[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 070852
TCDAT3
TROPICAL STORM MARCO DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL132008
500 AM EDT TUE OCT 07 2008

WITH NO ADDITIONAL RECONNAISSANCE DATA SINCE YESTERDAY AFTERNOON...
THE INTENSITY OF MARCO IS VERY DIFFICULT TO ESTIMATE.  THE OVERALL
SATELLITE PRESENTATION LOOKS ABOUT THE SAME AS WHEN THE AIRCRAFT
WAS THERE LAST...SO I'LL LEAVE THE ADVISORY INTENSITY AT 55 KT.
THE CYCLONE HAS PROBABLY ANOTHER 6-9 HOURS OVER WATER...SO SOME
FURTHER STRENGTHENING IS POSSIBLE...AND THE OFFICIAL FORECAST IS
SIMILAR TO THE PREVIOUS ADVISORY AND THE SHIPS GUIDANCE IN CALLING
FOR MARCO TO BE NEAR HURRICANE STRENGTH AT LANDFALL.  AS WE HAVE
NOTED PREVIOUSLY...HOWEVER...SMALL CYCLONES ARE PARTICULARLY
SUBJECT TO LARGE AND MOSTLY UNPREDICTABLE CHANGES IN INTENSITY.
EXAMINATION OF THE HIGH-RESOLUTION QUIKSCAT DATA FROM 0100 UTC
SUGGESTS THAT THE RADIAL EXTENT OF TROPICAL STORM FORCE WINDS IS
EXCEEDINGLY SMALL...PERHAPS NO MORE THAN ABOUT 10 NMI.

THE INITIAL MOTION ESTIMATE IS 295/7.  A NARROW MID-LEVEL RIDGE OF
HIGH PRESSURE SEPARATES MARCO FROM A MID- TO UPPER-LEVEL TROUGH
MOVING INTO THE NORTHERN GULF OF MEXICO.  GIVEN THE SIZE OF THE
TROPICAL CYCLONE...THIS RIDGE SHOULD BE SUFFICIENT TO KEEP MARCO ON
BASICALLY THE SAME TRACK UNTIL LANDFALL...ALTHOUGH I WOULDN'T BE
SURPRISED IF THE TRACK BENDS SLIGHTLY TO THE RIGHT...WHICH WOULD
KEEP MARCO OVER WATER LONGER THAN CURRENTLY FORECAST.  THE OFFICIAL
FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND IN BEST AGREEMENT
WITH THE UKMET AND BAM GUIDANCE.


FORECAST POSITIONS AND MAX WINDS

INITIAL      07/0900Z 20.1N  96.1W    55 KT
 12HR VT     07/1800Z 20.5N  97.1W    60 KT...JUST INLAND
 24HR VT     08/0600Z 20.9N  98.5W    20 KT...REMNANT LOW
 36HR VT     08/1800Z...DISSIPATED

$$
FORECASTER FRANKLIN



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