Just out today from the National Climatic Data Center in Asheville, NC: March 2012 will go down (at least preliminarily) as the warmest March ever on record for the Continental U.S.! What’s really significant, though, is that the beginning of the entire year of 2012 has been very warm when compared to other late winters on record. Meaning, from January through March much of the Central and Eastern United States experienced much warmer than average temperatures!
So what can we make of all of this? I’ll leave the climate scientists to speculate on the biggest piece of that question, but from a local meteorologist’s perspective this past “late winter” was a historic event. A number of factors make this heat wave so unique: such warm temperatures so early in the year, the number of extremely high overnight temperatures, such a large portion of the U.S. with records, and my personal favorite – a number of record high temperatures set by the morning low!
So how did Washington do in this record warmth?
Even though I know it felt very warm the entire month, we only set one record high temperature at Regan National Airport. On Thursday the 15th we hit 82°. But from Monday the 19th through Wednesday the 21st, we set three consecutive records for warmest morning low temperatures. That means for those days, the coldest it got officially at Regan National Airport was 56°, 62°, and 59°! On Saturday the 24th, we woke up to another morning low that tied a record… 54°. So add all this up, and D.C. set 5 temperature records for the month of March in 2012. Even BWI Thurgood Marshall set two temperature records for warmth, while Dulles gets the “record-breaker award” coming in with 11!
All right, it’s all numbers at this point and the record warm low temperature thing might be a bit confusing, but maybe these graphs will help visualize this warm pattern a little bit better. Let’s take each day dating back to New Year’s Day, and record the averages up through March 31st. Overall, it’s the end of the graph that paints the picture here. By the time you get to the very most right-hand part of these graphs, one has a set of 81 days (yes, this is a leap year) to give you a fairly large data set to average. Remember, the average is just adding up all the particular temperatures you want to compare and divide by the number of days. So let’s say I want to average 5 days of fake temperatures I just made up that were: 40°, 50°, 60°, 70°, and 80°. Add up all those temperatures and you get 300°, divide that by 5 days and you get an average of 60°. So when you look at these graphs, you’ll see lines going way up and down on the left-hand side (or the beginning) of the graph because we only have a handful of days to compute an average from, but when you get to the end of the graph the lines start to flatten out and you can then compare other record warm years to see how they all relate to one another!
Here’s the graph that compares 2012’s high temperature running average from January through March with other very warm years: Note that it was really the month of March the pushed 2012 over the edge as being the warmest January-April on record in Washington D.C. (the temperature line for 2012 [red] overtakes the year of 1990 [orange] by the very last few days of March).
- Courtesy NCDC
This is the graph comparing 2012’s running low temperature average from January through March with other notable years: Note here that beginning around the 11th of March, the 2012 low temperature running average line (red) begins to close in on the 1990 line (orange) and eventually overtake it by the middle of the month!
- Courtesy NCDC
Finally, my favorite notable temperature occurrence of March: the morning low temperatures in the Upper-Midwest that set record highs! Over the course of 4 days, such warm (and humid) air was transported all the way from the Southern Plains and Gulf of Mexico region, several locations recorded record high temperatures with their morning lows!
- Courtesy NCDC
Here's the link to the full report found on the NCDC's website:
So what can we make anything of this data? For starters, it’s clear that for not only Washington, but for a large area of the U.S. east of the Rockies a mild/warm January and February was pushed to the extreme by a VERY warm month of March. Again, I’ll leave it to the climate scientists to commentate on if this late winter/early spring of 2012 means anything significant with relation to potential climate change. But the facts here clearly state, that this was an unprecedented warm spell for a HUGE area of the WORLD for that matter! One can’t say that we’ve never done this before, but ever since our larger climate record in the U.S. has been kept (1895) we have never been this warm! That is a very notable weather event for sure!