WDPN31 PGTW 151500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (KALMAEGI) WARNING NR 20//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 15W (KALMAEGI), LOCATED APPROXIMATELY 204 NM SOUTH OF
HONG KONG, HAS TRACKED WEST-NORTHWESTWARD AT 17 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS 
CURVED CONVECTIVE BANDING WRAPPING INTO A DEFINED LOW LEVEL 
CIRCULATION CENTER WHILE A LARGE BANDING FEATURE CAN BE OBSERVED 
BUILDING ACROSS THE WESTERN PERIPHERY. A 151009Z CORIOLIS 37 GHZ 
MICROWAVE IMAGE DEPICTS IMPROVED BANDING IN ALL QUADRANTS AS AN 
IRREGULAR EYE FEATURE HAS DEVELOPED. THERE IS GOOD CONFIDENCE IN THE 
INITIAL POSITION AND DIRECTION BASED ON THE AFOREMENTIONED SATELLITE 
IMAGERY. THE INITIAL INTENSITY HAS BEEN INCREASED TO 70 KNOTS BASED 
ON THE IMPROVED STRUCTURE AND DVORAK INTENSITY ESTIMATES THAT RANGE 
FROM 65 TO 77 KNOTS. UPPER LEVEL ANALYSIS REVEALS MODERATE (15 TO 25 
KNOTS) NORTHEASTERLY VERTICAL WIND SHEAR (VWS) CONTINUES TO PRESS 
UPON THE SYSTEM WHICH IS BEING OFFSET BY STRONG EQUATORWARD OUTFLOW 
AND THE MOTION OF THE SYSTEM. TY 15W IS CURRENTLY TRACKING ALONG THE 
SOUTHERN PERIPHERY OF A BROAD, EAST-WEST ORIENTED SUBTROPICAL RIDGE 
(STR) ENTRENCHED TO THE NORTH.
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. A SHORT WINDOW 
OF INTENSIFICATION IS EXPECTED IN THE NEXT 12 HOURS DUE TO FAVORABLE 
ENVIRONMENTAL CONDITIONS OF WARM SEA SURFACE TEMPERATURES ACROSS THE 
SOUTH CHINA SEA AND FAVORABLE OUTFLOW. AFTER TAU 12, THE SYSTEM IS 
EXPECTED TO CROSS NORTHERN HAINAN ISLAND WHICH WILL INDUCE A 
WEAKENING TREND. AS TY KALMAEGI APPROACHES THE COAST OF VIETNAM, THE 
SYSTEM IS FORECAST TO FURTHER WEAKEN AS IT TRACKS FURTHER INLAND AND 
DISSIPATES BY TAU 72. 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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