Tropical Storm PEIPAH Advisory 9月16日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 17W (PEIPAH) WARNING NR
05//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 17W (PEIPAH), LOCATED APPROXIMATELY 270 NM
NORTH-NORTHEAST OF SAIPAN, HAS TRACKED NORTH-NORTHWESTWARD AT 21
KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY AND A 151530Z AMSR2 37 GHZ MICROWAVE IMAGE SHOW
THE LOW LEVEL CIRCULATION CENTER FULLY EXPOSED. FOR THAT REASON,
THERE IS HIGH CONFIDENCE IN THE INITIAL POSITION. THE INITIAL
INTENSITY OF 35 KTS IS PLACED ON THE HIGH SIDE OF THE PGTW DVORAK
CURRENT INTENSITY ESTIMATE OF T2.0 (30 KTS) TO ACCOUNT FOR THE
SYSTEM TRACKING AT 21 KTS. DESPITE STRONG EQUATORWARD OUTFLOW AND
WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURE (SST), THE ENVIRONMENT
IS UNFAVORABLE DUE TO HIGH (35-40 KT) VERTICAL WIND SHEAR (VWS). TS
17W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A NORTH-TO-SOUTH
ORIENTED SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. FOR THE DURATION OF THE FORECAST, TS 17W WILL TRACK
NORTHWESTWARD ALONG THE STR. THE ENVIRONMENT IS EXPECTED TO REMAIN
HOSTILE AND THE CIRCULATION IS EXPECTED TO FALL BELOW WARNING
THRESHOLD BY TAU 36. THE FORECAST TRACK CLOSELY FOLLOWS THE
CONSENSUS BUT, WITH SPREAD IN THE MODEL GUIDANCE EXCEEDING 200 NM BY
TAU 36, THERE IS LOW CONFIDENCE IN THE JTWC FORECAST TRACK.//
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