* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL902021 07/23/21 18 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 12% 29% LAT (deg N) 30.9 29.9 29.4 29.5 29.4 28.2 27.8 27.7 27.7 27.9 28.2 28.7 29.3 LON (deg W) 78.4 78.3 77.3 76.7 76.5 77.5 77.8 77.3 77.3 78.5 80.4 82.9 85.1 DTL (km) 254 271 336 394 411 286 248 284 290 185 17 15 45 TRACK SOURCE AP16 AP16 AP16 AP16 AP16 AP16 TABM TABM TABM TABM TABM TABM TABM TCGI 0-48h Genesis Forecast: 12% is 0.4 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 29% is 0.7 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 -1.4 3.2% 1.0 -0.7 7.7% VORTICITY 1.7 1.4 2.9% 1.4 0.6 6.1% VERTICAL SHEAR 16.3 21.1 5.0% 18.4 14.8 12.4% RH 73.1 68.5 -0.1% 70.9 67.8 1.7% GOES 29.1 19.8 0.4% 29.3 19.8 0.4% DVORAK 0.8 0.5 0.7% 0.8 0.5 1.1% --------------------------------------------------------------------------------------------- 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