[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT43 KNHC 022031
TCDAT3
TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT TUE AUG 02 2005

WHILE THE CIRCULATION CENTER IS PERHAPS NOT REAL WELL DEFINED IN
SATELLITE IMAGERY...THE IMAGERY DOES SHOW A NUMBER OF SMALL SWIRLS
ROTATING AROUND A COMMON CENTER.  THIS IS ALSO NOT THE MOST
TROPICAL OF TROPICAL CYCLONES.  HOWEVER...THE CENTER IS CLOSE
ENOUGH TO THE DEEP CONVECTION...WITHIN 60 NMI...AND THE UPPER LOW
TO THE SOUTHWEST IS FAR ENOUGH AWAY TO CONSIDER THIS SYSTEM MORE
TROPICAL THAN SUBTROPICAL.  THE DEPRESSION ALSO LIES SLIGHTLY ON
THE SYMMETRIC WARM CORE SIDE OF BOB HART'S FSU CYCLONE PHASE SPACE
ANALYSIS DIAGRAMS.  THE INITIAL INTENSITY IS SET TO 30 KT BASED ON
EARLIER SHIP REPORTS OF 25 KT THAT WERE OUTSIDE OF THE DEEP
CONVECTION.

THE INITIAL MOTION IS ESTIMATED TO BE 010/11.  THE DEPRESSION IS
LOCATED TO THE NORTHEAST OF AN UPPER-LEVEL LOW THAT IS DISPLACING
THE CONVECTION TO THE NORTH AND NORTHEAST OF THE CENTER.  THIS
ASYMMETRY MAY CONTRIBUTE TO SOME REFORMATION OR APPARENT MOTION OF
THE CENTER NORTHEASTWARD.  THERE ARE A COUPLE OF WEAK 500 MB
SHORT-WAVE TROUGHS IN THE WESTERLIES THAT SHOULD HELP TO NUDGE THE
CYCLONE NORTHEASTWARD OVER THE NEXT COUPLE OF DAYS.  MODEL GUIDANCE
IS IN RATHER POOR AGREEMENT AND OF LIMITED HELP.  THE GFS DEVELOPS
A POSSIBLY SPURIOUS SECOND LOW CLOSE TO THE DEPRESSION THAT
COMPLICATES INTERPRETATION OF ITS FORECAST TRACK.  THE UKMET
APPEARS TO BE INITIALIZED TOO FAR TO THE SOUTH AND THE NOGAPS TOO
FAR TO THE WEST.  THE OFFICIAL FORECAST IS PRIMARILY A BLEND OF THE
GFDL AND MEDIUM BAM MODELS.

THE TREND TODAY HAS BEEN FOR THE CIRCULATION CENTER AND DEEP
CONVECTION TO BECOME SOMEWHAT BETTER ALIGNED...AND IF THE CYCLONE
CAN GET A LITTLE FARTHER AWAY FROM THE UPPER LOW IT WOULD BE IN A
MORE FAVORABLE ENVIRONMENT FOR STRENGTHENING. GLOBAL MODELS
INDICATE THAT THIS UPPER LOW IS GOING TO SLIDE EASTWARD AND FOLLOW
THE CYCLONE. IF THIS HAPPENS...VERTICAL WIND SHEAR COULD INCREASE
AGAIN. THE OFFICIAL FORECAST ALLOWS FOR A MODEST WINDOW OF
OPPORTUNITY FOR SOME STRENGTHENING.

IF THE DEPRESSION BECOMES A TROPICAL STORM AS FORECAST...IT WOULD BE
THE EARLIEST 8TH TROPICAL STORM ON RECORD.  THE CURRENT RECORD IS
AUGUST 15TH.

FORECASTER FRANKLIN


FORECAST POSITIONS AND MAX WINDS

INITIAL      02/2100Z 28.5N  68.7W    30 KT
 12HR VT     03/0600Z 30.3N  68.3W    40 KT
 24HR VT     03/1800Z 32.0N  66.7W    45 KT
 36HR VT     04/0600Z 33.3N  64.7W    45 KT
 48HR VT     04/1800Z 33.8N  62.2W    40 KT
 72HR VT     05/1800Z 34.0N  57.0W    35 KT
 96HR VT     06/1800Z 34.5N  54.0W    30 KT
120HR VT     07/1800Z 35.0N  52.0W    30 KT


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