Tropical Depression ANA

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TROPICAL DEPRESSION ANA DISCUSSION NUMBER  21
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL022009
500 AM AST MON AUG 17 2009
 
IT IS UNCLEAR IF ANA STILL HAS A CLOSED LOW-LEVEL WIND FIELD.  A
MID-LEVEL CIRCULATION IS NOTED IN RADAR IMAGERY FROM GUADELOUPE AND
SAN JUAN PUERTO RICO...BUT NO SURFACE OBSERVATIONS FROM THE
NORTHERN LEEWARD ISLANDS HAVE SHOWN A WESTERLY WIND COMPONENT.  IN
ADDITION...AN ASCAT PASS AROUND 0140 UTC STRONGLY SUGGESTED THAT
THE SYSTEM IS A SHARP TROPICAL WAVE.  BECAUSE OF THE RECENT
CONVECTIVE DEVELOPMENT...ADVISORIES ARE BEING CONTINUED FOR THE
DEPRESSION AT THIS TIME UNTIL VISIBLE SATELLITE IMAGERY CAN CONFIRM
OR DENY THE EXISTENCE OF A WELL-DEFINED LOW-LEVEL CENTER LATER THIS
MORNING.
 
ANA IS MOVING AT AN UNCERTAIN BUT FAST 285/24.  THE MODEL GUIDANCE
IS TIGHTLY CLUSTERED FOR THE NEXT 36 HOURS OR SO AND INDICATES THAT
ANA WILL MOVE OVER HISPANIOLA LATER TODAY.  THEREAFTER...MOST OF
THE DYNAMICAL GUIDANCE WEAKEN THE VORTEX AND BRING THE REMNANTS
TOWARD THE EASTERN GULF OF MEXICO OR FLORIDA BY DAYS 3 THROUGH
5...SIMILAR TO THE SHALLOW LAYER BAM TRACK.  THE OFFICIAL FORECAST
IS CLOSE TO THE MODEL CONSENSUS THROUGH 36 HOURS AND THEN SHOWS A
SLIGHT NORTHEASTWARD SHIFT THEREAFTER TOWARDS BAM SHALLOW SINCE THE
REST OF THE GUIDANCE LOSES THE VORTEX.  THIS FORECAST IS HIGHLY
UNCERTAIN AS IT IS ENTIRELY POSSIBLE THAT THE CIRCULATION MAY NOT
MAKE IT ACROSS HISPANIOLA INTACT.

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      17/0900Z 16.6N  63.9W    30 KT
 12HR VT     17/1800Z 17.6N  67.2W    30 KT
 24HR VT     18/0600Z 19.3N  71.5W    25 KT...REMNANT LOW
 36HR VT     18/1800Z 21.2N  75.2W    25 KT...REMNANT LOW
 48HR VT     19/0600Z 22.8N  78.0W    25 KT...REMNANT LOW
 72HR VT     20/0600Z 25.5N  82.0W    25 KT...REMNANT LOW
 96HR VT     21/0600Z 28.0N  84.0W    25 KT...REMNANT LOW
120HR VT     22/0600Z 30.0N  84.5W    25 KT...REMNANT LOW
 
$$
FORECASTER BERG
 
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