* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL972021 06/30/21 00 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 54% 77% LAT (deg N) 8.0 8.1 8.6 9.1 9.4 10.4 11.2 12.3 13.3 14.7 16.4 16.7 18.0 LON (deg W) 37.0 38.2 39.5 41.3 43.2 47.4 51.6 56.4 61.0 65.4 69.2 72.3 75.1 DTL (km) 1256 1238 1272 1222 1062 823 665 527 277 370 196 138 71 TRACK SOURCE AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 TCGI 0-48h Genesis Forecast: 54% is 1.8 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 77% is 1.8 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 -2.0 10.2% 1.0 -0.5 12.7% VORTICITY 1.7 3.4 15.4% 1.4 3.1 29.0% VERTICAL SHEAR 16.3 10.0 20.2% 18.4 10.6 24.2% RH 73.1 82.8 -0.2% 70.9 79.2 3.1% GOES 29.1 29.8 1.6% 29.3 29.8 1.1% DVORAK 0.8 1.0 6.9% 0.8 1.0 6.9% --------------------------------------------------------------------------------------------- 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