000
WTNT45 KNHC 040257
TCDAT5
 
TROPICAL STORM OSCAR DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL152012
1100 PM AST WED OCT 03 2012
 
THE CLOUD PATTERN OF THE CYCLONE HAS MORPHED INTO A LARGE CLUSTER OF
COLD-TOPPED CONVECTION THAT HAS BEEN INCREASING IN INTENSITY AND
COVERAGE DURING THE PAST SEVERAL HOURS. HOWEVER...THE LOW-LEVEL
CENTER REMAINS EXPOSED ABOUT 60 N MI WEST OF THE NEAREST DEEP
CONVECTION AS A CONSEQUENCE OF MODERATE SOUTHWESTERLY SHEAR. AT
0000 UTC...DVORAK T-NUMBERS WERE 2.0 AND 2.5 FROM SAB AND TAFB...
RESPECTIVELY...AND A 0030 UTC ASCAT PASS INDICATED SEVERAL
UNCONTAMINATED 35 KT WIND BARBS ABOUT 100 N MI EAST OF THE CENTER.
BASED PRIMARILY ON THE ASCAT PASS...THE SYSTEM HAS BEEN UPGRADED TO
TROPICAL STORM OSCAR WITH A CONSERVATIVE INTENSITY ESTIMATE OF 35
KT. OSCAR IS ON THE CUSP OF ENTERING AN EVEN HIGHER SHEAR
ENVIRONMENT IN THE NEXT 12-24 HOURS...WHICH SHOULD PRECLUDE
SIGNIFICANT INTENSIFICATION. THE GLOBAL MODELS DEPICT OSCAR OPENING
UP INTO A TROUGH AND THEN LOSING ITS IDENTITY AHEAD OF A COLD FRONT
IN 36-48 HOURS. THE OFFICIAL FORECAST IS SLIGHTLY HIGHER THAN THE
PREVIOUS ONE...BUT STILL SHOWS DISSIPATION IN 48 HOURS.  
 
THE FORWARD SPEED OF OSCAR HAS SLOWED SOME IN RECENT HOURS...AND THE
INITIAL MOTION ESTIMATE IS NOW 335/10.  STEERED BY THE FLOW IN
BETWEEN A MID-LEVEL RIDGE NORTH OF THE CAPE VERDE ISLANDS AND A
MID-/UPPER-LEVEL TROUGH NORTHEAST OF THE LESSER ANTILLES...OSCAR
SHOULD GRADUALLY TURN NORTHWARD DURING THE NEXT 12 HOURS OR SO AS
IT DECELERATES FURTHER.  AFTER THAT...THE CYCLONE SHOULD BECOME
EMBEDDED IN A STRONG AND DEEP-LAYER WESTERLY FLOW SOUTH OF A
LARGE MID-/UPPER-LEVEL CYCLONE OVER THE NORTHEAST ATLANTIC...WHICH
IS EXPECTED TO RESULT IN A SHARP RECURVATURE AND A NORTHEASTWARD
ACCELERATION.  ONLY SMALL ADJUSTMENTS WERE MADE TO THE PREVIOUS
FORECAST THROUGH 24 HOURS...WITH THE TRACK SHIFTED A BIT TOWARD THE
RIGHT PRIOR TO DISSIPATION...WHICH IS IN AGREEMENT WITH THE
DYNAMICAL MODEL CONSENSUS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  04/0300Z 19.3N  42.2W   35 KT  40 MPH
 12H  04/1200Z 20.5N  42.5W   40 KT  45 MPH
 24H  05/0000Z 22.0N  41.4W   40 KT  45 MPH
 36H  05/1200Z 23.8N  39.4W   40 KT  45 MPH
 48H  06/0000Z...DISSIPATED
 
$$
FORECASTER KIMBERLAIN