WDPN33 PGTW 072100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W (HAIKUI) WARNING NR
21//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 12W (HAIKUI), LOCATED APPROXIMATELY 135 NM SOUTH
OF SHANGHAI, CHINA, HAS TRACKED NORTHWESTWARD AT 11 KNOTS OVER THE
PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY AND RADAR
IMAGERY DEPICT A WELL-DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC)
WITH TIGHTLY-CURVED CONVECTIVE BANDING WRAPPING INTO THE CENTER.
RADAR IMAGERY AND A 071800Z TRMM IMAGE SUPPORT THE CURRENT POSITION
WITH HIGH CONFIDENCE AND INDICATE THAT THE SYSTEM CENTER IS
BEGINNING TO MOVE OVER LAND. SURFACE OBSERVATIONS FROM SHANGHAI, 140
NM NORTH, SHOW SUSTAINED WINDS OF 25-30 KNOTS WITH GUSTS TO 40-45
KNOTS. A 071500Z OCEANSAT IMAGE SHOWED 50-55 KNOT WINDS OVER THE
EASTERN SEMI-CIRCLE. UPPER-LEVEL ANALYSIS CONTINUES TO SHOW NEAR
RADIAL OUTFLOW AND FAVORABLE ENVIRONMENTAL CONDITIONS. TS 12W IS
TRACKING ALONG THE SOUTHWEST PERIPHERY OF THE SUBTROPICAL RIDGE
(STR). THE 07/12Z 500MB ANALYSIS INDICATES THAT THE STR HAS
MAINTAINED OVER EASTERN CHINA AS A SHORT-WAVE TROUGH CURRENTLY NEAR
THE GULF OF POHAI TRACKS EASTWARD.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS 12W IS FORECAST TO CONTINUE TRACKING WEST-NORTHWESTWARD TO
NORTHWESTWARD THROUGH THE PERIOD AND WILL DISSIPATE OVER LAND BY TAU
36. THERE IS HIGH CONFIDENCE IN THE FORECAST TRACK BASED ON THE
TIGHTLY-GROUPED DYNAMIC MODELS. AFTER TAU 48, THERE IS A LOW
PROBABILITY OF THE REMNANTS TRACKING BACK OVER THE EAST CHINA SEA;
HOWEVER, REGENERATION AS A TROPICAL CYCLONE IS UNLIKELY DUE TO
MIDLATITUDE WESTERLIES STRENGTHENING OVER THE EAST CHINA SEA.//