Tropical Storm LEKIMA Advisory 10.08.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (LEKIMA) WARNING NR 25//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 10W (LEKIMA), LOCATED APPROXIMATELY 135 NM SOUTH
OF SHANGHAI, CHINA, HAS TRACKED NORTH-NORTHWESTWARD AT 07 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A RAPIDLY WEAKENING SYSTEM WITH LIMITED DEEP
CONVECTION DISPLACED OVER THE NORTHERN PERIPHERY. A 092310Z SSMIS
91GHZ IMAGE AND RADAR IMAGERY INDICATE A DEFINED LOW-LEVEL
CIRCULATION CENTER, THEREFORE, THERE IS GOOD CONFIDENCE IN THE
INITIAL POSITION. UPPER-LEVEL ANALYSIS REVEALS LOW VERTICAL WIND
SHEAR AND ROBUST POLEWARD OUTFLOW ENHANCED BY A SHORTWAVE TROUGH TO
THE NORTHWEST. THEREFORE, INTERACTION WITH LAND / FRICTIONAL EFFECTS
ARE THE PRIMARY WEAKENING MECHANISM. TY 10W IS TRACKING ALONG THE
SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) POSITIONED TO
THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 10W IS FORECAST TO TRACK NORTHWARD THROUGH TAU 72 ALONG THE
WESTERN PERIPHERY OF THE STR, WHICH REORIENTS NORTH-SOUTH. THE
SYSTEM IS FORECAST TO RAPIDLY WEAKEN AS IT TRACKS OVER THE EASTERN
COAST OF CHINA. NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT,
THEREFORE, THERE IS HIGH CONFIDENCE IN THIS PORTION OF THE JTWC
FORECAST TRACK.
   C. AFTER TAU 72, TY 10W WILL TRACK UNDER STRONG SOUTHWESTERLY
FLOW ASSOCIATED WITH A DEEP SHORTWAVE TROUGH OVER NORTHEAST CHINA,
WHICH WILL FURTHER WEAKEN THE SYSTEM DUE TO INCREASING VERTICAL WIND
SHEAR AND CONVERGENCE ALOFT. NUMERICAL MODEL GUIDANCE DIVERGES WITH
SEVERAL MODELS JUMPING ERRONEOUSLY TO MIDLATITUDE VORTICITY CENTERS.
THE REMAINDER OF THE GUIDANCE INDICATES A SLOW NORTHEASTWARD TRACK
OVER THE GULF OF POHAI. TY 10W IS FORECAST TO DISSIPATE BY TAU 96 AS
IT TRACKS CLOSE TO THE UPPER-LEVEL JET. OVERALL, TRACK CONFIDENCE
REMAINS HIGH.//
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