Wednesday, March 7, 2012

February Report Card

January's grades weren't so hot. I've promised improvement. February offered another shot at some winter weather forecasting as well which may threaten that record being that is so difficult to forecast winter weather this late in the winter season. The grades for the second month fall like this:

I made a forecast for 18 days in February, I took a few sick days early in the month. That didn't stop the numbers from being the best so far. My temperature accuracy topped out at 88% (16/18) and conditions reached 100%. The two missed temperature days were off by 4 degrees.

A late-month snow threat had a near-perfect forecast with accurate temps and conditions. The timing and location of the forecasted snow-showers were predicted well, too. Winter weather forecasting becomes an issue this late in the month and season. The angle of the sun is on the increase as the days are getting longer. The way the sun angle works is like this:

During the winter, the sun angle is rather low. This means that the sun's energy is spread across a wider surface. That results in less heat across a larger area. As the summer months roll around, the sun becomes stronger. As the sun passes higher in the sky, it's energy is concentrated all on a smaller area at the surface. By the time we reach the end of February, our average temperatures are up to 54 degrees. That makes it difficult to get any sort of winter weather that would fall widespread down to the surface. We would need a good push of cold air from Canada in order to get that "wintery" weather. That's what happened in this case. Cold air sagged south from the boarder but it only brought temps down to the lower 30's. With those temperatures and enough moisture it becomes a borderline rain/snow event. Add in the strengthening sun angle, it becomes nearly impossible to forecast exactly where snow showers will pop up.

Despite the challenges, my forecast for those final few days of February were rather accurate. That was much to my surprise but the confidence from January's snow event definitely spilled over into February's "winter finale". As far as March's snow outlook, I think we can write it off. There is roughly a 1.5% statistical chance of snow in March.

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