Find next 5 days of surface winds

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Andrew Revering
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Location: Cambridge, MN

Find next 5 days of surface winds

Post by Andrew Revering » Thu Jul 23, 2009 11:52 pm

First a couple notes... the 3 models available are really ideal for different time frames. RUC for example is a short term model, and handles the next 12 hours better than the other two models will. The NAM-WRF is best for the 12-84 hour time frame, and then GFS for any period after that. So as we're looking over the next 5 days you probably want to switch between models to get the most accurate forecast. With that in mind, for simplicities sake, I'm going to just use the GFS as it will give you a forecast from now through day 16... but again, the first 3 days would be handled better by the other two models. So here we go...

1) Launch F5

2) In the upper left, 3rd button from the upper left.. looks like a color gradient, select that and then choose GFS from the drop down.

3) Select the forecast hour from the next button to the right... looks like a clock. This is tricky because it depends on what time of the day you're doing the forecast and what model is the 'current' run. The model runs 4 times a day, so a 24 hour forecast for example is going to be valid at 12z (7am central) if you are forecasting in the morning, but if you forecast from the evening a 24 hour forecast would be from 00z so it would be valid at 6pm central. The map when it draws will tell you in plain English when it is valid at the bottom of the map. So for experimental sake, pick the 24 hour forecast.

4) Now push the 9th button from the left, looks like 3 pages of paper stacked on each other. This puts you into multiple overlay mode. We want this for what we're about to do because I want to overlay wind speeds (contoured) with wind barbs (direction).

5) Now double click General in the map listing on the left. This will expand the tree to see some 'general' map choices. For what we need for wind forecasts, the maps we need are available under this list.

6) Double click SFC Wind Speed. The map will download and plot.

7) Now double click SFC Wind Barb. The wind barbs will download and overlay on the map.

8) You can zoom in and pan over the Ohio River as you please. You can also go to File and save an image if you want. Also note the time stamp at the bottom. 00z is 7pm central. 18z is 1pm central, etc. To tweak when the forecast is for, if that's not when you want it for, you can now hit the green forward and back buttons in the menu or change your forecast time (the clock icon)... then when you make a change, just wait and be patient for the data to download and re-draw.

9) Now by changing your forecast time (clock.. 4th button from the upper left) you can change and flip through the next 5+ days. You can go forward or back in time by 3 hours if you use the green arrows, but to jump ahead 24 hours its much easier to select the times from the 'clock' drop-down.
Andrew Revering
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