Rare March tornado rips Michigan; record March heat wave sets more records

As I stepped out of my front door into the pre-dawn darkness from my home near Ann Arbor, Michigan yesterday morning, I braced myself for the cold shock of a mid-March morning. It didn't come. A warm, murky atmosphere, with temperatures in the upper fifties--30 degrees above normal--greeted me instead. Continuous flashes of heat lightning lit up the horizon, as the atmosphere crackled with the energy of distant thunderstorms. Beware the Ides of March, the air seemed to be saying. I looked up at the hazy stars above me, flashing in and out of sight as lightning lit up the sky, and thought, this is not the atmosphere I grew up with.


Video 1. Video taped at Hudson Mills Metro Park in Dexter about 5:30PM on March 15, 2012, by Matthew Altruda from Tree Town Sound, http://www.treetownsound.com. Caution: foul language.

That afternoon, as the Detroit temperature soared to 77°F, the second warmest on record so early in the year, going back to 1871, I watched as late afternoon thunderstorms built with remarkable speed. Though NOAA's Storm Prediction Center had placed Southeast Michigan in their "Slight Risk" area for severe weather, I wasn't too concerned about tornadoes. We don't get many tornadoes in Michigan this early in the year, and certainly not strong ones. Prior to yesterday, there were only sixteen tornadoes on record in Michigan that occurred before March 16, going back to 1950. Though the air was remarkably unstable for this time of year, the upper level winds were not strong enough to generate much shearing action on the air, meaning that tornadoes would have a tough time getting spinning. But the atmosphere had other ideas. In a remarkably short half-hour period, a severe thunderstorm sprang up west of Ann Arbor, began spinning, and dropped a strong tornado down on the unfortunate town of Dexter, Michigan. The tornado skipped along a ten-mile path, damaging or destroying 128 buildings, but fortunately not causing any deaths or injuries. While most of the damage was light to moderate, thirteen homes were demolished, and preliminary damage estimates from the National Weather Service put the twister at the boundary between EF-2 and EF-3 strength, with winds of 135 mph. If confirmed as an EF-3, this would be the earliest EF-3 or stronger tornado in Michigan history, going back to 1950, according to data from The Tornado History Project. The previous earliest appearance of an F-3 tornado in Michigan was on March 20, 1976. At least two other tornadoes touched down in Michigan yesterday, making it the second largest tornado outbreak in state history so early in the year. The record outbreak for so early in the year was the eight tornadoes that touched down on March 12, 1976.



Figure 1. Radar reflectivity image (top) and Doppler velocity image (bottom) of the March 15, 2012 Dexter, Michigan tornado.


Video 2. This video report by AnnArbor.com's Nathan Bomey shows tornado damage in the Dexter, Michigan, about 90 minutes after the tornado came through on Thursday, March 15, 2012.

I talked to a friend in Dexter who relayed the story of her friend who was driving through town, saw the tornado, and pulled over into the Dexter car wash to take shelter. Some strangers living next door to the car wash yelled at him to come shelter in their basement, since the car wash didn't have a basement. He joined them, and was glad he did, because his car and the car wash were heavily damaged by a tree that was flung into it (see damage to the car wash in the video above.)

Hail, Hail, to Michigan
The Dexter storms also brought golfball to baseball-sized hail and a deluge of 4 - 5 inches of rain that caused street flooding in Ann Arbor. My Ph.D. advisor and co-founder of Weather Underground, Dr. Perry Samson, related this story to me: "I was traveling home by bus to go chase, but the bus came to a stand still at Michigan Stadium as cars were sunk up to their windows in water on Main Street. I told the driver I had to chase this storm, and came up with a story about what I do. He gunned the bus and drove through the flood to get me home. So I didn't actually commandeer a bus to chase the tornado, but it was darn close!"

Record Midwest March heat wave topples more records
For the second consecutive day, large portions of Illinois, Wisconsin, and Iowa, including the cities of Chicago, Madison, and Dubuque, recorded their all-time warmest temperatures for so early in the year. Perhaps the most extraordinary record occurred in Madison, Wisconsin, which hit 82°F--a temperature 39°F above average. It was the hottest temperature ever recorded in March, and three degrees warmer than any day so early in the year, going back to 1869. Not as many all-time hottest temperature records for so early in the year were set in Michigan and other surrounding states, due to plentiful moisture that generated afternoon cloud cover. The records will continue to fall across the Midwest for another week, as the ridge of high pressure responsible stays locked in place.

Major airports that set all-time heat records yesterday
For the second consecutive day, Chicago, Illinois hit 81°F; the warmest it's ever been this early in the year, going back to 1872, and 35°F above average. This ties the record set on March 12, 1990.

For the second consecutive day, Springfield, Illinois hit 83°F, the warmest it's ever been this early in the year, going back to 1879, and 32°F above average. This ties the record of 83°F on March 13, 1918.

Rockford, Illinois hit 82°F, the warmest it's ever been this early in the year, going back to 1893, and 36°F above average. Previous record: 79°F set the previous day.

Moline, Illinois hit 81°F, the warmest it's ever been this early in the year, going back to 1874, and 33°F above average. Previous record: 80°F on March 12, 1990.

Dubuque, Iowa hit 78°F, the warmest it's ever been this early in the year, going back to 1874, and 34°F above average. Previous record: 75°F set the previous day, and also on March 12, 1990.

Waterloo, Iowa hit 79°F, the warmest it's ever been this early in the year, going back to 1895, and 34°F above average. This ties the record set on March 7, 2000.

Madison, Wisconsin hit 82°F, the warmest it's ever been this early in the year, going back to 1869, and 39°F above average. This is also the warmest temperature ever recorded in March (tied with March 29th, 1986 and March 31, 1981), as is also (by two weeks) the earliest 80° reading ever measured there. The previous record for a temperature so hot this early in the year was 79°F set the previous day, on March 14, 2012.

Data for the previous records was taken from NOAA's National Climatic Data Center (NCDC).

I'll have a new post on Saturday.

Jeff Masters