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TROPICAL STORM MITCH DISCUSSION NUMBER   5
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT THU OCT 22 1998

MITCH HAS COMPLETED A CYCLONIC LOOP IN THE SOUTHWESTERN CARIBBEAN
AND NOW IS MOVING NORTHWARD ABOUT 5 KNOTS.  THIS GENERAL NORTHWARD
MOTION SHOULD CONTINUE DURING THE NEXT 12 TO 24 HOURS.  ONCE THE
MID-LATITUDE TROUGH CURRENTLY SWINGING ALONG THE EASTERN UNITED
STATES AND THE WESTERN ATLANTIC MOVES OUT...A RIDGE IS FORECAST TO
DEVELOP IN THAT AREA.  THIS PATTERN SHOULD STEER MITCH ON A SLOW
NORTHWESTERLY TRACK.   MODELS RESPOND TO THAT BUILDING RIDGE AND
MOVE THE STORM NORTHERLY AND THEN NORTHWESTERLY.  THE MODELS
DISAGREE BEYOND 48 HOURS WHEN THE GFDL AND NOGAPS TURN THE TROPICAL
CYCLONE SLOWLY WESTWARD WHILE THE OTHERS CONTINUE TO SHOW A GENERAL
NORTHWESTWARD TRACK.   NEVERTHELESS...AT LONGER RANGE...ANOTHER
TROUGH IS FORECAST TO MOVE EASTWARD OVER THE UNITED STATES...AND
WILL PROBABLY FORCE MITCH TO MOVE MORE NORTHWARD AGAIN AS SUGGESTED
BY NOGAPS AND THE UK MODELS.  BOTH MODELS PLACE MITCH NEAR THE
YUCATAN CHANNEL BY DAY 5. IT APPEARS THAT WE ARE GOING TO BE BUSY
FOR SEVERAL DAYS.
  
THE OUTFLOW IS GRADUALLY BECOMING BETTER ORGANIZED AND THE CENTER IS
UNDER DEEP CONVECTION.  MOST OF THE GLOBAL MODELS ARE DEVELOPING A
200 MB ANTICYCLONE OVER THE WESTERN CARIBBEAN...A PATTERN WHICH IS
VERY FAVORABLE FOR STRENGTHENING.  MITCH IS A 45-KNOT TROPICAL STORM
AND IS FORECAST TO BE A HURRICANE IN 24 HOURS AS SUGGESTED BY SHIPS
AND THE GFDL. 

WATCHES OR WARNINGS ARE NOT REQUIRED YET...BUT INTERESTS IN THE
WESTERN CARIBBEAN SHOULD CLOSELY MONITOR THE PROGRESS OF THIS SYSTEM
WHICH COULD BECOME A POTENTIALLY DANGEROUS HURRICANE.

AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     23/0300Z 12.3N  77.6W    45 KTS
12HR VT     23/1200Z 13.0N  77.6W    55 KTS
24HR VT     24/0000Z 14.0N  78.0W    65 KTS
36HR VT     24/1200Z 15.0N  78.5W    75 KTS
48HR VT     25/0000Z 16.0N  79.0W    80 KTS
72HR VT     26/0000Z 17.5N  80.5W    80 KTS
 
 
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