* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL972021 08/27/21 12 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 38% 43% LAT (deg N) 34.1 33.7 33.9 33.8 33.9 34.9 36.0 36.6 37.1 37.8 40.3 44.2 47.3 LON (deg W) 51.9 51.5 51.1 50.7 50.1 48.8 46.0 43.8 41.1 38.4 33.0 26.6 24.5 DTL (km) 1403 1450 1432 1447 1444 1360 1328 1362 1457 1562 1769 1414 1151 TRACK SOURCE AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 AP19 TCGI 0-48h Genesis Forecast: 38% is 1.3 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 43% is 1.0 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 -0.8 6.6% 1.0 -1.2 11.4% VORTICITY 1.7 0.8 5.3% 1.4 1.6 13.4% VERTICAL SHEAR 16.3 14.4 15.2% 18.4 34.8 7.3% RH 73.1 57.2 -0.1% 70.9 64.1 1.9% GOES 29.1 12.3 0.6% 29.3 12.3 0.4% DVORAK 0.8 1.5 10.1% 0.8 1.5 8.8% --------------------------------------------------------------------------------------------- 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