Tropical Storm HAIKUI Advisory vie, 10-11

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 30W (THIRTY)
WARNING NR 02//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 30W (THIRTY), LOCATED APPROXIMATELY 122
NM SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD
AT 16 KNOTS OVER THE PAST SIX HOURS. DESPITE TRACKING OVER THE
CENTRAL PHILIPPINE ISLANDS, ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH
CONVECTIVE BANDING WRAPPING INTO THE LLCC. A 090630Z SSMI 85GHZ
IMAGE INDICATES THAT THE BULK OF THE DEEP CONVECTION IS LOCATED OVER
THE NORTHERN SEMI-CIRCLE, HOWEVER, CONVECTIVE ORGANIZATION IS
IMPROVING WITH A DEFINED CENTER, WHICH SUPPORTS THE INITIAL POSITION
WITH GOOD CONFIDENCE. UPPER-LEVEL ANALYSIS INDICATES A FAVORABLE
ENVIRONMENT WITH LOW VERTICAL WIND SHEAR AND NEAR-RADIAL OUTFLOW.
THE INITIAL INTENSITY IS ASSESSED AT 30 KNOTS BASED ON DVORAK
INTENSITY ESTIMATES RANGING FROM T1.5 TO T2.0 (25 TO 30 KNOTS). TD
30W IS TRACKING QUICKLY ALONG THE SOUTHERN PERIPHERY OF A LOW- TO
MID-LEVEL SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD IS FORECAST TO CONTINUE TRACKING WEST-NORTHWESTWARD UNDER
THE STEERING INFLUENCE OF THE DEEP-LAYERED STR THROUGH TAU 72. THE
SYSTEM IS EXPECTED TO INTENSIFY SIGNIFICANTLY AFTER TRACKING OVER
THE SOUTH CHINA SEA AFTER TAU 12 WITH FAVORABLE ENVIRONMENTAL
CONDITIONS PERSISTING. DYNAMIC GUIDANCE REMAINS IN GOOD AGREEMENT
WITH A 100-NM SPREAD IN SOLUTIONS AT TAU 72.
   C. AFTER TAU 72, DYNAMIC GUIDANCE SPLITS INTO TWO DISTINCT GROUPS
WITH INCREASING UNCERTAINTY IN THE FORECAST TRACK. THE FIRST GROUP
(AFUM, UKMO, HWRF, NVGM, ECMF AND EEMN) WEAKEN THE SYSTEM RAPIDLY
AND TRACK THE REMNANTS SOUTHWESTWARD TO WEST-SOUTHWESTWARD. THE
SECOND GROUP (AEMN, AVNO, CTCX AND UEMN) DEPICT A SLOW POLEWARD
TRACK. IN GENERAL, THE MODEL FIELDS INDICATE INCREASING WESTERLY
FLOW ACROSS SOUTHEAST CHINA AFTER TAU 72, WHICH WILL SERVE TO WEAKEN
THE STR AND LEAD TO A SIGNIFICANT TRACK SLOW-DOWN. THE JTWC FORECAST
TRACK FAVORS A SLOW POLEWARD MOTION OVER HAINAN ISLAND AS THE SYSTEM
ENCOUNTERS WESTERLY FLOW AND TRACKS ALONG THE WESTERN PERIPHERY OF
THE STR. DUE TO THE INCREASING UNCERTAINTY IN THE TRACK FORECAST
AFTER TAU 72, THERE IS LOW OVERALL CONFIDENCE IN THE JTWC FORECAST.//
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