Tropical Storm ONE Advisory sam, 25.07.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 01C (HALOLA) WARNING NR 60//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 01C (HALOLA), LOCATED APPROXIMATELY 115 NM EAST-
SOUTHEAST OF KADENA AB, HAS TRACKED NORTHWESTWARD AT 09 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
DEPICTS TIGHTLY-CURVED BANDING WRAPPING INTO A WELL-DEFINED CENTER,
THEREFORE, THERE IS GOOD CONFIDENCE IN THE CURRENT POSITION AND
RECENT TRACK MOTION. A 242229Z SSMIS 91 GHZ IMAGE SHOWS THE BULK OF
THE DEEP CONVECTION DISPLACED OVER THE SOUTHERN SEMI-CIRCLE DUE TO
STRONG NORTHEASTERLY VERTICAL WIND SHEAR (VWS), HOWEVER, OVERALL
STRUCTURE REMAINS WELL ORGANIZED. THE CURRENT INTENSITY REMAINS
ASSESSED AT 65 KNOTS BASED ON DVORAK INTENSITY ESTIMATES OF T4.0 (65
KNOTS) FROM PGTW AND KNES. THE INTENSITY IS CONSISTENT WITH RECENT
SURFACE OBSERVATIONS FROM MINAMIDAITO ISLAND (PEAK 10-MINUTE WINDS
ABOUT 60 KNOTS). ANIMATED WATER VAPOR IMAGERY REVEALS EXCELLENT
EQUATORWARD OUTFLOW, ENHANCED BY A BROAD TUTT CELL NEAR GUAM, WHICH
IS OFFSETTING THE STRONG VWS. ALTHOUGH THERE IS NO DIRECT EVIDENCE
OF DRY AIR ENTRAINMENT, RECENT SOUNDINGS FROM NAZE SHOW DRY AIR
THROUGH THE COLUMN, WHICH (ALONG WITH STRONG VWS) APPEARS TO BE
HINDERING CONVECTIVE DEVELOPMENT. ADDITIONALLY, THE TOTAL
PRECIPITABLE WATER IMAGERY SHOWS A SHRINKING DEEP MOISTURE ENVELOPE
WITH DRY AIR OVER THE WESTERN PERIPHERY OF THE SYSTEM. TY 01C HAS
CLEARLY TRACKED NORTHWESTWARD BASED ON THE RADAR FIXES AND SATELLITE
IMAGERY. THE 24/12Z 500 MB ANALYSIS DEPICTS A WEAKENING STR TO THE
NORTHWEST AS STRONG SOUTHWESTERLY FLOW STRENGTHENS OVER EASTERN
CHINA, THE KOREAN PENINSULA AND JAPAN.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY HALOLA WILL CONTINUE TRACKING WEST-NORTHWESTWARD TO
NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR OVER THE NEXT
12 HOURS. BEYOND TAU 12, TY HALOLA WILL REACH THE WESTERN EXTENT OF
THE STEERING STR AND BEGIN TO ROUND THE SOUTHWESTERN PERIPHERY.
AFTERWARDS, TY 01C WILL TURN NORTHEASTWARD AND START TO ACCELERATE
ALONG THE NORTHWESTERN PERIPHERY OF THE STR. DYNAMIC MODEL GUIDANCE
HAS COME INTO BETTER AGREEMENT AS THE TYPHOON'S CENTER PASSES
THROUGH THE RYUKYU ISLANDS WITH A 50 NM SPREAD. THE JTWC TRACK IS
POSITIONED AT THE WESTERN EDGE OF THE GUIDANCE DUE TO THE FORECASTED
CONTINUED WEAKENING AND WEAKENING STR. TY 01C WILL FURTHER WEAKEN
THROUGH TAU 48 DUE TO THE MARGINAL ENVIRONMENTAL CONDITIONS. BEYOND
TAU 48, TY HALOLA WILL ACCELERATE NORTHEASTWARD WITHIN THE
MIDLATITUDE WESTERLY FLOW. TY 01C WILL RAPIDLY WEAKEN DUE TO STRONG
VWS, COLD SSTS (23C TO 22C) AND CONTINUED LAND INTERACTION. TY 01C
IS FORECAST TO FULLY DISSIPATE BY THE END OF THE FORECAST PERIOD.
THERE IS NO BAROCLINIC SUPPORT FOR EXTRA-TROPICAL TRANSITION AT THIS
TIME. THERE IS STILL SOME UNCERTAINTY AS TY HALOLA ROUNDS THE STR AS
MODEL GUIDANCE IS WITHIN 170 NM AT TAU 48. ALTHOUGH THERE IS HIGHER
CONFIDENCE WITH THE IMPROVED MODEL GROUPING, THERE REMAINS LOW
OVERALL CONFIDENCE IN THE TIMING OF THE RE-CURVE AND, THEREFORE, IN
THE OVERALL TRACK FORECAST.//
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