Saturday, May 22, 2010

Suddenly Summer

Tornado Tales. Andy Gabrielson from Severe Studios captured this footage of a powerful tornado near Pierre, South Dakota - as many as half a dozen individual tornadoes touched down. That frontal boundary will push east, possibly sparking a few strong/severe T-storms across Minnesota by mid/late afternoon on Sunday. It's ripe for some watches and warnings - stay alert and check into updates throughout the day. Yes, we are due.

Wild Saturday Evening. The storms that bubbled up near Bowdle, South Dakota (Edmunds County) spun up a few tornadoes, with numerous reports of damaged farms, toppled powerlines and a few impassable highways, because of debris on the roads.

Saturday Almanac. In spite of the morning rain (sorry - really thought the storms would stay over far northern/western MN, but those storms rippled all the way east along a vigorous warm frontal boundary) the mercury hit 77 in St. Cloud, 82 in the Twin Cities, and 86 at Redwood Falls. Contrast that with a BRISK 55 at Grand Marais. What spring?

Paul's Conservation MN Outlook for the Twin Cities and all of Minnesota

Today: Hazy sun, windy and hot (very muggy!) A few strong/severe T-storms possible by late afternoon/evening. Winds: S/SE 15-25. High: near 90

Sunday night: A few lingering T-storms. Low: 73

Monday: Partly sunny, still breezy and hot - VERY humid (dew points near 70). High: near 90

Tuesday: More clouds, unsettled and sticky - another round of heavy T-storms. High: 88

Wednesday: Mostly-gray, showers and T-storms around town. High: 85

Thursday: Partly sunny, another shower or T-shower, but starting to dry out. High: 83

Friday: Better, sunnier - no blobs on Doppler. High: 82

Saturday: A mix of clouds and sun, a bit more humidity - chance of late-day thunder? High: 84

Welcome to the Dog Days of May, more like instant-July. A warm frontal boundary surging northward across the Upper Midwest will continue to ignite strong/severe thunderstorms today. Tornadoes touched down across the Dakotas late Saturday - although the dynamics won't be quite as impressive Sunday, I could still see a few rough storms bubbling up. The best chance of thunder: early Sunday morning, and again late afternoon. There should be enough midday and early afternoon sun for highs well up in the 80s to near 90. Pack a little Dramamine for the boat ride - it'll be choppy on your favorite lake as winds gust from the south/southeast at 20-30 mph, a lot higher than that if severe storms mushroom by the dinner hour. Stay alert and stay tuned for possible watches and warnings.

No Need to Water. The latest NAM model prints out over .50" of rain for the metro area, with a bulls-eye of over 1.5" from near River Falls, WI to Red Wing. We'll see, that just may be some noise in the model, but it points out the obvious: summer "convective" (showery) rainfall amounts are extremely fickle and variable. One town picks up over 1" of rain in 2 hours - 10 miles down the road the sun is out and people are wondering what all the fuss is about.

Severe Risk. Most of Minnesota is in a "slight risk" of severe storms Sunday - but the greatest risk is farther south and west, closer to Sioux Falls, South Dakota - where the possibility of isolated tornadoes is greatest. Keep an eye on the sky - I expect some watches/warnings later today.

Have you invested in a NOAA Weather Radio yet? During the day, when you're up and around, you can get critical information you and your family needs from TV, radio, the Internet (sirens if you're outdoors), your cell phone - a lot of options. The problem is during the overnight hours, when some of us are trying to grab a few winks of sleep. Although late-night tornadoes are rare, these are the twisters that cause a disproportionate number of injuries and deaths, catching people totally unprepared. The ONLY technology that will wake up you up, in the middle of the night, with a tornado warning for YOUR county, is NOAA Weather Radio. They start at $30, you can pick them up at Radio Shack or online - it's worth repeating: it's the cheapest life insurance you'll ever buy, a little additional piece of mind on these warm, muggy, partly-threatening days.

Models print out nearly 1" of rain by Tuesday, the best chance of heavy rain coming from this evening through lunchtime Monday as that dying cool frontal boundary stalls right over Minnesota. It should dry out (a little) by Thursday and Friday, temperatures cooling off, humidity levels dropping off to more tolerable levels. But today, with highs near 90, and a dew point of 64-67, it will feel like mid summer out there. Time to evacuate to the beach, pool or lake - but keep a wary eye on the western sky. Things may get lively out there later - this morning the greatest risk is downpours and lightning - the greatest potential for severe weather comes between 4 pm and 8 pm, right after the hottest weather of the day, when the atmosphere drifting overhead will be most unstable.

Have a great Sunday!

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