meteo





STY Hagibis, category 5, gradually weakening next 3 days while approaching Tokyo area



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WESTERN NORTH PACIFIC

STY HAGIBIS(20W)
As of 12:00 UTC Oct 09, 2019:

Location: 21.2°N 139.6°E
Maximum Winds: 140 kt ( 260km/h)
Gusts: 170 kt ( 315km/h)

Minimum Central Pressure: 910 mb
CATEGORY 5 US

WDPN31 PGTW 091500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 20W (HAGIBIS) WARNING NR
018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 20W (HAGIBIS), LOCATED APPROXIMATELY 236
NM SOUTH-SOUTHWEST OF IWO TO, HAS TRACKED NORTH-NORTHWESTWARD AT
06 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS A WELL-DEFINED, SYMMETRIC EYE WITH
CONVECTIVE BANDING WRAPPING INTO THE CENTER AND COOLING CLOUD TOPS
IN THE DEEP CONVECTION SURROUNDING THE EYE. STY 20W HAS MAINTAINED A
25 NM DIAMETER EYE, SUPPORTING THE INITIAL POSITION WITH GOOD
CONFIDENCE. THE INITIAL INTENSITY IS SET AT 140 KTS WITH FAIR
CONFIDENCE BASED ON DVORAK CURRENT INTENSITY (CI) ESTIMATES OF T7.0
(140 KTS) FROM PGTW AND RJTD AND THE COOLING CLOUD TOPS. THE INITIAL
INTENSITY IS SLIGHTLY ABOVE A 090540Z AUTOMATED DVORAK TECHNIQUE
ESTIMATE OF 125 KTS, BUT SUPPORTED BY A 091144Z SATCON ESTIMATE OF
143 KTS. THE WESTERN WIND RADII WERE ADJUSTED USING A 091146Z METOP-
B ASCAT PASS. UPPER-LEVEL ANALYSIS SHOWS EXCELLENT EQUATORWARD AND
EASTWARD OUTFLOW, AND A ROBUST POLEWARD OUTFLOW CHANNEL IS TAPPING
INTO A PASSING TROUGH TO THE NORTH. THE OVERALL ENVIRONMENT REMAINS
FAVORABLE FOR MAINTAINING SUPER TYPHOON INTENSITY WITH LOW (5-10
KTS) VERTICAL WIND SHEAR (VWS) AND WARM (29-31 CELSIUS) SEA SURFACE
TEMPERATURES (SST). STY 20W IS TRACKING NORTHWESTWARD ALONG THE
SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST, ALTHOUGH IT SLOWED SLIGHTLY IN THE LAST 6 HOURS.
3. FORECAST REASONING.     
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE LAST PROGNOSTIC REASONING MESSAGE.
   B. STY 20W WILL CONTINUE ALONG ITS NORTH-NORTHWESTWARD TRACK AS A
PASSING MID-LATITUDE TROUGH TO THE NORTH CAUSES THE STR TO REORIENT.
THE FAVORABLE ENVIRONMENT IS EXPECTED TO PERSIST WITH LOW VWS, WARM
SST, AND STRONG UPPER-LEVEL OUTFLOW. STY 20W IS EXPECTED TO MAINTAIN
INTENSITY FOR THE FIRST 12 HOURS DUE TO THE ENHANCED POLEWARD
OUTFLOW. HOWEVER, STY 20W IS EXPECTED TO BEGIN A GRADUAL WEAKENING
TREND AFTER TAU 12 AS THE TROUGH BEGINS TO INTERFERE WITH OUTFLOW.
NUMERICAL MODELS REMAIN IN GOOD CROSS-TRACK AGREEMENT BUT POOR ALONG-
TRACK SPEED AGREEMENT. AFTER TAU 48, A SHORTWAVE TROUGH WILL PASS
OVER JAPAN, WEAKENING THE STR AND ALLOWING STY 20W TO BEGIN
RECURVING. GFS AND THE GFS ENSEMBLE REMAIN THE EASTERNMOST OUTLIERS
WITH NAVGEM AS THE WESTERNMOST OUTLIER IN THE SHORT TERM. PLACED
NEAR THE MULTI-MODEL CONSENSUS AND MAIN MODEL GROUPING, THERE IS
GOOD CONFIDENCE IN THE OFFICIAL JTWC FORECAST IN THIS PORTION OF THE
TRACK.
   C. AFTER TAU 72, VWS WILL INCREASE, SSTS WILL DROP BELOW 26
DEGREES CELSIUS, FRICTIONAL EFFECTS FROM SKIRTING HONSHU WILL
DISRUPT THE STRUCTURE, AND A LOW LEVEL NORTHEASTERLY COLD SURGE WILL
BUILD IN TO THE WEST, ALL COMBINING TO CAUSE MORE RAPID WEAKENING.
STY 20W WILL BEGIN INTERACTING WITH THE TROUGH AROUND TAU 72,
ACCELERATING NORTHEASTWARD AS EXTRATROPICAL TRANSITION OCCURS. BY
TAU 96, THE SYSTEM WILL BE FULLY EXTRATROPICAL AND EMBEDDED IN THE
MID-LATITUDE WESTERLIES. NUMERICAL MODELS ARE IN FAIR CROSS-TRACK
AGREEMENT AFTER RECURVATURE OF STY 20W. HOWEVER, AS THE SYSTEM
ACCELERATES, ALONG-TRACK SPREAD GREATLY INCREASES TO 535 NM THROUGH
TAU 96. ECMWF, NAVGEM, AND COAMPS-TC ARE SLOWER THAN THE MULTI-MODEL
CONSENSUS AT LATER TAUS. GFS MOVES TO WEST OF CONSENSUS IN LATER
TAUS, WHILE JGSM IS TO THE INSIDE OF AND FASTER THAN CONSENSUS. THE
JTWC FORECAST TRACK IS PLACED NEAR BUT SLIGHTLY SLOWER THAN THE
MULTI-MODEL CONSENSUS AFTER TAU 72 TOWARDS THE ECMWF SOLUTION. 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
 

CURRENT INTENSITY SET AT 140KTS. FORECAST TO WEAKEN NEXT 72H WHILE APPROACHING TOKYO AREA
CURRENT INTENSITY SET AT 140KTS. FORECAST TO WEAKEN NEXT 72H WHILE APPROACHING TOKYO AREA



09/1350UTC
09/1350UTC


09/1112UTC
09/1112UTC

TRACK AND INTENSITY GUIDANCE
TRACK AND INTENSITY GUIDANCE

HWRF: 138KT AT +0H
HWRF: 138KT AT +0H
Rédigé par PATRICK HOAREAU le Mercredi 9 Octobre 2019 à 18:06