Earliest Tornado for Milwaukee, Wisconsin | March 2000

Mar 07, 2012
Southern Wisconsin is experiencing a pleasant first week of March with mild temperatures across the region. This early start of nice weather reminded me of the warm weather Milwaukee felt the first week of March in 2000. The city had many days reaching high temperatures in the 70's. The warm weather continued, until a cold front swept through on March 8, 2000 that brought a rare, early season tornado southwest of Milwaukee at the General Mitchell International Airport. Let's take a look back on how that day unfolded.

A low pressure system featured a strong cold front and dryline, worked its way into Wisconsin and Illinois during the afternoon hours. A Tornado Watch was issued for most of the area by the Storm Prediction Center highlighting the threat of tornadoes. What was unique about this storm system was the presence of a strong dryline that provided the focal point for convection. Usually this front is confined to the southern and central plains. The dryline had initiated "mini-supercells" that raced northeast over 50 mph across Illinois and Wisconsin.

There was a specific storm that developed in northern Illinois and had its sights for the Milwaukee metro. The National Weather Service (NWS) had issued a severe thunderstorm warning for Milwaukee County noting the severity of the storm. I left work as this event was unfolding, and I could see the mini-supercell to my east, moving fairly fast and producing ominous flashes of intra-cloud lightning. Soon after, the NWS upgraded the storm to a tornado warning. Within minutes of the newly issued warning, reports on the car radio were coming in of a tornado on the ground near the Milwaukee Airport. The tornado path began on the northeast part of the airport runway and traveled through the intersection of Layton and Pennsylvania Avenues. Damage was confined to businesses, homes and gas stations.

The base reflectivity radar image (shown above) notes the storm hooking at its southwest flank as it entered Milwaukee County. This radar signature is called a hook echo, which indicates rain is wrapping around the rotating updraft. The velocity radar image (shown below) clearly illustrates the reds and greens, bright and close together indicating strong rotation. The tornado dissipated after 10 minutes just before moving out over Lake Michigan and was rated an F1. What made this weather event interesting? It was the earliest occurrence of a tornado to hit Milwaukee since 1840. That's over 160 years!

Many thought Wisconsin would be plagued by tornadoes in 2000 due to an early start to the tornado season. 18 tornadoes were confirmed by the National Weather Service across Wisconsin that year which is slightly below the Wisconsin average of 23. Interestingly, Milwaukee County was hit by another tornado on July 2, 2000, however there hasn't been another twister since. Can we expect a repeat of severe weather this March like we did in 2000 due to the early warm temperatures? It's probably not likely. No major synoptic storm systems are expected in the long range forecast, but the warm temperatures look to continue across the Milwaukee area for the next week and possibly beyond.

Radar Images provided by GRLevel3

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