We spring ahead this weekend into Daylight Saving time, but the temperatures are going to be acting like their springing ahead to April! But, after another brutal night, rivaling many that we saw in the month of February.
The last month has been cold. In fact, February 2015 was the 5th coldest in recorded history in Rochester, MN. The average temperature was 7.8°, 12.5° below normal! It hasn't been this cold in the month of February since... well... last year. February 2014 is our current #4 spot in the record books!
The cold really dominated last month over the eastern part of the country.
The upper air pattern really dictated the flow of the cold air, consistently bringing the arctic air down our way. The following map helps illustrate this, showing geopotential heights on the 500 millibars (mb) surface averaged over the entire month. Basically, we're looking at how high or low (in decameters) in the atmosphere you must go to find a pressure of 500 mb. Generally speaking, the lower the height, the colder the airmass.
And the difference from what we observed in February compared to normal. Again, accentuating how abnormally cold the airmasses were throughout the month.