Hurricane JUAN

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HURRICANE JUAN DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT SAT SEP 27 2003
 
JUAN HAS CONTINUED TO BECOME BETTER ORGANIZED OVERNIGHT WITH A 
DISTINCT 15 NMI EYE APPARENT IN INFRARED SATELLITE IMAGERY. THE
INTENSITY HAS BEEN INCREASED TO 75 KT BASED ON A CONSENSUS DVORAK
SATELLITE INTENSITY ESTIMATE OF T4.5...OR 77 KT...FROM ALL THREE
AGENCIES...AND A 3-HOUR OBJECTIVE T-NUMBER OF T4.4...OR 75 KT.
 
THE INITIAL MOTION ESTIMATE IS 350/11. JUAN APPEARS TO HAVE MADE A
SLIGHT NORTHWESTWARD JOG AS AN UPPER-LEVEL SHORTWAVE TROUGH OR LOW
HAS PASSED JUST TO THE SOUTH. WATER VAPOR IMAGERY INDICATES THAT
THIS FEATURE HAS BECOME LESS DISTINCT DURING THE PAST FEW HOUS...SO
A RETURN TO A BASE NORTH OR NORTH-NORTHWESTWARD COURSE IS EXPECTED
TO RESUME SHORTLY. OTHER THAN THAT...THERE REMAINS NO SIGNIFICANT
CHANGE TO THE PREVIOUS FORECAST TRACK REASONING. THE DEEP-LAYER
RIDGE LOCATED NORTHEAST THROUGH EAST OF JUAN IS CONTINUING TO
AMPLIFY NORTHWARD AS A STRONG DEEP-LAYER TROUGH OVER THE CENTRAL 
UNITED STATES CONTINUES TO DIG SOUTHEASTWARD. THE RESULTANT
INCREASING SOUTHERLY FLOW SHOULD GRADUALLY ACCELERATE JUAN
NORTHWARD TOWARD NOVA SCOTIA. ALL OF THE NHC MODEL GUIDANCE AGREES
WITH THIS SCENARIO...AND THE OFFICIAL TRACK IS IN THE MIDDLE OF THE
GUIDANCE ENVELOPE. ON THIS TRACK...JUAN IS EXPECTED TO MAKE
LANDFALL ALONG THE SOUTH COAST OF NOVA SCOTIA BY LATE SUNDAY OR
EARLY MONDAY.
 
THERE IS LITTLE TIME LEFT FOR JUAN TO STRENGTHEN...ALTHOUGH THE
HURRICANE IS EXPECTED TO REMAIN OVER 26C SSTS FOR ANOTHER 24 HOURS
SO. THEREFORE...ONLY SLIGHT STRENGTHENING IS FORECAST FOR THE NEXT
12 TO 24 HOURS. JUAN SHOULD START TO WEAKEN ONCE IT MOVES NORTH OF
THE GULF STREAM LOCATED ALONG 40N LATITUDE. ALTHOUGH UPPER-LEVELS
ARE FORECAST TO INCREASE TO 40 KT BY 60 HOURS...JUAN SHOULD ALREADY
BE EXTRATROPICAL BY THAT TIME...SO VERTICAL SHEAR MAY NOT PLAY A
SIGNIFICANT ROLE IN THE FORECAST WEAKENING TREND AFTER 24 HOURS.
THEREFORE...IT IS POSSIBLE THAT JUAN COULD MAKE LANDFALL ON NOVA
SCOTIA AS A HURRICANE...AND COASTAL WATCHES OR WARNINGS MAY BE
REQUIRED LATER TODAY. THE CANADIAN WEATHER SERVICE HAS ALREADY
ISSUED HURRICANE FORCE WIND WARNINGS FOR THE NOVA SCOTIA MARINE
AREAS.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      27/0900Z 34.9N  62.4W    75 KT
 12HR VT     27/1800Z 36.4N  62.8W    80 KT
 24HR VT     28/0600Z 38.9N  63.4W    80 KT
 36HR VT     28/1800Z 43.0N  63.2W    75 KT
 48HR VT     29/0600Z 48.7N  62.0W    65 KT...BECOMING EXTRATROPICAL
 72HR VT     30/0600Z 61.0N  57.0W    40 KT...EXTRATROPICAL
 96HR VT     01/0600Z...ABSORBED BY A LARGER EXTRATROPICAL LOW
 
 
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