Tropical Depression NINETEEN

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TROPICAL DEPRESSION NINETEEN DISCUSSION NUMBER   1
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL192012
500 PM AST MON OCT 22 2012
 
DEEP CONVECTION ASSOCIATED WITH THE LOW PRESSURE SYSTEM OVER THE
CENTRAL ATLANTIC HAS BECOME A BIT MORE ORGANIZED DURING THE
DAY...AND BOTH TAFB AND SAB PROVIDED 1800 UTC DVORAK ESTIMATES OF
T2.0.  ADVISORIES ARE THEREFORE BEING INITIATED ON TROPICAL
DEPRESSION NINETEEN WITH 30-KT WINDS.  THE DEPRESSION IS FORECAST
TO BE IN AN ENVIRONMENT OF LIGHT UPPER-LEVEL WINDS FOR THE NEXT DAY
OR TWO...SO SOME STRENGTHENING APPEARS LIKELY.  AFTER 48 HOURS...
THE VERTICAL SHEAR IS EXPECTED TO INCREASE TO AT LEAST 30 KT...AND
THE CYCLONE WILL BE MOVING OVER SUB-26C WATERS.  IN ADDITION...THE
GLOBAL MODELS ARE INDICATING THAT THE SYSTEM IS LIKELY TO BECOME A
FRONTAL LOW...AND A WEAK ONE AT THAT...BY 72 HOURS.  THEREFORE...
THE NHC INTENSITY FORECAST SHOWS A PEAK IN INTENSITY OCCURRING IN
48 HOURS WITH STEADY WEAKENING THEREAFTER.  INTERESTINGLY...THE
SHIPS MODEL BRINGS THE SYSTEM TO NEAR HURRICANE STRENGTH ON DAYS 3
THROUGH 5 EVEN IN THE FACE OF MORE HOSTILE CONDITIONS.  GIVEN THAT
THE GLOBAL MODELS DO NOT SUGGEST THAT EXTRATROPICAL LOW WILL FEED
OFF OF BAROCLINIC ENERGY...THE NHC FORECAST LEANS LOWER THAN MOST
OF THE HURRICANE MODELS.  DISSIPATION IS ANTICIPATED BY DAY 5 WHEN
THE SYSTEM IS FORECAST TO BECOME ABSORBED BY A COMPLEX AREA OF LOW
PRESSURE WEST OF THE AZORES.
 
THE DEPRESSION IS BEING STEERED NORTHWARD ON THE EASTERN SIDE OF A
MID- TO UPPER-LEVEL CUTOFF LOW...AND THE INITIAL MOTION ESTIMATE IS
350/6 KT.  THE CUTOFF LOW IS EXPECTED TO WEAKEN DURING THE NEXT
COUPLE OF DAYS...AND THE TROPICAL CYCLONE SHOULD THEN BE PICKED UP
BY FASTER MID-LATITUDE WESTERLIES.  THERE IS NOT MUCH SPREAD IN THE
TRACK GUIDANCE...AND THE OFFICIAL TRACK FORECAST IS CLOSEST TO THE
GFS MODEL AND THE MODEL CONSENSUS TVCA.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  22/2100Z 22.3N  51.7W   30 KT  35 MPH
 12H  23/0600Z 23.7N  51.8W   35 KT  40 MPH
 24H  23/1800Z 25.4N  51.2W   40 KT  45 MPH
 36H  24/0600Z 26.7N  49.6W   45 KT  50 MPH
 48H  24/1800Z 27.7N  47.1W   50 KT  60 MPH
 72H  25/1800Z 30.0N  40.5W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  26/1800Z 33.5N  34.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  27/1800Z...DISSIPATED
 
$$
FORECASTER BERG
 
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