[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 312049
TCDAT3
TROPICAL STORM FIONA DISCUSSION NUMBER   5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL082010
500 PM AST TUE AUG 31 2010

THUNDERSTORM ACTIVITY HAS RECENTLY DEVELOPED NEAR THE CENTER OF
FIONA...HOWEVER THE CONVECTION SHOWS LITTLE BANDING.  THE AIRCRAFT
FOUND PEAK 925 MB FLIGHT-LEVEL WINDS OF 41 KT AND SEVERAL UNFLAGGED
SFMR WINDS OF AROUND 35 KT TO THE NORTH OF THE CENTER.  BASED ON
THESE DATA...THE INITIAL INTENSITY REMAINS 35 KT.  AN UPPER-LEVEL
ANTICYCLONE TO THE NORTHWEST OF FIONA IS FORECAST TO PRODUCE
INCREASING UPPER-LEVEL NORTHEASTERLY SHEAR OVER THE CYCLONE.  THE
SHEAR IS EXPECTED TO REMAIN STRONG DURING THE NEXT SEVERAL DAYS AND
ONLY A LITTLE STRENGTHENING IS SHOWN IN THE OFFICIAL FORECAST.

THE INITIAL MOTION ESTIMATE IS 290/21 KT.  FIONA IS FORECAST
TO TURN NORTHWESTWARD AND DECELERATE VERY SOON AS IT APPROACHES
THE WESTERN EDGE OF THE SUBTROPICAL RIDGE.  IN 36-48 HOURS...THE
CYCLONE SHOULD TURN NORTHWARD BETWEEN THE RIDGE AND HURRICANE EARL
TO THE NORTHWEST.  ALL OF GLOBAL MODELS DISSIPATE THE STORM IN 2-3
DAYS AS THE SMALLER CIRCULATION OF FIONA BECOMES AN OPEN TROUGH IN
THE STRONG SOUTHWESTERLY FLOW ON THE SOUTHEASTERN SIDE OF EARL.  THE
OFFICIAL FORECAST FOLLOWS THIS SCENARIO...HOWEVER DISSIPATION COULD
OCCUR EARLIER THAN SHOWN BELOW.

FORECAST POSITIONS AND MAX WINDS

INITIAL      31/2100Z 16.7N  57.7W    35 KT
 12HR VT     01/0600Z 17.9N  60.8W    40 KT
 24HR VT     01/1800Z 20.2N  63.7W    40 KT
 36HR VT     02/0600Z 23.0N  66.0W    40 KT
 48HR VT     02/1800Z 26.5N  67.7W    35 KT
 72HR VT     03/1800Z 33.5N  67.5W    35 KT
 96HR VT     04/1800Z...DISSIPATED

$$
FORECASTER BROWN

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