Tropical Storm SONGDA Advisory 10 Οκτ.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 23W (SONGDA)
WARNING NR 07//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 23W (SONGDA), LOCATED APPROXIMATELY 331 NM
EAST OF IWO TO, HAS TRACKED NORTHWESTWARD AT 14 KNOTS OVER THE PAST
SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A
RAPIDLY-CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH
TIGHTLY-CURVED DEEP CONVECTIVE BANDING WRAPPING INTO A DEFINED
CENTER. A 091806Z SSMIS 37GHZ IMAGE SHOWS MULTIPLE CONVECTIVE BANDS
WRAPPING INTO THE COMPACT, WELL-DEFINED CENTER, WHICH SUPPORTS THE
CURRENT POSITION WITH GOOD CONFIDENCE. ANIMATED WATER VAPOR IMAGERY
REVEALS NEAR-RADIAL OUTFLOW, WHICH IS FUELING THE RAPID
CONSOLIDATION. RECENT DVORAK ESTIMATES OF T3.5 FROM ALL AGENCIES
SUPPORT THE CURRENT INETNSITYE ESTIMATE OF 55 KNOTS. TS 23W IS
TRACKING QUICKLY NORTHWESTWARD ALONG THE SOUTHWEST PERIPHERY OF THE
DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST.
3. FORECAST REASONING.
   A.  NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 23W IS FORECAST TO TRACK NORTHWESTWARD THROUGH TAU 12 THEN
RE-CURVE NORTHEASTWARD AND ACCELERATE AS IT ROUNDS THE WESTERN
PERIPHERY OF THE STR. TS SONGDA WILL RAPIDLY INTENSIFY AFTER TAU 12
DUE TO IMPROVING POLEWARD OUTFLOW ASSOCIATED WITH AN APPROACHING
MIDLATITUDE SHORTWAVE TROUGH AND IS EXPECTED TO REACH A PEAK
INTENSITY OF 90 KNOTS BY TAU 36.
   C. AFTER TAU 72, TS SONGDA WILL BEGIN EXTRA-TROPICAL TRANSITION
(ETT) AS IT BEGINS TO INTERACT WITH THE MIDLATITUDE WESTERLIES AND
THE ASSOCIATED STRONG BAROCLINIC ZONE. THE SYSTEM IS EXPECTED TO
WEAKEN AS IT ENCOUNTERS INCREASING VERTICAL WIND SHEAR AND
ACCELERATES NORTHEASTWARD. TS 23W WILL COMPLETE ETT BY TAU 96 AS IT
GAINS FRONTAL CHARACTERISTICS AND BECOMES EMBEDDED WITHIN THE
MIDLATITUDE WESTERLY FLOW. NUMERICAL MODEL GUIDANCE REMAINS IN
EXCELLENT AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC
FORECAST TRACK.//
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