* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL982021 09/21/21 18 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 54% 74% LAT (deg N) 9.1 8.8 9.0 9.1 9.4 10.0 10.9 12.1 13.2 14.3 15.2 16.0 16.9 LON (deg W) 28.0 28.5 29.4 30.3 32.3 35.8 38.3 40.6 43.1 45.5 47.6 49.2 50.5 DTL (km) 1270 1332 1421 1513 1611 1507 1544 1469 1358 1291 1253 1258 1301 TRACK SOURCE AVNI AVNI AVNI AVNI AVNI AVNI AVNI AVNI AVNI AVNI AVNI AVNI AVNI TCGI 0-48h Genesis Forecast: 54% is 1.8 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 74% 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 -2.3 10.8% 1.0 -2.4 19.4% VORTICITY 1.7 1.8 9.4% 1.4 1.6 17.4% VERTICAL SHEAR 16.3 7.8 21.3% 18.4 14.6 21.5% RH 73.1 84.7 -0.1% 70.9 76.4 3.6% GOES 29.1 7.2 0.4% 29.3 7.2 0.3% DVORAK 0.8 1.5 11.8% 0.8 1.5 11.6% --------------------------------------------------------------------------------------------- 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 2.1, February 2018