Tropical Depression NINE

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM
TROPICAL DEPRESSION NINE DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL092006
500 PM EDT WED SEP 27 2006
 
VISIBLE SATELLITE IMAGERY INDICATES THAT THE LOW-LEVEL CIRCULATION
HAS CONTINUED TO GRADUALLY BECOME BETTER-DEFINED IN THE LOW
PRESSURE AREA OVER THE CENTRAL ATLANTIC.  ALTHOUGH THE DEEP
CONVECTION DOES NOT WRAP MUCH AROUND THE CENTER...THE SYSTEM HAS
SUFFICIENT ORGANIZATION TO BE DESIGNATED AS A 30 KT TROPICAL
DEPRESSION AT THIS TIME.  AN 1800 UTC SHIP REPORT ABOUT 60 MILES TO
THE NORTHWEST OF THE CENTER REPORTED A RATHER HIGH CENTRAL PRESSURE
OF 1016.5 MB...A 21 KT SUSTAINED WIND...AND 13 FT SEAS.  BASED ON
THIS SHIP REPORT...12 FT SEA RADII HAVE BEEN INCLUDED IN THE
ADVISORY.
 
THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 315/12...SINCE THE LOW-
LEVEL CENTER HAS REFORMED AT LEAST ONCE DURING THE PAST 12 TO 24
HOURS.  THE DEPRESSION IS CURRENTLY SITUATED BETWEEN AN UPPER-LEVEL
CYCLONE TO ITS WEST AND A LOW- TO MID-LEVEL RIDGE TO ITS EAST.  THE
GFS...UKMET... AND NOGAPS MODELS ALL TAKE THE CYCLONE AROUND THE
WESTERN PERIPHERY OF THE RIDGE...THEN ACCELERATE THE SYSTEM AT DAYS
THREE THROUGH FIVE NORTHEASTWARD AHEAD OF A DEEP-LAYER TROUGH FROM
THE WEST.  THE OFFICIAL TRACK FORECAST FOLLOWS CLOSELY WITH A
CONSENSUS OF THE AFOREMENTIONED GUIDANCE.
 
THE CURRENT POOR ORGANIZATION OF THE DEEP CONVECTION AND THE
PRESENCE OF THE UPPER LOW JUST TO THE WEST OF THE TROPICAL CYCLONE
ARGUES AGAINST ANY RAPID STRENGTHENING.  HOWEVER...THE VERTICAL
SHEAR IS NOT EXPECTED TO BE STRONG ENOUGH TO PROHIBIT SOME GRADUAL
INTENSIFICATION.  THE OFFICIAL INTENSITY FORECAST IS IN REASONABLE
AGREEMENT WITH THE SHIPS GUIDANCE.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      27/2100Z 26.5N  53.1W    30 KT
 12HR VT     28/0600Z 27.6N  54.5W    35 KT
 24HR VT     28/1800Z 29.1N  56.0W    40 KT
 36HR VT     29/0600Z 31.0N  57.5W    45 KT
 48HR VT     29/1800Z 34.0N  58.0W    50 KT
 72HR VT     30/1800Z 39.0N  56.0W    50 KT
 96HR VT     01/1800Z 42.0N  50.0W    50 KT...EXTRATROPICAL
120HR VT     02/1800Z 46.0N  40.0W    50 KT...EXTRATROPICAL
 
$$
FORECASTER MAINELLI/PASCH
 
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