WDPN32 PGTW 191500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (HAIMA) WARNING NR
20//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 25W (HAIMA), LOCATED APPROXIMATELY 206 NM NORTHEAST
OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 16 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY INDICATES A GENERAL WEAKENING TREND AS THE SYSTEM BEGINS TO
INTERACT WITH LUZON. EIR SHOWS A CLOUD-FILLED EYE, WHICH SUPPORTS
THE CURRENT POSITION WITH HIGH CONFIDENCE. AS MENTIONED IN THE
PREVIOUS PROGNOSTIC REASONING BULLETIN, RECENT MICROWAVE IMAGERY TO
INCLUDE A 190956Z CORIOLIS 37GHZ IMAGE CONTINUES TO SHOW CONCENTRIC
EYEWALLS AND AN APPARENT EYEWALL REPLACEMENT CYCLE (ERC). THE ERC AS
WELL AS INTERACTION WITH LAND HAS CONTRIBUTED TO THE RECENT
WEAKENING TREND. DVORAK INTENSITY ESTIMATES CONTINUE TO DECREASE
WITH RECENT ESTIMATES RANGING FROM 115 TO 127 KNOTS, WHICH SUPPORTS
THE INITIAL INTENSITY ESTIMATE OF 120 KNOTS. UPPER-LEVEL ANALYSIS
INDICATES A FAVORABLE UPPER-LEVEL ENVIRONMENT INCLUDING RADIAL
OUTFLOW AND LOW VERTICAL WIND SHEAR. TY 25W IS TRACKING ALONG THE
SOUTHERN PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING BULLETIN.
   B. TY HAIMA IS FORECAST TO MAKE LANDFALL NEAR TAU 06 OVER THE
NORTHEASTERN COAST OF LUZON AS IT TRACKS WEST-NORTHWESTWARD ALONG
THE SOUTHWEST PERIPHERY OF THE STR. TY 25W WILL WEAKEN AS IT
APPROACHES THE COAST DUE TO THE ERC AND THEN MORE RAPIDLY OVER THE
MOUNTAINOUS TERRAIN OF LUZON BEFORE RE-EMERGING OVER WATER NEAR TAU
12. AFTER TAU 24, THE SYSTEM WILL TURN NORTHWESTWARD AS IT TRACKS
ALONG THE SOUTHWEST PERIPHERY OF THE STR BEFORE MAKING LANDFALL
AGAIN JUST NORTHEAST OF HONG KONG NEAR TAU 48. DYNAMIC GUIDANCE
REMAINS IN EXCEPTIONALLY TIGHT AGREEMENT THROUGH TAU 72 LENDING HIGH
CONFIDENCE TO THIS PHASE OF THE FORECAST TRACK.
   C. AFTER TAU 72, TY WILL RE-CURVE OVER SOUTHEAST CHINA WHILE
RAPIDLY WEAKENING DUE TO INCREASED VERTICAL WIND SHEAR AND LAND
INTERACTION. THE SYSTEM IS FORECAST TO REMAIN OVER LAND FOR ABOUT
TWO DAYS WHICH WILL SIGNIFICANTLY WEAKEN THE SYSTEM TO TROPICAL
DEPRESSION STRENGTH BEFORE IT TRACKS OVER THE EAST CHINA SEA NEAR
TAU 90. AS IT RE-EMERGES BACK OVER WATER, TY 25W WILL BEGIN TO
INTERACT WITH THE SOUTHERN PERIPHERY OF THE BAROCLINIC ZONE AND WILL
BEGIN TO TRANSITION TO AN EXTRA-TROPICAL LOW. ADDITIONALLY, TY 25W
WILL ACCELERATE EASTWARD AS IT BECOMES EMBEDDED WITHIN THE WESTERLY
FLOW NORTH OF THE STR. ALTHOUGH THE SYSTEM IS EXPECTED TO WEAKEN
BELOW 25 KNOTS AFTER TAU 96, THERE IS SOME POTENTIAL FOR THE SYSTEM
TO RE-STRENGTHEN AS AN EXTRA-TROPICAL LOW AFTER TAU 120; HOWEVER,
THERE IS NO POTENTIAL FOR REGENERATION AS A TROPICAL LOW AS THE
SYSTEM WILL GAIN FRONTAL CHRACTERISTICS. OVERALL, THERE IS HIGH
CONFIDENCE IN THE JTWC FORECAST TRACK.//