Tropical Storm USAGI Advisory 11月20日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 33W (THIRTYTHREE)
WARNING NR 07//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 33W (THIRTYTHREE), LOCATED APPROXIMATELY
337 NM NORTHWEST OF SONSOROL, HAS TRACKED NORTHWESTWARD AT 11 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
CONTINUES TO DEPICT AN ELONGATED AND PARTIALLY EXPOSED LOW-LEVEL
CIRCULATION CENTER (LLCC). THE DEEP CONVECTION CONTINUES TO BE
SHEARED TO THE NORTHWEST OF THE LLCC. THE INITIAL POSITION IS PLACED
WITH LOW CONFIDENCE AND IS BASED ON A 191647Z AMSR2 89 GHZ MICROWAVE
IMAGE WHICH CONFIRMS THE DEEP CONVECTION IS TO THE NORTHWEST OF THE
LLCC. THE INITIAL INTENSITY OF 30 KNOTS IS HEDGED BETWEEN A DVORAK
CURRENT INTENSITY (CI) ESTIMATE OF T1.0 (25 KNOTS) FROM PGTW AND AN
ADT ESTIMATE OF T2.2 (32 KNOTS). TD 33W IS EXPERIENCING MODERATE TO
UNFAVORABLE VERTICAL WIND SHEAR (20 TO 25 KNOTS). TD 33W HAS MODERATE
POLEWARD AND EQUATORWARD OUTFLOW CHANNELS. SEA SURFACE TEMPERATURES
ALSO REMAIN FAVORABLE, BETWEEN 28 AND 29 DEGREES CELSIUS. TD 33W IS
TRACKING WESTWARD ALONG THE SOUTHERN EDGE OF THE SUBTROPICAL RIDGE
(STR) LOCATED TO THE NORTH.
3. FORECAST REASONING.
   A.  THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 33W IS EXPECTED TO TRACK WESTWARD THROUGH TAU 72 AS IT
TRACKS ALONG THE SOUTHERN PERIPHERY OF THE AFOREMENTIONED STR. IN THE
SHORT TERM TD 33W WILL MAINTAIN AN INTENSITY OF 30 KNOTS DUE TO THE
MODERATE TO UNFAVORABLE VERTICAL WIND SHEAR ALONG WITH LAND
INTERACTION WITH THE PHILIPPINES. BY TAU 36, TD 33W WILL TRACK OVER
THE FAVORABLE SEA SURFACE TEMPERATURES IN THE SULU SEA. AS IT TRACKS
INTO THE SOUTH CHINA SEA, TD 33W WILL CONTINUE TO GRADUALLY INCREASE
IN INTENSITY, REACHING 50 KNOTS BY TAU 72. DYNAMIC MODEL GUIDANCE IS
IN GOOD AGREEMENT BUT DUE TO THE UNCERTAINTY IN THE INITIAL POSITION
THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.
   C. AFTER TAU 72, TD 33W WILL BEGIN TO TRACK WEST-NORTHWESTWARD AND
REACH A PEAK INTENSITY OF 55 KNOTS BY TAU 96 WHILE UNDER MARGINALLY
FAVORABLE CONDITIONS (DECREASED VERTICAL WIND SHEAR AND WARM SEA
SURFACE TEMPERATURES). NEAR TAU 108, TD 33W WILL MAKE LANDFALL IN
SOUTHERN VIETNAM. AS TD 33W TRACKS INLAND IT WILL BEGIN TO DISSIPATE
DUE TO LAND INTERACTION. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT.
HOWEVER, BECAUSE OF THE UNCERTAINTY IN THE INITIAL POSITION, THERE IS
OVERALL LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.//
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