HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM
HURRICANE GERT DISCUSSION NUMBER  38
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT MON SEP 20 1999
 
AFTER THREE DAYS WITHOUT RECON...AIR FORCE AIRCRAFT HAS FOUND THE
CENTRAL PRESSURE OF 948 MB AT 1748Z...SUPPORTING THE CURRENT MAX
WIND SPEED OF 105 KNOTS.  A FLIGHT LEVEL WIND OF 105 KNOTS WAS
REPORTED 70 NM NORTHEAST OF THE CENTER.  THE 18Z DVORAK
CLASSIFICATIONS HAVE CURRENT INTENSITY NUMBERS OF 5.0 OR 90 KNOTS AS
THE DEEP CONVECTION ASSOCIATED WITH THE SYSTEM DECREASES AND BECOMES
MORE ASYMMETRIC.  A GRADUAL WEAKENING IS FORECAST DURING THE NEXT
FEW DAYS AS THE HURRICANE ENCOUNTERS SHEAR AND COOLER SEA SURFACE
TEMPERATURES.
 
INITIAL MOTION IS 340/08.  THE GLOBAL MODELS...AVN...UKMET AND
NOGAPS...AS WELL AS THE TRACK MODELS RUN OFF THE AVIATION RUN
...REMAIN IN GOOD AGREEMENT...TURNING THE HURRICANE NORTHWARD AND
THEN NORTHEASTWARD AHEAD OF THE APPROACHING TROUGH.  THE FORECAST
TRACK IS ADJUSTED A LITTLE MORE WESTWARD THEN 6 HOURS EARLIER.  THIS
FORECAST PLACES THE STORM IN THE VICINITY OF 90 NM EAST OF BERMUDA
AT ABOUT THE 24-HOUR FORECAST PERIOD.  MODELS VARY ON THE FORWARD
SPEED BEYOND 48 HOURS BUT THE GENERAL TREND IS TOWARD ACCELERATION
AHEAD OF THE TROUGH.

GROSS
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     20/2100Z 28.6N  62.9W   105 KTS
12HR VT     21/0600Z 29.8N  63.4W   100 KTS
24HR VT     21/1800Z 31.8N  63.6W    95 KTS
36HR VT     22/0600Z 34.2N  62.6W    90 KTS
48HR VT     22/1800Z 37.7N  60.1W    85 KTS
72HR VT     23/1800Z 47.0N  50.1W    75 KTS
 
 
NNNN