Tropical Storm IN-FA Advisory 11月24日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 27W (IN-FA) WARNING NR 28//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 27W (IN-FA), LOCATED APPROXIMATELY 685 NM SOUTHWEST
OF IWO TO, HAS TRACKED NORTH-NORTHEASTWARD AT 07 KNOTS OVER THE PAST
SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY CONTINUES TO
DEPICT A WELL-ORGANIZED LOW-LEVEL CIRCULATION CENTER (LLCC)
POSITIONED BENEATH A LARGE, EXPANDING AREA OF DEEP CONVECTION. A
231756Z SSMI 85GHZ IMAGE SHOWS A MICROWAVE EYE FEATURE WITH THE BULK
OF DEEP CONVECTION DISPLACED OVER THE NORTHERN SEMI-CIRCLE. HOWEVER,
WITH THE EXCEPTION OF THE SOUTHWEST QUADRANT, THE SYSTEM HAS
RETAINED ORGANIZED CORE CONVECTION. OVERALL, THERE IS GOOD
CONFIDENCE IN THE CURRENT POSITION BASED ON THE MICROWAVE IMAGERY.
ANIMATED WATER VAPOR IMAGERY DEPICTS AN UPPER-LEVEL TROUGH
POSITIONED OVER THE WESTERN PERIPHERY OF THE SYSTEM PRODUCING
MODERATE SOUTHWESTERLY VERTICAL WIND SHEAR (VWS) AND DIFFLUENT FLOW.
THE CURRENT INTENSITY IS MAINTAINED AT 90 KNOTS BASED ON THE
CONVECTIVE STRUCTURE AND IS SUPPORTED BY DVORAK INTENSITY ESTIMATES
OF T5.0 (90 KNOTS) FROM RJTD AND PGTW. TY 27W HAS ACCELERATED
SLIGHTLY AS IT BEGINS TO ROUND THE WESTERN PERIPHERY OF THE
SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 27W WILL CONTINUE TO ROUND THE STR AXIS OVER THE NEXT 12 TO
24 HOURS. INCREASING INTERACTION WITH THE APPROACHING MID-LATITUDE
TROUGH WILL LEAD TO A NORTHEASTWARD ACCELERATION INTO THE BAROCLINIC
ZONE. ENVIRONMENTAL CONDITIONS WILL CONTINUE TO DETERIORATE AS VWS
RAPIDLY INCREASES DUE TO THE STRONG WESTERLY WINDS FROM THE
APPROACHING TROUGH. TY IN-FA WILL BEGIN EXTRA-TROPICAL TRANSITION
(ETT) NEAR TAU 72.
   C. IN THE EXTENDED FORECAST, TY 27W WILL CONTINUE TO ACCELERATE
NORTHEASTWARD ALONG THE NORTHWESTERN PERIPHERY OF THE STEERING STR.
TY 27W WILL CONTINUE ETT AS IT EMBEDS DEEPER INTO THE MID-LATITUDE
WESTERLY FLOW AND WILL COMPLETE ETT BY THE END OF THE FORECAST
PERIOD. DYNAMIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT, LEADING TO
HIGH CONFIDENCE IN THE JTWC TRACK FORECAST.//
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