* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL972021 08/28/21 18 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 20% 66% LAT (deg N) 32.8 33.8 34.5 35.0 35.9 38.4 41.8 46.3 51.6 55.1 57.0 57.7 57.5 LON (deg W) 50.9 50.0 49.1 47.5 45.5 40.9 36.3 35.1 38.3 44.0 45.6 46.2 44.1 DTL (km) 1555 1457 1397 1382 1357 1359 1443 1350 1099 802 779 789 885 TRACK SOURCE AP05 AP05 AP05 AP05 AP05 AP05 AP05 AP05 AP05 AP05 AP05 AP05 AP05 TCGI 0-48h Genesis Forecast: 20% is 0.7 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 66% is 1.5 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 -1.9 5.4% 1.0 -1.4 15.3% VORTICITY 1.7 1.6 4.9% 1.4 2.5 23.6% VERTICAL SHEAR 16.3 35.8 3.1% 18.4 30.3 11.9% RH 73.1 61.4 -0.1% 70.9 69.0 3.1% GOES 29.1 10.5 0.3% 29.3 10.5 0.4% DVORAK 0.8 1.5 6.4% 0.8 1.5 11.4% --------------------------------------------------------------------------------------------- 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