* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL952021 09/18/21 12 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 55% 72% LAT (deg N) 15.1 15.9 16.3 16.6 17.1 18.3 18.5 19.3 20.3 21.2 22.4 23.5 25.2 LON (deg W) 50.8 52.2 53.4 54.4 55.3 57.6 60.1 62.1 64.4 66.5 68.6 70.3 71.5 DTL (km) 1101 1107 1023 960 931 854 590 394 260 300 328 416 599 TRACK SOURCE AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 TCGI 0-48h Genesis Forecast: 55% is 1.8 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 72% is 1.7 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 -1.2 8.7% 1.0 -0.5 12.5% VORTICITY 1.7 2.4 11.8% 1.4 1.9 19.6% VERTICAL SHEAR 16.3 17.5 16.2% 18.4 16.9 20.1% RH 73.1 67.9 -0.2% 70.9 63.4 2.4% GOES 29.1 30.4 1.7% 29.3 30.4 1.1% DVORAK 0.8 2.0 17.0% 0.8 2.0 16.4% --------------------------------------------------------------------------------------------- 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