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TROPICAL STORM JOYCE DISCUSSION NUMBER  23
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT SUN OCT 01 2000
 
SATELLITE IMAGERY INDICATES THAT SOME DEEP CONVECTION HAS
REDEVELOPED NEAR THE SYSTEM CENTER WITH SOME BANDS TO THE EAST. AIR
FORCE RECON AIRCRAFT HAD A DIFFICULT TIME FINDING THE BROAD
CIRCULATION CENTER...BUT THEY MADE A SECOND PASS THROUGH THE EAST
SIDE AND FOUND AT LEAST 34 KT AT 1500 FT.  BASED ON THE RECON WIND
REPORT AND INCREASE IN CONVECTION...THE INITIAL INTENSITY IS KEPT AT
MINIMAL TROPICAL STORM STRENGTH...MAINLY IN SQUALLS TO THE EAST.
 
THE INITIAL MOTION ESTIMATE IS 285/15.  THERE IS NO SIGNIFICANT
CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING.  THE NEW MODEL
GUIDANCE REMAINS TIGHTLY CLUSTERED AROUND THE PREVIOUS TWO FORECAST
TRACKS...SO THE OFFICIAL FORECAST TRACK IS JUST AN EXTENSION OF THE
PREVIOUS FORECAST.  THE SUBTROPICAL RIDGE TO THE NORTH IS EXPECTED
TO GRADUALLY STRENGTHEN THROUGH THE FORECAST PERIOD...WHICH SHOULD
KEEP JOYCE ON A GENERAL WEST-NORTHWEST TRACK.  AFTER 48 HOURS...SOME
OF THE MODELS INDICATE A MORE WESTWARD TRACK AND THIS SEEMS
REASONABLE GIVEN THE AMOUNT OF NORTHERLY OUTFLOW ACROSS THE CENTRAL
CARIBBEAN SEA FROM HURRICANE KEITH.
 
THE INTENSITY MODELS CONTINUE TO SHOW SOME STRENGTHENING IN ABOUT
24 HOURS.  THE PROBLEM CONTINUES TO BE THE NORTHERLY MID-LEVEL SHEAR
AS INDICATED IN WATER VAPOR IMAGERY.  HOWEVER...THERE IS AN UPPER-
LEVEL LOW TO THE WEST OF JOYCE THAT HAS BEEN AIDING THE OUTFLOW TO
THE NORTH.  THIS LOW IS FORECAST TO MOVE WITH JOYCE...WHICH MAY
ALLOW THE CYCLONE TO INTENSIFY ONCE JOYCE GETS INTO THE EASTERN
CARIBBEAN.  THE NEXT QUESTION IS HOW MUCH OF THE NORTHERLY OUTFLOW
FROM KEITH WILL AFFECT JOYCE.  MOST OF THE MODELS GRADUALLY TURN THE
UPPER-LEVEL FLOW FROM NORTHERLY TO NORTHEASTERLY AFTER 36 HOURS...
WHICH MAY HELP TO KEEP THE STRONG SHEAR OFF OF JOYCE.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     01/0900Z 11.0N  60.4W    35 KTS
12HR VT     01/1800Z 11.5N  62.6W    35 KTS
24HR VT     02/0600Z 12.4N  65.0W    40 KTS
36HR VT     02/1800Z 13.3N  67.2W    45 KTS
48HR VT     03/0600Z 14.0N  69.5W    55 KTS
72HR VT     04/0600Z 15.5N  74.5W    70 KTS
 
 
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