* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL172020 09/21/20 06 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 17% 46% LAT (deg N) 33.6 33.2 33.1 33.3 33.7 34.7 35.2 34.2 32.9 31.6 29.8 29.3 29.2 LON (deg W) 31.1 30.2 28.8 26.9 24.7 21.4 19.6 19.1 19.3 20.7 23.6 27.9 32.0 DTL (km) 1815 1720 1596 1449 1289 1098 979 901 820 849 994 1346 1711 TRACK SOURCE AP15 AP15 AP15 AP15 AP15 AP15 AP15 AP15 AP15 AP15 AP15 AP15 AP15 TCGI 0-48h Genesis Forecast: 17% is 0.6 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 46% is 1.1 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 0.9 2.1% 1.0 0.7 6.7% VORTICITY 1.7 2.9 6.5% 1.4 2.5 19.4% VERTICAL SHEAR 16.3 17.2 7.7% 18.4 13.9 17.6% RH 73.1 56.4 0.0% 70.9 57.6 1.3% GOES 29.1 0.8 0.0% 29.3 0.8 0.0% DVORAK 0.8 0.5 0.9% 0.8 0.5 1.5% --------------------------------------------------------------------------------------------- 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