Thursday, March 4, 2010

Saturday Slop-Storm

Ice potential Saturday night? Although temperatures should stay above freezing most of Saturday night, Sunday morning lows will be in the 28-32 F range, and some roads may be icy/slushy, especially north and west of the Twin Cities. Be careful if you're heading to church first thing Sunday, watch the bridge overpasses (cooling from above and below accelerates ice formation) and some of the secondary roads.

Melting fast. Check out the latest high-res satellite image of the Upper Midwest and Great Lakes. Most of the white on the map is snow on the ground (some cloud cover mixed in across the Dakotas). Snow extends as far south as the suburbs of Kansas City, although most of the Great Lakes are ice-free, a bit unusual for early March. To see the latest image from NOAA click here.

Saturday system. Granted, it doesn't look terribly impressive - and the next weak storm will move too quickly to tap much moisture from the Gulf of Mexico. From space storms look like comma clouds (or question marks, especially to dumbfounded meteorologists). The bottom line: the atmosphere over southern MN should be warm enough for mostly rain. But some wet snow may mix in from St. Cloud and Monticello into the northern suburbs and western Wisconsin, possibly enough to slush up some roads late Saturday night and early Sunday. The very latest infrared satellite image (which measures the temperatures of the surface below, the coldest, thickest, heaviest-precipitation-producing clouds show up as bright white) is here.

And suddenly the wild, wicked winds of winter are in our rear-view mirror. At least for the foreseeable future - which is 15 to 20 days, give or take. How did this happen? We shovel our way through 13" of snow during the first 2 weeks of February, slapped around by sloppy southern storms and a family of windchill-stinging clippers. Then the sun comes out (and stays out) for the better part of 3 weeks, high pressure camped overhead, unusually light winds whipping up day after (endless, magnificent) day of blue skies, tinged with the faint whiff of smog. That's right, we're still under an air pollution health advisory, although a stronger weekend breeze coupled with precipitation should ease our stagnant air within 24-36 hours a bit. Let me get this straight: enough snow to shovel and plow from central Texas to the suburbs of Atlanta, 4 FEET of snow in some of New York's suburbs in February alone, and we're dealing with air pollution? Strange, but true. But wait, there's more! In the 80s I distinctly remember being lectured on the snowy vicissitudes of March, then the snowiest month of the year in Minnesota. I distinctly remember hushed whispers, talk of the dreaded "Tournament Storms". Beware, the meteorological ides of March...

Dueling weather models. Now you know why Minnesota meteorologists tug at their (gray) thinning hair. 4 different models: 4 different solutions about how much rain will fall Saturday night. In such a scenario it's smart to go for the average: somewhere around .20 to .25", give or take. If it falls as all snow (however unlikely) it would be 2-3". The more likely outcome: a cold rain, tinged with wet snow from near St. Cloud into western Wisconsin.

We waited 3 weeks - for this? The fairly reliable NAM model prints out a coating to 1" of slush from near St. Cloud and Monticello on east to Mille Lacs, maybe 1-2" of slushy snow across parts of west central Wisconsin Saturday night and early Sunday morning. South of I-94 precipitation is forecast to fall as mostly-rain.

It's official: winter has been neutered, at least until further notice. Subzero weather? Still possible, but the odds roughly equivalent to the chance of yours truly spontaneously grow new hair. Doubtful. The sun is as high in the sky as it was in early October, daylight increasing by nearly 2 minutes/day. The more snow that melts, the more of the sun's energy can go into heating up the air instead of melting the dirty, stubbly glacier in your yard. It's a feedback cycle, and it bodes well for spring-weather-lovers. Daytime highs consistently reach 40 through much of next week, nights dipping below freezing every night insuring that potholes will expand into pot-craters by month's end. Now there's something to look forward to.

Saturday night puddles? All the models bring a trough of low pressure across the state late Saturday; the lowest mile of the atmosphere should be just warm enough for mostly rain, at least south of a rough line from Willmar to Elk River to Taylors Falls. The models print out .20 to .30" of rain - and although a coating to 1" of slushy snow can't be ruled out from St. Cloud, Wadena and Little Falls to the Mille Lacs area (and the far, far northern suburbs of MSP) this should be a rain-event for most of the area. One caveat? Saturday night lows will be close to freezing, so rain may freeze into glaze ice. Watch the bridges and side streets late Saturday night and first thing Sunday morning.

I could build a sand castle with the grit in my garage - anxious to think ahead. Spring break. Tax time. Forget tax time, sorry to bring that up. Twins Opener. Fishing Opener. Get the dock in. Open up the cabin. The next few weeks will fly by, so let me be the first to congratulate you on surviving a ho-hum, fairly average winter of '09-10. Looking back it wasn't really all that tough; we're averaging warmer than average, a few inches of snow less than normal to date. So far: 40.9" - but keep in mind that average March snowfall is close to 10". I don't see any accumulating snow for the Twin Cities looking out through mid March, in fact the GFS model brings a chance of moderate/heavy rain into town the middle of March, highs in the low, even some mid 40s - consistently - through the middle of the month. More cold fronts? Yes, but the potential for sustained (nanook) weather, highs in the teens/20s with nights dipping below zero? I don't see it. I think we've turned a very big corner. El Nino may be to thank for taking the edge off our late winter weather.

It's a little premature to be babbling about spring fever, but I honestly can't help myself, and chances are you can't either. It's programmed into our DNA. We exhale at 30 F, celebrate 40, 50 is cause to hug a complete stranger, and God help us all if the mercury spikes to 70 anytime soon. All bets are off if that happens (especially along Minnesota's streams and rivers). For many valid, logical reasons I'm hoping for a nice, gradual, reasonable thaw.

Weather Stories

"Monster Wave." Click here to see video of the incredible rogue wave (25-30 feet high?) that hit a cruise ship in the Mediterranean Sea - unexpectedly I might add. At least two people on the cruise ship were killed with the wave crashed through the ship's windows, possibly crushed by furniture whipped up by the churning water.

"Undersea arctic methane could wreak havoc on climate". Click here for a bizarre story about what's lurking deep beneath the sea - methane is 17 times more potent than carbon dioxide - this may have some implications in the ongoing climate puzzle.

"Glacier melting a key to tracking climate change". An interesting story from Reuters here.

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

Today: Fading sun, breezy, still very pleasant for early March. Winds: SE 10-15. High: 43

Friday night: Partly to mostly cloudy. Low: 26

Saturday: Mostly cloudy, rain late in the day and at night, possibly mixed with wet snow. High: near 40

Sunday: Ice/slushy start outside of the metro, lingering clouds, drizzle? High: 41

Monday: Becoming partly sunny, a brighter day. High: 42

Tuesday: Plenty of sun, still above average. High: 41

Wednesday: Sun giving way to increasing clouds. High: 42

Thursday: Another chance of rain. High: 43

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