WTIO21 PGTW 290200 COR
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 98B) CANCELLATION
CORRECTED//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/280921Z SEP 21//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. REMARKS: THIS CANCELS REF A (WTPN21 PGTW 280930). THE AREA OF
CONVECTION (INVEST 98B) PREVIOUSLY LOCATED NEAR 21.8N 88.3E, IS NOW
LOCATED NEAR 22.8N 87.5E, APPROXIMATELY 291 NM WEST-NORTHWEST OF
KOLKATA. INVEST 98B HAS TRACKED OVER LAND AND IS FORECAST TO REMAIN
OVER LAND AS IT CONTINUES ON ITS NORTHWESTWARD TRAJECTORY. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. IN VIEW OF THE
UNFAVORABLE FORECAST FOR THIS SYSTEM, IT IS NO LONGER CONSIDERED
SUSPECT FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN
THE NEXT 24 HOURS.
2. JUSTIFICATION FOR CORRECTION: CORRECTED INITIAL POSITION IN PARA
1.//
NNNN

JTWC發布TCFA

WTIO21 PGTW 280930
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THAT INVEST
98B CONTINUES TO RAPIDLY CONSOLIDATE, WITH BANDS OF DEEP CONVECTION
NOW WRAPPING INTO A WELL-DEFINED CENTER JUST OFFSHORE SOUTH OF
KOLKATA, INDIA. ANIMATED RADAR DATA FROM INDIA INDICATES THE
PRESENCE OF A WELL-DEFINED LOW LEVEL CIRCULATION CENTER (LLCC) WITH
MODERATE TO STRONG CONVECTIVE BANDS, PARTICULARLY ON THE SOUTHEAST
SIDE, WRAPPING INTO AND AROUND THE LLCC. SIMILARLY AT 280726Z AMSR2
89 GHZ MICROWAVE IMAGE SHOWS DEVELOPMENTAL BANDING WRAPPING INTO THE
CENTER DEFINED BY A LOW EMISSIVITY REGION. A PREVIOUS 280246Z ASCAT-
B AND 280314Z ASCAT-C PASS INDICATED 30-35 KNOT WINDS WITH SOME
HIGHER WINDS UNDER DEEP CONVECTION IN THE EASTERN SEMICIRCLE, THOUGH
WINDS IN THE REMAINDER OF THE CIRCULATION WERE 25 KNOTS OR LESS. THE
ENVIRONMENT IS FAVORABLE FOR DEVELOPMENT, WITH AN ANTICYCLONE ALOFT
JUST TO THE NORTHEAST PROVIDING GOOD RADIAL OUTFLOW AND LOW VERTICAL
WIND SHEAR. SSTS REMAIN VERY WARM. WHILE THE SYSTEM IS CURRENTLY
MOVING ONSHORE, IT WILL DO SO OVER A REGION OF SWAMPY GROUND IN A
RIVER DELTA. THUS INTENSIFICATION OVER LAND IS A DISTINCT
POSSIBILITY. NUMERICAL MODEL GUIDANCE IS CURRENTLY LIMITED, BUT
GENERALLY AGREES ON SLOW BUT STEADY NORTHWEST MOVEMENT OVER THE NEXT
24 HOURS. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE
WITHIN 055 NM EITHER SIDE OF A LINE FROM 21.3N 88.9E TO 22.9N 87.5E
WITHIN THE NEXT 00 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 28 TO 33 KNOTS. METSAT
IMAGERY AT 280600Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 21.3N 88.9E. THE SYSTEM IS MOVING NORTHWESTWARD AT 07 KNOTS.
2. REMARKS:
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 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
290930Z.
//
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(1) AN AREA OF CONVECTION (INVEST 98B) HAS PERSISTED NEAR
13.1N 89.0E, APPROXIMATELY 39.8 NM EAST OF KOLKATA. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 27 TO 33 KNOTS. ANIMATED
VISIBLE IMAGERY SHOWS THAT INVEST 98B HAS RAPIDLY CONSOLIDATED INTO
A COMPACT TROPICAL DEPRESSION OVER THE PAST SIX HOURS. ANIMATED
RADAR DATA FROM INDIA AND BANGLADESH INDICATE THAT A WELL DEFINED
LOW LEVEL CIRCULATION CENTER (LLCC) HAS FORMED JUST SOUTH OF THE
COASTLINE OF BANGLADESH. A 280246Z ASCAT-B PASS INDICATED A COMPACT
LLCC SURROUNDED BY 25 KNOT WINDS, WITH A PATCH OF 35-40 KNOT WINDS
IN THE EASTERN SEMICIRCLE UNDER DEEP, FLARING CONVECTION. THE SYSTEM
IS EXPECTED TO MAKE LANDFALL WITHIN THE NEXT HOUR TO TWO TO THE
SOUTHEAST OF KOLKATA AS A HIGH-END TROPICAL DEPRESSION WITH WIND
GUSTS ABOVE TROPICAL STORM STRENGTH. ONCE ASHORE, THE SYSTEM SHOULD
RAPIDLY DISSIPATE. THE ENVIRONMENT IS CURRENTLY FAVORABLE, WITH VERY
WARM SSTS, LOW TO MODERATE SHEAR AND GOOD DIFFLUENT OUTFLOW TO THE
WEST. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS MEDIUM.