* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL982020 09/18/20 12 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 46% 64% LAT (deg N) 11.8 12.0 12.6 13.0 13.5 14.4 15.4 16.0 16.5 16.9 17.1 18.6 20.0 LON (deg W) 32.2 33.6 35.2 36.7 38.1 40.6 43.4 46.0 47.9 49.3 50.7 52.2 52.7 DTL (km) 1624 1767 1802 1804 1780 1639 1529 1415 1369 1345 1312 1282 1354 TRACK SOURCE AP20 AP20 AP20 AP20 AP20 AP20 AP20 AP20 AP20 AP20 AP20 AP20 AP20 TCGI 0-48h Genesis Forecast: 46% is 1.5 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 64% is 1.5 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 -0.4 6.3% 1.0 0.2 9.8% VORTICITY 1.7 2.5 11.0% 1.4 2.1 21.0% VERTICAL SHEAR 16.3 13.5 16.4% 18.4 18.5 18.8% RH 73.1 71.4 -0.2% 70.9 63.5 2.3% GOES 29.1 35.4 1.7% 29.3 35.4 1.3% DVORAK 0.8 1.5 10.7% 0.8 1.5 11.3% --------------------------------------------------------------------------------------------- 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