Tuesday, January 12, 2010

Midwinter Intermission

Think of this as intermission, half-time (in honor of our remarkable Vikings). Old Man Winter isn't nearly through with us, he's just resting up for the Second Act. Make the most of our little mini-siesta from wind chill, snow and ice - because there is little doubt in my muddled mind that winter will come roaring back into Minnesota by late January and early February. With a little luck maybe it won't be quite as bad as late December and the first 11 days of January. We are roughly 2 weeks away from the date when the average temperature begins to CLIMB again, for the first time in 6 months. By late January the higher sun angle finally balances out the lingering snow and long winter nights, budging the thermometer higher. But the truth of the matter: we won't really begin to warm up (significantly) until we lose the snow, which can happen anytime from late March through early May, depending on the year. There's something to look forward to.

A Category 3 winter storm. Yes, the NWS is now rating winter storms. The Mid Atlantic storm that struck from December 18-21 was rated a "3" on a scale from 1 to 5. Makes me wonder what a Category 5 storm would look like. For a detailed explanation click here.

* Forecast for Sunday's Vikes-Cowboys game at the Dome: Partly sunny, high of 34. Vikes by 7.

Yesterday was chillier than predicted, a fickle inversion (warmer aloft than at ground-level) and a hefty 10" snow pack conspiring to keep temperatures a few degrees cooler than expected....20 in St. Cloud, 22 in the Twin Cities, just a notch above average, for a change. Out of the breeze it didn't feel half-bad out there yesterday, and today will be another big step in the right direction. I think we'll see enough of a southerly breeze (and sun peeking through) to partially break through that nagging inversion, and filter some of that milder, Pacific-originating air down to ground-level. That could be good for 30-34 degrees by mid afternoon. Yesterday the mercury held in the teens across most of southern and southwestern Minnesota, where there's 15-30" of snow on the ground. The thicker the snowcover, the cooler the temperatures. The air is literally refrigerated from below. In the coming days, in spite of a bulging ridge of high pressure and plenty of moderate Pacific air floating overhead, much of the sun's (feeble) energy will go into melting snow vs. warming up the air. That will limit just how high the mercury can climb, but it will still feel VERY NICE out there, with temperatures 10-15 degrees above average. The PM hours will be sloppy, mushy and wet on area highways - hard to see through muck-caked windshields at times. And I'm still a little freaked out about partial snow melt each afternoon, only to re-freeze each night as the temperature tumbles back into the upper teens to around 20. Be careful first thing in the morning - there may be some glaze ice on the driveway or sidewalk. Snowmelt may also lead to patchy (ice) fog at times, but that's about the only pint-size weather headache lurking out there through the middle of next week.

GFS Model for Monday, January 25. There is a potential for a significant storm for the Upper Midwest in about 10 days, give or take. Enough warm air may wrap around the storm (forecast to be centered over Iowa) for a changeover to ice and snow, especially across far eastern and southern Minnesota and much of Wisconsin.

After than the maps begin to look a bit more intriguing. The weather pattern across North America is undergoing a major transformation - rapidly evolving from the high-amplitude pattern that hurled Siberian air into the lower 48 states, to more of a zonal (El Nino impacted?) flow, characterized by storms taking a more southerly track across the USA, and milder, Pacific air engulfing the northern tier states, including Minnesota. The models are hinting at a little drizzle or freezing drizzle (yes, the lowest mile of the atmosphere may be just mild enough for a little liquid precipitation by the middle of next week, possibly freezing on contact with cold surfaces). Something to look forward to. Nothing worse than ice - ugh. By the weekend of January 23-24 a more substantial storm is forecast to lift northward across the Plains, treating Minnesota to a conglomeration of snow/ice/rain, with the greatest potential for a "plowable" snow over the northwestern half of Minnesota. It's still way too early to be speculating about precise timing or amounts - I want to see a lot more computer runs, see if the models are at all consistent in how they treat this series of southern storms. I think it's realistic to think that dry weather will prevail through at least Tuesday of next week, with the weather becoming increasingly stormy, and highways becoming increasingly messy/slushy/icy by the end of next week.

ECMWF (European) Model Output valid next Friday, Jan. 22. Check out the southerly fetch stretching from Texas northward to Minnesota, implying an ample supply of moisture from the Gulf of Mexico, which may translate into significant snow/ice/rain for much of the Upper Midwest. Note how the main core of the jet stream has shifted south, with major storms slamming into California, then taking a more southerly track across the USA - all possible symptoms of El Nino.

A few deep weather thoughts:

* This upcoming weekend may be one of the best weekends of the winter to get out and PLAY in the snow. Conditions should be excellent for snowmobiling, cross-country skiing and downhill, with very comfortable temperatures (highs within a few degrees of freezing statewide).

* A little rain/ice may cause snow conditions to deteriorate by the weekend of Jan. 23-24.

* The period of Sunday through Monday, Jan 24-25 may feature significant snow across much of Minnesota. We'll keep fine-tuning the forecast as the (potential) storm draws closer. For now it's a distinct possibility, nothing more.

* 40 degrees is not out of the question by the weekend of Jan. 23-24.

* No rerun of brutal, arctic air is showing up through January 29. After that all bets are off.

Not a great week to be visiting the UK. Check out the latest (visible) satellite image of England, showing snow stretching from Scotland and Wales southward to the London area. The UK and most of Europe is experiencing the coldest, snowiest winter in decades, snow observed as far south as the Mediterranean.

An unpleasant omen?
The "Burj" just opened up, officially, in Dubai, in the United Emirates. Thunderstorms in the Middle East are somewhat rare, so officials must have been scratching their heads when lightning (repeatedly) struck what is now the tallest building in the world. On second thought, maybe they saw this coming. For more (amazing) pictures of this freak lightning storm in the deserts of the UAE click here.

Paul's Outlook for the Twin Cities

Today: Partly sunny, milder. Winds: South 5-10. High: near 30

Tonight: Mostly clear, patchy (ice) fog possible. Low: 19

Thurday: Intervals of sun, feels like a real January Thaw. High: 33

Friday: Plenty of sun, 10-15 degrees above average. High: 32

Saturday: Mix of clouds and sun, still quiet. High: 34

Sunday: Storm-free, feels more like late Feburary. High: 33

Monday: Still mild for mid January, some sun. High: 35

Tuesday: Peeks of sun, still quiet. High: 36

Wednesday: Clouds increase - chance of a little drizzle or freezing drizzle. High: 34

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