The Central Illinois Chapter and the Indiana Chapter of the American Meteorological Society held a joint meeting at the Beef House restaurant in Covington, Indiana on Thursday, June 27, 2003.  Approximately 40 were in attendance from both states, traveling from as far away as Lincoln in Illinois and Mishawaka and Muncie in Indiana. 

This meeting is an annual tradition as many members enjoy the pilgrimage to the Beef House, often listed as the “Best Steakhouse in Indiana.”   This year the food and service lived up to their reputation. 

Central Illinois President Ed Kieser opened the meeting at 6:30 PM with some pre-dinner welcoming remarks.  After dinner Ed Kieser and Dr. David Arnold, President of the Indiana Chapter, each spoke about upcoming events.  Both mentioned that the next meetings for each chapter will be held in September, with the Indiana Chapter meeting at WISH-TV in Indianapolis, IN and the Central Illinois Chapter meeting at Weldon Springs State Park in Clinton, IL.  Details on dates and times will be announced later in the summer.  Elections for officers will be held for each chapter at the September meetings.  Announcements were also made on preparations for the Midwest Extreme and Hazardous Weather Region Conference to be held in Champaign on October 17-18, 2003. 

The speaker for the evening was Dr. Jeff Trapp, recently appointed as Associate Professor of Earth and Atmospheric Sciences at Purdue University.  The title of his presentation was New Insight into Tornadoes and Damaging Winds with Squall Lines and Bow Echoes. 

Dr. Trapp started his presentation by showing a radar reflectivity image of a “quasi-linear convective system” (QLCS) from near Jackson, Mississippi on November 11, 1995.  This squall line produced an F3 tornado.  Most of the time we think of tornadoes as coming from parent storms that are individual cells, particularly super cells.  Yet, many tornadoes do occur with squall lines.  The speaker indicated that we should care about studying tornadoes associated with squall lines and bow echoes because (1) tornadoes can occur anywhere along an extensive line, (2) radar precursors are not as clearly understood for tornadoes associated with lines, so there tends to be less lead time for warnings, and (3) the climatological characteristics of squall line tornadoes are unknown, such as whether these tornadoes are weak and short lived, whether they occur with the same frequency as “cell” tornadoes, and whether they occur at the same general time of day. 

To determine the climatological characteristics of QLCS tornadoes, the following steps were followed: (1) gather tornado reports from Storm Data online, (2) use composite radar reflectivity images to classify each parent storm type as cell or line, (3) repeat steps 1 and 2 for all tornadoes during 1998-2000, and (4) analyze the results.  For 1998-2000 there were 3827 reported tornadoes in the continental U.S.  Of those, 80% were classified as having a parent storm as a “cell,” 18% as from a “line,” and 2% from “other” types like hurricane rainbands. 

In terms of tornado intensity, there were fewer F0 tornadoes reported than expected for lines.  The speaker speculated that F0 “line” tornadoes might be underreported, perhaps due to low visibility or that many might occur at night. The distribution of tornadoes by local time showed the typical peak in the late afternoon and evening for “cell” tornadoes.  For “line” tornadoes the frequency was also greater in the afternoon and evening, but the overall distribution was more even, with indeed many more “line” tornadoes occurring at night than “cell” tornadoes. 

In Illinois and Indiana, a higher percentage of tornadoes were reported from lines than the national average.  From 1998 through 2000 there were 274 tornadoes reported in Illinois and Indiana, with 59% from cells and 41% from lines, compared to 80% to 18% ratio nationally. 

More needs to be learned about QLCS tornadoes as it was found that (1) a high percentage of QLCS tornadoes occur in certain geographical areas, such as in Illinois and Indiana, (2) such tornadoes can be strong or violent, although they are rare events, for both line and cell classifications, and (3) QLCS tornadoes frequently occur during nighttime hours.  At night there is less warning information due to the spotter value being diminished and there is poorer warning dissemination as many affected citizens are sleeping. 

Next, Dr. Trapp spoke on damaging non-tornadic winds with squall lines and bow echoes.  He presented Fujita’s (1985) conceptualization of high-wind generation in (type “B”) bow echoes and asked if it tells the whole story.  He used the Klemp-Wilhelmson Model to simulate a damaging QLCS.  The model was initialized using a high value for CAPE and moderate low-level shear. 

The simulated squall line evolved into a bow echo with “straight-line” surface winds found at the bow-echo apex and additionally in association with numerous low-level mesovortices.  For certain environmental shears, the mesovortex-induced winds are more damaging in terms of intensity, duration, and areal extent that are the descending rear-inflow winds at the apex. 

Finally, research is continuing in part with the Bow Echo and MCV Experiment (BAMEX) this summer.  Dr. Trapp’s objectives from BAMEX include conducting detailed aerial and ground surveys of wind damage following bow echo events and relating the severity and scale of damage to (radar observed) location/structural characteristics.  They recently collected good data from a case on 31 May 2003, and look forward to analyzing data from BAMEX. 

After questions the meeting adjourned at about 9:15 PM. 

-Ed Kieser 

On the evening of 9 April 1953, an historic tornado-producing thunderstorm developed over east central Illinois. It wasn’t the severity of the tornado that made it historic, however, even though it was quite intense. Operators of a weather radar at the Illinois State Water Survey (ISWS), University of Illinois, detected a “hook echo” on that historic night, which was the first documented to be due to a tornado. 

The Central Illinois Chapter of the American Meteorological Society commemorated this event with a special meeting hosted by the Illinois State Water Survey. Over 60 attendees listened to an overview of radar meteorology both at ISWS and throughout the U.S., culminating in the development of the WSR-88D network. This overview was given by Steve Hilberg (ISWS). Three ISWS employees at the time of this historic observation were honored at this event, including Don Staggs, Glenn Stout, and Stan Changnon.  Don Staggs described what occurred on that day and the next morning when he reported it to others in the program. He showed videos of 1) several of the radars operated by the Survey during that time period, 2) damage caused by the storm, and 3) a time-lapse video of the hook echo itself. Glenn Stout described the evolution of the atmospheric sciences program at the Illinois State Water Survey at that time and discussed the major goals of the radar-related projects.  Stan Changnon could not be present.  Each of the special guests was presented letters of acknowledgement from the national Executive Director of the American Meteorological Society.

President Ed Kieser opened the meeting at 6:45 PM and outlined some of the major activities of the Chapter. Of particular interest is the Midwest Conference on Severe and Hazardous Weather, which is being organized by Vice-President Mike Tannura. While the conference is still months away, keynote speakers have already been lined up: Dr. Louis Uccellini (Director of NCEP), Dr. Gregory Forbes (Severe Weather Expert, The Weather Channel), and Dr. David Robinson (New Jersey State Climatologist).  The latest on the conference can be found at http://www.c-il-ams.org/conf.htm.  Other chapter news included efforts to update the Chapter By-Laws, upcoming chapter elections, and an essay contest for school-aged children organized by Dr. Walter Robinson, Department of Atmospheric Sciences, University of Illinois in Urbana-Champaign. 

The meeting adjourned around 9:30 PM. David Kristovich

The fourth meeting of the Central Illinois Chapter of the American Meteorological Society was held at Cheddars Restaurant in Decatur, IL. The meeting began at 7:00 PM on Wednesday, 12 March, 2003. Our guest speaker was Mr. Ron Przybylinski, Science and Operations Officer at the National Weather Service Forecast Office in St. Louis, MO. Mr.  Przybylinski spoke about the upcoming Bow Echo and MCV Experiment (BAMEX) field project. 

President Ed Keiser opened the meeting and discussed upcoming meetings for the chapter, while continuing to appeal for attendees to pay their dues for 2003. Mike Tannura, Vice President and organizer of the planned Midwest Conference on Severe and Hazardous Weather, discussed the rapid progress being made to plan for this regional conference. Several special invited speakers have accepted our invitation to attend and conference registration costs are being calculated. Keynote speakers include Dr. Louis Uccellini (head, NCEP), Dr. Gregory Forbes (The Weather Channel), and Dr. Robinson (Rutgers University).  Dave Kristovich distributed draft minutes from the January 2003 meeting and Mary Schoen Petersen reported that there were 37 dues-paying members. 

Bow echoes and mesoscale convective vortices are important components of the severe weather season in the U.S. Midwest.  The guest speaker for the night, Mr. Ron Przybylinski, is an organizer of the field experiment to collect a comprehensive dataset on these phenomena. Data collected by stationary and mobile radars, P-3 aircraft, a mobile integrated profiler, mobile sounding systems and a mobile mesonet will be used to better understand and ultimately predict these important convective phenomena. The project is centered at Mid-America Airport near Belleville, IL, from May to June 2003. 

The meeting adjourned around 9:15 PM. David Kristovich

The third meeting in a very active year for the Central Illinois Chapter of the American Meteorological Society was held at Chevyís Restaurant in Champaign, IL. The meeting began at 6:30 PM on Monday, January 13, 2003. Our guest speaker was Mr. Michael McClellan, founder of Mobile Weather Team, Inc. The evening began with guided tours of the Mobile Weather Van, which serves as the base of operations for many of the Mobile Weather Team on-site weather forecast support services. The van allows for receipt of real-time weather data and a location to brief clients on current and predicted weather conditions. 

Mobile Weather Team, Inc. was created in 1991 with only two employees, Mr. McClellan and his wife. The team has now grown to 13 full-time meteorologists. While the Mobile Weather Team offers weather support services for a large number of events, they are particularly well known for their work for major golf tournaments, including the PGA and LPGA tours. Mr. McClellan discussed many of the advantages and disadvantages of forecasting for events at a single location. Forecasting for a single location allows for particularly detailed predictions that can be greatly improved by knowledge of local weather peculiarities. 

One of the most important weather dangers for golf tournaments is lightning.  Mr. McClellan discussed the current understanding of lightning, particularly emphasizing issues related to forecasting and lightning dangers. He pointed out that people will react to rain by running for cover, but will often be slow to take cover when there is a threat for lightning, despite the greater danger. He went on to say that the population often forgets that lightning can occur far from the stormís rain shaft. He and his Team have had much success on short-term lightning forecasting using a Thor Guard lightning prediction system. 

In other AMS business, updates were given on two important coming events sponsored by the Central Illinois Chapter. In early April, the Chapter will sponsor an evening meeting commemorating the 50th anniversary of the first documented radar observation of a hook echo associated with a tornado. The Illinois State Water Survey, who will be hosting the evening meeting, took this historic observation. Finally, on 17-18 October 2003, the Chapter will host the first Midwest Regional Conference on Severe and Hazardous Weather. Keynote speakers are being lined up for the conference and advertising is well underway. The meeting adjourned around 9:30 PM. --- David Kristovich 

The Central Illinois Chapter met at The Depot Restaurant in Lincoln, Illinois on 12 September 2002. The business meeting consisted of elections, dues, and discussion on a possible conference to be hosted by the chapter. Dr. David Kristovich presented "Mesoscale Weather Systems Triggered by the Great Lakes." 

Dr. Kristovich briefly outlined some of the major wintertime and summertime mesoscale storms that occur due to the Great Lakes. He outlined some of the most common lake-effect snowbands and the environmental conditions in which they occur. He also discussed data collected during the recent Lake-Induced Convection Experiment (Lake-ICE), which are giving important insights into the processes involved in lake-effect storm development. Finally, Dr. Kristovich presented initial results of a COMET-funded study of thunderstorm evolution in the vicinity of the Lake Erie lake breeze front. Two cases were presented; one with storm intensification near the front and another with storm weakening near the front. This COMET study is in collaboration with the NWS Office in Cleveland, OH.---Scott Kampas.