* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL172020 09/20/20 06 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 37% 54% LAT (deg N) 35.5 35.2 34.8 34.3 34.2 34.4 34.7 34.5 33.4 31.9 31.2 30.5 29.7 LON (deg W) 29.7 30.1 30.6 30.6 30.2 28.7 25.6 21.4 18.6 16.7 15.3 16.4 18.1 DTL (km) 1790 1810 1829 1805 1766 1654 1414 1084 812 569 428 438 535 TRACK SOURCE AP12 AP12 AP12 AP12 AP12 AP12 AP12 AP12 AP12 AP12 AP12 AP12 AP12 TCGI 0-48h Genesis Forecast: 37% is 1.2 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 54% is 1.3 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 0.7 4.0% 1.0 0.7 7.1% VORTICITY 1.7 3.0 11.9% 1.4 3.1 24.7% VERTICAL SHEAR 16.3 5.2 19.3% 18.4 14.4 19.0% RH 73.1 51.4 0.0% 70.9 54.0 0.9% GOES 29.1 1.7 0.1% 29.3 1.7 0.1% DVORAK 0.8 0.5 1.7% 0.8 0.5 1.7% --------------------------------------------------------------------------------------------- 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