Tropical Storm MA-ON Advisory 8月22日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 10W (TEN) WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 16.5N 125.7E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 330 NM EAST-NORTHEAST OF SUBIC, PHILIPPINES
   MOVEMENT PAST 6 HOURS: WESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED
INFRARED (EIR) SATELLITE IMAGERY SHOWS FORMATIVE BANDS WRAPPING INTO A PARTLY
EXPOSED LOW LEVEL CIRCULATION CENTER (LLC) LOCATED NORTHEAST OF THE MAIN
CONVECTION THAT IS DISPLACED SOUTHWESTWARD OF THE LLCC. THE INITIAL POSITION AND
INTENSITY ARE ASSESSED WITH HIGH CONFIDENCE BASED ON THE 211317Z ASCAT-C BULLSEYE
PASS INDICATING A BROAD WIND FIELD WITH 25-KNOT WIND BARBS EXTENDING 100+ NM ON
THE NORTHERN AND SOUTHERN QUADRANTS AND 30-KNOT WIND BARBS WITHIN 30NM OF THE
LLCC. THE INITIAL INTENSITY IS ALSO SUPPORTED BY DVORAK INTENSITY ESTIMATES FROM
PGTW, KNEW, AND CIMSS ADT.
WIND RADII BASIS: THERE ARE NO WIND RADII IN THE ANALYSIS.
CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF DEEP-LAYER SUBTROPICAL RIDGE (STR) TO THE NORTH.
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T2.0 - 30 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 29 KTS AT 1840Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: HIGH OHC
ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: NA
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
FORECAST DISCUSSION: TD 10W WILL TRACK NORTHWESTWARD ALONG THE SOUTHERN SIDE OF
THE STEERING STR, CLIPPING THE NORTHERN TIP OF LUZON VIA LUZON STRAIT TOWARD HONG
KONG. THE MARGINALLY FAVORABLE ENVIRONMENT WILL PROMOTE STEADY INTENSIFICATION TO
A PEAK OF 55KTS BY TAU 72 BEFORE MAKING LANDFALL JUST NORTHEAST OF HONG KONG
AROUND TAU 84. AFTER LANDFALL, LAND INTERACTION WILL RAPIDLY ERODE THE SYSTEM TO
DISSIPATION BY TAU 120.
MODEL DISCUSSION: RELIABLE DETERMINISTIC MODEL TRACKERS ARE NOT CURRENTLY
AVAILABLE DUE TO TECHNICAL ISSUES AT JTWC, AND THUS THE TRACK FORECAST IS
GENERATED FOLLOWING DETERMINISTIC MODEL FIELDS FOR NAVGEM, GFS, AND ECMWF WHICH
ARE ALL IN GOOD AGREEMENT IN THE OVERALL TRACK SKIRTING THE NORTHEAST TIP OF
LUZON, WITH SOME TRACK SPREAD BETWEEN TAU 48 AND TAU 72 BEFORE MAKING LANDFALL
JUST NORTHEAST OF HONG KONG. THEREFORE, JTWC OFFICIAL FORECAST USES A CONSENSUS
BLEND OF ALL THREE DETERMINISTIC MODEL TRACK FORECASTS. BASED ON THE LACK OF
INTENSITY MODEL GUIDANCE, JTWC FORECAST WILL FOLLOW CLOSE TO THE PREVIOUS
FORECAST INTENSITY, WITH STEADY INTENSIFICATION AFTER TAU 48 UP UNTIL LANDFALL
BASED ON GLOBAL MODELS SHOWING AN IMPROVED UPPER-LEVEL ENVIRONMENT.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: LOW
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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