Northern IL finally gets some rain

It has honestly been so long since our last storm, that I may have forgotten to post about weather related events.  Nonetheless, tonight the northern part of IL got some much needed rain, but mother nature also provided an amazing light show to go with it.  I have never quite seen cloud-ground lightning like I did tonight.  My only regrets had to do with my lens choice given the distance I was actually away from the approaching multi-celled cluster (later forming into an MCS).  Too bad the other lens was accidentally left in my other camera bag at home.

This afternoon had incredible daytime heating, and had sporadic convection throughout the day.  Rockford managed 99 degrees, which was the warmest reading that I have found within the Chicago-CWA.  And although the convection was ongoing throughout the day, weaker upper level winds inhibited long-lasting growth, creating vertical towers that collapsed on their selves due to becoming cold air dominant (due to the rain shaft cutting off the inflow).  At the same time, the CAP to our west started to progressively weaken, and with that, and the somewhat diffuse cold front providing a source of lift, it allowed for initiation.  With northwest upper level winds, it allowed for some forward propagation of the cold pool, which eventually sustained itself into an MCS with a more established RIJ.

Just to give a little sneak-a-peak into my research, I have chosen the nine day period during March 2012 in which temperature records across the Chicagoland area were shattered.  There is a sigma value for each high  temperature to show how much this value differed from the average temperature for that time of the year.  In general, most extreme temperature anomalies fall within the 2-3 sigma range, with a few of them falling slightly below the minimum threshold.  Probably the most surprising feature of this past March, was the magnitude, or the length of time, that the record setting heat was in "place" for.  Throughout my research I found many single day records, but far fewer records were set in three consecutive days.  Knowing this, my research became less about the individual records their selves, but more about the extended periods.

I still have yet to get the supporting upper level data, but by isolating these extended periods, I am hoping that I can paint a more precise picture of the synoptic/mesoscale setups in regards to things such as 925 and 850hPa thermal axis, 850hPa ridge axis, and the corresponding temperatures.  Knowing this information could help develop a better idea of the certainty of record temperatures occurring.

Date	Precipitation	High	σ	Low
3/14/2012	0	81	3.171104381	54
3/15/2012	T	81	3.171104381	51
3/16/2012	0	81	3.171104381	48
3/17/2012	0	80	3.08183109	58
3/18/2012	0	81	3.171104381	61
3/19/2012	T	79	2.992557799	64
3/20/2012	0	85	3.528197546	66
3/21/2012	0	86	2.847322737	66
3/22/2012	0.04	84	2.687066087	62

Update

My spring semester was quite undulating, and robust. I am currently going through my blog, updating the profile, and the view of the blog in general. I have quite the collection of photographs to post, among other meteorology related articles. Along with that, I will make a portion of my research involving the climatology of record temperatures, available to the public. This will give a little insight as to what I had been working on during my senior year of college, and what I will continue to strive for in the future.

The weather around the nation has been quite interesting this spring, and summer. Thus far, northern Illinois has been stuck in a rather stagnant pattern; one which yields very little rain. Given the lack of appreciable rain (last was the > 1.00" rain event on 31 May, 2012), we remain well below normal rainfall amounts for the past couple months, and for 2012 thus far. Given the early planting season, in part thanks to the unusually warm March, certain crops such as Corn are rapidly approaching their most important growth stage. This is known as the V5 stage, or the fifth leaf. Precipitation becomes very important during this period, and previous research of mine has shown that dry weather during this period leads to poor corn yields during the fall. Given this knowledge, I think it is safe to say that our yields across the corn-belt region will suffer. And, this dry-spell does not look to end for at least a week. Current guidance keeps northern Illinois dry for much of the week, and possibly warmer towards the end of the week.

Of late, the dominant feature has been upper level ridging over much of the eastern United States. Although this feature breaks down from time to time (see today's shortwave in Ontario and associated sfc-low), most often the great synoptic forcing is displaced further north. Today was a prime example: there was an approaching cold front, which was associated with the sfc-low in Ontario. Best upper level winds and associated PVA were located north of the Canada/United States border, leaving the Midwest with poor upper level support, and weak forcing. The pre-frontal trof, and some PVA was enough to create some mid-morning cloud-cover, but never amounted to any rain, as radar returns diminished early this morning thanks to little instability. Another area of PVA was supposed to rotate through the base of the shortwave in association with the approaching cold front, but weak forcing proved to be too much to overcome in its case.

The current split flow pattern is common with an El Nino, which is the pattern that we transitioned into after being in the strong La Nina for much of the winter. Typically, this yields more active southerly jet stream, with the northerly jet stream displaced much further north than "normal". This is exactly the type of pattern that has evolved. Leaving much of the Midwest in a drought, and recently areas on the southeast and near the Canada/United States border, inundated with rain.

This is just an update for now, there will be more to come and I complete my updated profile.

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.