meteo





STY Hagibis, cat 5, moving slowly northwestward with a symmetric 40km wide eye



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WESTERN NORTH PACIFIC

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

Location: 19.8°N 140.3°E
Maximum Winds: 140 kt ( 260km/h)
Gusts: 170 kt ( 315km/h)

Minimum Central Pressure: 908 mb
CATEGORY 5 US

WDPN31 PGTW 090300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 20W (HAGIBIS) WARNING NR
016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   SUPER TYPHOON (STY) 20W (HAGIBIS), LOCATED APPROXIMATELY 305 NM
SOUTH OF IWO TO, HAS TRACKED NORTHWESTWARD AT 08 KNOTS (KTS) OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
DEPICTS A WELL-DEFINED, SYMMETRIC EYE WITH CONVECTIVE BANDING
WRAPPING INTO THE CENTER. STY 20W HAS MAINTAINED A 20 NM DIAMETER
EYE, SUPPORTING GOOD CONFIDENCE IN THE INITIAL POSITION. HOWEVER, THE
IMMEDIATE EXTENT OF THE CIRRUS SHIELD HAS DECREASED IN THE PAST SIX
HOURS. 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/RJTD/RCTP ALONG WITH A 090033Z SATELLITE CONSENSUS OF 152 KTS
AND A 090110Z ADVANCED DVORAK TECHNIQUE (ADT) ESTIMATE OF T6.9/137
KTS. UPPER-LEVEL ANALYSIS SHOWS EXCELLENT EQUATORWARD AND EASTWARD
OUTFLOW WITH DEVELOPMENT OF A POLEWARD OUTFLOW CHANNEL AS A TROUGH
PASSES TO THE NORTH. THE OVERALL ENVIRONMENT REMAINS FAVORABLE FOR
BRIEF DEVELOPMENT WITH LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS) AND
WARM (29-31 CELSIUS) SEA SURFACE TEMPERATURES (SST). TRACKING
NORTH-NORTHWESTWARD, STY 20W IS BEING STEERED BY 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. 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. THE OFFICIAL INTENSITY FORECAST
REMAINS MORE AGGRESSIVE THAN MULTI-MODEL INTENSITY GUIDANCE DUE TO
THE POSSIBILITY OF A BRIEF PERIOD OF ENHANCED POLEWARD OUTFLOW AS A
RESULT OF INTERACTION WITH THE PASSING TROUGH. HOWEVER, AS THE
OUTFLOW BEGINS TO BE SHEARED BY THE PASSING TROUGH, GRADUAL WEAKENING
IS EXPECTED. THROUGH TAU 36, NUMERICAL MODELS REMAIN IN GOOD
AGREEMENT. GFS AND THE GFS ENSEMBLE REMAIN THE EASTERNMOST OUTLIERS
WITH NAVGEM AND AFUM AS THE WESTERNMOST OUTLIERS. AT TAU 72, THERE IS
190 NM OF CROSS-TRACK AND 200 NM OF ALONG-TRACK SPREAD AS THE MODEL
SOLUTIONS DIFFER IN TIMING OF RECURVATURE. PLACED NEAR THE
MULTI-MODEL CONSENSUS, THERE IS GOOD CONFIDENCE IN THE OFFICIAL JTWC
FORECAST IN THIS PORTION OF THE TRACK.
   C. IN THE EXTENDED FORECAST PERIOD, STY 20W WILL BEGIN TO RECURVE
AS A SHORTWAVE TROUGH PASSES OVER JAPAN, WEAKENING THE STR. AS VWS
INCREASES AND SST COOL AFTER TAU 72, THE SYSTEM WILL CONTINUE TO
SLOWLY WEAKEN AS IT APPROACHES HONSHU. AS STY 20W TRACKS OVER LAND,
FRICTIONAL TERRAIN EFFECTS WILL ALSO BEGIN TO ERODE THE SYSTEM. STY
20W WILL BEGIN INTERACTING WITH THE TROUGH AROUND TAU 96,
ACCELERATING NORTHEASTWARD AS EXTRATROPICAL TRANSITION OCCURS. BY TAU
120, 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 THROUGH TAU 120.
THE JTWC FORECAST TRACK IS 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

CURRENT INTENSITY SET AT 140KTS(CATEGORY 5). THE STY HAS PROBABLY PEAKED.
CURRENT INTENSITY SET AT 140KTS(CATEGORY 5). THE STY HAS PROBABLY PEAKED.

09/0349UTC
09/0349UTC

09/0014UTC
09/0014UTC

08/2321UTC
08/2321UTC

08/2123UTC
08/2123UTC

TRACK AND INTENSITY GUIDANCE
TRACK AND INTENSITY GUIDANCE

HWRF: 139KT AT +0H
HWRF: 139KT AT +0H
Rédigé par PATRICK HOAREAU le Mercredi 9 Octobre 2019 à 08:16