IEM Daily Feature
Friday, 03 November 2023

Blues vs Reds

Posted: 03 Nov 2023 05:30 AM

The featured chart is an unscientific daily comparison between the number of NWS "CLI"mate reporting sites having a high temperature below average (blue) vs above (red) over the contiguous US. The major deficit of this plot is that there is no spatial weighting, so there is an eastern US bias due to having more stations there vs western US. That aside, it still tells an interesting story and the recent outbreak of cold weather is noticeable with the below average value peaking over 75% for the first time since late April. It is difficult to get values much higher than that in either direction as the length scale of long wave weather patterns is almost always shorter than the width of the contiguous US. Restating and for example, having an expansive ridge of high pressure that brings wide spread warmth is unable to cover both coasts at the same time, so there will almost always be some places left out for above average warmth.

Good = 14
Bad = 11
Abstain = 1