Tropical Storm HALONG Advisory Wed Aug 06

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (HALONG) WARNING NR 32//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 11W (HALONG), LOCATED APPROXIMATELY 404 NM SOUTH-SOUTHEAST
OF KADENA AB, OKINAWA, HAS TRACKED NORTHWARD AT 08 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS
THE LOW LEVEL CIRCULATION CENTER (LLCC) HAS BEEN STRUGGLING TO RE-
CONSOLIDATE OVER THE PAST FEW HOURS, WITH THE BEGINNING OF A CLEAR
EYE FORMING. DEEP CONVECTION ON THE NORTHERN HALF OF THE SYSTEM
REMAINS BROKEN BUT HAS SEEN MARGINAL IMPROVEMENTS WITH A MORE SYM-
METRIC CORE OF DEEP CONVECTION BUILDING. UPPER LEVEL ANALYSIS INDI-
CATES A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) TO THE NORTHEAST
AND A SUBTROPICAL RIDGE (STR) TO THE NORTHWEST CONTINUE TO INTERACT,
CREATING MODERATE LEVELS OF VERTICAL WIND SHEAR (VWS) (20 TO 30
KNOTS) IN THE VICINITY OF THE LLCC. THIS INTERACTION IS CAUSING THE
WEAKENING OF THE DEEP CONVECTION ALONG THE NORTHERN PERIPHERY BUT IS
ALSO PROVIDING THE AMPLY EQUATORWARD OUTFLOW SUPPORTING THE CURRENT
INTENSITY OF 90 KNOTS. DVORAK ESTIMATES FROM PGTW AND RJTD SUPPORT
THE STEADY INTENSITY FORECAST AS THE SYSTEM STRUGGLES TO MAINTAIN IN
THE MODERATE VWS. TY 11W IS CURRENTLY TRACKING ALONG THE WESTERN
PERIPHERY OF A DEEP LAYERED STR TO THE EAST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE PREVIOUS PROGNOSTIC
REASONING.
   B. THE SYSTEM WILL CONTINUE ITS NORTHWARD TRACK ALONG THE WESTERN
SIDE OF THE STR, WITH THE TUTT CELL TO THE NORTHEAST INDUCING A
SLIGHT EASTERLY COMPONENT IN THE TRACK THROUGH TAU 36. BETWEEN
TAUS 36 AND 72, HALONG'S MAIN STEERING INFLUENCE WILL BE THE STR,
WITH THE SYSTEM ROUNDING ITS WESTERN PERIPHERY BY TAU 72. TY 11W WILL
MAINTAIN IN INTENSITY IN THE MARGINAL ENVIRONMENT OVER THE NEXT 24
HOURS DUE TO THE PERSISTENT NORTHERLY VWS. FROM TAU 24 TO TAU 36 THE
RELAXATION IN THE VWS AND IMPROVED POLEWARD OUTFLOW WILL ALLOW FOR A
BRIEF PERIOD OF INTENSIFICATION FROM TAU 36 THROUGH TAU 48. A SLIGHT
DECREASE IN INTENSITY AT TAU 72 IS EXPECTED AS TY 11W STARTS TO SEE
INCREASED MID-LATITUDE BAROCLINIC INFLUENCES ALONG THE NORTHWESTERN
QUADRANT.
   C. BEYOND TAU 72, MODEL GUIDANCE VARIES SIGNIFICANTLY IN BOTH
SPEED AND TRACK OF THE STORM. MOST MODELS HAVE THE SYSTEM MAKING
LANDFALL IN SOUTHERN JAPAN AROUND TAU 108, WITH GFDN REMAINING THE
EASTERN OUTLIER, INDICATING TY 11W WILL RECURVE SOUTH OF JAPAN.
ALL INTENSITY GUIDANCE SHOWS A STEADY WEAKENING THROUGH TAU 120 AS
THE SYSTEM SEES INCREASING INTERACTION WITH THE MID-LATITUDE WESTER-
LIES AND THE EVENTUAL LANDFALL IN SOUTHERN JAPAN FURTHER WEAKENING
THE LLCC. BY TAU 120 MODEL GUIDANCE IS INDICATING THE START OF EXTRA-
TROPICAL TRANSITION BUT DUE TO THE LARGE SPREAD IN MODEL SOLUTIONS,
WITH REGARD TO THE DIFFERENT INTERPRETATION OF THE TROUGH AND THE
STRENGTH AND ORIENTATION OF THE STR, THERE IS OVERALL LOW CONFIDENCE
IN THE JTWC FORECAST AFTER TAU 72.//
NNNN
NNNN