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Our First Two Cities in the WxChallenge

San Antonio, TX & International Falls, MN

by Philip Lutzak - February 2007



Figure 1. San Antonio in a relatively rare winter moment, with frost on the ground. San Antonio averages only 20 days a year where the temperature reaches 32 degrees Fahrenheit or below. Photo courtesy Laura Gibson.
Figure 2. International Falls in a typical winter moment, at the shore of frozen Rainy Lake.  The city averages 198 days a year where the temperature reaches 32F or below. Courtesy polarisman/wunderground

INTRODUCTION In this report, as a follow-up to my practice week at San Antonio, I'd like to update my progress (or lack thereof!) in forecasting the weather for the National Collegiate Forecasting Contest, or WxChallenge. I now have spent four weeks officially forecasting the weather for this contest for San Antonio, Texas and International Falls, Minnesota, two very disparate locations. Figure 1 shows the occasional extent of a typical winter at San Antonio, where frost occurs once in a while but measurable snowfall is rare. Figure 2 shows a typical winter scene at International Falls, where frost penetrates 3 to 5 feet deep into the ground and many nights fall well below 0 degrees Fahrenheit. 

  The first two weeks were focused on San Antonio, and it was extremely difficult. There were wild temperature swings that were hard to forecast, and it seemed each time I made some progress in my forecasting skills, I slid backwards the next day. My rankings in the contest were not doing well at all. So that you can see the challenges I faced, I will cover a particular forecast "bust", explain why it happened, and what lessons I've learned from it. I will also show you a forecasting method I used for San Antonio's weather, one that was new to me, called the "delta method", including how it works and when it's appropriate to use it.

  For the second two weeks we forecasted for International Falls, Minnesota, located on the Canadian border and affectionately nicknamed the "Ice Box of the Nation" by its hearty residents. This is obviously a very different climate from San Antonio, as you will see by its frigid temperatures. Much to my surprise, even though I've never lived in such a climate, my forecasting skills improved markedly during those two weeks. But that doesn't mean I didn't also make some memorable blunders. So I'd also like to share my worst forecast failure at International Falls with you, as I did for San Antonio, so you can see how I've learned from my mistakes and how it has actually improved my forecasting skills.

  Finally, I'll wrap it up with some reflections on the entire experience so far, so you can get an overall idea of how I felt during this really difficult forecasting contest. I'll also share some of my ideas on how I plan to improve my score over the next few weeks. Hopefully I'll have an even more upbeat report a month from now.


  In my previous report on our practice week, I detailed the climatology of San Antonio. The following page covers the climatology of International Falls, which tells quite a different weather story.


Next Page: The Climate of International Falls, MN

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