WDPN31 PGTW 022100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 29W (KAMMURI) WARNING NR 029//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS. 
   TYPHOON (TY) 29W (KAMMURI), LOCATED APPROXIMATELY 166 NM EAST-
SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 13 KNOTS 
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE 
IMAGERY DEPICTS THE SYSTEM HAS FURTHER CONSOLIDATED WITH A 25-NM 
OBLONG EYE, WHICH SUPPORTS THE CURRENT POSITION WITH GOOD 
CONFIDENCE. TY 29W IS CURRENTLY SITUATED OVER THE PHILIPPINES, 21 NM 
WEST OF LEGASPI. LEGASPI (98444) REPORTED A MSLP OF 965 MB 
OBSERVATION AT 021700Z. THE CURRENT INTENSITY IS ASSESSED AT 105 
KNOTS BASED ON SLIGHT WEAKENING AS IT PASSES OVER THE PHILIPPINE 
ARCHIPELAGO. FRICTIONAL EFFECTS OF LAND INTERACTION ARE PARTIALLY 
NEGATING A MODERATELY FAVORABLE ENVIRONMENT WITH LOW (10-15 KNOTS) 
VERTICAL WIND SHEAR (VWS), MILD SEA SURFACE TEMPERATURES (26-27 
DEGREES CELSIUS) AND STRONG POLEWARD OUTFLOW. TY KAMMURI IS TRACKING 
WESTWARD ALONG THE SOUTHERN PERIPHERY OF AN EXTENSION OF THE 
SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM 
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 29W SHOULD GRADUALLY TURN WEST-NORTHWESTWARD TO 
NORTHWESTWARD THROUGH TAU 48 AS IT TRACKS ALONG THE SOUTHWESTERN 
PERIPHERY OF THE STR. TY 29W SHOULD WEAKEN AS IT TRACKS OVER THE 
CENTRAL PHILIPPINES DUE TO INCREASED FRICTIONAL EFFECTS; HOWEVER, 
THE SYSTEM SHOULD MAINTAIN TYPHOON STRENGTH DUE TO ITS TRACK OVER 
THE WARM WATERS OF THE INLAND SEAS. AFTER TAU 48, TY 29W WILL 
ENCOUNTER STRONG, COLD NORTHEASTERLY SURGE FLOW AND IS EXPECTED TO 
WEAKEN RAPIDLY DUE TO INCREASING VWS (25-30 KNOTS). NUMERICAL MODEL 
GUIDANCE IS IN OVERALL TIGHT AGREEMENT THROUGH TAU 72 WITH A 90 NM 
SPREAD IN SOLUTIONS AT TAU 72, WITH THE EXCEPTION OF NAVGEM AND 
AFUM, ALTHOUGH THERE IS SOME UNCERTAINTY IN THE EXACT TRACK AND 
TIMING OF THE SOUTHWESTWARD TURN AS THE SYSTEM HITS THE NORTHEAST 
SURGE. THERE IS HIGH CONFIDENCE IN THIS PORTION OF THE JTWC 
FORECAST.    
   C. AFTER TAU 72, TY 29W WILL CONTINUE TO WEAKEN RAPIDLY AS IT 
ACCELERATES WITHIN THE NORTHEAST SURGE FLOW, AND IS FORECAST TO 
DISSIPATE BY TAU 120. THERE IS MODERATE CONFIDENCE IN THE LATER 
PORTION JTWC FORECAST TRACK DUE TO ALONG TRACK SPREAD AND ITS 
SOUTHWESTWARD TURN TIMING.//
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