Areas across the Midwest, Great Lakes, and northern Plains saw temperatures the most above average with temperatures at least 9 degrees Fahrenheit above average across most of this area. In fact, some areas saw temperatures 15 degrees Fahrenheit above average for the month. The weather was so nice, instead of it feeling like March, many areas saw temperatures more typical of the month of April with some weeks feeling like midsummer. All together, 6199 high maximum temperature records were broken and another 1556 high maximum temperature records were tied. This means that a little over 3.5% of all the March United States high maximum temperature records broken! Below is an image depicting the areas where high temperature records were broken or tied, with areas showing more black overlaid on red having a higher concentration of record breaking or tying.
The great amount of broken records just did not apply to high maximum temperatures though, as high minimum temperature records also fell. By the end of the month, 6210 of these records had been broken and another 1307 tied. This meant that once again, just over 3.5% of all March United States high minimum temperature records were broken. Below is an image that depicts the areas where these events occurred.
You may have noticed in the first image showing temperature anomalies for the month of March that not all of the United States saw such warmth this past month. Some areas, mainly along the West Coast, actually saw below average temperatures during the month of March. However, this cold was nowhere near the heat that the rest of the nation experienced as only 603 low maximum temperatures were broken or tied and 287 low minimum temperatures were broken or tied, with the majority of these events occurring on the West Coast.
So what made this month so warm? Above is an image of the 500 mb geopotential height anomalies based on the 1981 to 2010 average for the month of March. As you can see, the eastern portion of the nation saw height anomalies at 500 mb well above average which means a couple of things. First off, it speaks to the trend of the jet stream for much of the month which was well to the north, allowing for warm air to flow in from the south. It was this large high pressure system which helped “block” intrusions of cold air from entering the eastern portions of the US. But also, it shows that areas with larger height anomalies saw generally, the most warming. This is because the warming of air causes it to expand and seeing as it cannot expand into the surface of the Earth, it must expand upward thus causing these height anomalies to exist.
However, global temperatures were not all that far above average with only about a .2 degree Fahrenheit anomaly based on the 30-year climatological average for the month of March. It is important to keep this in mind when making statements for or against the argument of global climate change. The United States is just one portion of the globe and therefore weather extremes that occur here may be totally negated by the opposite extreme in other portions of the world. No one can argue that March was a very warm month for the eastern two-thirds of the United States but blaming particular incidents on climate change is unwise when so little data has been collected in the realm for the entire history of the planet. If this past month taught us anything, it is that our climate can present us with very abnormal weather and it is these patterns that we should continue to monitor closely.