Tropical Storm MANGKHUT Advisory 9月15日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 26W (MANGKHUT) WARNING
NR 32//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON 26W (MANGKHUT), LOCATED APPROXIMATELY 217 NM NORTH-
NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT
18 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS A SYMMETRIC 12 NM EYE, FULLY SURROUNDED BY
DEEP CONVECTION. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON THE EYE FEATURE IN THE EIR AND PHILIPPINES RADAR IMAGERY.
THE INITIAL INTENSITY IS ASSESSED AT 145 KNOTS, SLIGHTLY ABOVE THE
PGTW, KNES AND RJTD DVORAK CURRENT INTENSITY ESTIMATES OF T7.0 (140
KTS). THIS IS CONSISTENT WITH A 140944Z SATCON ESTIMATE OF 147 KTS.
THE FAVORABLE ENVIRONMENT SURROUNDING STY 26W (WARM SEA SURFACE
TEMPERATURE, LOW VERTICAL WIND SHEAR (VWS) AND STRONG RADIAL
OUTFLOW), IS BEING OFFSET BY SIGNIFICANT SURFACE FRICTION FROM LAND
INTERACTION WITH THE MOUNTAINOUS TERRAIN OF NORTH LUZON. STY 26W IS
TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL
RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
    B. THROUGH TAU 72, THE STR TO THE NORTH WILL CONTINUE TO HELP
STY 26W MAINTAIN ITS WEST-NORTHWESTWARD TRACK. THE SYSTEM MADE
LANDFALL ON NORTH LUZON SHORTLY AFTER 141800Z AND IS FORECAST TO
WEAKEN WHILE QUICKLY PASSING OVER THE ISLAND. STY 26W WILL EMERGE
OVER THE SOUTH CHINA SEA (SCS) BEFORE TAU 12 AND SHOULD EXPERIENCE
SLIGHT INTENSIFICATION OVER THE WARM SCS WATERS BEFORE MAKING
LANDFALL SOUTH OF HONG KONG JUST PRIOR TO TAU 48. AFTER MAKING
LANDFALL, STY 26W WILL WEAKEN RAPIDLY. MODEL TRACK GUIDANCE IS IN
EXCELLENT AGREEMENT, LENDING HIGH CONFIDENCE TO THE JTWC TRACK
FORECAST.
   C. PRIOR TO DISSIPATING AROUND TAU 96, STY 26W WILL CONTINUE ITS
WEST-NORTHWESTWARD TRACK. SPREAD IN THE MODEL GUIDANCE INCREASES AT
THE END OF THE FORECAST, PRIMARILY DUE TO ALONG-TRACK SPEED
DIFFERENCES BETWEEN THE MODELS. AS A RESULT, THERE IS FAIR
CONFIDENCE IN THE OFFICIAL FORECAST THROUGH TAU 96.//
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