* ATLANTIC TC GENESIS INDEX * * GFS VERSION * * AL962021 08/15/21 18 UTC * TIME (hr) 0 6 12 18 24 36 48 60 72 84 96 108 120 Prob of Genesis 20% 25% LAT (deg N) 34.7 34.2 33.6 33.1 32.6 31.9 31.9 32.2 32.6 32.4 33.1 34.4 34.0 LON (deg W) 62.9 62.9 62.8 63.0 63.3 63.4 63.6 64.2 65.0 65.4 65.3 64.4 64.4 DTL (km) 1003 1057 1121 1157 1190 1225 1208 1143 1056 1029 1011 966 1006 TRACK SOURCE AP29 AP29 AP29 AP29 AP29 AP29 AP29 AP29 AP29 AP29 AP29 TABM TABM TCGI 0-48h Genesis Forecast: 20% is 0.7 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 25% is 0.6 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 0.0 3.3% 1.0 -0.2 5.8% VORTICITY 1.7 0.4 2.6% 1.4 0.5 4.7% VERTICAL SHEAR 16.3 11.9 10.5% 18.4 19.2 9.5% RH 73.1 60.2 -0.1% 70.9 60.9 1.0% GOES 29.1 6.9 0.2% 29.3 6.9 0.1% DVORAK 0.8 1.0 3.8% 0.8 1.0 3.4% --------------------------------------------------------------------------------------------- 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