Sunday, August 16, 2009

Pretty good (for a Monday)

An early morning celestial sight!

This morning, Aug. 17th, Venus and the crescent Moon will gather in the eastern sky for a beautiful close encounter. For many observers in North America, the International Space Station (ISS) will make an appearance, too. It's a dynamite way to begin your day. (credit: spaceweather.com)

Good news: the pattern seems to, in fact, be shifting - for the better. The drought does seem to be easing, the rains have returned in recent weeks, the showers and T-storms we should have experienced much of June and July have finally decided to show up, now that summer is mostly over. The drought won't ease overnight - it will take 3-6 months to pull out of this dry rut, maybe longer.

August Rainfall to date

St. Cloud: 3.12" (+1.24")

Twin Cities (MSP Airport): 3.73" (+1.56")

Eden Prairie: 5.05" (+2.88")

St. Paul: 3.85" (+1.68")

Why the improvement? Instead of prevailing winds blowing from the west to northwest, out of Canada, forcing wet storms to detour well south of Minnesota much of July, our steering winds are now more variable, switching around from southerly to westerly to northwesterly, back around to the southwest - all these variations helping to spark the atmospheric shoving matches necessary to squeeze out significant moisture. Hopefully this is not a fluke, but a trend, and we'll continue to see slow, steady improvement in the coming months, but any kind of widespread end of the drought probably won't happen until sometime in 2010. And remember, I'm the naive optimist.


Paul's Outlook for the Twin Cities


Today: Morning/midday sunshine. Clouds build this afternoon with a passing shower or two. Winds: SW 10-20. High: near 80

Tonight: Clearing skies, cooling off. Low: 54

Tuesday: Bright sun, still breezy (and less humid). Odds favor a dry day. High: 78

Wednesday: Becoming cloudy with showers, possible thunder. High: 76

Thursday: Cooler with more clouds than sun, windy with PM showers popping. High: 74

Friday: Partly cloudy, breezy and cool. High: 76

Saturday: More sun, warmer. High: 79

Sunday: Sunshine lingers, probably the better day to be hanging out by the lake or pool. High: 82



WRF/NMM Predicted Rainfall from 7 am to 1 pm today - dry weather prevails across Minnesota during the morning and midday hours, the atmosphere still quite dry (and stable).

WRF/NMM Rainfall Prediction from 1 pm to 7 pm today, hinting STRONGLY at more showers, and possible T-showers firing up in response to the sun's heating of the ground and a fairly strong "lapse rate" overhead, temperatures cooling with altitude faster than usual. A 30-45 minute shower or T-shower is possible later today, but I don't expect an all-day rain.

WRF/NMM Projected Temperatures at 7 pm this evening. Note late-day readings near 80 over Mankato, but holding in the 50s over far northern Minnesota, a 25 degree temperature contrast from north to south whipping up west/southwest winds as high as 20-25 mph. later this afternoon.

The front that sparked Sunday's heavy, wind-whipped showers and northwest gusts to 30 mph (tell me the truth, do you think Tiger Woods was a little freaked out about our weather yesterday? I swear it helped to contribute to his shaky putts and drives toward the end) is long gone - northwest winds behind this wind-shift line pumping cooler, cleaner, more comfortable Canadian air back into Minnesota. The sun should be out this morning and most of Tuesday, temperatures fairly close to average for mid August. A few instability showers, even a stray T-shower may sprout this afternoon, especially over the northwestern half of Minnesota. Tomorrow looks sunnier, drier (and more stable - probably no late-day convection popping up). Computer models print out nearly a half an inch of rain Wednesday with showers lingering into Thursday, an unusually cool wrinkle of air may have us reaching for light jackets and sweatshirts late in the week, especially up north. But conditions slowly improve over the weekend with sunshine on the increase, temperatures mellowing - Sunday probably the warmer, more lake-worthy day the way things look right now.

The odds of severe T-storms are fairly small; low-level moisture will be sparse, the fuel necessary for hail-producing storms not present in sufficient quantities. I guess I could see some pea or marble-size hail with a few storms Wednesday and Thursday, but probably nothing bumping up against the 1" diameter (quarter-size) threshold.

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