2023 04/27

SWMI AMS/NWA Chapter Meeting Minutes

Thursday, April 27, 2023

West Michigan Aviation Academy

5363 44th St., Grand Rapids, MI 49512

Officers Present: Cort & Kim Scholten, Linda Paige and Andy Schut

Attendance: John Boris (speaker), Jim Carpenter, Bill DeVries, Sara Foernssler, Matt Kirkwood, Rachael Kornoely, Stuart Kutsche, William Marino, Bill Oosterbaan, Tom Oosterbaan, Aubrey Papkey, Bill Steffen, Gayle Steffen, Kreigh Tomaszewski, Warren Wheeler

Call to order: 7:03 pm

Cort Scholten gave the treasurer's report on behalf of Andy Schut. The Chapter reports $61.68 in the checking account and $843.66 in the savings account.

Officer terms run from June 1 to May 31. Nominations are expected to open via email soon, and elections will be held at the next meeting if needed.

The atmospheric environment for the day was captured by rawinsonde (weather balloons) launched at the NWS office, located to the south of Gaylord, at 1200 UTC (8 AM EDT) followed by a special launch at 1910 UTC (3:10 PM). The special sounding revealed a potentially unstable atmosphere with MLCAPE of 1945 J/kg, a reduced strength of convective inhibition since the morning sounding as surface moisture had increased with the warm front passing through, and a sickle-shaped low-level hodograph indicating good storm-relative wind shear present at the level of the storm's inflow.

The Storm Prediction Center placed the area in a Slight Risk of severe weather, with a 5% chance of a tornado occurring within 25 miles of a given point. Initially, large hail (including a relatively high chance of 2-inch diameter hail) and damaging winds were anticipated to be the greater severe threat, and a Severe Thunderstorm Watch was issued at 1:55 PM. The thunderstorms arrived in Northwest Lower Michigan on the Lake Michigan shoreline after 2 PM as a quasi-linear convective system, making damaging winds and the possibility of embedded tornadic spin-ups a primary concern. Severe thunderstorm warnings were issued around the Grand Traverse region, west of Gaylord, as pockets of damaging wind gusts were occurring. A severe thunderstorm warning which included the city of Gaylord was issued at 3:24 PM, 11 minutes before the tornado formed. Then a tornado warning was issued at 3:38 PM, 3 minutes after the tornado formed but 8 minutes before the tornado reached the city of Gaylord. The tornado dissipated at 3:55 PM but the storm progressed through Northeast Lower Michigan and over Lake Huron, producing 2 to 3 inch diameter hail stones. The tornado in Gaylord had a maximum estimated intensity along its path of EF3 with winds up to 150 mph, up to a 200 yard width, and a path length over 16 miles. There were 2 deaths and 44 people injured.

The thunderstorm complex's evolution as it crossed northern Michigan from quasi-linear with damaging winds, to a tornado-producing supercell, to primarily a large-hail producing cell, was discussed; including identifying several key features on radar. One working theory is the northern portion of the convective system may have modified the storm-scale environment ahead of the southern portion, as the bookend vortex in the north may have increased mid-level wind shear and cast precipitation forward, creating an outflow boundary at the surface and source of horizontal vorticity for the southern portion of the complex which eventually became the tornadic cell. A cyclonic bookend vortex was also present within the southern portion of the convective line which eventually morphed into the mesocyclone as the storm became supercellular.

In addition to there being several other support roles during severe weather, a core of meteorologists on duty serves as the radar analysis and warning decision team at the Gaylord NWS office and can be split between a land vs. marine warning focus, or a phenomenon (hazard type) focus depending on the day. On this day, there was one meteorologist focused on issuing marine warnings and two meteorologists focused on land-based severe and tornado warnings.

When it became apparent to every meteorologist in the office that a tornado would directly threaten their friends and family within minutes, the conversational tone in the office became more muted. Many friends and family members of NWS employees were in or very near the path of the tornado, as the city and nearby area has a population of about 6,000. It was the first time John had to tell his wife to get to the basement. While a tornadic circulation and debris signature was already apparent on radar for several minutes, the first visual sighting of the tornado was reported to the NWS office from an off-duty meteorologist at 3:46 PM as the tornado was entering the west side of the city. The tornado tracked in between a church and school building where one employee's wife and kids were located.

Interesting social science questions still linger. Tornadoes, especially significant ones, are rare in northern Michigan, such that the city of Gaylord does not have outdoor warning sirens. The last time there was a tornado warning in any portion of Otsego County (where Gaylord is located) was four years prior. However, many people in Gaylord received the Wireless Emergency Alert of the tornado warning on their phones. Yet some said they initially shrugged it off as "just a warning." Despite a warning, it is fairly common for people anywhere to seek an additional source of confirmation before they personalize the threat. Then in the aftermath of the tornado through the rest of the summer, people in Gaylord became more sensitive to any type of thunderstorm.

The meeting adjourned at 8:15 pm.