Tropical Storm MUIFA Advisory 9月15日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (MUIFA) WARNING NR 034//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 31.2N 121.8E
   INITIAL INTENSITY: 70 KTS
   GEOGRAPHIC REFERENCE: 15 NM EAST OF SHANGHAI, CHINA
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 14 KTS
   SIGNIFICANT WAVE HEIGHT: 27 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED RADAR AND ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICT
THE CORE OF 14W PASSING TO THE EAST OF SHANGHAI AND RIDING ALONG
THE COAST OF CHINA. INNER CORE CONVECTION HAS WEAKENED, AND THE
LACK OF SURFACE OBSERVATIONS INDICATING SUSTAINED WINDS ABOVE STORM
FORCE SUGGEST THAT THE WIND FIELD IS BEING SIGNIFICANTLY IMPACTED
BY LAND INTERACTION. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON RADAR IMAGERY. THE INITIAL INTENSITY OF 70 KTS
IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A BLEND OF AGENCY DVORAK
ESTIMATES AND CORROBORATED BY A 141324Z METOP-C ASCAT PASS.
INITIAL WIND RADII BASIS: SCATTEROMETER DATA
CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T4.5 - 77 KTS
   RJTD: T5.0 - 90 KTS
   KNES: T4.0 - 65 KTS
   CIMSS SATCON: 71 KTS AT 1735Z
   CIMSS ADT: 77 KTS AT 141940Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 10-15 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: MODERATE POLEWARD
ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TY 14W IS FORECAST TO CONTINUE TRACKING TOWARD
THE NORTH-NORTHWEST FOLLOWED BY A GRADUAL TURN TOWARD THE NORTH AND
NORTHEAST BEYOND TAU 24. ALTHOUGH ATMOSPHERIC CONDITIONS REMAIN
SOMEWHAT FAVORABLE, WITH LOW VERTICAL WIND SHEAR (10-15) AND GOOD
POLEWARD OUTFLOW, SIGNIFICANT LAND INTERACTION IS CAUSING THE
SYSTEM TO WEAKEN AS IT PARALLELS THE COAST OF CHINA. THUS, 14W IS
FORECAST TO WEAKEN THROUGH THE DURATION OF THE FORECAST PERIOD. AS
IT BEGINS ITS RECURVE BEYOND TAU 24, VERTICAL WIND SHEAR IS
FORECAST TO INCREASE, AND COMBINED WITH CONTINUED LAND INTERACTION,
THE SYSTEM IS FORECAST TO BEGIN DISSIPATION PRIOR TO FINAL LANDFALL
IN NORTHERN CHINA BY TAU 36. THE LACK OF MID-LATITUDE FORCING WILL
PRECLUDE THE SYSTEM FROM UNDERGOING EXTRATROPICAL TRANSITION, SO
DISSIPATION OVER LAND IS FORECAST SHORTLY AFTER LANDFALL.
MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT THAT 14W
WILL CONTINUE TO PARALLEL THE COAST OF CHINA BEFORE TURNING
NORTHEASTWARD AND DISSIPATING NORTH OF THE YELLOW SEA. THE JTWC
TRACK FORECAST IS PLACED WITH HIGH CONFIDENCE. INTENSITY GUIDANCE
IS ALSO IN GOOD AGREEMENT, WITH STEADY WEAKENING FORECAST THROUGH
DISSIPATION BY TAU 48. THE JTWC INTENSITY FORECAST IS PLACED WITH
HIGH CONFIDENCE.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
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