TD WIPHA(08W) passing over the Leizhou Peninsula, struggling intensity


Warning 6/JTWC


WARNING 6. STRUGGLING SYSTEM WITH A 30KNOTS INTENSITY.
WARNING 6. STRUGGLING SYSTEM WITH A 30KNOTS INTENSITY.
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WESTERN NORTH PACIFIC

TD WIPHA(08W)
As of 00:00 UTC Aug 01, 2019:

Location: 20.7°N 110.9°E
Maximum Winds: 30 kt ( 55km/h)
Gusts: 40 kt ( 75km/h)
Minimum Central Pressure: 994 mb

WDPN31 PGTW 010300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 08W (WIPHA)
WARNING NR 06//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL DEPRESSION (TD) 08W (WIPHA), LOCATED APPROXIMATELY 281 NM
EAST OF HANOI, VIETNAM, HAS TRACKED NORTHWESTWARD AT 07 KNOTS OVER
THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED IMAGERY SHOWS A LARGE
AREA OF FRAGMENTED, FLARING, AND POORLY ORGANIZED DEEP CONVECTION
WITH MONSOON DEPRESSION CHARACTERISTICS. THE MAIN BANDS ARE FEEDING
IN FROM THE SOUTH INTO A BROAD, ELONGATED AND ASYMMETRICAL LOW LEVEL
CIRCULATION (LLC). THE INITIAL POSITION IS FROM AN LLC FEATURE IN THE
312212Z SSMIS IMAGE AND TRIANGULATED FROM MULTIPLE SURFACE
OBSERVATIONS INCLUDING HAIKOU, HAINAN. THE INITIAL INTENSITY OF 30
KNOTS IS AVERAGED FROM AGENCY DVORAK ESTIMATES AND SUPPORTED BY
NEARBY SURFACE OBSERVATIONS. UPPER LEVEL ANALYSIS INDICATES AN
EASTWARD OUTFLOW CHANNEL TOWARD A TUTT CELL ANCHORED OVER OKINAWA
THAT IS PROVIDING VENTILATION TO THE FLARING CONVECTION. HOWEVER,
THIS IS OFFSET BY A MODERATE (15-20 KNOT) EASTERLY VERTICAL WIND
SHEAR (VWS). TD 08W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A
SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 08W IS EXPECTED TO REMAIN ON ITS CURRENT TRACK THROUGHOUT
THE FORECAST, MAKING LANDFALL OVER THE LEIZHOU PENINSULA SHORTLY
AFTER TAU 06. AFTERWARD, IT WILL CROSS THE GULF OF TONKIN MOMENTARILY
BEFORE MAKING A FINAL LANDFALL IN SOUTH CHINA NEAR BEIHAI. LAND
INTERACTION, IN ADDITION TO THE MODERATE VWS, OFFSET BY THE MOMENTARY
DRIFT OVER WATER, WILL GRADUALLY ERODE THE SYSTEM, LEADING TO
DISSIPATION BY TAU 36. AVAILABLE NUMERICAL MODELS ARE IN GOOD
AGREEMENT WITH NAVGEM AS THE LEFT OF TRACK OUTLIER. THERE IS A SMALL
PROBABILITY THAT TD 08W WILL TRACK MORE WESTWARD, AS PROPOSED BY
NAVGEM, RESULTING IN A LONGER DRIFT OVER THE GULF OF TONKIN, HENCE, A
LONGER LIFESPAN. THERE IS OVERALL FAIR CONFIDENCE IN THE JTWC TRACK
FORECAST THAT IS LAID CLOSE TO CONSENSUS.//
NNNN

01/03UTC. MONSOON DEPRESSION CHARACTERISTICS
01/03UTC. MONSOON DEPRESSION CHARACTERISTICS

31/2331UTC. DMSP/F17
31/2331UTC. DMSP/F17

31/2317UTC. DMSP/F17
31/2317UTC. DMSP/F17

TRACK AND INTENSITY GUIDANCE
TRACK AND INTENSITY GUIDANCE
Rédigé par PATRICK HOAREAU le Jeudi 1 Août 2019 à 07:18