WDPN31 PGTW 140300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (KALMAEGI) WARNING NR 14//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 15W (KALMAEGI), LOCATED APPROXIMATELY 229 NM EAST-
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD
AT 14 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED 
SATELLITE IMAGERY INDICATES THAT THE SYSTEM HAS MAINTAINED 
CONVECTIVE STRUCTURE WITH AN OBLONG CENTRAL DENSE OVERCAST FEATURE 
AND DEEP CONVECTIVE BANDING CONFINED PRIMARILY TO THE SOUTHERN SEMI-
CIRCLE. A 132211Z SSMIS 91 GHZ IMAGE SHOWS AN ELONGATED MICROWAVE 
EYE FEATURE WITH INTENSE DEEP CONVECTIVE BANDING WRAPPING INTO THE 
SOUTHEASTERN QUADRANT OF THE LOW-LEVEL CIRCULATION CENTER. BASED ON 
THE SSMIS IMAGE AND RECENT VISIBLE IMAGERY, THERE IS FAIR CONFIDENCE 
IN THE INITIAL POSITION AND TRACK MOTION. THE INITIAL INTENSITY IS 
ASSESSED AT 70 KNOTS BASED ON AN AVERAGE OF DVORAK INTENSITY 
ESTIMATES RANGING FROM T4.0 (65 KNOTS) TO T4.5 (77 KNOTS). DESPITE 
PERSISTENT MODERATE NORTHEASTERLY VERTICAL WIND SHEAR (VWS), WHICH 
IS HINDERING DEEP CONVECTIVE DEVELOPMENT OVER THE NORTHERN SEMI-
CIRCLE, TY 15W APPEARS TO BE FIGHTING THE ENVIRONMENT AND HAS 
SLIGHTLY IMPROVED POLEWARD OUTFLOW OVER THE PAST 12 HOURS. 
ADDITIONALLY, THE MODERATE VWS IS BEING REDUCED BY THE WESTWARD 
TRACK MOTION. RECENT 500 MB ANALYSES SHOW A STRONG, BROAD, EAST-WEST 
ORIENTED SUBTROPICAL RIDGE (STR) ENTRENCHED TO THE NORTH AND 
NORTHWEST.
 3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE. 
   B. TY 15W IS FORECAST TO ACCELERATE WEST-NORTHWESTWARD UNDER THE 
STEERING INFLUENCE OF THE STRONG STR THROUGH TAU 72. TY 15W IS 
FORECAST TO INTENSIFY THROUGH TAU 12, PRIOR TO MAKING LANDFALL OVER 
THE EASTERN COAST OF LUZON, DUE TO FAVORABLE ENVIRONMENTAL 
CONDITIONS TO INCLUDE WARM SST, HIGH OCEAN HEAT CONTENT AND 
FAVORABLE OUTFLOW. AS TY 15W CROSSES THE MOUNTAINOUS TERRAIN OF 
LUZON, IT IS FORECAST TO WEAKEN BUT IS EXPECTED TO RE-INTENSIFY 
AFTER RE-EMERGING OVER THE SOUTH CHINA SEA. 
   C. IN THE EXTENDED TAUS, TY 15W IS EXPECTED TO MAINTAIN A 
PREDOMINANTLY WESTWARD TRACK THROUGH THE REMAINDER OF THE FORECAST 
PERIOD AS THE STR REMAINS ENTRENCHED TO THE NORTH. NEAR TAU 60, TY 
KALMAEGI IS FORECAST TO WEAKEN AS IT APPROACHES THE SOUTHERN COAST 
OF CHINA AND SHOULD DISSIPATE BY TAU 96 AS IT TRACKS WELL INLAND. 
DYNAMIC MODEL GUIDANCE (INCLUDING THE MODEL ENSEMBLES) IS IN TIGHT 
AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST 
TRACK, WHICH IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS.//
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