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Super Typhoon Hagibis back to Category 5



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WESTERN NORTH PACIFIC

STY HAGIBIS(20W)
As of 18:00 UTC Oct 08, 2019:

Location: 19.2°N 140.8°E
Maximum Winds: 140 kt ( 260km/h)
Gusts: 170 kt ( 315km/h)

Minimum Central Pressure: 909 mb
CATEGORY 5 US

WDPN31 PGTW 082100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 20W (HAGIBIS) WARNING NR
015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 20W (HAGIBIS), LOCATED APPROXIMATELY 337 NM
SOUTH OF IWO TO, HAS TRACKED NORTHWESTWARD AT 12 KNOTS (KTS) OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY
SHOWS THE NEWLY FORMED PRIMARY EYEWALL CONTRACTING INTO A FAIRLY
SYMMETRIC, 20 NM DIAMETER EYE WHILE A BROAD AREA OF CONVECTIVE
BANDING CONTINUES TO WRAP TIGHTLY INTO THE SYSTEMS CENTER. THERE IS
GOOD CONFIDENCE IN THE INITIAL POSITION. A 081932Z SSMIS 91GHZ
MICROWAVE IMAGE INDICATES THAT THE EYEWALL REPLACEMENT CYCLE (ERC) IS
COMPLETE AND THAT THE PREVIOUS EYEWALL HAS FULLY DISSIPATED. BASED ON
THE IMPROVED CONVECTIVE STRUCTURE AND DVORAK CURRENT INTENSITY (CI)
ESTIMATES OF T6.5/127 KTS FROM PGTW, T7.0/140 KTS FROM RJTD, AND
T6.9/137 KTS FROM ADVANCED DVORAK TECHNIQUE (ADT), THE INITIAL
INTENSITY ESTIMATE IS SET AT 140 KTS, FURTHER CORROBORATED BY THE
SATELLITE CONSENSUS INTENSITY ESTIMATE. UPPER-LEVEL ANALYSIS SHOWS
SUSTAINED STRONG RADIAL OUTFLOW, ENHANCED TOWARDS THE EAST AND SOUTH.
AN AREA OF DRY AIR WITH HIGH VERTICAL WIND SHEAR (VWS) TO THE NORTH
OF THE SYSTEM IS INHIBITING DEVELOPMENT OF A STRONG POLEWARD OUTFLOW
CHANNEL. WITH LOW (05-10 KTS) VWS AND WARM (29-31 CELSIUS) SEA
SURFACE TEMPERATURES (SST), STY 20W REMAINS IN A FAVORABLE
ENVIRONMENT FOR DEVELOPMENT. STY 20W IS TRACKING NORTHWESTWARD UNDER
THE STEERING INFLUENCE OF A SUBTROPICAL RIDGE (STR) TO THE NORTHEAST.
3. FORECAST REASONING.     
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE LAST PROGNOSTIC REASONING MESSAGE.
   B. AFTER TAU 24, A PASSING MIDLATITUDE TROUGH TO THE NORTH WILL
CAUSE THE STR TO RE-ORIENT, ALLOWING STY 20W TO TURN TO A MORE
NORTH-NORTHWESTWARD TRACK AS IT ROUNDS THE RIDGE AXIS. WITH LOW VWS,
HIGH SST, AND GOOD UPPER-LEVEL OUTFLOW, THE FAVORABLE ENVIRONMENT IS
EXPECTED TO PERSIST. THE OFFICIAL INTENSITY FORECAST REMAINS MORE
AGGRESSIVE THAN MULTI-MODEL INTENSITY GUIDANCE DUE TO THE POSSIBILITY
OF SLIGHT RE-INTENSIFICATION AS THE NEW EYE MAY CONTRACT FURTHER.
ADDITIONALLY, THERE MAY BE A BRIEF PERIOD OF ENHANCED POLEWARD
OUTFLOW DUE TO TROUGH INTERACTION. AFTERWARDS, GRADUAL WEAKENING IS
EXPECTED AS THE OUTFLOW BEGINS TO BE SHEARED BY THE TROUGH. GFS AND
THE GFS ENSEMBLE REMAIN THE EASTERNMOST OUTLIERS WHILE THE NAVGEM AND
AFUM SOLUTIONS ARE THE WESTERNMOST OUTLIERS, CREATING VARIATION IN
THE TIMING OF THE RECURVE. THE OFFICIAL JTWC FORECAST IS PLACED NEAR
THE MULTI-MODEL CONSENSUS, LENDING GOOD CONFIDENCE TO THIS PORTION OF
THE TRACK.
   C. IN THE EXTENDED PERIOD, A SHORTWAVE TROUGH OVER JAPAN WILL MOVE
THROUGH THE AREA, AGAIN ERODING THE STR AND ALLOWING STY 20W TO
RECURVE AFTER TAU 72. THE SYSTEM WILL SLOWLY WEAKEN IN RESPONSE TO
INCREASING VWS AFTER TAU 72, OFFSETTING THE OTHERWISE FAVORABLE
ENVIRONMENT. AS STY 20W APPROACHES HONSHU, LAND INTERACTION MAY BEGIN
TO ERODE THE SYSTEMS INTENSITY. AT TAU 120, AS STY 20W BEGINS
INTERACTING WITH THE BAROCLINIC ZONE, THE SYSTEM WILL ACCELERATE TO
THE NORTHEAST AND BEGIN EXTRATROPICAL TRANSITION. THROUGHOUT THE
EXTENDED FORECAST PERIOD, CROSS-TRACK AGREEMENT IS GOOD, WITH
APPROXIMATELY 180 NM OF SPREAD. HOWEVER, THE TIMING OF THE RECURVE
AND EXTRATROPICAL TRANSITION VARY BETWEEN MODELS; THUS, THERE IS 700
NM OF ALONG TRACK SPREAD AT TAU 120, WITH NAVGEM REMAINING THE
SLOWEST AND MOST WESTWARD MODEL, AND GFS, THE GFS ENSEMBLE, AND JGSM
SIGNIFICANTLY FASTER THAN AND EAST OF THE MULTI-MODEL CONSENSUS. THE
JTWC FORECAST TRACK IS SHIFTED SLIGHTLY WESTWARD TO BE PLACED NEAR
THE MULTI-MODEL CONSENSUS. BASED ON THE VARIATION IN MODEL TIMING OF
THE RECURVE AND ALONG-TRACK SPEEDS, THERE IS LOW CONFIDENCE IN THIS
PORTION OF THE JTWC TRACK FORECAST.//
NNNN

FORECAST PEAK INTENSITY OF 145KTS WITHIN 12H
FORECAST PEAK INTENSITY OF 145KTS WITHIN 12H


08/21UTC
08/21UTC

08/2139UTC
08/2139UTC

08/21UTC
08/21UTC

TRACK AND INTENSITY GUIDANCE
TRACK AND INTENSITY GUIDANCE

HWRF: 132KT AT +0H
HWRF: 132KT AT +0H
Rédigé par PATRICK HOAREAU le Mercredi 9 Octobre 2019 à 04:45