Tropical Storm TEMBIN Advisory 12月23日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 33W (TEMBIN) WARNING
NR 09//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 33W (TEMBIN), LOCATED APPROXIMATELY 403 NM
SOUTH OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 07 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY
SHOWS DEEP CONVECTION ON THE WESTERN SEMI-CIRCLE OF TS 33W. THE
LOCATION IS BASED ON A 221800Z HIMAWARI INFRARED SATELLITE IMAGE
SHOWING STRONG CONVECTION. THE LOW LEVEL CIRCULATION CENTER (LLCC) IS
LOCATED TO THE SOUTHWEST OF THE MASS OF CONVECTION. THE INITIAL
INTENSITY OF 50 KNOTS IS HEDGED ABOVE THE PGTW AND RJTD DVORAK
CURRENT INTENSITY ESTIMATES OF T3.0 (45 KNOTS). ENVIRONMENTAL
ANALYSIS REVEALS MODERATE TO HIGH VERTICAL WIND SHEAR (VWS) VALUES
BETWEEN 20 TO 25 KNOTS. SEA SURFACE TEMPERATURES REMAIN FAVORABLE
(28-29 CELSIUS). POLEWARD OUTFLOW IS STRONG WHILE EQUATORWARD OUTFLOW
IS WEAK. TS 33W IS TRACKING ALONG THE SOUTHERN EXTENT OF THE
SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY SINCE
THE LAST PROGNOSTIC REASONING MESSAGE.
   B. TS 33W WILL CONTINUE TO TRACK WEST-NORTHWESTWARD UNDER THE
INFLUENCE OF THE STR WHICH IS LOCATED TO THE NORTH. WARM SEA SURFACE
TEMPERATURES AND FAVORABLE POLEWARD OUTFLOW WILL ALLOW FOR A STEADY
INCREASE IN INTENSITY. TS 33W WILL REACH AN INTENSITY OF 70 KNOTS BY
TAU 24 BEFORE REACHING A PEAK INTENSITY OF 75 KNOTS BY TAU 36. AFTER
TAU 36 TS 33W WILL GRADUALLY BEGIN TO WEAKEN IN INTENSITY DUE TO
INCREASED VWS IN THE SOUTH CHINA SEA. SHORTLY BEFORE TAU 72 TS 33W
WILL MAKE LANDFALL IN SOUTHERN VIETNAM WITH AN INTENSITY OF 50 KNOTS.
   C. AFTER TAU 72, TS 33W IS FORECAST TO CONTINUE TO TRACK
WEST-NORTHWESTWARD AS THE STEERING STR LOCATED TO THE NORTH CONTINUES
TO WEAKEN. BY THIS TIME LAND INTERACTION COMBINED WITH INCREASING VWS
WILL FURTHER WEAKEN TS 33W AS IT TRACKS ACROSS SOUTHERN VIETNAM. TS
TEMBIN WILL EXIT BACK OVER THE GULF OF THAILAND AROUND TAU 90 AS A
WEAK TROPICAL STORM WHERE IT WILL REMAIN IN UNFAVORABLE CONDITIONS
AND WILL FURTHER WEAKEN. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT
PRIOR TO TAU 72. HOWEVER, AFTER TAU 72 THERE IS LESS CERTAINTY AND AN
INCREASED SPREAD IN MODEL TRACKS WITH THE JTWC TRACK IN AGREEMENT WITH
THE MAJORITY OF THE MEMBERS, WITH ONE MEMBER INDICATING A NORTHWARD
TURN AND THREE MEMBERS INDICATING A SOUTHWARD TURN. OVERALL THE JTWC
FORECAST HAS TRENDED SLIGHTLY MORE SOUTHWARD. NUMERICAL MODEL
GUIDANCE IS IN GOOD AGREEMENT AND THERE IS HIGH CONFIDENCE IN THIS
PORTION OF THE JTWC TRACK FORECAST.//
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