Tropical Depression FOURTEEN

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TROPICAL DEPRESSION FOURTEEN DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL142010
1100 PM EDT MON SEP 20 2010
 
SATELLITE IMAGES INDICATE THAT THE AREA OF LOW PRESSURE LOCATED
ABOUT 450 N MI WEST OF THE CAPE VERDE ISLANDS HAS DEVELOPED
ENOUGH ORGANIZED CONVECTION TO BE CLASSIFIED A TROPICAL
DEPRESSION...THE FOURTEENTH OF THE 2010 ATLANTIC HURRICANE SEASON.
SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE 35 KT AND 30
KT...RESPECTIVELY.  BASED ON THESE ESTIMATES...THE INITIAL INTENSITY
IS SET AT 30 KT.  DEEP CONVECTION HAS BEEN INCREASING IN INTENSITY
AND COVERAGE DURING THE PAST COUPLE OF HOURS AND THE DEPRESSION
IS NEARING TROPICAL STORM STRENGTH.
 
THE INITIAL MOTION ESTIMATE IS 360/5...BASED MAINLY ON SATELLITE
FIXES.  THE DEPRESSION IS CAUGHT IN WEAK STEERING CURRENTS TO THE
SOUTH OF A LARGE DEEP-LAYER TROUGH OVER THE EASTERN ATLANTIC OCEAN.
A GENERAL SLOW NORTHWARD MOTION IS EXPECTED FOR THE NEXT 24 TO 36
HOURS AS THE SYSTEM REMAINS IN THE WEAK FLOW.  A TURN TO THE
NORTHWEST IS PROBABLE IN A COUPLE OF DAYS AS THE TROUGH SHIFTS EAST
AND FLATTENS...ALLOWING FOR SOME MID-LEVEL RIDGING TO BUILD NORTH
OF THE CYCLONE.  ANOTHER TROUGH...HOWEVER...IS EXPECTED TO PASS
NORTH OF THE SYSTEM BY THE END OF THE FORECAST PERIOD AND WILL
LIKELY INDUCE A SLOW NORTHWARD MOTION BY THAT TIME.  THERE IS A
LARGE SPREAD IN THE MODEL GUIDANCE AND THE OFFICIAL TRACK FORECAST
IS OF LOWER CONFIDENCE THAN NORMAL.
 
MOST OF THE INTENSITY MODELS SHOW SOME STRENGTHENING DURING THE NEXT
FEW DAYS AS THE CYCLONE IS EXPECTED TO REMAIN OVER MARGINALLY WARM
SEA SURFACE TEMPERATURES AND IN A LOW WIND SHEAR ENVIRONMENT...BUT
JUST SOUTH OF STRONG WESTERLY UPPER-LEVEL WINDS.  WESTERLY SHEAR
OVER THE SYSTEM COULD INCREASE IN 4 OR 5 DAYS...ASSOCIATED WITH THE
AFOREMENTIONED SECOND TROUGH.  THE OFFICIAL FORECAST IS IN BEST
AGREEMENT WITH THE INTENSITY MODEL CONSENSUS AND SHOWS GRADUAL
STRENGTHENING FOR THE NEXT FEW DAYS FOLLOWED BY LITTLE CHANGE IN
STRENGTH THEREAFTER.

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      21/0300Z 17.1N  31.9W    30 KT
 12HR VT     21/1200Z 17.5N  31.7W    35 KT
 24HR VT     22/0000Z 18.0N  31.6W    40 KT
 36HR VT     22/1200Z 18.4N  31.8W    40 KT
 48HR VT     23/0000Z 18.9N  32.4W    45 KT
 72HR VT     24/0000Z 20.1N  34.4W    50 KT
 96HR VT     25/0000Z 22.0N  35.5W    55 KT
120HR VT     26/0000Z 23.5N  35.5W    55 KT
 
$$
FORECASTER CANGIALOSI
 
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