Home Photos By Year Severe Weather Data Information Winter Weather Links Contact About Aurora Joel's Forecast Page American Bald Eagle Info
6-18-10
Today was a tricky one. It seemed every model agreed on today's parameters, but what they did not forecast was an ongoing early/late morning to early afternoon mcs. The Quad Cities was actually hit by a pretty decent bow echo around 2:00 which generated wind speeds of around 70 mph in localized areas. But once again, models did not see this happening. RUC showed pretty dynamic parameters in eastern IA with 5,000 j/kg of CAPE, excellent wind shear, LI's around -13, a pretty primed and pumped atmosphere for a significant weather event. The afternoon bow echo wiped our area clean, killing instability and, at the time, ruining every hope I had for a chase. The only thought I still had was extreme NE Iowa as RUC still showed very decent wind shear with ok instability. But, the atmosphere destabilized extremely fast west of the lingering mcs and got me wondering once again. My forecast of around the Des Moines area was looking more and more like a go, but now the question was when to leave. In complete hindsight, I wish I would have left 2 hours earlier than I did to get on the storm as it had a tornado on the ground, but I also would be a millionaire if I had a dime every time I looked back in hindsight on a chase.
Meghan had just taken on a new job and was in training, so her hours were in early and out early. Seeing as how Joel had work obligations (as has been the story the entire year for us), I decided to take Meghan on her first ever chase! She was nervous, but I kept reassuring her that I knew what I was doing lol. The early morning line of storms that moved through Iowa had left an outflow boundary in southern IA and was retreating back northward. With the approaching front, a near bullseye of extreme instability around 5,500 j/kg of CAPE over Des Moines, and the outflow boundary, my target was now southwest of Des Moines. Almost as soon as we left, however, the storms began to fire right where my target would have been. Should have left two hours earlier.
Here's our storm, now booking south on RT 21 trying to get south of this thing. About the time this picture was taken, it had taken on a brief flying eagle appearance and was now digging in quite well. It went from heading northeast one minute to southeast about 30 minutes later. Oh yeah, it was now tornado warned as well. Velocity scans showed a pretty decent couplet and I was now starting to get pretty excited. It had a very favorable environment to work in with excellent shear. The low level jet was really starting to crank in from the southeast as well. So, even though we were still quite a distance away, I wasn't that worried that it would fall to pieces. I was actually starting to get more excited for Meghan thinking she would have a very legitimate chance at seeing a tornado on her first ever chase.
...storm must have known I was chasing it. Right about the time we jockey into perfect position to intercept a would be tornado, the storm went to crap. It was now 100% outflow dominant and had no supercell organization whatsoever anymore. THAT was disappointing. I still don't understand why it didn't stay tornadic until it congealed later on. It was the only storm in the area for a good while, yet still turned into an HP outflow dominant mess. Normally a storm like this would completely dominate it's environment with zero competition.
Gust front on our storm. Even though tornado chances were completely gone, Meghan still seemed to have a great time. She was pretty impressed! I told her if she liked this, then I couldn't wait until she saw her first tornado.
Once thing was pretty cool though. Our backs were sticking to our seats throughout this entire chase, especially since I don't have any a/c in the truck anymore. Right on the edge of this shelf, it went from a very chilly, humidity free feel to a miserable and muggy feel just as we would punch back east of it. Definitely an extremely sharp cutoff there. I love being under these gigantic, bubbly, menacing looking arcus clouds, otherwise known as whale's mouth. This happens as cool air rushes down and sort of "wedges" the warm air out ahead of the front upward, forming the shelf cloud you see on the other side of this arcus. Think of it as a rhino charging an automobile and flinging the car up over it's head as it keeps going. Same thing going on here, in a way. Sorry for the cheesy analogy.
Only so many pics I can take of a shelf. Every time I'd finally get ahead of it, the interstate would take me back north quite a ways and let this thing catch back up to me. It did have some fairly decent winds with it now. There was now a long line of thunderstorms at a NE slant doing some wind damage in eastern Iowa now.
So all in all, it wasn't a very thrilling chase as far as tornado possibilites go, but it did provide some pretty photo opportunities. I'm just tired of seeing shelf clouds this year though. It seems every storm we get on lately goes outflow dominant and shelfs out. Good to see Meghan have a good time though!