Tropical Storm IN-FA Advisory Dom, 22-11

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 27W (IN-FA) WARNING NR 22//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 27W (IN-FA), LOCATED APPROXIMATELY 726 NM SOUTH-
SOUTHWEST OF IWO TO, JAPAN HAS TRACKED WEST-NORTHWESTWARD AT 17
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS FLARING CENTRAL CONVECTION WITH GOOD CONVECTIVE
SPIRAL BANDING ALONG THE NORTHERN SEMI-CIRCLE WRAPPING INTO THE
CENTER. THE OVERALL STRUCTURE CONTINUES TO STRUGGLE DUE TO INCREASED
PRESSURE ALONG THE NORTHWESTERN PERIPHERY CAUSED BY SUBSIDENCE
ALOFT. A 220537Z SSMI 85GHZ MICROWAVE IMAGE SHOWS WELL DEFINED
SHALLOW BANDING WRAPPING INTO A COMPACT MICROWAVE EYE FEATURE WHICH
SUPPORTS THE INITIAL POSITION WITH HIGH CONFIDENCE. THE MICROWAVE
IMAGE ALSO FURTHER ILLUSTRATES THE LACK OF CONVECTION ALONG THE
WESTERN PERIPHERY. THE INTENSITY HAS BEEN HELD AT 105 KNOTS BASED ON
UNCHANGED CURRENT INTENSITY ESTIMATES OF T5.5 (102 KNOTS) FROM ALL
AGENCIES. THE CURRENT AND FORECASTED WIND RADII HAVE BEEN ADJUSTED
BASED ON A 220056Z ASCAT PASS SHOWING A SMALLER WIND FIELD. THE
CURRENT ENVIRONMENT IS MOSTLY FAVORABLE WITH STRONG DIVERGENT
OUTFLOW AND LOW VERTICAL WIND SHEAR (VWS); HOWEVER, THE INCREASING
PRESSURE ALONG THE WESTERN PERIPHERY IS HAMPERING FURTHER
INTENSIFICATION. TY 27W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY
OF THE DEEP LAYERED SUB-TROPICAL RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 27W WILL CONTINUE TO TRACK NORTHWESTWARD OVER THE NEXT 24
HOURS UNTIL IT REACHES THE WESTERN EXTENT OF THE STEERING STR AND
TURNS POLEWARD. ENVIRONMENTAL CONDITIONS WILL REMAIN MOSTLY
UNCHANGED, CONTINUING THE SLOW WEAKENING TREND. AFTERWARDS, THE
SYSTEM WILL ROUND THE STR AXIS AND ACCELERATE NORTHEASTWARD INTO THE
BAROCLINIC ZONE. VWS WILL INCREASE DUE TO THE STRONG WESTERLY WINDS
AND AN APPROACHING MID-LATITUDE TROUGH; ACCELERATING THE WEAKENING
TREND.
   C. IN THE EXTENDED FORECAST, TY IN-FA WILL CONTINUE ACCELERATING
TO THE NORTHEAST ALONG THE NORTHWESTERN PERIPHERY OF THE STR. AS THE
TYPHOON EMBEDS IN THE MID-LATITUDE WESTERLY FLOW, IT WILL BEGIN
EXTRA-TROPICAL TRANSITION (ETT). TY 27W WILL COMPLETE ETT BY THE END
OF THE FORECAST PERIOD AS A STRONG COLD-CORE LOW. DYNAMIC MODEL
GUIDANCE REMAINS IN TIGHT AGREEMENT, LENDING TO HIGH CONFIDENCE IN
THE JTWC TRACK FORECAST.//
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