[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 140252
TCDAT5
TROPICAL DEPRESSION FIFTEEN DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL152008
1100 PM EDT MON OCT 13 2008

THE RECONNAISSANCE AIRCRAFT INVESTIGATING THE TROPICAL DEPRESSION
FOUND PEAK FLIGHT-LEVEL WINDS OF 34 KT FROM 925 MB...WHICH DOES NOT
SUPPORT AN UPGRADE TO A TROPICAL STORM.  THERE WERE SFMR WINDS OF
TROPICAL STORM FORCE...BUT IN RAINY CONDITIONS THIS WIND SPEED
RANGE IS NOT WHERE THE INSTRUMENT PERFORMS BEST.  THE CENTER OF
CIRCULATION IS ON THE WESTERN EDGE OF THE DEEP CONVECTION WITH SOME
WESTERLY SHEAR STILL EVIDENT IN INFRARED AND WATER VAPOR IMAGERY.
WITH THE EXCEPTION OF THE GFS...ALL AVAILABLE GUIDANCE INDICATES
THAT THE CYCLONE SHOULD BE ABLE TO STRENGTHEN IN WHAT SHOULD BE A
MODERATE SHEAR ENVIRONMENT OVER THE NEXT FEW DAYS...WITH THE GFDL
AND HWRF BOTH MAKING THE SYSTEM A HURRICANE BEFORE IT EXITS THE
CARIBBEAN.  THE OFFICIAL FORECAST IS CLOSE TO THE CONSENSUS OF THE
INTENSITY GUIDANCE.

THERE IS VERY LITTLE SURROUNDING MID-LEVEL FLOW AND THE DEPRESSION
IS ESSENTIALLY STATIONARY.  A LARGE UPPER-LOW EAST OF NEW ENGLAND
IS DRIVING SOUTHWARD IN THE WESTERN ATLANTIC...AND THIS FEATURE IS
EXPECTED TO BEGIN LIFTING THE TROPICAL CYCLONE NORTHEASTWARD IN
ANOTHER 24-36 HOURS.  COMPARED TO SIX HOURS AGO THE GUIDANCE HAS
SHIFTED WESTWARD...WITH SOME UNCERTAINTY AS TO WHETHER THE CYCLONE
WILL BE CAPTURED BY THE UPPER LOW.  A MAJORITY OF THE MODELS NOW
SHOW THE CYCLONE BEING LEFT BEHIND BY THIS FEATURE.  THE OFFICIAL
FORECAST HAS BEEN SHIFTED TO THE LEFT AT THE LONGER RANGES AND IS
IN BEST AGREEMENT WITH THE ECMWF.  THE HWRF AND GFDL ARE MUCH
SLOWER BRINGING THE SYSTEM OUT OF THE CARIBBEAN AND CONSEQUENTLY
ARE EVEN FARTHER TO THE LEFT.


FORECAST POSITIONS AND MAX WINDS

INITIAL      14/0300Z 14.6N  69.4W    30 KT
 12HR VT     14/1200Z 14.8N  69.2W    40 KT
 24HR VT     15/0000Z 15.5N  68.6W    45 KT
 36HR VT     15/1200Z 16.5N  67.4W    50 KT
 48HR VT     16/0000Z 18.0N  66.0W    55 KT
 72HR VT     17/0000Z 21.0N  63.0W    65 KT
 96HR VT     18/0000Z 24.0N  60.0W    65 KT
120HR VT     19/0000Z 29.0N  58.0W    65 KT

$$
FORECASTER FRANKLIN
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