Tropical Storm ALPHA

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TROPICAL STORM ALPHA DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT SUN OCT 23 2005
 
ALPHA DEVELOPED SOME MODEST BANDING AROUND 6Z...AND THE DVORAK
INTENSITY ESTIMATE FROM TAFB CAUGHT UP WITH THE ADVISORY VALUE OF
45 KT.  THE CONVECTIVE PATTERN IS ALREADY DEGRADING HOWEVER AS THE
CENTER IS ABOUT TO MAKE LANDFALL IN HISPANIOLA.  ALTHOUGH SURFACE
OBSERVATIONS AT BARAHONA AND SANTO DOMINGO INDICATE THAT ALPHA HAS
PROBABLY WEAKENED...I WILL LEAVE THE ADVISORY INTENSITY AT 45 KT TO
BE ON THE SAFE SIDE.  GIVEN THE VERY SMALL SIZE OF THE
CIRCULATION...IT IS DIFFICULT TO IMAGINE IT SURVIVING THE
MOUNTAINOUS TERRAIN AHEAD OF IT.  ASSUMING THERE IS ANYTHING LEFT
ON THE OTHER SIDE...INCREASING SOUTHERLY FLOW ON THE EAST SIDE OF
WILMA IS LIKELY TO MAKE IT DIFFICULT FOR ALPHA TO MAINTAIN A CLOSED
CIRCULATION.  ALTHOUGH THE SHIPS AND GFDL MODELS INTENSIFY ALPHA IN
THE ATLANTIC IN A LOW SHEAR ENVIRONMENT...NONE OF THE GLOBAL MODELS
SHOW ANYTHING RESEMBLING A CLOSED SURFACE CIRCULATION.  THE
OFFICIAL FORECAST WILL CARRY ALPHA FOR 36 HOURS BUT I EXPECT IT TO
DISSIPATE MUCH SOONER THAN THAT.

THE INITIAL MOTION IS 305/12.  ALPHA IS NEARING THE SOUTHWEST EDGE
OF THE SUBTROPICAL RIDGE.  AS THE LARGE CIRCULATION OF HURRICANE
WILMA APPROACHES OVER THE NEXT 24 HOURS...ALPHA IS EXPECTED TO TURN
NORTHWARD AND ACCELERATE.  THE GLOBAL MODEL TRACKERS ARE LOCKING ON
TO THE LOW-LEVEL VORTICITY MAXIMUM...WHICH IS A DEGREE OR TWO TO
THE EAST OF THE SURFACE CIRCULATION IN THE MODELS.  THE OFFICIAL
FORECAST TRIES TO FOLLOW THE SURFACE CENTER...AND IS FAIRLY CLOSE
TO THE MEDIUM BAM.
 
ALPHA HAS THE POTENTIAL TO BE A SIGNIFICANT RAINFALL/FLOODING EVENT
OVER HISPANIOLA...WITH A STRONG LIKLIHOOD OF LIFE-THREATENING FLASH
FLOODS AND MUD-SLIDES.
 
FORECASTER FRANKLIN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      23/0900Z 18.1N  71.0W    45 KT
 12HR VT     23/1800Z 20.1N  72.4W    30 KT
 24HR VT     24/0600Z 23.3N  73.5W    30 KT
 36HR VT     24/1800Z 28.0N  73.5W    30 KT...DISSIPATING
 48HR VT     25/0600Z...DISSIPATED
 
 
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