Tropical Storm HALONG Advisory Paz, 10.08.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (HALONG) WARNING NR
50//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 11W (HALONG), LOCATED APPROXIMATELY 101 NM SOUTH-
SOUTHEAST OF IWAKUNI, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 7
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY SHOWS TS 11W MAINTAINING ITS INTENSITY AS IT TRACKS TOWARDS
THE SOUTHERN COAST OF SHIKOKU. THE MID-LATITUDE WESTERLIES CONTINUE
TO ENHANCE THE POLEWARD OUTFLOW CHANNEL. HOWEVER, DRY AIR
ENTRAINMENT FROM THE NORTHEAST AND INCREASED PRESSURE FROM THE
WESTERLIES HAMPER INTENSIFICATION. RADAR IMAGERY FROM SHIKOKU
INDICATES THAT THE LOW LEVEL CIRCULATION CENTER REMAINS FAIRLY WELL
DEFINED WITH THE MAJORITY OF CONVECTION ON THE EASTERN SIDE OF THE
STORM. A 091723Z AMSU-B MICROWAVE IMAGE CONFIRMS THE LACK OF DEEP
CONVECTION ON THE WESTERN SIDE OF THE STORM AS IT BEGINS ITS EXTRA-
TROPICAL TRANSITION (ETT) BY BEING HEAVILY IMPACTED BY THE
WESTERIES. THIS ENHANCED CONVECTION ON THE EASTERN SIDE OF THE STORM
IS DUE TO THE UPPER LEVEL DIVERGENCE FLOW PROVIDED BY THE WESTERLIES
AND SOME OROGRAPHIC LIFT PROVIDED BY THE MOUNTAINOUS REGION OF
SOUTHERN SHIKUKO. THE CURRENT INTENSITY HAS BEEN MAINTAINED BASED ON
DVORAK ESTIMATES AND SOME OBSERVATIONS FROM THE COASTAL AREAS OF
JAPAN'S SMALLEST MAIN ISLAND. TS 11W CONTINUES TO TRACK ALONG THE
WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING.
   B. TS 11W IS EXPECTED TO CONTINUE TO TRACK NORTH-NORTHEASTWARD
THROUGH THE FORECAST PERIOD ALONG THE STR AND WILL WEAKEN RAPIDLY AS
THE SYSTEM PROGRESSES OVER THE TERRAIN OF SOUTHERN JAPAN AND
CONTINUES TO BE SUPPRESSED BY DRY AIR AND SUBSIDENCE FROM THE WEST.
BY TAU 12 HALONG WILL CONTINUE TO TAKE ON MORE COLD CORE FEATURES AS
THE SYSTEM MOVES INTO THE SEA OF JAPAN, DRIVEN BY THE WESTERIES.
ADDITIONALLY, UNFAVORABLE SEA SURFACE TEMPERATURES AMPLIFY THE
ALREADY POOR ENVIRONMENTAL CONDITIONS LEADING TO PERSISTENT
WEAKENING OF TS 11W. EXPECT THE SYSTEM TO BE COMPLETELY ABSORBED BY
THE SHORT-WAVE TROUGH, CURRENTLY NORTH OF THE SYSTEM, AND COMPLETE
ETT BY TAU 24. MODEL GUIDANCE CONTINUES TO REMAIN IN VERY GOOD
AGREEMENT LEADING JTWC’S HIGH CONFIDENCE TRACK STAYING CLOSE TO THE
MULTI-MODEL CONSENSUS.//
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