* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL982021 09/22/21 00 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 51% 78% LAT (deg N) 8.0 8.0 7.8 8.0 7.8 8.3 8.8 9.9 10.7 11.7 12.9 13.7 14.7 LON (deg W) 30.0 31.1 32.2 34.0 35.1 37.2 39.4 42.8 45.4 48.0 49.7 51.4 52.7 DTL (km) 1517 1542 1470 1382 1307 1282 1296 1130 984 897 924 933 998 TRACK SOURCE AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 AP27 TCGI 0-48h Genesis Forecast: 51% is 1.7 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 78% 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 -2.1 10.0% 1.0 -2.1 18.5% VORTICITY 1.7 1.8 9.3% 1.4 1.8 19.3% VERTICAL SHEAR 16.3 9.4 19.7% 18.4 9.1 25.2% RH 73.1 81.0 -0.2% 70.9 78.7 3.2% GOES 29.1 9.7 0.5% 29.3 9.7 0.4% DVORAK 0.8 1.5 11.4% 0.8 1.5 11.8% --------------------------------------------------------------------------------------------- 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