Tropical Storm MUIFA Advisory 9月7日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 14W (FOURTEEN)
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUMMARY:
   INITIAL POSITION: 18.6N 136.5E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 676 NM SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A LARGE
CLUSTER OF PERSISTENT DEEP CONVECTION OVER THE WESTERN SEMICIRCLE
OF A BROAD LOW-LEVEL CIRCULATION. EIR INDICATES INTENSE CONVECTIVE
BURSTS, VORTICAL HOT TOWERS, FLARING WITHIN THE CONVECTIVE MASS
WITH TOPS AS HIGH AS 58,000 FEET (-87C). A 061625Z AMSR2 89GHZ
COLOR COMPOSITE MICROWAVE IMAGE REVEALS SHALLOW BANDING WRAPPING
INTO AN ELONGATED LOW-LEVEL CIRCULATION CENTER POSITIONED ALONG THE
NORTHEASTERN EDGE OF A CURVED CONVECTIVE BAND. THE INITIAL POSITION
IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE AMSR2 IMAGE. A
061625Z AMSR2 WINDSPEED IMAGE SHOWS A SWATH OF 20-30 KNOT WINDS
OVER THE WESTERN SEMICIRCLE WITH WEAKER WINDS OVER THE CENTER AND
EASTERN SEMICIRCLE. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED
WITH HIGH CONFIDENCE BASED ON THE AMSR2 WINDSPEED IMAGE, RECENT
ASCAT IMAGERY AND THE PGTW DVORAK ESTIMATE. ENVIRONMENTAL
CONDITIONS ARE FAVORABLE WITH MODERATE EQUATORWARD OUTFLOW,
IMPROVING EASTWARD OUTFLOW INTO THE TUTT POSITIONED TO THE NORTH
AND NORTHEAST, AND LOW VERTICAL WIND SHEAR.
INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).
CURRENT STEERING MECHANISM: LOW- TO MID-LEVEL SUBTROPICAL RIDGE
(STR) POSITIONED TO THE NORTHWEST AND WEST.
AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T2.0 - 30 KTS
   CIMSS ADT: 31 KTS AT 061800Z
FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: NOT APPLICABLE
3. FORECAST REASONING.
SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.
FORECAST DISCUSSION: TD 14W IS TRACKING SOUTHWARD ALONG THE EASTERN
PERIPHERY OF THE SUBTROPICAL RIDGE (STR) POSITIONED TO THE WEST,
AND WILL CONTINUE TRACKING SOUTH-SOUTHWESTWARD TO SOUTHWESTWARD
THROUGH TAU 12. THE STR IS EXPECTED TO STRENGTHEN TO THE EAST AND
REALIGN TO THE NORTH WHICH WILL TURN THE SYSTEM WESTWARD,
INITIALLY, THEN NORTHWESTWARD TO WEST-NORTHWESTWARD THROUGH TAU
120. A DEEP MIDLATITUDE SHORTWAVE TROUGH WILL DIG OVER EASTERN
CHINA AFTER TAU 96, WHICH COULD DRIVE THE SYSTEM MORE
NORTHWESTWARD. TD 14W WILL STEADILY INTENSIFY THROUGH TAU 24 WITH
RAPID INTENSIFICATION LIKELY FROM TAU 24 TO TAU 60 AS POLEWARD
OUTFLOW IMPROVES.
MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN POOR AGREEMENT
THROUGH THE FORECAST PERIOD WITH A LARGE SPREAD OF 300-400NM FROM
TAU 72 TO TAU 120. THE PRIMARY OUTLIERS ARE NAVGEM, AFUM AND UEMN
ON THE SOUTHERN EDGE OF THE AIDS ENVELOPE, AND AEMN ON THE NORTHERN
EDGE. THE STATISTICALLY BETTER GUIDANCE (ECMWF, EEMN AND AVNO) ARE
CLUSTERED CLOSELY TOGETHER AND INDICATE A TRACK TOWARD THE
ISHIGAKI-JIMA REGION. THE JTWC FORECAST TRACK IS POSITIONED CLOSE
TO THESE TRACKERS AND IS POSITIONED JUST NORTH OF THE MULTI-MODEL
CONSENSUS. THE BULK OF THE ECMWF ENSEMBLE (EPS) SOLUTIONS SUPPORT
THE JTWC FORECAST TRACK WITH MEDIUM OVERALL CONFIDENCE. THE
RELIABLE INTENSITY GUIDANCE IS IN FAIR AGREEMENT AND SUPPORTS A
RAPID INTENSIFICATION PHASE WITH HWRF INDICATING A PEAK INTENSITY NEAR
115 KNOTS, JUST ABOVE THE INTENSITY CONSENSUS PEAK OF 110 KNOTS. RAPID
INTENSIFICATION (RI) GUIDANCE IS TRIGGERED LENDING ADDITIONAL SUPPORT
TO THE IMMINENT RI PHASE.
FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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