922 
 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