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Tropical Depression TWO (Text)

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TROPICAL DEPRESSION TWO DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT WED AUG 04 2004
 
CONVECTION ASSOCIATED WITH TROPICAL DEPRESSION TWO HAS BECOME MORE
CONCENTRATED NEAR THE WINDWARD ISLANDS THIS MORNING.  HOWEVER...
SURFACE OBSERVATIONS SHOW PRESSURES OF 1010-1011 MB AND SUGGEST
THAT THERE IS NO CLOSED CIRCULATION.  AN AIR FORCE RESERVE
HURRICANE HUNTER AIRCRAFT IS CURRENTLY ENROUTE TO SEE IF THAT IS
THE CASE.  FOR NOW...THE INITIAL INTENSITY REMAINS 30 KT.

THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 275/22.  THE SYSTEM IS ON
THE SOUTH SIDE OF A LOW/MID LEVEL RIDGE...WHICH LARGE SCALE-MODELS
FORECAST SHOULD WEAKEN AS AN UNSEASONABLY STRONG DEEP-LAYER TROUGH
DEVELOPS OVER THE EASTERN UNITED STATES AND WESTERN ATLANTIC.  THIS
SUGGESTS THE SYSTEM SHOULD SLOW AND TURN NORTHWESTWARD...AND THEN
POSSIBLY NORTHWARD LATER IN THE FORECAST PERIOD.  DYNAMICAL TRACK
GUIDANCE IS REMARKABLY TIGHTLY CLUSTERED FOR A SYSTEM OF THIS STATE
OF DEVELOPMENT...CALLING FOR A WEST-NORTHWESTWARD TURN TOWARD
HISPANIOLA...FOLLOWED BY A NORTHWARD MOTION INTO THE ATLANTIC AND
THEN A NORTH-NORTHEASTWARD TURN BY 120 HR.  THERE ARE A COUPLE OF
ALTERNATIVE SOLUTIONS.  FIRST...THE BAMD...BAMM...AND LBAR CALL FOR
A MORE GRADUAL TURN AND BRING THE SYSTEM FATHER WEST TO THE CENTRAL
BAHAMAS BY 120 HR.  SECOND...THE NHC90 AND NHC98 BOTH CALL FOR A
MUCH MORE WESTWARD MOTION TO THE NORTHWEST CARIBBEAN BY 120 HR. 
THE OFFICIAL FORECAST WILL CONTINUE TO CALL FOR A EVENTUAL
NORTHWARD TURN IN AGREEMENT WITH THE DYNAMICAL MODELS...ALTHOUGH
THIS FORECAST IS SHIFTED WESTWARD FROM THE PREVIOUS FORECAST BASED
ON THE INITIAL POSITION AND MOTION.  AN ALTERANTIVE SCENARIO IS
THAT THE SYSTEM MAY TRACK MUCH FARTHER TO THE WEST AS A TROPICAL
WAVE.

THE INTENSITY FORECAST IS PROBLEMATIC.  EVEN IF THERE WAS A
BETTER-DEFINED CENTER...THE COMBINATION OF RAPID WESTWARD MOTION AND
SOUTHERLY UPPER-LEVEL WINDS IS CREATING A SHEAR ENVIRONMENT OVER
THE SYSTEM.  THIS SHEAR IS FORECAST TO SUBSIDE AS THE SYSTEM SLOWS
AND TURNS WEST-NORTHWESTWARD...WHICH WOULD ALLOW THE STRENGTHENING
INDICATED IN THE INTENSITY FORECAST.  A SECOND PROBLEM IS PASSAGE
OVER HISPANIOLA...WHICH HAS DESTROYED STRONGER CYCLONES THAN THIS
ONE.  THE INTENSITY FORECAST WILL OPTIMISTICALLY ASSUME THAT THE
PASSAGE WILL ONLY TEMPORARILY STOP DEVELOPMENT...WITH THE
ALTERNATIVE BEING THAT THE CYCLONE COULD DISSIPATE.  FINALLY...
THERE IS A POSSIBILITY THAT THE AIRCRAFT WILL NOT FIND A
CIRCULATION...AND THE SYSTEM COULD BE DOWNGRADED TO A TROPICAL WAVE. 
 
GIVEN THE RELATIVELY FAST FORWARD SPEED OF THE DEPRESSION...EVEN IF
A CIRCULATION DOES NOT EXIST TROPICAL STORM FORCE WINDS CAN STILL
OCCUR AT HIGHER ELEVATIONS ACROSS THE ISLANDS...ESPECIALLY ABOVE
1000 FEET.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      04/0900Z 13.8N  60.7W    30 KT
 12HR VT     04/1800Z 14.6N  63.5W    35 KT
 24HR VT     05/0600Z 15.8N  66.8W    40 KT
 36HR VT     05/1800Z 17.3N  69.2W    45 KT
 48HR VT     06/0600Z 19.5N  70.8W    45 KT...INLAND
 72HR VT     07/0600Z 23.5N  71.5W    50 KT...OVER WATER
 96HR VT     08/0600Z 28.0N  71.0W    60 KT
120HR VT     09/0600Z 32.0N  69.0W    65 KT
 
 
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