Tropical Depression TEN

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TROPICAL DEPRESSION TEN DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL102007
500 PM EDT FRI SEP 21 2007
 
THE BAND IN THE EASTERN SEMICIRCLE OF THE DEPRESSION HAS LARGELY
DISSIPATED...WHILE CONVECTION OVER THE CENTER HAS INCREASED...
ALBEIT MODESTLY.  ADDITIONAL SATELLITE...BUOY...AND RECONNAISSANCE
OBSERVATIONS HAVE CONFIRMED THAT A SINGLE WELL-DEFINED LOW-LEVEL
CENTER EXISTS.  IN ADDITION...WATER VAPOR IMAGERY INDICATES THAT
THE LOW-LEVEL VORTEX IS SEPARATING FROM THE UPPER-LOW.
CONSEQUENTLY...THE STATUS OF THE CYCLONE IS NOW JUDGED TO BE
TROPICAL.  THE CENTRAL PRESSURE HAS REMAINED FAIRLY STEADY TODAY.
EARLIER FLIGHT-LEVEL DATA IN THE BAND TO THE EAST OF THE CENTER
SUGGESTED WINDS MIGHT HAVE BEEN AT TROPICAL STORM FORCE...ALTHOUGH
DROPSONDES IN THE BAND DID NOT INDICATE THAT MUCH WIND.  IN ANY
EVENT...THE BAND HAS SINCE WEAKENED...AND THE INITIAL INTENSITY
ESTIMATE REMAINS 30 KT.
 
BASED ON TODAY'S AIRCRAFT FIXES...THE INITIAL MOTION ESTIMATE IS
300/8.  THE FORECAST SCENARIO IS BASICALLY UNCHANGED...WITH THE
DEPRESSION EXPECTED TO CONTINUE MOVING WEST-NORTHWESTWARD TO THE
SOUTH OF A MID-LEVEL RIDGE OF HIGH PRESSURE STRETCHING
NORTHEASTWARD FROM TEXAS. MODEL GUIDANCE REMAINS IN GOOD AGREEMENT
AND THE OFFICIAL FORECAST FOLLOWS THE DYNAMICAL MODEL CONSENSUS.
BECAUSE THE FORECAST TRACK IS NEARLY PARALLEL TO THE COASTLINE...A
LANDFALL LOCATION IS DIFFICULT TO PINPOINT.  AFTER LANDFALL...AS
THE RIDGE BUILDS EASTWARD...THE DEPRESSION OR ITS REMNANTS SHOULD
TURN NORTHWESTWARD AND THEN NORTHWARD.
 
THE UPPER FLOW OVER THE DEPRESSION NOW IS LIGHT EASTERLY BUT NOT
VERY DIFLUENT.  WITH A RELATIVELY WEAK CONVECTIVE CORE AND LIMITED
UPPER-AIR SUPPORT...IT WOULD NOT SEEM AS THOUGH MUCH
INTENSIFICATION IS IN ORDER PRIOR TO LANDFALL.  ALL THE OBJECTIVE
GUIDANCE INDICATES THAT THE SYSTEM SHOULD MAKE LANDFALL AS A WEAK
TROPICAL STORM.  IF THE DEPRESSION MOVES A LITTLE TO THE LEFT OF
THE FORECAST TRACK IT WOULD REMAIN OVER WATER LONGER THAN
FORECAST...WHICH COULD ALLOW THE SYSTEM TO GET A LITTLE STRONGER
THAN FORECAST.

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      21/2100Z 29.9N  86.4W    30 KT
 12HR VT     22/0600Z 30.3N  87.6W    35 KT...INLAND
 24HR VT     22/1800Z 30.7N  89.5W    35 KT...INLAND
 36HR VT     23/0600Z 31.5N  92.0W    30 KT...INLAND
 48HR VT     23/1800Z...DISSIPATED
 
$$
FORECASTER FRANKLIN
 
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