Nonprofit, nonpartisan journalism. Supported by readers.


2009: fewer tornadoes than average

* 20s the next few days.* No major storms in sight (here) but accumulating snow possible next week just south/east.* Even colder after Christmas? A few subzero daytime highs are possible after Dec. 26.* Expect a white Christmas.

* 20s the next few days.
* No major storms in sight (here) but accumulating snow possible next week just south/east.
* Even colder after Christmas? A few subzero daytime highs are possible after Dec. 26.
* Expect a white Christmas. No thaws showing up on the weather menu anytime soon.

My first Minnesota tornado. I snapped this photo at 8:26 pm on Saturday, August 8, from my dock in Tonka Bay, facing west, towards Mound. You can see a tornado in the center of the screen. There were no watches or warnings when this twister formed, a reminder that, during some severe storm scenarios you’re on your own. Use common sense: if you see a wall cloud, funnel or tornado, even if the sirens aren’t sounding, take evasive action and err on the side of safety.

There was a silver lining to Minnesota’s nagging drought and cooler-than-average summer. The tornado count was significantly lower than average: according to the National Weather Service a total of 24 tornadoes were observed in the sky above Minnesota during calendar year 2009. Nearly all of the tornadoes were “minimal” EF-0 and EF-1 twisters, with winds under 100 mph. But two tornadoes were slightly more significant: an EF-2 that hit near Austin on June 17, on the ground for nearly 10 miles. Another EF-2 tornado hit Swift Falls on July 17, on the ground for a path length of 8 miles. During a typical year closer to 30-35 tornadoes touch down, with a higher percentage of EF2-3 storms capable of more significant damage. Keep in mind much of Minnesota was experiencing moderate to severe drought conditions much of the summer. That, and we never really had a superheated, super-muggy spell with highs consistently in the 90s and dew points above 70. We dabbled at 90, but a lack of extreme heat, humidity, instability (and wind shear aloft) all contributed to an easier-than-usual tornado season.

24 Minnesota tornadoes in 2009. Most of the tornadoes that formed in the sky over Minnesota were minor, EF0 and EF1, with wind speeds under 100 mph. The EF-2 tornadoes that struck near Austin and Swift Falls had estimated winds of 95-135 mph, capable of more significant structural damage.

This summer I saw my first Minnesota tornado. I had seen 3 in Oklahoma (I did tornado-chasing stories for KARE-11 in 1985 and again for WBBM-TV in Chicago in 1995). But I had never seen a twister close to home, until Saturday, August 8, around 8:30 pm. I was just finishing up dinner, staring out the window, looking west, toward Mound. The sky was scrappy and foreboding, the air still, muggy and ripe – you could just feel the pent-up energy in the atmosphere. No watches, no warnings, but I knew the atmosphere was very unstable with sufficient wind shear (changing wind speed/direction with altitude) to support a marginal tornado. I looked out the window again and thought I was hallucinating. “Is that a wall cloud?” Sure enough, the cloud base was lowering toward the lake. At this point adrenaline kicked in – I grabbed one of my cameras and ran down to the dock. By the time I got down to lake-level a funnel was visible off to the west, maybe 2 miles away, hard to be sure. What struck me was the number of boats on ‘Tonka, even the big Al and Alma tour boats cruising by, totally oblivious to what was unfolding just 1-2 miles to the west. So I’m down there on the dock and the sirens start to sound, about 45 seconds later my 2 boys, home for summer break, and my wife (Laurie) come running down to the dock, telling me they just saw a tornado warning on KARE-11. I said, “yep, that’s right. There’s the tornado right there!” They were so excited they started jumping up and down, so on my footage you hear me shouting “stop jumping! stop jumping!” Oh well, it was a cheap thrill – happy that nobody was injured, but damage was fairly significant, especially in the Orono and Wayzata area, a blunt reminder that tornadoes can and will hit the metro area.

Classic “Hook”. On radar tornadic “supercell” thunderstorms (rotating, spinning like a top) often show up with a distinctive signature, resembling a hook, or the number “6” on radar. Such was the case with the small EF-0 tornado that formed near Mound and then tracked across Orono into Wayzata on August 8. This image is from GR2 Analyst, an amazing Doppler program that you can load up onto your PC (for a reasonable fee). Click here to learn more about GR2 (and no, I don’t get a commission). It’s just a damn fine software program, and I want to give credit where credit is due.

The other memorable tornado was the one that hit South Minneapolis around 2 pm on August 19, 2009, footage captured (exclusively) by one of our WeatherNation meteorologists, Kristin Clark. She spotted a lowering, rotating wall cloud and began shooting with her iPhone. Once again: no watches, no warnings, no lightning, no hail…. but just enough vorticity (spin) in the atmosphere to whip up a brief tornado. Downright freakish. BTW, the link for the South Minneapolis tornado is here.

Minnesota tornado count since 1950. Why does Hennepin county seen 4 times more tornadoes than Ramsey county? It’s not a local “tornado alley”, it’s a function of the size of the county. The bigger the county, the greater the frequency of tornado touchdowns. The safest place to hang out during tornado season? Cook county: only 2 tornadoes since 1950, the result of consistently chilly, stable winds blowing off Lake Superior during the summer months. All that free air conditioning tends to kill off the potential for twisters.

East coast snowstorm this weekend? Heading to D.C., Norfolk or Richmond this weekend? Computer models are hinting at a “plowable” snowfall for parts of the Carolinas and Virginias Saturday into part of Sunday. The NAM model whisks the storm quickly out to sea, sparing the major east coast cities like Philadelphia and New York. But the GFS solution (above) shows the storm hugging the coast, throwing down a fresh carpet of white along the eastern seaboard. If you’re flying/driving east this weekend stay up on the very latest forecasts.

Christmas Morning 2009. The extended (GFS) outlook is printing out a major storm (mostly rain) for the east coast by Christmas. A swath of moderate/heavy snow is possible from St. Louis and Chicago to Detroit, Pittsburgh and Buffalo, deeper into the cold air. Again, if your travels take you south/east of Minnesota next week you’ll want to stay up on the very latest forecast updates. It could get very interesting out there as early as the upcoming weekend. Mercifully (or not) it appears that Minnesota will miss most of the moisture – but not the cold. If you thought the beginning of the week was brutal, just wait….immediately after Christmas we may have a spell where highs don’t go above zero for a few days, nighttime lows in the -10 to -25 F range. The period from Christmas to New Year’s may be one of the coldest weeks of the entire winter.

Wednesday Almanac. High: 12. Low: 0

Paul’s Outlook for the Twin Cities

Today: Clouds increase, light winds. Winds: SE 3-8. High: 24

Tonight: Patchy clouds, not as cold as recent nights. Low: 13

Friday: Mostly cloudy, few flurries, steadier light snow far northern MN. High: 26

Saturday: Mostly gray, a little light snow late in the day, no more than a dusting. High: 25

Sunday: Better chance of light snow/flurries, dusting or coating possible. High: 23

Monday: Partly sunny, windy and colder. High: 19

Tuesday: Numbing sun, cold again. High: 16

Wednesday: Mix of clouds and sun, dry for Minnesota (snow possible Iowa into Illinois, Michigan, even Wisconsin). High: 17

Christmas Eve: Patchy clouds, nothing more than a few flakes, a bit milder. High: 24