GFS trend image from Levi Cowan of the setup over the US
Posted by
Chris in Tampa on 9/1/2017, 8:32 pm
This can be viewed by going here for example for the GFS out around as far as he has:
https://www.tropicaltidbits.com/analysis/models/?model=gfs®ion=npac&pkg=z500a&fh=192
Then use the up and down arrows to toggle between model runs. Normally you use left and right arrows to go to different frames within a model run, but up and down arrows allow you to see previous runs to see how the model has changed for the same forecast time period. If you want to save an animated GIF image, click "TREND GIF" button.
He's showing the same forecast time in that image for lots of previous runs and you can see how the setup over the US changes. That will be what helps to decide how Irma moves. Yet the setup changes from run to run. If the setup kept being around the same each run, for the exact same forecast time, you would think that the model has a better handle on the setup. GFS isn't being consistent, but then again, this is still over a week out we're talking about.
"Init" is the day amd time the model was initialized.
"Forecast Hour" is the number of hours from that initialization.
"valid at" shows the date and time that the model forecasts what is in the image.
The trend goes by 6 hour increments for the GFS, because that's how often that model comes out. For the trend, a forecast 6 hours ago will need to show a frame that has a "Forecast Hour" 6 hours more than the "Forecast Hour" you are looking at for the current run in order to show you the conditions at the 'valid at" time you are looking at. As you go back with the down arrow the "valid at" time stays the same. But each time the "Init" goes back by 6 hours more and the "Forecast Hour" goes up by 6. You can do this for any hour of the forecast you want for the current model run. As soon as you move the slider at the top or click the left or right arrow, the image returns to the current run.
At the moment the link takes you to 18Z run's Forecast Hour of 192. If you click the down arrow, here's what the trend would show as you keep clicking the down arrow.
| Init: | Forecast Hour | valid at | | 18Z Sep 01 2017 | 192 | 18Z Sat, Sep 09 2017 | | 12Z Sep 01 2017 | 198 | 18Z Sat, Sep 09 2017 | | 06Z Sep 01 2017 | 204 | 18Z Sat, Sep 09 2017 | | 00Z Sep 01 2017 | 210 | 18Z Sat, Sep 09 2017 |
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In this thread:
Irma at 5pm AST on Friday: 120mph -
Chris in Tampa,
9/1/2017, 4:53 pm- Latest Model Runs from the South Florida Water Management District - tvsteve, 9/1/2017, 9:15 pm
- GFS trend image from Levi Cowan of the setup over the US - Chris in Tampa, 9/1/2017, 8:32 pm
- NHC's Key Messages for Hurricane Irma - Chris in Tampa, 9/1/2017, 7:52 pm
- GFS around Lesser Antilles - Chris in Tampa, 9/1/2017, 5:13 pm
- Re: Irma at 5pm AST on Friday: 120mph - 327hanna, 9/1/2017, 5:12 pm
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