* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL902021 09/28/21 18 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 80% 85% LAT (deg N) 6.3 6.3 6.1 5.9 5.7 6.5 8.5 10.4 12.7 15.2 17.8 20.3 23.4 LON (deg W) 21.3 22.5 23.5 24.2 24.4 24.2 25.0 27.1 29.8 33.0 35.8 37.7 38.2 DTL (km) 820 910 1002 1073 1102 1030 989 1138 1346 1660 1977 2152 2192 TRACK SOURCE TABM TABM TABM TABM TABM TABM TABM TABM TABM TABM TABM TABM TABM TCGI 0-48h Genesis Forecast: 80% is 2.7 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 85% is 2.0 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 -7.8 27.3% 1.0 -4.7 28.3% VORTICITY 1.7 3.2 18.4% 1.4 2.8 26.8% VERTICAL SHEAR 16.3 8.9 25.9% 18.4 16.2 21.2% RH 73.1 85.9 -0.2% 70.9 80.1 3.0% GOES 29.1 86.5 5.8% 29.3 86.5 3.3% DVORAK 0.8 0.5 2.5% 0.8 0.5 2.0% --------------------------------------------------------------------------------------------- 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