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SUBTROPICAL STORM TWO DISCUSSION NUMBER   1
NATIONAL WEATHER SERVICE MIAMI FL
4 PM EST SAT NOV 24 2001
 
A NON-TROPICAL LOW IN THE CENTRAL NORTH ATLANTIC APPEARS TO HAVE
DEVELOPED A CORE OF STRONG WINDS.  THIS IS BASED ON A MESSAGE
CONCERNING A SHIP THAT WENT THROUGH A STORM CENTER AT 29.5 NORTH AND
50.5 WEST...LOWEST PRESSURE 989 MB AND "LOTS OF DAMAGE"  THE TIME OF
THE EVENT OR THE HIGHEST WINDS WERE NOT GIVEN.  CURRENTLY THERE IS
MODERATE CONVECTION SPIRALING AROUND THE CENTER AS WELL AS GALE
FORCE WINDS EXTENDING HUNDREDS OF MILES TO THE NORTH.  SO WHAT WE
HAVE HERE IS A SMALL TROPICAL-LIKE CENTER EMBEDDED WITHIN A HUGE
NON-TROPICAL CYCLONE.  THE WINDS ARE STRONG NEAR THE CENTER BASED
ON THE SHIP REPORT...BUT ARE ALSO STRONG FOR HUNDREDS OF MILES TO
THE NORTH.  SO I AM CALLING THE SYSTEM A 50-KNOT SUBTROPICAL
STORM...A NON FRONTAL LOW PRESSURE SYSTEM COMPRISING INITIALLY
BAROCLINIC CIRCULATIONS OVER SUBTROPICAL WATERS.
 
THE AVIATION MODEL SHOWS THE SYSTEM CAUGHT IN A WEAK STEERING
PATTERN AND FORECASTS A SLOW MOSTLY NORTHWESTWARD MOTION FOR THE
NEXT 72 HOURS.  THE OFFICIAL FORECAST FOLLOWS THIS GUIDANCE.
 
INTENSITY GUIDANCE SUGGESTS LITTLE CHANGE IN STRENGTH FOR THE NEXT
72 HOURS.
 
THE PURPOSE OF THIS ADVISORY PACKAGE IS TO ADVISE SHIPS AT SEA THAT
THERE COULD BE STRONG WINDS CONCENTRATED NEAR THE CYCLONE CENTER AS
WELL AS EXTENDING FAR TO THE NORTH.  I DO NOT KNOW HOW LONG THE
CENTRAL FEATURE WILL PERSIST.  IF IT IS SHEARED AWAY...AND THE SHIPS
MODEL HAS 27 KNOTS OF SHEAR INCREASING TO 32 KNOTS IN 24 HOURS...
THEN THESE SUBTROPICAL ADVISORIES WILL BE TERMINATED.
 
FORECASTER LAWRENCE
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     24/2100Z 30.5N  49.5W    50 KTS
12HR VT     25/0600Z 31.0N  49.5W    50 KTS
24HR VT     25/1800Z 32.0N  50.0W    50 KTS
36HR VT     26/0600Z 33.0N  50.9W    50 KTS
48HR VT     26/1800Z 33.8N  52.0W    50 KTS
72HR VT     27/1800Z 34.5N  54.0W    50 KTS
 
 
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