Tropical Storm KALMAEGI Advisory Mon Sep 15

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15W (KALMAEGI) WARNING NR 18//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 15W (KALMAEGI), LOCATED APPROXIMATELY 702 NM EAST-
SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED WESTWARD AT 13 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY INDICATES IMPROVED DEEP CONVECTIVE BANDING AS THE SYSTEM
TRACKS QUICKLY AWAY FROM LUZON. A 150007Z SSMIS IMAGE DEPICTS
TIGHTLY-CURVED BANDING WRAPPING INTO A MORE DEFINED CENTER. BASED ON
THE SSMIS IMAGE AND A 142346Z GMI IMAGE, THERE IS GOOD CONFIDENCE IN
THE INITIAL POSITION. THE INITIAL INTENSITY IS ASSESSED AT 65 KNOTS
BASED ON THE IMPROVED STRUCTURE AND A PGTW DVORAK INTENSITY ESTIMATE
OF T4.0 (65 KNOTS). 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 24, PRIOR TO MAKING LANDFALL OVER
NORTHERN HAINAN AFTER TAU 24, DUE TO FAVORABLE ENVIRONMENTAL
CONDITIONS TO INCLUDE WARM SST AND FAVORABLE OUTFLOW. NEAR TAU 36,
TY KALMAEGI IS FORECAST TO WEAKEN AS IT APPROACHES THE COAST OF
VIETNAM AND SHOULD DISSIPATE BY TAU 72 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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