* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL172020 09/21/20 00 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 21% 26% LAT (deg N) 34.4 33.8 33.5 33.5 33.3 34.3 35.1 35.3 34.5 33.7 32.5 30.7 30.3 LON (deg W) 30.9 31.0 30.1 28.6 26.6 22.2 18.8 16.3 14.9 14.2 13.5 13.1 6.8 DTL (km) 1834 1815 1725 1599 1424 1127 907 693 559 459 350 305 -268 TRACK SOURCE AP03 AP03 AP03 AP03 AP03 AP03 AP03 AP03 AP03 AP03 AP03 AP03 AP03 TCGI 0-48h Genesis Forecast: 21% is 0.7 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 26% is 0.6 times the sample mean ( 43%) --------------------------------------------------------------------------------------------- INDIVIDUAL PREDICTOR CONTRIBUTIONS TO PROBABILITY OF GENESIS ******* 48-HR ****** ******* 120-HR ****** AVG TCGI CONT AVG TCGI CONT DIVERGENCE -1.0 0.2 3.1% 1.0 1.2 3.4% VORTICITY 1.7 2.8 7.3% 1.4 2.2 11.4% VERTICAL SHEAR 16.3 16.8 9.0% 18.4 19.3 9.9% RH 73.1 52.2 0.0% 70.9 52.0 0.4% GOES 29.1 0.0 0.0% 29.3 0.0 0.0% DVORAK 0.8 0.5 1.1% 0.8 0.5 1.0% --------------------------------------------------------------------------------------------- PREDICTOR DEFINITIONS (Averaged Over 500 km Radius) GENESIS CLIM = Climatological Prob (%) of Genesis (Source: NHC-TAFB Invest Database) DIVERGENCE = GFS 850 hPa Horizontal Divergence (x10-7 s-1) VORTICITY = GFS 850 hPa Vorticity (x10-6 s-1) VERTICAL SHEAR = GFS 200-850 hPa Vertical Shear (kt) RH = GFS 600-850 hPa Relative Humidity (%) GOES = GOES Water Vapor Pixels Colder than -40C (%) DVORAK = Dvorak T-number, source: TAFB Version 3.0, July 2018