Thursday, May 26, 2011

5/24-5/25 2011 "High Risk" of Busting

Tuesday and Wednesday featured "high risks" of tornadoes from the Storm Prediction Center (SPC). I have a poor history of chasing high risk events, mainly because there is just too much going on dynamically to make for an easy chase. Both setups appeared favorable for long-track, violent tornadoes, but the morphologies of the storms (especially on Wednesday) made for a convective mess that made for very difficult visibility. As an example of why these type of days are so frustrating, I have included a radar image depicting all of the messy storm interactions and hundreds of chasers all searching for the same prize.
These big days typically offer plenty o' CAPE and Shear leading to a large convective overturning QLCS later in the evolution. On Tuesday, we were caught too far north (we drove from IL earlier in the morning), despite high risks for tornadoes in south-central KS. We ended up staying in Springfield, MO that night in preparation for and IL play on Wednesday. The IL setup proved just as "messy." Thus, despite two high risks, I only took my camera out of the bag one time! This occurred near St. Louis on Wednesday as a clear slot began to cut into a wallcloud. After making a quick report to the NWS, the storm produced a funnel cloud that lasted for about 30 seconds. I thought this storm may produce a tornado, but quickly dissipated and became outflow dominant. In all, two high risk days proved to be two relatively expensive car washes. Sorry for the poor quality of the funnel picture, but it was a frame capture from Ryan's video camera. I will be down from chasing for Memorial Day weekend, but plan on chasing the following week.
Weakly rotating lowering near St. Louis, MO
Rapidly rotating funnel just minutes later

Monday, May 23, 2011

5/22/2011 Another Iowa Letdown

Paul Sirvatka and I were excited in the morning with our target area being just E of DSM. I'll offer a few thoughts as to why I think the supercell potential was limited through the afternoon in this area (feel free to debate this with me, as I may be incorrect). Without going back and doing a substantial reanalysis, it appeared to me that the gravity wave that induced an MCS in east/central WI created a meso-high in its wake, causing pressures to rise creating a small surface ridge in eastern IA. This location was then characterized by largely unidirectional hodographs with little 'focus' for convergence and plenty of large-scale ascent ahead of the approaching shortwave. Thus, especially after the very beginning of the event, many storms were multicellular in nature. I'm sure there was more going on, but those are just some of my initial thoughts. The environment of the Joplin, MO tornado was comparable to the environment eastern IA (via 00z 23 May upper air observations), but IA and IL were lucky this time.

5/21/2011 Emporia/Reading, KS Tornado

Woke up in the Oldtown district of Wichita with a tough forecast on our plate. Go north to Emporia, KS with a better probability of storms, or wait in Witchita, KS and points east with potential for more isolated supercells moving into higher θe later in the evening. Decided to stop and hang out at El Derado Lake State Park while watching towering cumulus to our NE (initial Emporia cells). Filled up with gas in Cassoday, KS ($4.06/gal!; very high for the plains) after leaving the park while watching towers immediately to our W. Main tower was relatively mushy and orphaned several times. At this point, we had a sinking feeling inside, with several reports of a beautiful supercell and attendant tornado just outside of Topeka, KS. We decided to cut our losses and begin to head northeast on the KS turnpike. Just as we pull onto the turnpike, we began to notice signals of rapid strengthening (anvil knuckles/ radar echo tops). Unfortunately, we were now on the turnpike with no exits until emporia (figures). After backtracking to the storm, we were treated to a picturesque high-based supercell near El Derado. We then got back on the turnpike and paralleled the now looking multicelluar mess. Morphology of the storm through this next stage was rather interesting. Radar evolution suggests a split occurred, with two separate updraft echo tops. However, visually it almost appeared as if the "left split" was now beginning to slow and deviate to the right of the mean flow. This cell pulled a Pacman on the updraft to its southeast and merged into a beautiful bell-shaped monster. While it did not initially appear tornadic, Paul Sirvatka (CoD) noticed a small clear slot begin to cut from the west towards the location of the updraft (no great wall cloud or rotation was present at this time). We reported this via Spotter Network, and about 10 min. later a well-defined funnel began to form. We checked back in with the National Weather Service office in Topeka to let them know that a tornado appeared imminent. Tornado began to impact the outskirts of northeast Emporia and moved off into the countryside. We followed the storm to Reading, KS where we witnessed several power flashes and a new lightning illuminated elephant trunk tornado (we later found out that EF3 damage and 1 fatality occurred in Reading). The supercell had a beautiful bell-shaped appearance and was easy to see with some of the best lightning (anvil zits & CGs) I've ever seen. After this tornado occluded, Paul and I called off the "tornado" chase and hurried north on I-35 to get ahead of the storm (we had a hotel in KC in preparation for 5/22/11) to photograph lightning. A quick lightning pitstop near Wellsville, KS offered a "cherry on top" to a rollercoaster day. Met up with former adviser Walker Ashley and shared stories before calling it a night.
Initial high-based supercell
Supercell near Emporia, KS

Clear slot beginning to cut...
Wide shot of tornado as it moves northeast out of Emporia
Cherry on top!

Saturday, May 21, 2011

5/20/2011 Cold Pools & Cutoffs

Yesterday was the first 'good' chase day for the students enrolled in College of Dupage's ESAS 1800 experiential learning lab course as a vertically stacked 'cutoff' low has been creating unfavorable supercell environments across the Great Plains. We started the day in Norman, OK, with eyes on two potential targets (S central KS & N central TX). We opted for the northern target, which was characterized by marginal CAPE and less than ideal hodographs (backing in the upper-levels). While storms never exhibited any rotation and were surely not to be imminently tornadic, the bubbling CU up and over the cold pool along Hwy 61 between Pratt and Turon KS offered for a pretty view in the early evening hours. We finished the day off in Wichita's Oldtown district with steaks and beverages from Whiskey Creek Wood Fire Grill. Today (Saturday) looks like a play near the Flinthills in KS with tomorrow shaping up to be interesting in IA/IL. More pics later as we are about to leave for lunch...

Jeff and Paul discuss the importance of nanometers per fortnight
CU's bubbling up over the cold pool near Pratt, KS

Friday, May 13, 2011

5-13-2011 Gentelman's Chase

Didn't really expect much out of today as I am killing a few days in DeKalb, IL with my former roommate Ryan Coomer before heading out on another chasing expedition this weekend. We got on a multicell early that was interacting with a cold front and the lake breeze from Lake Michigan. The storm produced a brief wall cloud and made for a little excitement. A few good chase days in the southern Plains look possible in the offing...
Rugged wall cloud feature near Sycamore, IL

Almost had me excited...

Monday, May 9, 2011

5/8/2011 Consolation Prize

Capping inversion held most of the day across our initial target of E central Nebraska. A few cumulus started to exhibit vertical development near Oneil, NE, but quickly morphed into orphan anvils with a lack of focused convergence. Storms began to fire in a post-frontal airmass in S central South Dakota, so we drifted towards the border and our overnight location of Winner, SD. A stationary supercell north of Winner proved to be in reach (this storm was nearly stationary for over an hour), so we jogged north to investigate. This proved to be a consolation prize for a relatively frustrating day. Lightning was impressive, along with some great sunlit mammatus.

Friday, May 6, 2011

Sluggish Start to May

After Ma' Nature's vorticity frenzy in April, a slow start to May led to a day spent at Starved Rock State Park in Utica, IL. I highly recommend visiting this park for hiking and sightseeing if you are ever in the area. We will be leaving in the morning for the first day of a mini chase vacation while making a last minute decision on the typical north vs. south play. Better dynamics, low-level shear, and precipitation probabilities to the north, while better instabilities along the dryline to the south, albeit with a stronger cap. However, the southern play may lend to better positioning for storm prospects on Mon. and Tues. I'll likely make a last minute decision in the morning after looking at data.

Lovers Leap (looking NW)

Starved Rock Point (looking E)