Tropical Storm IN-FA Advisory 7月25日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (IN-FA) WARNING NR 035//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 28.7N 123.7E
   INITIAL INTENSITY: 65 KTS
   GEOGRAPHIC REFERENCE: 189 NM SOUTHEAST OF SHANGHAI, CHINA
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 33 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS FEEDER
BAND CONVECTIVE TOPS HAVE BEGUN TO WARM UP AND UNRAVEL; HOWEVER THE
CENTRAL DENSE OVERCAST FEATURE REMAINS INTACT AND MAINTAINED A
LARGE 44NM RAGGED EYE. THE INITIAL INTENSITY IS PLACED WITH HIGH
CONFIDENCE BASED ON THE EIR EYE THAT WAS CONCENTRIC WITH AN LLC
FEATURE IN A RECENT COMPOSITE RADAR LOOP. THE INITIAL INTENSITY OF
65KTS IS HELD ON THE LOWER END OF AGENCY AND AUTOMATED DVORAK FIXES
TO REFLECT THE DETERIORATING STAGE BUT MAINTAINED THE TYPHOON
STRENGTH.
INITIAL WIND RADII BASIS: PERSISTENCE.
CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST.
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T4.0 - 65 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T4.5 - 77 KTS
   KNES: T4.5 - 77 KTS
   CIMSS ADT: 55 KTS AT 241730Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD
ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TYPHOON 09W WILL TURN MORE WESTWARD AFTER TAU
12 AND MAKE LANDFALL SOUTH OF SHANGHAI, TRACK INLAND, THEN RECURVE
NORTHEASTWARD AFTER TAU 72 IF IT MAINTAINS ITS LOW LEVEL STRUCTURE.
THE DEGRADING ENVIRONMENT CAUSED BY COOLING SSTS AND LAND
INTERACTION WILL GRADUALLY THEN RAPIDLY WEAKEN THE SYSTEM DOWN TO
25KTS BY TAU 120 AS IT ATTEMPTS TO EXIT BACK INTO THE YELLOW SEA.
MODEL DISCUSSION: NUMERICAL MODELS REMAIN IN TIGHT AGREEMENT UP TO
TAU 72 THEN DIVERGE SIGNIFICANTLY AFTERWARD, LENDING HIGH
CONFIDENCE TO THE JTWC TRACK FORECAST UP TO TAU 72 ONLY.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: HIGH
   INTENSITY 72-120 HR: LOW//
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