WDPN31 PGTW 160300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (KALMAEGI) WARNING NR 22//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 15W (KALMAEGI), LOCATED APPROXIMATELY 209 NM SOUTHWEST OF 
HONG KONG, HAS TRACKED WEST-NORTHWESTWARD AT 15 KNOTS OVER THE PAST 
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS TY 15W IS 
BEGINNING TO INTERACT WITH THE EASTERN EXTENT OF HAINAN ISLAND AND 
THE SOUTHEASTERN COAST OF CHINA, LEADING TO A BREAKDOWN IN DEEP 
CONVECTION ALONG THE NORTHERN HALF OF THE LOW LEVEL CIRCULATION 
CENTER (LLCC). INTENSITY HAS BEEN MAINTAINED AT 70 KNOTS AS THE 
ORGANIZATION OF TY 15W HAS NOT IMPROVED OVER THE PAST SIX HOURS. 
DVORAK ESTIMATES FROM ALL AGENCIES SUPPORT THE CURRENT INTENSITY 
ESTIMATE. UPPER LEVEL ANALYSIS INDICATES A WEAK POINT-SOURCE 
ANTICYCLONE IS LOCATED OVER THE LLCC, PROVIDING GOOD RADIAL OUTFLOW 
IN A LOW VERTICAL WIND SHEAR ENVIRONMENT. TY 15W CONTINUES TO TRACK 
QUICKLY WESTWARD ALONG THE SOUTHERN PERIPHERY OF A DEEP LAYERED 
SUBTROPICAL RIDGE (STR). 
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TY 15W IS FORECAST TO REMAIN ON A QUICK TRACK TO THE WEST-
NORTHWEST UNDER THE STEERING INFLUENCE OF THE STRONG STR THROUGHOUT 
THE FORECAST. AS TY 15W PASSES OVER HAINAN ISLAND, A STEADY 
WEAKENING TREND, INFLUENCED BY LAND INTERACTION, WILL BEGIN. 
LANDFALL IN NORTHERN VIETNAM WITHIN THE NEXT 18 HOURS WILL LEAD TO A 
RAPID DISSIPATION OF THE LLCC BY TAU 36. 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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