Tropical Storm YUTU Advisory Wed Oct 31

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 31W (YUTU) WARNING NR
40//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 31W (YUTU), LOCATED APPROXIMATELY 291 NM
NORTHWEST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 08
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS A PARTIALLY-EXPOSED LOW LEVEL CIRCULATION CENTER
(LLCC) WITH LIMITED DEEP CONVECTION IN THE NORTH AND SOUTH
QUADRANTS. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE USING
A 310540Z AMSR2 37GHZ IMAGE WHICH DEPICTS A RAGGED MICROWAVE EYE
FEATURE. THE CURRENT INTENSITY IS ASSESSED AT 45 KNOTS BASED ON
MULTI-AGENCY DVORAK ESTIMATES OF T2.5-T3.5 (35-55 KNOTS) AND A
310212Z ASCAT-B SCATTEROMETER IMAGE WHICH SHOWS LARGE REGIONS OF 40
KNOT WIND BARBS TO THE NORTHWEST AND NORTHEAST OF THE LLCC. OVERALL,
ENVIRONMENTAL CONDITIONS ARE FAVORABLE WITH LOW TO MODERATE (10-20
KT) VERTICAL WIND SHEAR, WARM (27-28 CELSIUS) SEA SURFACE
TEMPERATURE, AND EXCELLENT POLEWARD OUTFLOW. TS 31W IS TRACKING
ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 31W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD TO
NORTHWARD ALONG THE WESTERN PERIPHERY OF THE STR. FAVORABLE
ENVIRONMENTAL CONDITIONS SHOULD ALLOW THE SYSTEM TO INTENSIFY TO A
PEAK OF 60 KNOTS BY TAU 24. AFTER TAU 24, HIGHER VERTICAL WIND SHEAR
(VWS) AND COOLER SST VALUES WILL CAUSE GRADUAL WEAKENING. AFTER TAU
48, A HOSTILE ENVIRONMENT WILL RAPIDLY DISSIPATE THE CYCLONE OVER
WATER. MODEL GUIDANCE VARIES BETWEEN THE CYCLONE DISSIPATING OR
RECURVING INTO THE MID-LATITUDE WESTERLIES. THE JTWC TRACK FORECAST
MIRRORS THE DISSIPATION SCENARIO. AS A RESULT OF THE TWO DISTINCT
BUT PLAUSIBLE SCENARIOS, UNCERTAINTY IN THE FORECAST TRACK IS HIGH.//
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