METR 361 Spring 2014

Nor’easter Lab

If you’ve been following the model forecasts (and you should be), you must have noticed that early in this week, even before our snow day on Wednesday, the GFS was predicting a large and very intense coastal storm in New England for Sunday, Feb 9 and Monday Feb 10. Some forecasters on TV and on the Web were warning the public even though the forecast was for a time period that was 168 hours away:

However, GFS runs on Wednesday and later show this storm would affect New England only minimally. What happened? That’s your job today. Using the IDV and current (Friday) maps you get from the Web, discover how the GFS forecast was different from what actually will occur this weekend.

Procedure:

1. Go into the computer lab. Pick your favorite computer. Get the IDV running and load the file GFS Feb 3 2014 storm.zidv which you will find in the Nor’easter lab folder inside the METR 360 folder. MSL isobars and precipitation maps are already created and will be shown.

2. Using the web browser (the spherical icon at the top of the screen), display the current and near-future state of the atmosphere as shown by the current GFS model run, hopefully initialized at 12Z Friday.

3. Compare today’s GFS run with the one from Monday, that you loaded to the IDV. Save images from the web and the IDV. Side-by-side comparisons of the forecasts for the same date/time may be particularly revealing. You know how to save web images. On the IDV, you do it this way: In the MapView window, there is a View menu just above the left side of the display map itself. Pulling that down, there is a submenu called “Capture”. When you let the cursor linger on the word Capture, another sub-menu pops up next to it. Images can be saved by clicking on Image or by keying in Ctrl-I. Movies are also possible, although not quite what you think. Saving movies means capturing successive images. You then need to put them together as animated gifs, using another program. We have one. Ask if you want to use it. Please don’t click on Print.

4. As you did last week, write up what you found in a report. What are the differences, i.e., what is the atmosphere doing now, Saturday, and Sunday as forecast by the short-term GFS, that is different from what was forecast by Monday’s GFS? Explain what you discovered in as much detail as you need to account for the lack of a big coastal storm in New England. Refer to your images and include the ones you need in your report.

Your write-ups are due next week, on Friday before you leave the lab. Email them to me at Jerome.Blechman@oneonta.edu