An incredibly long and impressive line of thunderstorms swept through the central United States on Thursday night, stretching more than 1,200 miles long at its largest extent. The storms left more than 300 of reports of damaging winds and large hail in its wake.
Yesterday's supersized squall line is a classic type of severe weather setup for the fall months, and one of the most beautiful to watch unfold on weather radar imagery. The United States experiences a second peak in severe weather activity in autumn as colder air dives southward and clashes up against a warmer, more humid airmass. The result is usually a powerful cold front digging into unstable air, creating an explosive line of storms that can easily extend the entire longitudinal extent of the country.
The line of storms that occurred last night is larger than most regional radar views can pack into one image, so the only way to see it in full is to look at the national radar mosaic like the one at the top of this post. Looking at regional radar imagery lets you get a great look at the system's structure, though:
Here's an even better look at one of the healthier line segments within the squall as it pushed into eastern Arkansas, courtesy of the radar site in Little Rock:
Enormous squall lines like this are responsible for some of the most memorable severe weather outbreaks in recent years, including one that struck in mid-April 2011 and another that caused extensive damage across much of the United States in late-October 2010. The latter system formed as a result of "The Chiclone," which was the strongest non-tropical low pressure system ever recorded over the United States.
Major severe weather events are always terrible for the human and financial toll they take on the ground, but it's a sight to see when it unfolds before your eyes. Yesterday's incredible squall line is one of those times where you don't have to feel guilty for admiring its structure and power. And it is pretty refreshing to have a severe weather outbreak that doesn't involve the term "wedge tornadoes" for once (sorry, Fake Reed Timmer).
Taking a look at the water vapor imagery as of 100PM EDT leaves no question as to where the cold front is located. The great news (or terrible news if you're a warm-weather person) is that our first shot of breath-seeing weather is on its way. To give you an idea of how widespread this cool air will be, the low temperature on the outskirts of Gulf-straddling Mobile, Alabama could reach the mid-40s on Saturday night. Low temperatures bottoming-out in the upper-30s are possible as far south as northern Alabama and Georgia.
If you're worried that this is temporary, fear not! This cold front heralded the return of fall temperatures for good for a large part of the United States. For example, here's model guidance showing potential temperatures for the next 16 days in Greensboro, North Carolina.
[Images: NWS, COD, COD, NASA, WeatherBELL]