ROPICAL DEPRESSION TWO SPECIAL DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
600 AM AST TUE AUG 11 2009
FIRST LIGHT VISIBLE SATELLITE IMAGES SHOW THAT THE BROAD LOW
PRESSURE AREA ASSOCIATED WITH A TROPICAL WAVE THAT WE HAVE BEEN
TRACKING OVER THE FAR EASTERN TROPICAL ATLANTIC HAS ACQUIRED
SUFFICENT ORGANIZED DEEP CONVECTION TO BE DESIGNATED AS A TROPICAL
DEPRESSION. THE TROPICAL CYCLONE IS SITUATED OVER MARGINALLY WARM
SEA SURFACE TEMPERATURES AND THE VERTICAL SHEAR IS CURRENTLY RATHER
WEAK. THE OFFICIAL FORECAST SHOWS GRADUAL STRENGHENING OVER THE
NEXT COUPLE OF DAYS AND IS A BLEND OF THE VARIOUS NUMERICAL
GUIDANCE TOOLS. AS USUAL THERE IS CONSIDERABLE UNCERTAINTY AS TO
THE STRENGTH OF THIS SYSTEM LATER IN THE FORECAST PERIOD. IF THE
CYCLONE MOVES FARTHER NORTH THAN ANTICIPATED BELOW IT WILL PROBABLY
ENCOUNTER STRONGER SHEAR AND NOT INTENSIFY AS MUCH AS FORECAST. ON
THE OTHER HAND IF THE SYSTEM MOVES FARTHER SOUTH THAN EXPECTED LATE
IN THE PERIOD...IT WILL PROBABLY BECOME STRONGER THAN ANTICIPATED
HERE.
INITIAL MOTION IS ABOUT 270/11. THIS TRACK IS LIKELY TO MORE OR
LESS CONTINUE FOR THE NEXT 2-3 DAYS DUE TO THE FLOW SOUTH OF A
FAIRLY WELL-ESTABLISHED MID-LEVEL SUBTROPICAL RIDGE. LATER IN THE
PERIOD...A SLIGHT WEAKNESS IN THE RIDGE IS LIKELY TO INDUCE A MORE
WEST-NORTHWESTWARD MOTION. THE OFFICIAL FORECAST IS A LITTLE
SLOWER THAN THE MODEL CONSENSUS AND WELL TO THE SOUTH AND WEST OF
THE BAM TRACKS. THIS IS ALSO SOUTH OF THE LATEST HWRF TRACK.
FORECAST POSITIONS AND MAX WINDS
INITIAL 11/1000Z 14.4N 28.6W 25 KT
12HR VT 11/1800Z 14.6N 30.1W 30 KT
24HR VT 12/0600Z 14.8N 32.3W 35 KT
36HR VT 12/1800Z 15.0N 34.6W 35 KT
48HR VT 13/0600Z 15.2N 36.8W 40 KT
72HR VT 14/0600Z 16.0N 41.2W 45 KT
96HR VT 15/0600Z 17.5N 45.5W 50 KT
120HR VT 16/0600Z 19.5N 49.5W 50 KT
