Tropical Storm CHAN-HOM Advisory Tue Jul 07

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W (CHAN-HOM) WARNING
NR 24//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 09W (CHAN-HOM), LOCATED APPROXIMATELY 321 NM
NORTHWEST OF ANDERSEN AFB, HAS TRACKED NORTHWESTWARD AT 15 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH
TIGHTLY-CURVED CONVECTIVE BANDING WRAPPING INTO A WELL-DEFINED
CENTER. A 060534Z SSMI IMAGE SHOWS MULTIPLE CONVECTIVE BANDS
OVER, PRIMARILY, THE WESTERN SEMI-CIRCLE OF THE LLCC. BASED ON THIS
IMAGERY, THERE IS GOOD CONFIDENCE IN THE CURRENT POSITION. THE
CURRENT INTENSITY IS ASSESSED AT 60 KNOTS BASED ON AN AVERAGE OF
DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM 55 TO 65 KNOTS,
WHICH ARE CONSISTENT WITH THE IMPROVED CONVECTIVE STRUCTURE. UPPER-
LEVEL ANALYSIS INDICATES THAT TS 09W IS LOCATED IN A FAVORABLE
ENVIRONMENT WITH LOW VWS AND NEAR-RADIAL OUTFLOW, ENHANCED BY A TUTT
CELL TO THE NORTHEAST. TS 09W IS TRACKING ALONG THE SOUTHERN
PERIPHERY OF THE DEEP-LAYERED STR.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TS 09W IS FORECAST TO CONTINUE TRACKING WEST-NORTHWESTWARD
UNDER THE STEERING INFLUENCE OF THE STR ENTRENCHED TO THE NORTH.
DYNAMIC GUIDANCE IS IN TIGHT AGREEMENT THROUGH TAU 72 WITH A SPREAD
OF 100 NM IN SOLUTIONS AT TAU 72. TS 09W IS FORECAST TO INTENSIFY
STEADILY THROUGH TAU 72 TO A PEAK INTENSITY OF 130 KNOTS DUE TO
FAVORABLE CONDITIONS.
   C. AFTER TAU 72, TS 09W WILL CONTINUE TO TRACK WEST-NORTHWESTWARD
TO NORTHWESTWARD UNDER THE INFLUENCE OF THE DOMINANT STEERING STR.
VWS AND UPPER-LEVEL DIVERGENCE WILL REMAIN FAVORABLE THROUGH THE END
OF THE FORECAST PERIOD; HOWEVER, COOLER SST AND LOWER OHC VALUES
WILL BEGIN TO WEAKEN THE SYSTEM AS WELL AS LAND INTERACTION AFTER
TAU 96. DYNAMIC MODEL GUIDANCE DIVERGES AFTER TAU 72, HOWEVER, THE
BULK OF THE GUIDANCE IS IN GOOD AGREEMENT WITH A TRACK NORTH OF
TAIWAN. OVERALL, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST
TRACK.//
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