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.

Disheartening

Today will go down in the record books for tornadoes, and could vault this month to the top of the worst month in regards to severe, ever. Before I write about the outbreak, I want to express my heartfelt sympathy for the people of Mississippi, Alabama, Georgia, Tennessee, etc. There has been a great loss of life today.

This morning started out with an expected high risk from the SPC. For the Mid-South we had very high forecasts of Bulk Shear, and Storm Relative Helicity values. In the picture that follows (18z Birmingham, AL Sounding), the things that are so noticeable are: significant CAPE, backed LL winds, strong LLJ around 850mb, coupled with a relatively strong jet streak around 400mb, and great moisture. We had values ranging anywhere from 200-500+ m^2/s^2 for SRH, and Bulk Shear above 65 knots. Those two ingredients alone are downright scary. When you add it all together, you have an atomic situation; one which supports large, long track tornadoes. And that is exactly what happened.



The follow radar pictures are associated with some of the Mississippi and Alabame storms, they have the tightest couplets I have ever seen on any supercell. And, every storm which fired was discrete, and every one of them were supercells.







Luckily, the SPC has been great for the whole duration of this event. My hat is off to them! Here is a picture of all the reports:

Very Dangerous setup for 4/26 and 4/27

Storms have already begun initiation in and near Dallas/Ft. Worth. SPC has progged that area with a High Risk for severe wx. It's with great sympathy that I write this, considering the tornadoes and severe wx that occurred in the region last night. But, if people thought yesterday was bad, today will be worse.

19z surface obs show slight backed winds at the surface, along with dewpoints in the low 70's. There is plenty of instability avalaible, in upwards of 2000 j/kg. The storms are initiating on the instability gradient/Theta-e gradient. These storms went severe in a matter of 5 minutes; and once rooted in the boundary layer, should make a classic right turn. I don't feel that I need to mention the parameters for today, because I will sum them up with one word: "atomic". SRH values are most likely underdone, but I would expect them to approach 600 m^2/s^2, with Effective Bulk Shear at 50+ knots, and with plenty of quality moisture and instability, you're talking about a downright scary situation for the Arklatex region of the United States. There could potentially be a large swath of damage from Dallas to Memphis.

As for tomorrow: right now SPC has it pegged in a Moderate Risk, but I would not be surprised to see it upgraded to another High Risk. There should be ample low level helicity, and plenty of shear available. Couple that with sufficient instability, and good moisture, and you have another volatile situation. With that said, I feel that Southern and Central Indiana into Southern, Central, North Central, and Eastern Ohio could experience some rather unpleasant weather tomorrow. With the given parameters, I could see a tornado outbreak, with storms forming into a QLCS (quasi-linear convective system), with possible embedded HP supercells.

I will update more later.

April 19, 2011 IL Storms

Yesterday started out in Geneva, IL; where I and a friend met up with two fellow storm chasers. I had a preliminary idea of where I wanted to head, and we confirmed that as we traveled south towards Springfield, IL. We knew where the track of the Sfc-Low was going to be, and with that track, the best backed surface winds were going to be in that vicinity. That meant we had to hang relatively close to the warm front where this enhanced helicity and shear would be. Right off the bat, we knew moisture was not going to be a concern. Sfc dewpoints ranged from the low 60's to low 70's, with a very impressive pool of 60+ dewpoints at 850mb (~1.5km). We decided on Litchfield, IL for a target area. As we drove just south of Springfield, we finally got south of the Warm Front, and that was where our extensive stratus deck finally ended. Temperatures climbed rapidly within the next 30 miles; going from a mere 61 to a high of 78. We sat at McDonalds in Litchfield watching our setup. Around downtown St. Louis a boundary of some sort had set up (moisture boundary!?), and was evident with radar loops. This was one of our main focuses because of it possibly being the cap breaker. Instead storms started initiating ahead of the cold front, close to a triple point. They were WNW of St. Louis. We watched the scans come in on those cells, and quickly decided to head towards Carrolton, IL across the river from a cell that was going "super" quickly as it headed towards Bowling Green, MO. That cell looked beautiful on radar; but it would not hold.



As that cell hit the Mississippi River bluffs on the IL state line, it fell apart. It went from a supercell to what we described as "blobish". We continued to follow the cell, and experienced two Gustnados, but unfortunately, the cell looked to be gusted out, with a forming shelf cloud.

We quickly traversed back towards Carlinville, and noticed that our original player (convergence along that radar viewable boundary) had initiated a supercell. There were a few wall cloud reports coming off the cell as we headed towards it. As we approached, we saw a visible wall cloud and tightening rotation in the low level mesocyclone. And as we headed east on IL-108, that cell developed a small funnel cloud eventually making a brief touchdown. Within seconds, the RFD ramped up on the south side of the storm, and a very low inflow tail developed on the north side of the mesocyclone south of the FFD. The inflow coming into the cell went from mere 20 knot winds to 60+ knot winds in a matter of no time. We got to the junction of I-55 and IL-108 which provided a perfect vantage point for this storm. SSW of the Pioneer seed plant, the storm started to produce a classic cone shaped funnel cloud, with the start of debris showing near the ground as well.

The funnel cloud finally made full contact with the ground, putting up a rather large debris cloud. We were viewing this tornado from ~ 1-1.5 mile(s), and even at that distance it looked large! It became more defined as it moved ENE across I-55. After about a mile or so east of I-55, it finally lifted a bit as it started progressing into an HP Supercell.







We continued to try to get ahead of this storm, but unfortunately we encountered quite a bit of traffic, which slowed us down greatly. Eventually the cells quickly developed into a rather large derecho, moving at an unbelievable pace. There were still embedded supercells within this system, but most of them were dealing with heavy rain wrapped precipitation, thus making it far more dangerous to chase. We eventually took shelter in Greenville, IL off of I-70, and after the line passed, we headed back home.

Here's the Double Derecho!