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TROPICAL STORM GORDON DISCUSSION NUMBER   7
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT FRI SEP 15 2000

THIS HAS BEEN A BUSY EVENING TO SAY THE LEAST.  AIR FORCE RECON
FOUND 59 KT FLIGHT LEVEL WINDS AT 850 MB JUST EAST OF THE CENTER
WHICH EQUATES TO ABOUT 50 KT AT THE SURFACE.  SATELLITE INDICATE
THAT CENTER HAS MOVED/DEVELOPED FURTHER NORTHEAST INTO THE DEEP
CONVECTION AND TOPS CONTINUE TO COOL NEAR THE CENTER.  OUTFLOW IS
GOOD TO EXCELLENT IN THE EAST SEMICIRCLE AND SLIGHTLY RESTRICTED BUT
IMPROVING TO THE WEST.
 
GORDON HAS BEEN MAKING A STEADY NORTHEAST MOTION OF 8 TO 10 KT
DURING THE PAST 9 HOURS.  16/00Z UPPER AIR SOUNDINGS INDICATE 30
METER 500 MB HEIGHT FALLS AT MIAMI AND 20 METER FALLS FARTHER NORTH
UP THE FLORIDA PENINSULA AND OVER THE SOUTHEAST U.S.  THE SHORTWAVE
TROUGH RESPONSIBLE FOR THESE HEIGHT FALLS HAS SUPPRESSED THE RIDGE
SOUTHWARD TO CUBA WHICH HAS ALLOWED GORDON TO FINALLY MAKE A MOVE TO
THE NORTHEAST.  AS THE SHORTWAVE TROUGH PASSES EAST OF FLORIDA...I
EXPECT THE RIDGE TO THE SOUTH TO GRADUALLY BUILD BACK TO THE
NORTHWEST WHICH SHOULD NUDGE GORDON BACK TO A MORE NORTH-NORTHEAST
OR EVEN NORTHERLY TRACK.  THE NEXT TROUGH IS FORECAST TO DROP INTO
THE SOUTHCENTRAL U.S. WHICH SHOULD KEEP SOME SOUTHWESTERLY STEERING
FLOW ON THE SYSTEM.  THE KEY WILL BE HOW FAR NORTH GORDON TRACKS
DURING THE NEXT 12 TO 24 HOURS BEFORE THE RIDGE BUILDS BACK IN
ACROSS SOUTH FLORIDA.  THE NEW MODEL GUIDANCE IS SPLIT INTO TWO
CAMPS...WITH HALF THE MODELS...INCLUDING THE VARIOUS GFDL
MODELS...TAKING GORDON TO THE NORTHEAST. THE OTHER HALF TAKE GORDON
BASICALLY NORTHWARD...EXCEPT FOR THE UKMET WHICH TAKES GORDON
SOUTHWEST FROM ITS CURRENT POSITION AS A WEAK TROPICAL CYCLONE. 
SINCE IT APPEARS THAT GORDON HAS NOW BECOME A VERTICALLY DEEP
SYSTEM...WE HAVE LEANED TOWARD THE GFDL MODELS...ONLY SLOWER AND A
LITTLE TO THE LEFT OF THOSE TRACKS.  THIS FORECAST IS A SIGNIFICANT
TRACK SHIFT TO THE EAST.  HOWEVER...RECON ALSO FOUND A SECOND CENTER
FURTHER EAST FROM THE OFFICIAL POSITION...WHICH COULD RESULT IN THE
STORM BEING FURTHER EAST THAN THE OFFICIAL FORECAST INDICATES.
 
SINCE THE SHEAR HAS LET UP ON GORDON...STEADY INTENSIFICATION IS
FORECAST IN LINE WITH THE SHIPS INTENSITY MODEL.  THE 48 AND 72 HOUR
INTENSITIES REFLECT OVER LAND CONDITIONS...WHICH ARE SUBJECT TO
ERRORS SHOULD GORDON SPEED UP OR SLOW DOWN ITS FORWARD MOTION.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     16/0300Z 22.6N  87.1W    50 KTS
12HR VT     16/1200Z 23.9N  86.0W    60 KTS
24HR VT     17/0000Z 25.8N  85.0W    70 KTS
36HR VT     17/1200Z 27.8N  83.8W    75 KTS
48HR VT     18/0000Z 30.0N  82.0W    55 KTS
72HR VT     19/0000Z 34.5N  78.5W    50 KTS
 
 
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