Tropical Depression SIX

ZCZC MIATCDAT1 ALL
TTAA00 KNHC DDHHMM
TROPICAL DEPRESSION SIX DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062006
500 AM EDT MON SEP 04 2006
 
CONVENTIONAL SATELLITE IMAGERY SUGGEST THAT THERE HAS BEEN LITTLE
OVERALL CHANGE IN THE ORGANIZATION OF THE DEPRESSION.  THE
CIRCULATION CONTINUES TO BE BROAD WITH SEVERAL POSSIBLE CENTERS. 
ALTHOUGH BANDING FEATURES REMAIN IMPRESSIVE...THEY ARE SOMEWHAT
REMOVED FROM THE ESTIMATED CENTER.  BASED ON THIS ANALYSIS AND
UNCHANGED DVORAK INTENSITY ESTIMATES...THE INITIAL INTENSITY
REMAINS 30 KT FOR THIS ADVISORY.  THE DEPRESSION APPEARS TO BE
ENCOUNTERING SOME SOUTHWESTERLY SHEAR ASSOCIATED WITH AN
UPPER-TROPOSPHERIC TROUGH TO THE NORTHWEST.  THIS TROUGH IS
EXPECTED TO SLOWLY LIFT NORTHEASTWARD OVER THE NEXT 2 TO 3
DAYS...SO VERTICAL SHEAR MAY LIMIT STRENGTHENING IN THE SHORT-TERM.
LATER IN THE FORECAST PERIOD...GLOBAL MODELS INDICATE THAT THE
UPPER-LEVEL ENVIRONMENT COULD BECOME MORE CONDUCIVE FOR
STRENGTHENING AS A LARGE UPPER-LEVEL ANTICYCLONE FORMS OVER
CYCLONE.  THE OFFICIAL FORECAST IS BASED ON A BLEND OF THE SHIPS
AND GFDL MODELS...AND IS ESSENTIALLY AN UPDATE OF THE PREVIOUS
ADVISORY. 
 
GIVEN THE POORLY DEFINED CENTER...THE ESTIMATED INITIAL MOTION OF
310/10 IS UNCERTAIN.  THE DEPRESSION IS CURRENTLY MOVING TOWARD A
WEAKNESS IN THE MID-LEVEL RIDGE BETWEEN 45W-55W LONGITUDE.  THIS
WEAKNESS IS EXPECTED TO REMAIN ESSENTIALLY STATIONARY DURING THE
NEXT 2 TO 3 DAYS ALLOWING A CONTINUATION OF THE CURRENT MOTION.
THEREAFTER...A RIDGE OVER THE WESTERN ATLANTIC IS FORECAST TO SHIFT
EASTWARD NORTH OF THE CYCLONE RESULTING IN A MORE WESTWARD MOTION. 
WHILE ALL GLOBAL MODELS AND THE GFDL ARE IN GOOD AGREEMENT ON THIS
GENERAL WESTWARD TURN...NEARLY ALL OF THEM ARE NOW MUCH SLOWER IN
THE FORWARD SPEED.  THIS REQUIRES SOME ADJUSTMENT AND THE NEW
FORECAST IS ALONG BUT SLOWER THAN THE PREVIOUS ONE. 

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      04/0900Z 15.6N  41.1W    30 KT
 12HR VT     04/1800Z 16.5N  42.4W    30 KT
 24HR VT     05/0600Z 17.5N  44.0W    35 KT
 36HR VT     05/1800Z 18.4N  45.6W    45 KT
 48HR VT     06/0600Z 19.0N  47.1W    55 KT
 72HR VT     07/0600Z 20.0N  51.0W    60 KT
 96HR VT     08/0600Z 21.0N  54.0W    70 KT
120HR VT     09/0600Z 22.0N  57.0W    75 KT
 
$$
FORECASTER RHOME/AVILA
 
NNNN