WDPN31 PGTW 240900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W (BAILU) WARNING NR
13//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 12W (BAILU), LOCATED APPROXIMATELY 172 NM
SOUTH-SOUTHWEST OF TAIPEI, TAIWAN, HAS TRACKED NORTHWESTWARD AT 13
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS PERSISTENT AND DEEP CONVECTION LOCATED AROUND THE LOW
LEVEL CIRCULATION CENTER (LLCC) WITH THE WITH THE DEEPEST CONVECTION
TO THE SOUTH OF THE LLCC. THE INITIAL POSITION IS PLACED WITH GOOD
CONFIDENCE AND IS BASED ON A 230536Z AMSR2 89GHZ MICROWAVE IMAGE,
WHICH SHOWS THE BROAD EXTENT OF THE DEEP CONVECTION. THE INITIAL
INTENSITY OF 55 KNOTS BASED ON A DVORAK CURRENT INTENSITY (CI)
ESTIMATE OF T3.5 (55 KNOTS) FROM PGTW. ENVIRONMENTAL ANALYSIS SHOWS A
ROBUST EQUATORWARD OUTFLOW CHANNEL BUT A LIMITED POLEWARD OUTFLOW
CHANNEL. VERTICAL WIND SHEAR IS FAVORABLE TO NEUTRAL (15 TO 20
KNOTS). TS 12W IS CURRENTLY OVER LAND BUT THE SURROUNDING SEA SURFACE
TEMPERATURES ARE FAVORABLE, BETWEEN 29 AND 30 DEGREES CELSIUS. TS 12W
IS TRACKING ALONG THE SOUTHWEST PERIPHERY OF THE SUBTROPICAL RIDGE
(STR) TO THE NORTHEAST.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. THE AFOREMENTIONED STR WILL CONTINUE TO STEER TS 12W
NORTHWESTWARD FOR THE REMAINDER OF THE FORECAST. LAND INTERACTION
WITH TAIWAN AND EVENTUALLY CHINA WILL CAUSE TS 12W TO QUICKLY WEAKEN
IN INTENSITY. BY TAU 24, BAILU WILL BE WELL INLAND AND WILL HAVE
DECREASED TO AN INTENSITY OF 35 KNOTS. BAILU WILL DISSIPATE BY TAU
36. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT WITH A SPREAD OF 105
NM. THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.//
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