Tropical Storm KALMAEGI Advisory dim, 14.09.

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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