Tropical Storm TWENTYTHREE Advisory Tue Oct 10

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 23W (TWENTYTHREE)
WARNING NR 03//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 23W (TWENTYTHREE), LOCATED APPROXIMATELY
151 NM EAST-NORTHEAST OF DA NANG, VIETNAM, HAS TRACKED WEST-
NORTHWESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY SHOWS BANDING CONVECTION TO THE SOUTH
OF HAINAN ISLAND WHICH IS ASSOCIATED WITH THE LOW LEVEL CIRCULATION
CENTER (LLCC). THE CONVECTIVE STRUCTURE HAS IMPROVED IN ORGANIZATION
OVER THE PAST SEVERAL HOURS. THE INITIAL INTENSITY OF 30 KNOTS IS
BASED ON AN AVERAGE OF A PGTW DVORAK ESTIMATE OF T1.5 (25 KNOTS) AND
A SATCON ESTIMATE OF 36 KNOTS. UPPER LEVEL ANALYSIS SHOWS LOW TO
MODERATE VERTICAL WIND SHEAR (10 TO 20 KNOTS) AND STRONG POLEWARD AND
EQUATORWARD OUTFLOW. SEA SURFACE TEMPERATURES REMAIN FAVORABLE (28-29
CELSIUS). TD 23W IS TRACKING WEST-NORTHWESTWARD ALONG THE SOUTHERN
PERIPHERY OF THE DEEP LAYERED SUBTROPICAL RIDGE (STR) WHICH IS
CENTERED IN THE EAST CHINA SEA.
3. FORECAST REASONING.
     A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY
FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
     B. TD 23W WILL CONTINUE TRACKING WEST-NORTHWESTWARD AS IT
REMAINS UNDER THE STEERING INFLUENCE OF THE STR TO THE NORTH. TD 23W
WILL CONTINUE TO CONSOLIDATE AND INCREASE IN INTENSITY TO 35 KNOTS BY
TAU 12. LIMITED TIME OVER WATER AND MODERATE VERTICAL WIND SHEAR
VALUES WILL PREVENT ADDITIONAL INTENSIFICATION. TD 23W WILL TRACK
SOUTH OF HAINAN ISLAND AND MAKE LANDFALL IN NORTHERN VIETNAM BEFORE
TAU 24 AND WILL DISSIPATE BY TAU 36. MODEL GUIDANCE IS IN GOOD
AGREEMENT FOR BOTH TRACK AND INTENSITY. OVERALL CONFIDENCE FOR THE
JTWC FORECAST IS HIGH.//
NNNN
NNNN