Tropical Storm HAIMA Advisory чт, 20.10.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (HAIMA) WARNING NR
21//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 25W (HAIMA), LOCATED APPROXIMATELY 200 NM NORTH OF
MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 17 KNOTS
OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON ANIMATED
INFRARED SATELLITE IMAGERY, RADAR DATA FROM APARRI, PHILIPPINES, AND
SYNOPTIC OBSERVATIONS FROM NORTHERN LUZON. THE INTENSITY ESTIMATE OF
100 KNOTS IS CONSISTENT WITH RECENT AUTOMATED SATELLITE INTENSITY
ESTIMATES, A 191800Z RTJD SUBJECTIVE DVORAK ESTIMATE, AND
OBSERVATIONAL DATA FROM TUGEUGARAO, PHILIPPINES. TY 25W HAS WEAKENED
CONSIDERABLY OVER THE PAST SIX HOURS DUE TO AN EYEWALL REPLACEMENT
CYCLE AND LAND INTERACTION. UPPER-LEVEL ANALYSIS INDICATES THAT
EASTERLY VERTICAL WIND SHEAR HAS ALSO INCREASED OVER THE PAST SIX
HOURS. WHILE THE CONVECTIVE STRUCTURE REMAINS IMPRESSIVE, THE EYE
HAS BECOME FULLY CLOUD FILLED. THE SYSTEM CONTINUES TO TRACK WEST-
NORTHWESTWARD ALONG THE PERIPHERY OF A SUBTROPICAL STEERING RIDGE
POSITIONED TO THE NORTH AND EAST.
3. FORECAST REASONING.
   A. THE MEDIUM-RANGE FORECAST TRACK HAS SHIFTED SLIGHTLY TO THE
WEST BASED ON AN ASSESSMENT OF THE LATEST NUMERICAL MODEL GUIDANCE
PACKAGE. THE FORECAST PERIOD HAS ALSO BEEN REDUCED TO 72 HOURS BASED
ON ANTICIPATED DISSIPATION OVER LAND BY THAT TIME.
   B. TY 25W IS EXPECTED TO CROSS NORTHERN LUZON AND REEMERGE OVER
WATER IN THE NORTHERN PORTION OF THE SOUTH CHINA SEA WITHIN THE NEXT
SEVERAL HOURS. STEADY WEAKENING IS ANTICIPATED IN THE NEAR-TERM DUE
TO LAND INTERACTION AND MODERATE EASTERLY VERTICAL WIND SHEAR. THE
SYSTEM IS EXPECTED TO ROUND THE WESTERN PERIPHERY OF THE STEERING
RIDGE DURING THE REMAINDER OF THE FORECAST PERIOD, MAKING LANDFALL
TO THE EAST OF HONG KONG AROUND TAU 36. ADDITIONAL WEAKENING IS
EXPECTED DUE TO PERSISTENT EASTERLY VERTICAL WIND SHEAR AND
DECREASING ALONG-TRACK OCEAN HEAT CONTENT AS THE CIRCULATION TRACKS
ACROSS THE NORTHERN PORTION OF THE SOUTH CHINA SEA. TY 25W IS
EXPECTED TO DISSIPATE BY TAU 72 AS IT TRACKS INLAND. NUMERICAL MODEL
FORECAST TRACK GUIDANCE INDICATES VERY GOOD AGREEMENT, AND THE
CURRENT FORECAST TRACK LIES NEAR THE MULTI-MODEL CONSENSUS WITH HIGH
CONFIDENCE.//
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