Sunday, June 21, 2009

Partly soggy Father's Day

Yep, looks like a weekend out there. Welcome to the official first day of summer (it arrived at 12:45 am in case you forgot to celebrate). Today marks the magical Summer Solstice, the day the sun is higher in the sky than it ever gets in the Northern Hemisphere - in theory, the best day of the year for a sunburn. That won't be much of a problem today - you'd have to work pretty hard to wind up with a memorable burn out there with thickening clouds and a good chance of showers, even some embedded thunderstorms, by midday and afternoon.

I wish I had better news for dad. This is, after all, his day, and if you forgot to send out a card (like I did) at least pick up the phone and call your pop. An e-mail is just too lame, make an effort! At least dad won't have to do any watering today; an area of disturbed weather surging into Minnesota from the south will wring anywhere from .5 to 1" of rain on much of the area today, the best chance of a cool, soaking inch or more of rain coming over central Minnesota, from Mankato and Willmar to St. Cloud and Little Falls. The pattern is marginal for severe weather; SPC has only extreme southeastern Minnesota in a "slight risk" (see below), but the atmosphere may be just unstable enough for a few claps of thunder during the afternoon hours. From Austin and Rochester to the La Crosse area, on the warmer, more unstable eastern side of this disturbance, there may be enough additional wind shear and heating of the ground for large hail and a few isolated reports of wind damage, even a fleeting tornado, but right now it does not look like a widespread outlook.



Although the sun is strongest today, historically, our hottest weather of the year usually lags the Summer Solstice by about 3-4 weeks, usually coming the latter half of July. That may be true, but we'll get a pretty good taste of the Dog Days come Monday and Tuesday as the mercury surges into the low 90s. Factor in a dew point near 70 (if you must) and the "humature", the temperature-humidity index, may approach upper 90s, even 100 degrees. Leave it to a meteorologist to leave you feeling worse than you thought possible. In the winter its the dreaded wind chill. Now we have "humature". Oh well, a couple weeks ago we were all pretty much praying for a hot spell. It's almost here.

SPC outlook for Sunday showing a slight risk of severe thunderstorms extending into extreme southeastern MN, including Rochester, Austin, Albert Lea and Winona, where wind profiles and additional heating of the ground may be sufficient to spawn a few isolated storms capable of large hail and damaging winds.

WRF outlook for 7 am today. A sunny start is likely up north, in the lakes region, but people living in Windom, Pipestone and Fairmont may wake up to puddles. Get out EARLY if you want to beat the rain.

WRF forecast for 1 pm Sunday showing the heaviest showers/storms stretching from southwest into central Minnesota, maybe some 1"+ rainfall amounts from Redwood Falls into St. Cloud and Willmar. It should be raining in St. Cloud and the Twin Cities by midday.

WRF temperature prediction for 1 pm today, showing cool 60s over much of southwestern and central Minnesota, where the heaviest, steadiest rain is predicted. This time of year thick cloud cover and rain can make a 15-20 degree difference in temperatures. Warmer weather is expected over southeastern Minnesota and far northern counties, where precipitation will be spotty and more showery.

WRF prediction for 7 pm today. The heaviest showers/storms spread into Little Falls, Brainerd and Wadena. A few storms far southeast may be strong to severe, but any severe weather will affect a tiny percentage of Minnesota, well under 1/2 of 1% of the state.

Weather Headlines

* 84 degree high on Saturday, 86 in the Twin Cities.

* Today: rain likely, best chance midday into the evening hours, over 1" for much of central MN by late tonight.

* Slight severe storm threat far southeastern Minnesota later today.

* 90 degree+ highs Monday and Tuesday, heat index may approach 100 south/west of the MN River.

* Turning slightly cooler and less humid the latter half of the week.

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