Saturday, July 21, 2012

A season ready to be put on the "shelf"

Wednesday July 18th was a rather odd day for this year in Southern Wisconsin terms, we have been experiencing a drought that has been what seems like a never ending cycle. I woke up that morning to some beautiful pictures of a sunrise Cumulus tower over Dane and Jefferson county. Now if you know me, you know that I am a sucker for structure shots, so I was feeling a little disappointed that I missed it.

Courtesy Jason Schwartzlow Dane/Jefferson county sunrise storm

A few meteorologists I know began talking about the possibility of a few storms reforming that afternoon along a cold front that would be draped somewhere across Southern Wisconsin/Northern Illinois. I was a bit skeptical at 1st due to lack of shear, or so it seemed but my interest was still quite peaked. With the 8am update that morning the SPC issued a slight risk of severe storms for much of Southern Wisconsin, still a bit skeptical I decided to go look over models one more time, a few of the HD models did indicate a pretty hefty complex of storms swinging thru the area by around 7pm. Looking further into the models it seemed right across southern Wisconsin was a nice axis of instability and at least a little shear would be present along the boundary. After talking it over with Jason, we decided that since we haven't had much to chase around here in 2 months, we would go out and give it a try just to see if we could get a storm form discretely and work some magic along the boundary. Around 11:30 am a mesoscale discussion was issued concerning a potential severe threat across the area, issuance of watch was only 40% and seemed unlikely at the time but the plan to head west a bit and mess around with anything that formed was still in place. At around 1pm, much to our excitement and a Severe thunderstorm watch was issued for most of S. Wisc/N. Illinois and part of MN and IA.
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When you have not seen much action in the last month or so, this became a very exciting moment.
The plan was just to drift off to the west, maybe near Monroe and follow the storms back home. We left Janesville about 2:30pm and headed west as planned, while on the way there was a very thick patch of broken Cumulus and "turkey towers" everywhere. At around 4:00pm a small storm (rain shower) formed just to our north in Green County. We decided to hang around it and see if it would do anything at all. About an hour later after watching this storm pulse up and die and do the same thing several time, we were considering abandoning it as many little spuds were firing up all around us and had a few lightning indicators with them,also a bigger and stronger line was on the fringe of entering Wisconsin from IA and we thought that may be our only play on something decent and maybe a decent shelf cloud (remember this). Around 5:30pm the storm we where on all of the sudden went into beast mode, on radar and visually, all of the sudden it was spitting out CGs and had a nice little hail core on it. About 10 minutes later the weather radio went off and the storm was now severe warned in Rock county for quarter size hail and damaging winds. We hung back a bit to get a few quick shots of the beautiful Anvil from the storm and the weather radio went of again, now we where caught between 2 severe warned storms, and had to make a choice as to which one to get into.

Caught between 2 severe warned storms

The decision was made to go after the storm to our east since it was headed for home and showed a very nice looking base on it. Now Southern Wisc has nice road networks for chasing, but this particular time we needed it, an east road was nowhere to be found, a very frustrating occurrence when chasing storms. We finally found our east option and were able to get near the base of the storm at this time, the base was very rugged and sloppy but it did show a tiny bit of broad rotation in it so we decided to go in for a closer look. At this time we got a clear view of the hail shaft in the storm which looked to be quite healthy.


(c) Jason Schwartzlow Rock county hail shaft with rainbow

After playing around in the storm for a little bit, a decision was now needed to either abandon the storm and head north to intercept the incoming bow echo or stick with the storm. After going back and forth on the decision for a little bit, the decision was made to abandon the storm we where on since it looked to be weakening, and head north thru Orfordville towards Dane county to see if the shelf on the incoming bow was worth it. While driving north out of Orfordville, it was apparent that the storm we were on had a bit of a wrath with it, leaving many large branches strewn all over the roadways, few roofs with hail damage, and crop fields storm damaged.
At this point the line of storms was moving at a decent place across the state and we knew we would have to decide on a place with good visibility to watch the storm come in.



Stoughton was the general area we decided on since you get east of town it is pretty wide open farm land, only problem was this path would take us directly thru the town, which is always a pain in the butt. After being stuck being some of the slowest drivers we have ever encountered, we finally arrived on a nice road off of the highway with a great view of the incoming storm, what we thought was gonna be a decent shelf,exceeded the expectations like I could never explain. It took us a brief few minutes to get our tripods and cameras set up, what happened next will be a few minute I will never forget. The horizon started to darken in a way it always does with an approaching squall line/bow echo. There was almost a freakishly calm feeling in the air. As the horizon grew more and more dark, one of the most beautiful sights I've ever seen broke thru.




After watching that amazing shelf come thru and standing there in awe for several minutes, a quick peak at radar became evident that we could make it back 20 miles south by my house south of Janesville in time for quite possibly another shelf cloud.
We encountered some heavy rain and gusty winds getting to the interstate to head south but quickly approached the front edge of the line again. With sunset approaching fast and an already dark sky, we were unsure what we would be able to capture on camera. We arrived at one of our favorite parks in Rock county that gives you an almost unobstructed 360 view of the sky and got set up, a few minutes later we where rewarded again!

(c) Jason Schwartzlow


After this shelf had passed we sat in a lightning barrage that lasted a good 30 minutes, the 15 minute ride home was one of the most awesome rides ever, the mood in the car was just of pure joy and disbelief that Wisconsin can produce such beautiful storm structure, with a year that's been anything but decent to chase, this may have revived it, even if just for a short time :)