Good day all,
Full chase report details can be seen at the link below...
http://www.sky-chaser.com/mwcl2008.htm#MAY1
Summary is below...
This was both a chase trip and vacation combined, with the chasing focused on a significant severe weather setup from Kansas and eastward, with May 1-2 being the best chase prospects, according to computer forecasting models 4-5 days prior. The decision to tackle this setup was made about 3 days before the actual departure on April 29, and utilized some "reward points" for my frequent-flyer program, so not much was at stake. I was most interested in May 1, where a classic dryline setup, and lee cyclogenesis would set the state for a severe event in Kansas. I was able to get tickets to fly from Fort Lauderdale, Florida to Kansas City, Missouri (with a stop in Tampa, Florida) and car rental from the same destination. The original plan was to fly out on April 29, head west to NW Kansas / SW Nebraska (for a slight and very conditional probability of storms there) on April 30, then chase the "big setup" in Kansas on May 1. May 2 was also to be a chase day farther east, but was not pin-pointable at the time. From May 3-5, the plan was to head to Chicago after chasing as no storms were expected those days, and spending vacation Tim there, then returning to Kansas City early on May 5, and returning to Florida that same day from Kansas City (airport).
After arriving in Kansas City on April 29 and getting the car rental, I headed west on I-70 to spend the night in Abilene, Kansas. On April 30, I headed west to Hays, KS anticipating that the intense 500 MB trough, over N California the day before, would begin affecting the high plains after clearing the Rocky Mountains (via a lee trough and subsequent lee cyclogenesis). Moisture return was the big problem with this prospect, so the target (SW Nebraska) was abandoned and some sight-seeing near highways 183 and 136 (Harlen County Lake in Nebraska) was done instead. The forecast for the following day was still promising, so a track back along 136 east to highway 75, then south through Holton, NE, and eventually into Lawrence, Kansas via highway 24 to spend the night.
May 1 was to be the main chase day for this trip. The original target area, after much forecasting, was to be near Chanute, Kansas, which was about 80 miles south on highway 59. Two other target areas existed as well, one near Sioux City, Iowa (way to the north) and another in central Oklahoma. All looked good, with a departing low to the north, and more cyclogenesis expected to the southwest. Dewpoints finally began re-bounding, and reached the mid 50's. Meanwhile, a strong south / southeast wind was blowing in response to the developing low and winds aloft began increasing. By mid day, a dryline boundary began establishing itself near Wichita. Another main concern was the cap (inversion) over both the Kansas and Oklahoma targets. This forecast was not an easy one to say the least, but I wanted to stick with my original plan of SE Kansas. I waited in Chanute for a few hours waiting for the signs of the cap breaking, while communicating with fellow chasers Tony Laubach and Tim Samaras in Wichita at the time.
With signs that the cap was about to break, I continued west out of Chanute at about 4 PM on highway 39. Meanwhile, the Storm Prediction Center (SPC) had the area I was in outlooked at a moderate risk of severe storms, with 5% tornado, 45% severe hail, and 30% severe wind probability. The hail outlook was hatched meaning significant (2" or larger) was possible. Another 5% tornado outlook was for the farther north area in SW Iowa. SPC issued Mesoscale Discussion (MD) 758 and then tornado watch box 244 including SE Kansas by 5:30 PM, valid until 1 AM CDT. After heading west on highway 39 / 400, the dryline boundary was encountered. Dewpoint dropped from 57 to 48 and a line of towering cumulus was noted to my west. I dropped south on highway 99 to near Howard. This is where a large towering cumulus field was noted to the south. In mere minutes, the cap breached and this mass of agitated cumulus quickly and explosively developed into a supercell storm near highway 160 SW of Fredonia by 6 PM. This storm began by producing large hail, some as large as tennis balls.
The storm moved northeast, eventually affecting areas in Wilson County near highways 160 and 75 (Fredonia, Benedict, and Altoona). The storm produced several wall clouds, then funnels / possible tornadoes. There were MANY chasers on this storm, including the ROTATE team, Doppler On Wheels (DOW) truck and new Tornado Intercept Vehicle (TIV II), and many others. A tornado was observed with this storm while it cycled through an intense HP stage near the intersection of highways 39 and 75 at about 8 PM. The storm was continually followed until about 10 PM past Chanute and into Allen county. The storm weakened afterwards. The chase was wrapped up on this supercell and I tracked back north on Highway 59 and 169 to spend the night in Ottawa (where Tony Laubach and Tim Samaras were also to stay after back-tracking to Wichita to pick up a rental vehicle). I was able to shoot some lightning still images from along highway 31 between highways 59 and 169 along the way. I arrived in Ottawa, KS where an intense squall line raced through about midnight, with winds gusting over 70 MPH. Tim and Tony decided to spend the night in Wichita. The plan was to head into SE Missouri (and possibly S Illinois) on May 2 as the intensifying system would make an even higher tornado threat there (SPC was already forecasting a 15% hatched probability).
After spending the night in Ottawa, I got up very early anticipating a long drive east. I was rather disgusted to see that the squall line, which pretty much erases any storm chasing prospects in its wake due to the cool air pool, has pushed all the way across to the MO / IL border (near Saint Louis). Tim Samaras and Tony Laubach, who were going to chase with me, decided to call it off. I decided to continue east, passing through Kansas City by 8:30 AM, and east on I-70 making Saint Louis by 11:30 AM. Saint Louis was "decision time", should I take my chances going south, to E Arkansas, still 4 hours away, or just make my way north to northern Illinois? The target area for May 2 was not only "hosed" by the cool pool in the squall lines wake, but now confined to an area in eastern Arkansas, parts of west Tennessee, and NW Mississippi. It became apparent that with on-going convection and the area now being too far south, it would be both impossible and impractical to continue south (via I-270 then I-55), so that target was abandoned. Attention shifted to the north, to near eastern Iowa, NW Illinois, and SW Wisconsin. A small area of warmer air was in place there, and a strong occluding low (over Iowa) with great upper-air support (strong winds, cold air aloft, 500 MB DVA) above it.
I got east of Saint Louis and headed NORTH on I-55 instead of south, crossing the Mississippi River and into Illinois. The squall line was far enough east of the area to allow clearing and (hopefully) heating of the boundary layer air. Sure enough, the Storm Prediction Center issued a new outlook for the northern (new) target, and had a 10% probability of tornadoes. Subsequently, MCD 778 and tornado watch box 252 was issued at 4:30 PM CDT for the area and points north (valid until 10 PM). Tim and Tony also considered chasing this setup as well, as they needed to go to Minneapolis on May 3 anyway. With this seeming to be a promising cold-core setup, I headed up I-55 to Springfield, IL then took I-74 through Peoria and north to I-88. Much towering cumulus was encountered in this region, with a strangely-oriented cold-front / shear axis extending from NW to SE and a warm front ahead of that extending WNW to ESE. Surface winds ahead of the warm front were SE, but S ahead of the cold front, and SW behind that, so there was little room for "backed" winds. Highway 78 was taken north of I-88. Two things were noted. First, the warm front spawned some small "mini supercell-like" cells that were highly sheared and visible to my north, but did not develop any farther. Second, a cluster of strong storms developed to my west near Stockton, IL at the point where the warm front and cold front intersect.
The developing storm was observed while crossing into Wisconsin from Warren, IL and produced strong winds and small hail near Gratiot, WI. It began acquiring some supercell characteristics, with a small RFD clear area, and wall cloud / small funnels. After that, the storm quickly became linear and weakened as the cold front and warm front, now both oriented NW to SE, occluded near Argyle, WI. The chase was wrapped up with a track east to highway 15, then I-39 to I-90 (toll) to make my way towards my planned stay in the Chicago area. This pretty much wrapped up my chasing, and started my short get-away in the windy city. Meanwhile, the original southern target, that was fouled by the cool pool and abandoned because of lack of interest in chasing in Arkansas (trees, rivers, squall lines with little or no development ahead of them - That's my experience at least), became the prolific tornado producer ;-(
The remaining time was spent in Chicago until my return on May 5. The original plan was to leave on the early morning of May 5 and drive back to Kansas City (about 8 hours) for my trip back to Florida. With gas prices so high and my connection (from Kansas City to Florida) happening to be in Midway (Chicago's smaller airport), I decided to pay a little extra on the rental and return the car in Midway on the evening of May 5 and take the connection (simply not get on the plane in Kansas City). I arrived back in Fort Lauderdale, Florida during the late evening of May 5.
