Tropical Depression SIX

ZCZC MIATCDAT1 ALL
TTAA00 KNHC DDHHMM
TROPICAL DEPRESSION SIX DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062010
1100 PM AST SAT AUG 21 2010
 
CONVENTIONAL SATELLITE AND A 2202 UTC SSMIS MICROWAVE OVERPASS SHOW
IMPROVED CURVED BANDING...PARTICULARLY OVER THE WESTERN PORTION OF
THE CYCLONE. ALTHOUGH DEEP CONVECTION REMAINS A BIT LIMITED OVER
THE EASTERN SEMI-CIRCLE...A 2300 UTC ASCAT PASS INDICATED A MORE
SYMMETRIC CIRCULATION THAN EARLIER NOTED...AND BELIEVABLE 25 KT
WINDS OVER THE SOUTHEAST QUADRANT. OUTFLOW OVER THE NORTHWESTERN
AREA OF THE SYSTEM APPEARS TO BE IMPROVING AND HAS BECOME MORE
DIFFLUENT. SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE 2.0
AND 1.5 RESPECTIVELY. BASED ON THE PREMISE THAT THE WINDS ARE
PROBABLY A LITTLE STRONGER IN THE CONVECTIVE BANDING TO THE WEST
AND NORTHWEST OF THE CENTER...THE INITIAL INTENSITY IS ADJUSTED UP
TO 30 KT. 

THE CYCLONE SHOULD GRADUALLY STRENGTHEN AS IT REMAINS OVER WARM SEA
SURFACE TEMPERATURES AND WITHIN A RELATIVELY LOW NORTHEASTERLY
SHEAR ENVIRONMENT DURING...AT LEAST FOR THE NEXT 3 DAYS. THE SHIPS
AND THE GFDL CONTINUE TO INDICATE THAT THE SYSTEM WILL BECOME A
HURRICANE WITHIN 3 DAYS...AND THIS IS ALSO INDICATED IN THE
OFFICIAL FORECAST.  THROUGH THE REMAINING PERIOD...INCREASING
SOUTHWESTERLY SHEAR IS EXPECTED OVER THE TRACK IN RESPONSE TO A MID
TO UPPER TROUGH MOVING OFF OF THE EASTERN SEABOARD AROUND DAY 5. 
SUBSEQUENTLY...THE INTENSITY FORECAST INDICATES ONLY MODEST
STRENGTHENING DURING THIS TIME-FRAME.

THE SYSTEM HAS BEEN MOVING WEST-NORTHWESTWARD...OR...290/7. THE DEEP
TRADES ASSOCIATED WITH THE SUBTROPICAL RIDGE TO THE NORTH OF THE
DEPRESSION NOW APPEAR TO BE THE MORE DOMINANT STEERING
MECHANISM...WITH LESS OF AN INFLUENCE FROM THE SOUTHWESTERLY
MONSOONAL FLOW.  DYNAMICAL MODELS ARE IN GOOD AGREEMENT WITH THE
RIDGE STEERING THE CYCLONE IN A WEST-NORTHWESTWARD MOTION THROUGH
DAY 3.  AFTERWARD...A TURN TOWARD THE NORTHWEST IS INDICATED IN THE
OFFICIAL FORECAST AS A DEEP-LAYER MID-LATITUDE TROUGH MOVES OVER
THE CENTRAL ATLANTIC AND BREAKS DOWN THE WESTERN PERIPHERY OF THE
RIDGE.  THE NHC TRACK FORECAST IS A LITTLE SLOWER THAN THE PREVIOUS
ADVISORY...AND IS BASED ON THE MULTI-MODEL CONSENSUS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      22/0300Z 11.3N  32.6W    30 KT
 12HR VT     22/1200Z 12.0N  33.9W    35 KT
 24HR VT     23/0000Z 12.9N  36.0W    40 KT
 36HR VT     23/1200Z 13.8N  38.4W    50 KT
 48HR VT     24/0000Z 14.7N  41.3W    60 KT
 72HR VT     25/0000Z 18.0N  47.0W    80 KT
 96HR VT     26/0000Z 21.5N  51.5W    90 KT
120HR VT     27/0000Z 25.0N  55.0W    95 KT
 
$$
FORECASTER ROBERTS/BEVEN
 
NNNN