Tropical Storm SAOLA Advisory 27 Οκτ.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (SAOLA)
WARNING NR 29//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 27W (SAOLA), LOCATED APPROXIMATELY 392 NM
SOUTH-SOUTHEAST OF KADENA AB, HAS TRACKED NORTHWESTWARD AT 11 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY DEPICTS A SLOWLY CONSOLIDATING LOW-LEVEL CIRCULATION CENTER
WITH DEEP CONVECTIVE BANDING WRAPPING INTO A DEFINED CENTER. A
261856Z SSMIS 91GHZ IMAGE DEPICTS TIGHTLY-CURVED SHALLOW BANDING
WRAPPING INTO THE CENTER AND DEEP CONVECTIVE BANDING OVER THE
WESTERN AND SOUTHERN SEMI-CIRCLES. THE INITIAL POSITION IS BASED ON
ANIMATED EIR AND THE 261856Z SSMIS IMAGE. THE INITIAL INTENSITY IS
ASSESSED AT 45 KNOTS BASED ON DVORAK INTENSITY ESTIMATES OF T3.0 (45
KNOTS) FROM ALL AGENCIES. UPPER-LEVEL ANALYSIS DEPICTS A FAVORABLE
ENVIRONMENT WITH IMPROVING POLEWARD OUTFLOW AND LOW VERTICAL WIND
SHEAR (VWS). TS 27W IS TRACKING POLEWARD ALONG THE WESTERN PERIPHERY
OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TOWARD A BREAK SITUATED
NEAR OKINAWA.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. WITH THE EXCEPTION OF EEMN (ECMWF ENSEMBLE MEAN), WHICH
INDICATES A SHARP SOUTHWEST TURN ASSOCIATED WITH A COLD SURGE EVENT,
THE MODEL TRACKERS ARE IN TIGHT AGREEMENT THROUGH TAU 72. TS 27W IS
FORECAST TO TRACK NORTH-NORTHWESTWARD TO NORTHWARD THROUGH TAU 36
AND IS EXPECTED TO RECURVE JUST NORTH OF OKINAWA. NEAR TAU 48, THE
SYSTEM WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) AND TRACK
NORTHEASTWARD TO EAST-NORTHEASTWARD. TS 27W WILL CONTINUE TO
INTENSIFY TO A PEAK INTENSITY OF 65 TO 70 KNOTS BY TAU 36 AS
POLEWARD OUTFLOW IMPROVES SIGNIFICANTLY WITH VENTING INTO THE
MIDLATITUDE WESTERLIES. AS THE SYSTEM RECURVES AND TRACKS SOUTH OF
JAPAN, INCREASING VWS AND ENTRAINMENT OF COOLER, DRIER AIR WILL
SERVE TO STEADILY WEAKEN THE SYSTEM.
   C. IN THE EXTENDED PERIOD, TS 27W IS FORECAST TO ACCELERATE
EAST-NORTHEASTWARD WITHIN THE MIDLATITUDE WESTERLIES. THE SYSTEM
WILL COMPLETE ETT BY TAU 96 AS IT GAINS FRONTAL CHRACTERISTICS AND
BECOMES EMBEDDED WITHIN THE MIDLATITUDE WESTERLIES. THE GLOBAL
MODELS DEVELOP A STRONG COLD SURGE EVENT OVER AND TO THE SOUTH OF
MAINLAND JAPAN, WHICH WILL SERVE TO SIGNIFICANTLY WEAKEN THE SYSTEM.
DUE TO THE UNCERTAINTY IN MODEL GUIDANCE AFTER TAU 72, THERE IS LOW
OVERALL CONFIDENCE IN THE JTWC FORECAST TRACK.//
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