* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL912021 08/04/21 06 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 15% 50% LAT (deg N) 15.7 16.0 15.1 14.7 14.8 14.3 14.8 13.6 14.4 14.8 15.3 15.8 16.4 LON (deg W) 24.8 25.1 26.4 27.0 27.4 28.5 30.0 31.2 32.1 35.0 37.2 39.8 42.9 DTL (km) 788 825 956 1020 1063 1184 1342 1481 1570 1880 1979 1811 1649 TRACK SOURCE AP07 AP07 AP07 AP07 AP07 AP07 AP07 AP07 AP07 AP07 AP07 AP07 AP07 TCGI 0-48h Genesis Forecast: 15% is 0.5 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 50% is 1.2 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 0.0 2.5% 1.0 0.3 8.0% VORTICITY 1.7 2.0 4.4% 1.4 2.4 19.3% VERTICAL SHEAR 16.3 18.1 6.5% 18.4 14.3 18.2% RH 73.1 85.5 -0.1% 70.9 81.2 2.3% GOES 29.1 14.9 0.3% 29.3 14.9 0.5% DVORAK 0.8 0.5 0.8% 0.8 0.5 1.6% --------------------------------------------------------------------------------------------- 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