IEM Daily Feature
Wednesday, 14 February 2018

Rule of 43

Posted: 14 Feb 2018 05:33 AM

High temperatures are expected to soar to levels of warmth you should express to your significant other today. But how warm can it get with deep snow cover existing over much of the state? A local forecasting rule of thumb is to not forecast a high temperature over 43 degrees when there is at least four inches of snow depth to start the day. Does this rule hold against long term observations? With a bunch of caveats with how daily snow depth and high temperatures are reported, the featured chart depicts binned box plots for a given snow depth and the following day high temperature. So in general this rule mostly holds, but there are a few observations shown above the 43 degrees and four inch depth. Of course, the reason for this rule is energy is consumed by melting available snow that would otherwise go into heating the air.

Good = 13
Bad = 0

Tags:   snowcover   highs   forecasting