JTWC解除TCFA

WTPN21 PGTW 081700
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91W) CANCELLATION//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/071651ZAUG21//
AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT (WTPN21 PGTW 071700)//
RMKS/
1. REMARKS: THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED
NEAR 34.0N 140.6E IS NOW LOCATED NEAR 38.8N 159.4E, APPROXIMATELY
850 NM SOUTH OF PETROPAVLOVSKI, RUSSIA. ANIMATED ENHANCED INFRARED
(EIR) SATELLITE IMAGERY DEPICTS AN ILL-DEFINED LOW LEVEL CIRCULATION
(LLC) ABSENT OF ORGANIZED CONVECTION. THE SYSTEM APPEARS TO HAVE
UNDERGONE EXTRATROPICAL TRANSITION. ANALYSES INDICATE AN OVERALL
UNFAVORABLE ENVIRONMENT CHARACTERIZED BY LOW TO MODERATE (10-20 KT)
VERTICAL WIND SHEAR (VWS), EQUATORWARD OUTFLOW, AND COOL (25-26C)
SEA SURFACE TEMPERATURES (SST). GLOBAL MODELS GENERALLY AGREE THAT
INVEST 91W WILL BECOME MORE ELONGATED AS IT PROPAGATES EAST-
NORTHEASTWARD. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18
TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004
MB. IN VIEW OF THE UNFAVORABLE ENVIRONMENT, AND THE EXTRATROPICAL
TRANSITION, INVEST 91W IS NO LONGER SUSPECT FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE IN THE NEXT 24 HOURS. THIS CANCELS REF
A.//
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JTWC發布TCFA

WTPN21 PGTW 071700
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
140 NM EITHER SIDE OF A LINE FROM 37.4N 149.2E TO 42.0N 162.3E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 25 TO 30 KNOTS. METSAT
IMAGERY AT 071630Z INDICATES THAT AN ILL-DEFINE CIRCULATION CENTER
IS LOCATED NEAR 37.6N 149.4E. THE SYSTEM IS MOVING NORTH-
NORTHEASTWARD AT 19 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED
NEAR 33.7N 147.2E IS NOW LOCATED NEAR 37.6N 149.4E, APPROXIMATELY
415 NM EAST-SOUTHEAST OF MISAWA AB. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS PERSISTENT CONVECTION TO THE NORTH OF A
PARTIALLY EXPOSED ILL-DEFINED LOW LEVEL CIRCULATION (LLC). A 071130Z
METOP-B ASCAT PASS REVEALS AN ILL-DEFINED LLC WITH 25-30 KT WINDS IN
THE EASTERN PERIPHERY. ANALYSES INDICATE A MARGINALLY FAVORABLE
ENVIRONMENT CHARACTERIZED BY POLEWARD OUTLFOW ALOFT, LOW (<15 KT)
VERTICAL WIND SHEAR (VWS), AND MARGINAL (26C) SEA SURFACE
TEMPERATURES (SST). GLOBAL MODELS GENERALLY AGREE THAT INVEST 91W
WILL CONSOLIDATE AND REMAIN NEAR CURRENT INTENSITY AS IT PROPAGATES
EAST-NORTHEASTWARD DURING THE NEXT 36 HOURS. ANY INCREASE IN THE
ORGANIZATION OF THE LLC WOULD CAUSE THE SYSTEM TO MEET WARNING
CRITERIA. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
081700Z.//
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JTWC評級提升至Medium

(1) THE AREA OF CONVECTION (INVEST 91W) PREVIOUSLY LOCATED
NEAR 29.4N 145.0E IS NOW LOCATED NEAR 32.0N 146.4E, APPROXIMATELY
399 NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY (EIR) AND A 061559Z AMSR2 89GHZ IMAGE DEPICT A
CONSOLIDATING LOW-LEVEL CIRCULATION (LLC) WITH FLARING CONVECTION
BEING SHEARED TOWARD THE EASTERN SEMI CIRCLE WITH FORMATIVE BANDING
WRAPPING IN FROM THE SOUTH INTO THE LLC. UPPER-LEVEL ANALYSIS
INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH DUAL-CHANNEL
OUTFLOW AND WARM SEA SURFACE TEMPERATURES OF 28 TO 29C. HOWEVER,
DEVELOPMENT REMAINS OFFSET BY HIGH VERTICAL WIND SHEAR (30 TO 40
KNOTS). GLOBAL MODELS ARE IN AGREEMENT THAT THE SYSTEM WILL TRACK TO
THE NORTHEAST. HOWEVER, THEY ARE SPLIT ON WHETHER 91W WILL
CONSOLIDATE AND INTENSIFY TO WARNING CRITERIA. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS UPGRADED TO MEDIUM.

JTWC評級Low

B. TROPICAL DISTURBANCE SUMMARY:
      (1) AN AREA OF CONVECTION (INVEST 91W) HAS PERSISTED NEAR
29.4N 145.0E, APPROXIMATELY 446 NM SOUTH-SOUTHEAST OF YOKOSUKA,
JAPAN. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) AND A
060826Z SSMIS 91GHZ IMAGE DEPICT A POORLY-ORGANIZED LOW-LEVEL
CIRCULATION (LLC) WITH FRAGMENTED CONVECTION DISPLACED IN THE EAST
TO SOUTH QUADRANT. A 061033Z ASCAT METOP-A IMAGE DEPICTS AN
ASYMMETRIC CIRCULATION WITH 30 TO 35 KNOT WIND VECTORS TO THE EAST.
UPPER-LEVEL ANAYLSIS INDICATES A UNFAVORABLE ENVIRONMENT WITH HIGH
VERTICAL WIND SHEAR (30-40 KTS), OFFSET BY DUAL-CHANNEL OUTFLOW DUE
TO AN UPPER-LEVEL LOW ORIENTED TO THE NORTHWEST THE SUBTROPICAL HIGH
TO THE EAST. SEA SURFACE TEMPERATURES ARE BETWEEN 28 TO 29C. GLOBAL
MODELS ARE IN AGREEMENT THAT THE SYSTEM WILL TRACK TO THE NORTHEAST
HOWEVER, THEY ARE SPLIT ON WHETHER 91W WILL CONSOLIDATE AND
INTENSIFY TO WARNING STRENGTH. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1007 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO
LOW.
      (2) NO OTHER SUSPECT AREAS.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.
2. SOUTH PACIFIC AREA (WEST COAST OF SOUTH AMERICA TO 135 EAST):
   A. TROPICAL CYCLONE SUMMARY: NONE.
   B. TROPICAL DISTURBANCE SUMMARY: NONE.
   C. SUBTROPICAL SYSTEM SUMMARY: NONE.
3. JUSTIFICATION FOR REISSUE: UPGRADED AREA IN PARA. 1.B.(1) TO
LOW.//
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