* 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 41% 41% LAT (deg N) 32.7 33.3 33.6 33.1 33.3 34.6 35.5 36.4 37.8 39.4 40.5 40.5 39.1 LON (deg W) 52.4 51.9 51.4 50.8 50.1 48.8 47.6 45.3 41.8 37.4 33.0 28.9 24.7 DTL (km) 1556 1492 1462 1523 1510 1397 1331 1311 1360 1515 1753 1662 1334 TRACK SOURCE AP21 AP21 AP21 AP21 AP21 TABM TABM TABM TABM TABM TABM TABM TABM TCGI 0-48h Genesis Forecast: 41% is 1.4 times the sample mean ( 30%) TCGI 0-120h Genesis Forecast: 41% 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 -0.2 6.0% 1.0 -0.2 9.0% VORTICITY 1.7 1.4 7.5% 1.4 1.1 10.9% VERTICAL SHEAR 16.3 13.7 16.4% 18.4 28.2 10.6% RH 73.1 55.4 -0.1% 70.9 56.6 1.1% GOES 29.1 12.3 0.6% 29.3 12.3 0.4% DVORAK 0.8 1.5 10.8% 0.8 1.5 9.2% --------------------------------------------------------------------------------------------- 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