GHZ IMAGE SHOWS A COMPACT 50 TO 60NM DIAMETER EYEWALL WITH TIGHTLY-
CURVED SPIRAL BANDING. ANIMATED WATER VAPOR IMAGERY CONTINUES TO
SHOW RADIAL OUTFLOW, WHICH SHOULD ALLOW THE SYSTEM TO INTENSIFY
FURTHER. IN ADDITION, SEA SURFACE TEMPERATURES (SSTS) ARE NEAR 31
CELSIUS. STY 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. PEAK INTENSITY HAS BEEN
INCREASED FROM 135 TO 150 KNOTS WITH STY INTENSITY OCCURRING QUICKER
THAN PREVIOUSLY ANTICIPATED.
   B. STY 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 STY 13W TO INTENSIFY OVER THE NEXT 36 TO 48
HOURS, MAINTAINING SUPER TYPHOON INTENSITY DURING THIS PERIOD. AFTER
TAU 48, ENVIRONMENTAL CONDITIONS BECOME SLIGHTLY LESS FAVORABLE
LEADING TO GRADUAL WEAKENING.
   C. IN THE EXTENDED TAUS, STY 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, STY SOUDELOR
WILL BEGIN TO MAKE LANDFALL OVER THE NORTHERN COAST OF TAIWAN, WHICH
WILL FURTHER WEAKEN THE SYSTEM 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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