* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL992020 07/21/20 18 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 47% 67% LAT (deg N) 11.1 11.3 11.5 11.7 11.8 11.6 11.3 10.7 10.6 10.6 11.3 12.1 12.9 LON (deg W) 38.3 39.4 40.6 42.1 43.8 47.6 51.3 54.8 58.2 61.5 64.8 67.8 70.9 DTL (km) 1562 1527 1432 1316 1190 920 689 538 302 -1 104 115 78 TRACK SOURCE TABM TABM TABM TABM TABM TABM TABM TABM TABM TABM TABM TABM TABM TCGI 0-48h Genesis Forecast: 47% is 1.6 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 67% is 1.6 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 -0.6 6.6% 1.0 -0.5 12.4% VORTICITY 1.7 1.3 7.2% 1.4 1.2 14.1% VERTICAL SHEAR 16.3 4.4 21.2% 18.4 6.0 26.2% RH 73.1 66.5 -0.1% 70.9 64.8 2.5% GOES 29.1 19.7 1.0% 29.3 19.7 0.7% DVORAK 0.8 1.5 10.8% 0.8 1.5 11.4% --------------------------------------------------------------------------------------------- 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