It's been too long

It has been far too long since I have last posted to me blog. I've been quite the busy bee, lately. This season has started off with a bang in regards to severe weather. And unfortunately, these events have cost a lot of people their lives. I'd just like to re-visit the 2 March, 2012 outbreak.

Models had been hinting at a rather potent negatively tilted trough affecting the midwest for several days. Unlike so many systems this winter, this one involved phasing between the two jet streams, which eventually caused the formation of a longwave trough (with actual cold air involved). Along with the track of this sfc-low, the ridge in the SE was in the optimal position to allow for a great return of moisture. Back to the jet streams: with the strong polar jet stream involved, there was substantial upper level support, to the tune of 110 knots at 500mb. There were actually two areas of wind maximas at 500mb, which caused a coupling effect, which only enhanced the upper level support. Among that upper level support, the lower level winds were backed at the surface, with 40+ knot winds at 850mb. Helicity values from 0-1km were more than adequate to support tornadoes (150+ m^2/s^2), and the 0-3km Helicity values were above 250 m^2/s^2. Deep layer shear was >50 knots, and lower level shear 0-3km was greater than 20 knots, which is often a rule of thumb used to forecast the possibility of tornadoes.

When Friday morning arrived, it was evident that the models had underestimated the strength of this system, in fact, it was strengthening faster than anticipated, whilst moving slower. The only model that actually had it forecasted rather well, was the RUC (rapid refresh). By 9am, the clearing was quite evident up and down the Mississippi River valley, which meant that conditions were becoming even more unstable. ML Cape values of 1500-2000 j/kg were present. And because the forcing was so strong with the upper level support, and advancing cold front, it wasn't but 10am, when storms started to initiate. Several cells advanced into southeast IL, where the atmosphere was much more conducive to rotating supercells. By the time that supercell crossed the IL/IN border, its couplet had tightened tremendously, and dropped its first tornado about 15min north of Evansville, IN. About that time, two cells popped up east of that cell basically on I-64. Both went tornadic very quickly, and both traversed all the way to Ohio, producing tornadoes the whole time.

Even more amazing than the Indiana tornadoes, were the ones which affected Kentucky, particularly, Liberty, KY. Here is an excellent comparison by Jim LaDue, of some rather strong tornadoes in recent years (including the Liberty, KY tornado): http://jimladueview.blogspot.com/2012/03/how-does-west-liberty-ky-tornado.html?m=1

People continue to clean up from these devastating storms, and my thoughts and prayers go out to everyone involved. A lot of people lost their lives last Friday, and that is unfortunate. Fortunately, it looks like a rather warm/stable pattern is establishing itself in the near term.