Tropical Storm IN-FA Advisory вт, 17.11.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 27W (TWENTYSEVEN)
WARNING NR 01//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 27W (TWENTYSEVEN), LOCATED APPROXIMATELY
315 NM EAST-SOUTHEAST OF POHNPEI, HAS TRACKED WESTWARD AT 14 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) SHOWS DEVELOPING CENTRAL CONVECTION OVER A POORLY DEFINED LOW
LEVEL CIRCULATION CENTER (LLCC). A BAND OF DEEP CONVECTION IS LOCATED
ALONG THE SOUTHERN PERIPHERY OF THE LLCC. THE CURRENT POSITION IS
BASED ON THE POSITIONING FIXES FROM PGTW AND RJTD. A RECENT 151927Z
WINDSAT 37GHZ MICROWAVE IMAGE SUPPORTS THE POSITIONING OF TD 27W, AND
IS IN AGREEMENT WITH MSI. THE INITIAL INTENSITY OF 25 KNOTS IS BASED
ON DVORAK ESTIMATES OF 1.5/1.5 FROM PGTW AND AN EARLIER 151233Z
RAPIDSCAT IMAGE SHOWING 20 KNOT WINDS ALONG BOUNDARY OF THE LLCC.
THE RECENT IMPROVEMENTS IN ORGANIZATION SUPPORT THE INCREASE IN
INTENSITY TO 25 KNOTS AT 0000Z.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING BULLETIN AND SETS THE
FORECAST PHILOSOPHY ON THIS SYSTEM.
   B. TD 27W IS EXPECTED TO TRACK WESTWARD UNDER THE INFLUENCE OF A
WEAK EXTENSION OF THE SUBTROPICAL RIDGE (STR), LOCATED TO THE NORTH
OF GUAM. TD 27W WILL SLOWLY INTENSIFY OVER THE NEXT 48 HOURS WITH
FAVORABLE SEA SURFACE TEMPERATURES (SSTS) (28 TO 29 CELSIUS), UPPER
LEVEL OUTFLOW BEING SUPPORTED BY A DEVELOPING POINT SOURCE ANTI-
CYCLONE WITH A WEAKENING LINK TO A MID-LATITUDE JET, AND LOW VERTICAL
WIND SHEAR (VWS) (5 TO 10 KNOTS). THE INTENSIFICATION WILL WEAKEN THE
STR, AND ALLOW FOR A SLIGHT SHIFT IN THE TRACK TO THE WEST-NORTHWEST
AFTER TAU 24 AND WILL PERSIST THROUGH TAU 72.
   C. BEYOND TAU 72, TD 27W WILL CONTINUE TO INTENSIFY AS A MID-
LATITUDE JET TRACKS OVER SOUTHERN JAPAN, WITH A WEAK SOUTHERN JETMAX
ENHANCING THE POLEWARD OUTFLOW FOR THE SYSTEM. THE POINT-SOURCE
ANTI-CYCLONE OVER THE LLCC IS EXPECTED TO BE FULLY DEVELOPED,
ENHANCING THE RADIAL OUTFLOW IN THE REMAINING QUADRANTS. SSTS AND VWS
WILL REMAIN FAVORABLE THROUGH TAU 120, PROVIDING A STRONGLY FAVORABLE
ENVIRONMENT THROUGH THE FORECAST PERIOD. MODEL GUIDANCE IS IN FAIR
AGREEMENT BUT NAVGEM AND COAMPS-TC INDICATE A STRONGER NORTHWARD
TURN IN THE EARLY PORTIONS OF THE FORECAST. THIS FORECAST IS SOUTH
AND FASTER THAN THE CONSENSUS, BUT DUE TO THE UNCERTAINTY IN THE
INITIAL POSITION OF THE SYSTEM AND TRACK SPEEDS, THERE IS LOW
CONFIDENCE IN THE JTWC FORECAST.//
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