91W TCFA - 颱風討論

圖：http://imgur.com/eWJV0VZ
文：

WTPN21 PGTW 170400
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 19.1N 130.3E TO 23.5N 127.3E
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 20 TO 25 KNOTS. METSAT
IMAGERY AT 170000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 19.4N 130.0E. THE SYSTEM IS MOVING NORTHWESTWARD AT 10
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 18.3N
131.8E IS NOW LOCATED NEAR 19.4N 130.0E, APPROXIMATELY 435 NM SOUTH-
SOUTHEAST OF KADENA AIR BASE, OKINAWA. RECENT ANIMATED MULTISPECTRAL
SATELLITE IMAGERY SHOWS DEEP CONVECTION PERSISTING OVER THE WESTERN
PORTION OF A CONSOLIDATING, PARTIALLY-EXPOSED LOW LEVEL CIRCULATION
CENTER (LLCC). A 170030Z METOP-B ASCAT IMAGE INDICATES 20 KNOT WINDS
ON THE SOUTHERN AND EASTERN PERIPHERIES OF THE CIRCULATION WRAPPING
INTO THE CENTER. THE UPPER-LEVEL ENVIRONMENT IS MARGINAL, WITH GOOD
WESTWARD DIFFLUENCE AND MODERATE EASTERLY VERTICAL WIND SHEAR THAT
IS EXPECTED TO INCREASE OVER THE NEXT DAY OR TWO. GIVEN INCREASING
ORGANIZATION DURING THE PAST 12 HOURS, IT IS LIKELY THE DISTURBANCE
WILL REACH THE MINIMUM WARNING THRESHOLD INTENSITY OF 25 KNOTS AND
REMAIN A WEAK TROPICAL DEPRESSION FOR A SHORT PERIOD BEFORE
INCREASING VERTICAL SHEAR ULTIMATELY RESULTS IN DISSIPATION. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. BASED ON THE
CONSOLIDATING LOW LEVEL SIGNATURE AND PERSISTENT CONVECTIVE
SIGNATURE, THE POTENTIAL FOR FORMATION FOR A SIGNIFICANT TROPICAL
CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
180400Z.//
NNNN

老J認為未來1~2天還有發展空間，但也就這1~2天能夠發展到勉強符合TD下限程度。

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