Tropical Storm KROSA Advisory śro., 14.08.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (KROSA) WARNING NR 034//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 11W (KROSA), LOCATED APPROXIMATELY 341 NM SOUTH OF
IWAKUNI, JAPAN, HAS TRACKED NORTHWESTWARD AT 05 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A
BROAD SYSTEM WITH FRAGMENTED, FLARING CONVECTIVE BANDS WRAPPING INTO
A LARGE, RAGGED AND FULLY EXPOSED LOW-LEVEL CIRCULATION (LLC). THE
INITIAL POSITION IS BASED ON MSI IMAGERY AND A 132216Z SSMIS 89GHZ
MICROWAVE IMAGE. THE INITIAL INTENSITY OF 50 KNOTS IS HEDGED SLIGHTLY
BELOW THE PGTW AND RJTD DVORAK CURRENT INTENSITY ESTIMATES OF T3.5
(55 KTS) AND IN CLOSE AGREEMENT WITH A 131105Z SATCON ESTIMATE OF 53
KTS. DESPITE LOW VERTICAL WIND SHEAR (10-15 KNOTS), UPPER LEVEL
ANALYSIS INDICATES AN OVERALL MARGINAL ENVIRONMENT WITH AN UPPER
LEVEL LOW DIRECTLY OVER THE LLC, WHICH IS INHIBITING CENTRAL
CONVECTION. SEA SURFACE TEMPERATURES (SST) REMAIN CONDUCIVE (28-29
DEGREES CELSIUS). THE CYCLONE IS TRACKING ALONG THE WESTERN PERIPHERY
OF AN EXTENSION OF THE SUBTROPICAL RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. OVER THE NEXT 24 HOURS, TS 11W WILL CONTINUE ON ITS CURRENT
TRACK AS IT ROUNDS THE WESTERN PERIPHERY OF THE AFOREMENTIONED STR.
NEAR TAU 24, A MIDLATITUDE TROUGH WILL APPROACH FROM THE WEST,
ERODING THE STR AND ALLOWING TS 11W TO RECURVE POLEWARD AROUND THE
STR AXIS, SKIRTING WESTERN SHIKOKU JUST AFTER TAU 24. INCREASING
POLEWARD OUTFLOW AHEAD OF THE AFOREMENTIONED TROUGH WILL MAINTAIN
INTENSITY AT 50 KNOTS AS TS 11W MAKES LANDFALL THROUGH TAU 24. LAND
INTERACTION, UNFAVORABLE (20-30 KNOTS) VERTICAL WIND SHEAR (VWS), AND
COOLER SST (22-25 DEGREES CELSIUS) IN THE SEA OF JAPAN (SOJ) WILL
COMBINE TO WEAKEN THE SYSTEM GRADUALLY DOWN TO 35 KNOTS BY TAU 72 AS
IT TRACKS THROUGH THE SOJ. CROSS-TRACK AGREEMENT HAS DECREASED
SLIGHTLY, AS THE SPREAD HAS INCREASED TO 300 NM AT TAU 72, WITH UKMET
AND NAVGEM SIGNIFICANTLY NORTH AND SOUTH OF THE REMAINING CONSENSUS
MODELS. THE JTWC FORECAST TRACK IS IN OVERALL CLOSE AGREEMENT WITH
THE MULTI-MODEL CONSENSUS. TS 11W WILL BEGIN EXTRATROPICAL TRANSITION
AS IT INTERACTS WITH THE AFOREMENTIONED TROUGH AND IS EXPECTED TO
BECOME FULLY EXTRATROPICAL AS IT APPROACHES THE WATERS WEST OF
HOKKAIDO NEAR TAU 72. THERE IS OVERALL HIGH CONFIDENCE IN THE JTWC
FORECAST TRACK FOR THIS PORTION OF THE FORECAST.//
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