Tropical Storm BAILU Advisory 22.08.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W (BAILU) WARNING NR
04//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 12W (BAILU), LOCATED APPROXIMATELY 674 NM
SOUTHEAST OF TAIPEI, TAIWAN, HAS TRACKED WEST-NORTHWESTWARD AT 12
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) SHOWS CONVECTION CONTINUES TO CONSOLIDATE AROUND THE
LOW LEVEL CIRCULATION CENTER (LLCC) WITH MOST OF THE DEEP CONVECTION
OFFSET TO THE SOUTHWEST. THE INITIAL POSITION IS PLACED WITH LOW
CONFIDENCE BASED ON EIR IMAGERY WHICH SHOWS BANDING WRAPPING INTO THE
LLCC. THE INTENSITY OF 45 KNOTS IS SET ABOVE DVORAK CURRENT INTENSITY
ESTIMATES OF T2.0-2.5 (30-42 KNOTS) AND IS SLIGHTLY ABOVE A 212214Z
SATCON ESTIMATE OF 43 KNOTS. A PARTIAL 210030Z METOP-B ASCAT PASS
SHOWS A SMALL SWATH OF 40-45 KNOT WIND BARBS WITHIN THE SOUTHERN
SEMI-CIRCLE. ENVIRONMENTAL ANALYSIS SHOWS TS 12W IS EXPERIENCING
FAVORABLE VERTICAL WIND SHEAR (5 TO 15 KNOTS). TS 12W HAS A STRONG
EQUATORWARD OUTFLOW CHANNEL AND A TROPICAL UPPER TROPOSPHERIC TROUGH
IS BEGINNING TO ENHANCE POLEWARD OUTFLOW TO THE NORTHEAST. SEA
SURFACE TEMPERATURES REMAIN FAVORABLE (28-29 DEGREES CELSIUS) FOR
DEVELOPMENT. TS 12W IS TRACKING NORTHWESTWARD WHILE UNDER THE
INFLUENCE OF A SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. IN THE SHORT TERM, TS 12W WILL CONTINUE TO EXPERIENCE FAVORABLE
VERTICAL WIND SHEAR AND WILL REMAIN OVER WARM SEA SURFACE
TEMPERATURES. THESE CONDITIONS WILL ALLOW FOR A RAPID INCREASE IN
INTENSITY, REACHING 80 KNOTS BY TAU 48. HOWEVER, A POOR UPPER LEVEL
ENVIRONMENT AROUND TAU 48 WILL HINDER FURTHER INTENSIFICATION. THE
STR TO THE NORTHEAST WILL REMAIN IN PLACE THROUGH TAU 72 AND ALLOW TS
12W TO TRACK NORTHWESTWARD. TS 12W WILL MAKE LANDFALL IN TAIWAN
AROUND TAU 60. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT, WITH A
SPREAD OF 110NM AT TAU 48; HOWEVER, DUE TO THE UNCERTAINTY IN THE
INITIAL POSITION THERE IS MODERATE CONFIDENCE IN THIS PORTION OF THE
JTWC FORECAST TRACK.
   C. AFTER TAU 72, TS 12W WILL CONTINUE TO TRACK NORTHWESTWARD WHILE
UNDER THE INFLUENCE OF THE STR. BY TAU 72, TS 12W WILL EMERGE INTO
THE TAIWAN STRAIT AND THEN MAKE LANDFALL IN CENTRAL CHINA. LAND
INTERACTION WITH CHINA WILL CAUSE TS 12W TO WEAKEN QUICKLY AFTER
LANDFALL AND WILL DISSIPATE BY TAU 120. DYNAMIC MODEL GUIDANCE IS IN
POOR AGREEMENT DURING THIS PORTION OF THE FORECAST DUE TO A
BIFURCATION IN MODEL GUIDANCE. THE JTWC TRACK IS IN AGREEMENT WITH A
WEST-NORTHWESTERN PATH SOUTH OF THE STR AND IS NOT EXPECTED TO
RECURVE, AS SEEN IN THE ECMWF AND UKMET TRACKS. DUE TO THE MODEL
SPREAD AND THE HIGH UNCERTAINTY IN THE INITIAL POSITION THERE IS LOW
CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.//
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