[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 052025
TCDAT4
TROPICAL DEPRESSION NINE DISCUSSION NUMBER   5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT FRI AUG 05 2005

THE DEPRESSION CONTINUES TO HAVE A VIGOROUS LOW-LEVEL CIRCULATION.
SOME CONVECTIVE CURVED BANDS ARE TRYING TO DEVELOP TO THE SOUTH AND
WEST OF THE CENTER WHERE THE SSTS ARE A LITTLE BIT HIGHER. IT IS
ESTIMATED THAT THE MAXIMUM WINDS ARE 25 KNOTS. THE EVOLUTION OF A
LARGE MID TO UPPER LEVEL LOW CURRENTLY LOCATED TO THE NORTH OF THE
DEPRESSION WILL BE CRUCIAL FOR BOTH THE INTENSITY AND TRACK
FORECASTS. IF THE LOW MOVES AS FAR SOUTH AS SHOWN BY THE GFS...IT
COULD INDUCE WIND SHEAR AND ALSO A NORTHERLY COMPONENT OF MOTION TO
THE DEPRESSION...RESULTING IN WEAKENING. HOWEVER...IF THE
DEPRESSION PASSES SOUTH OF THE LOW...THE ENVIRONMENT COULD BE LESS
HOSTILE..AND THE OCEAN IS WARMER THERE.

BECAUSE THE DEPRESION DOES NOT HAVE DEEP CONVECTION AT THIS TIME AND
IS A SHALLOW SYSTEM...IT IS MOVING TOWARD THE WEST-NORTHWEST AT
14-16 KNOTS STEERED BY THE LOW-LEVEL FLOW.  THE OFFICIAL FORECAST
CALLS FOR A WEST-NORTHWEST TRACK...WITH A GRADUAL DECREASE IN
FORWARD SPEED...AND A MODEST STRENGHTENING BEYOND 3 DAYS.  THIS
FORECAST IS HIGHLY UNCERTAIN SINCE THERE IS ALSO A STRONG
POSSIBILITY THAT THE DEPRESSION WILL NOT SURVIVE.  THE OFFICIAL
FORECAST IS IN THE MIDDLE THE GUIDANCE ENVELOPE. THE NORTHERNMOST
TRACK IS THE GFS AND THE SOUTHERNMOST IS THE UK MODEL.

FORECASTER AVILA


FORECAST POSITIONS AND MAX WINDS

INITIAL      05/2100Z 17.0N  39.1W    25 KT
 12HR VT     06/0600Z 18.0N  41.0W    25 KT
 24HR VT     06/1800Z 19.0N  43.5W    25 KT
 36HR VT     07/0600Z 20.0N  45.5W    30 KT
 48HR VT     07/1800Z 21.5N  48.0W    30 KT
 72HR VT     08/1800Z 23.0N  51.0W    35 KT
 96HR VT     09/1800Z 25.0N  54.0W    40 KT
120HR VT     10/1800Z 28.0N  56.0W    45 KT


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