Wednesday, March 10, 2010

Impending Flood Warnings

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

Today: Dense fog, patchy rain and drizzle. Winds: NE 10-15+ High 49

Tonight: More fog, more rain and drizzle. Low: 40

Friday: Periods of rain, becoming showery. High: 47

Saturday: Mostly gray, damp, a few light showers linger around town. High: 48

Sunday: More clouds than sun, an isolated shower or two (but drier overall). High: 48

Monday: Partly sunny, unseasonably mild. High: 50

Tuesday: Intervals of sun, more like early April. High: 51

Wednesday: Snow is mostly-gone, fading sun, hints of spring. High: 53

Weather Photo of the Day. Don't try this with your own Zamboni. Yes, the photo pretty accurately tells the story. For more (vaguely embarrassing) details of the mishap at Keystone Lake, Colorado click here.

* The NWS has issued the first (local) flood warning for the South Fork of the Crow River, below Mayer - affecting portions of Carver County. The complete text alert is here. A comprehensive outlook for all of Minnesota's rivers can be found here.

An Increasingly Bad Feeling. Computer models are hinting at another 1 to 1.25" of rain over the next 84 hours across much of southwestern MN, where the most snow remains on the ground (with the exception of Lake Superior's North Shore). There is still 4-8" of liquid water wrapped up in the snow pack near Windom and Marshall - a sudden thaw coupled with moderate/heavy rain will increase the risk of significant, potentially major, flooding on the Red River and Minnesota River. The Twin Cities "Spring Flood Monitor" web site from the local NWS office is here.

One Mixed Up Weather Pattern. Wednesday's high in the Twin Cities was 42, but only 38 F at Redwood Falls and 40 in Rochester - both towns have more snow on the ground. One of the warmest spots: International Falls (50 F) with some mid 50s observed over the Minnesota Arrowhead. Bizarre, huh? Click here to see Minnesota's latest climate information.

Is there anywhere else you'd rather spend your summer than Minnesota? I defy you to find a more glorious spot on the planet from May through October. the lakes, the green, the fishing, boating, biking - the weekly pilgrimages to the cabin. Before the flame-mail arrives, let me preface this by saying that I enjoy every month (except for maybe February). A change of seasons is invigorating. I happen to like the snow, a couple of Polaris snowmobiles makes a snowy day a true adventure, the blue runs on Minnesota's ski resorts good enough for this mediocre skier.

24 Hour Rainfall. Doppler Radar estimates show some .50 to .75" amounts south of Mankato Wednesday, amounts decreasing the farther north you travel across the state. For the latest rainfall amounts and flood updates from the NWS click here.

More than anywhere else in North America (with the possible exception of Fairbanks and remote regions of the Yukon) Minnesotans take NOTHING FOR GRANTED. When the sun comes out and the mercury hits 70 in Denver, Phoenix or L.A. local smile - and shrug. No big deal. Business as usual. But here? Forget 70, we get giddy when the thermometer first hits 50. Vital layers come flying off at breakneck speed, people wander outside in inappropriate clothing choices, showing entirely too much skin, celebrating the first (not-as-cold) front limping north. Here in the Land of Low Weather Expectations we cheer on weather that would horrify other Americans. Every spring I'm amazed that a). the spring green-up arrives right on schedule, and b). we treat every sunny, lukewarm day as if it's a minor meteorological miracle. I've said it before, we EARN our springs (and summers). If every day was a vacation-day you might (eventually) lose interest. The crazy extremes and crummy, foul weather we endure much of the year makes our summers extra-special. We tolerate the watches, warnings and advisories, knowing full well that a Norman Rockwell Summer awaits.

Wednesday Highs. The chilliest readings: southwestern MN, highs in the 30s, the result of more snow on the ground, chilling the air from below. Peeks of sun (coupled with a lack of rain) lead to highs in the low 50s over northeastern Minnesota Wednesday.

The rain will hang on - possibly through the weekend, the weather pendulum swinging in the other direction after more than 3 consecutive weeks of sunshine, light winds (and usual air pollution alerts). So we slog through a runny, sloppy, rainy week (some of us giving thanks that the mercury isn't 10 degrees colder - meaning we don't have to dig out from a potentially back-breaking 6-12" snowfall).

If I appear a little blue in the gills in the weather videos it's because I'm holding my breath. On some level thrilled that we'll probably bask in the low 50s tomorrow - but simultaneously nervous about the implications of this rapid thaw/significant rain event on Minnesota's streams and rivers. No flooding is imminent, but with a frozen, saturated ground - all this melting snow will run off into area tributaries, and at some point there will be implications for the meltdown. Hydrology, river forecasting, is a science within a science. The local National Weather Service office in Chanhassen has a team of river forecasters doing nothing but analyzing water content in the remaining snow, depth of the frost layer, formulas for tracking mild temperatures and the rate of snow melt - feeding this into supercomputers to try and estimate the timing and extent of inevitable river flooding days - weeks from now.

First 50s? The rain will finally migrate to our east by Sunday or Monday, high pressure settling over the Upper Midwest, enough sun to coax the mercury above 50, for the first time since late November. The more snow we melt, the more of the sun's energy can go into warming up the air vs. melting snow. We may see a streak of low, even some mid 50s, the first half of next week. Low 50s are typical for the first week of April, btw.

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