Tropical Storm HALONG Advisory Tue Jul 29

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (ELEVEN) WARNING NR
03//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 11W (ELEVEN), LOCATED APPROXIMATELY 218 NM
EAST-SOUTHEAST OF ANDERSEN AFB, GUAM HAS TRACKED WEST-NORTHWESTWARD
AT 07KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS IMPROVED DEEP CENTRAL CONVECTION WITH
FORMATIVE BANDING WRAPPING INTO A RAPIDLY-CONSOLIDATING LOW-LEVEL
CIRCULATION CENTER (LLCC). A 282210Z SSMIS MICROWAVE IMAGE ALSO
REVEALS TIGHTLY-CURVED CONVECTIVE BANDING WRAPPING TOWARDS THE WELL-
DEFINED LLCC. THE CURRENT POSITION IS BASED ON THE MSI AND ABOVE
MICROWAVE IMAGE WITH HIGH CONFIDENCE. THE INITIAL INTENSITY HAS
INCREASED TO 45 KNOTS BASED ON A 290008Z ASCAT PASS SHOWING 40 TO 45
KNOT WIND BARBS ALONG THE SOUTHERN SEMI-CIRCLE WITH WEAKER WINDS (25
TO 35 KNOT) OVER THE NORTHWESTERN QUADRANT. UPPER-LEVEL ANALYSIS
INDICATES ENHANCED EASTWARD OUTFLOW SUPPORTED BY A TROPICAL UPPER
TROPOSPHERIC TROUGH (TUTT) TO THE NORTHEAST, AS EVIDENT IN THE WATER
VAPOR IMAGERY. ADDITIONALLY, PERSISTENT FAVORABLE VERTICAL WIND
SHEAR AND EXCELLENT EQUATORWARD OUTFLOW HAS CAUSED THE SYSTEM TO
RAPIDLY CONSOLIDATE OVER THE PAST SIX HOURS.
3. FORECAST REASONING.
   A. THE SHORT-TERM INTENSITY FORECAST HAS BEEN INCREASED FROM THE
PREVIOUS WARNING.
   B. TD 11W IS FORECAST TO TRACK WEST-NORTHWESTWARD ALONG THE
SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE NORTH.
UPPER-LEVEL CONDITIONS ARE EXPECTED TO IMPROVE; HOWEVER,
ANOTHER TUTT LOCATED TO THE NORTHWEST OF TS 11W IS FORECAST TO
SLIGHTLY HINDER THE DEVELOPMENT DUE TO SUBSIDENCE ON THE
NORTHWESTERN EDGE, CAUSING SLOW INTENSIFICATION THROUGHOUT THE
FORECAST PERIOD.
   C. IN THE EXTENDED TAUS, THE SYSTEM IS EXPECTED TO SLIGHTLY SHIFT
NORTHWESTWARD AS THE STR WEAKENS. AVAILABLE MODEL GUIDANCE IS IN
GOOD AGREEMENT; HOWEVER, DUE TO THE UNCERTAINTY IN THE TRACK AND
INTENSITY AT EXTENDED TAUS, THERE IS OVERALL LOW CONFIDENCE IN THE
JTWC FORECAST.//
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