*          ATLANTIC TC GENESIS INDEX           *
                      *                GFS VERSION                   *
                      *           AL912021 09/28/21 18 UTC           *

TIME (hr)           0     6    12    18    24    36    48    60    72    84    96   108   120
Prob of Genesis                                       35%                                 55%

LAT  (deg N)      8.9   8.7   8.6   8.6   8.6   8.8   9.0  10.2  12.9  15.7  18.0  20.5  23.4
LON  (deg W)     32.7  32.3  32.6  33.0  33.1  32.8  32.2  32.1  33.1  35.0  37.0  38.6  40.0
DTL  (km)        1541  1546  1519  1495  1489  1526  1580  1664  1696  1878  2108  2245  2372
TRACK SOURCE     AVNI  AVNI  AVNI  AVNI  AVNI  AVNI  AVNI  AVNI  AVNI  AVNI  AVNI  AVNI  AVNI

TCGI  0-48h Genesis Forecast:   35% is  1.2 times the sample mean (  30%)
TCGI 0-120h Genesis Forecast:   55% is  1.3 times the sample mean (  43%)

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INDIVIDUAL PREDICTOR CONTRIBUTIONS TO PROBABILITY OF GENESIS 

               *******  48-HR ******   ******* 120-HR ******
                   AVG   TCGI   CONT       AVG   TCGI   CONT
DIVERGENCE        -1.0   -1.8   7.9%       1.0   -1.8  15.0%
VORTICITY          1.7    1.7   7.6%       1.4    2.1  18.9%
VERTICAL SHEAR    16.3    9.3  16.8%      18.4   23.3  14.5%
RH                73.1   77.2  -0.2%      70.9   75.0   3.4%
GOES              29.1   29.4   1.3%      29.3   29.4   1.0%
DVORAK             0.8    0.5   1.6%       0.8    0.5   1.7%

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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