Wednesday, February 17, 2010

Loading the Dice?

Weather Factoids

Forecasting a snowfall: the bigger the better. Wait a minute. Snow + TV = Ratings? Amazing! For a big dose of what you probably already knew click here.

Sportsmen key in global warming debate. Do the recent snowstorms in Dallas and D.C. refute climate change, or are these extreme events more evidence? Hunters and fishermen are already noticing changes, literally out in the field. For more click here to read a story from the Sioux Falls Argus Leader.

Minnesota's evolving winters. According to Professor Mark Seeley at the U. of Minnesota the frequency of ice events in January and February have QUADRUPLED since 2003. Coincidence? Maybe. For more details click here.

An Upside Down Winter. Classic El Nino winters are on the right, showing a trend toward cooler south and warmer north. But this winter has been an extreme case, with temperatures as much as 10 degrees warmer than average across Canada, some 8-10 degrees colder for the southeastern USA. This takes "odd weather" to an entirely new level.

El Nino is in full swing, loading the weather-dice to favor more frequent, moist and intense storms across the southern and eastern USA. Freakish one foot plus snowfalls for Dallas, 80+" of snow in the suburbs of Baltimore, so much that authorities have run out of places to push the slush. Although every El Nino event is unique, the vast majority favor milder, drier weather over the northern tier states of the USA and Canada. Vancouver's blooming cherry blossoms and slushy ski runs are just the tip of the iceberg. Canada is enjoying /enduring the 3rd warmest winter on record as Pacific steering winds push well inland, boosting temperatures as much as 10 degrees F. warmer than average since early January. Meanwhile, numbing air from the Arctic Circle has been draining south across Hudson Bay and Quebec, circulating all the way into the Great Lakes and New England. In recent weeks these prevailing winds, the core of the jet stream, the main superhighway for storms, has been running from California to Oklahoma, Memphis and D.C., taking a detour well south of Minnesota. At some point the storm track will shift north again, but I don't see that happening through at least the first week of March. Our winter weather siesta will continue another 10-14 days. Good news for travelers. Bad news for snow lovers (although it won't warm up enough to melt significant snow anytime soon).

An Historic Snowfall. 40-45" in a 5 day period? This high-resolution satellite image was taken days after "Snowmageddon", showing the bright, intense white of fresh snow across the Mid Atlantic States (vs. the scalloped white of low clouds off the east coast).

The weak bubble of high pressure responsible for a week's worth of sunshine and temperatures a good 5 degrees above average (two days above freezing with dripping icicles!) will hang on through Friday. Once again today we may eclipse freezing under a partly-blue sky, a light northwest breeze, the sun as high in the sky as it was back on October 23. If you wander outside into direct sunlight you can really FEEL the difference now. We're picking up 1-2 minutes of additional daylight every day, average temperatures are on the rise, and with each passing day the risk of subzero weather drops off rapidly. I seriously doubt we'll see another subzero daytime high, although a couple more subzero lows are likely before warm fronts have the strength to reach this latitude.

Loading The Dice? Climatologists tell us that there is an estimated 5% more water vapor in the air today than there was a generation ago. A warmer atmosphere can hold more water. There is a growing body of evidence that this spike in water vapor is sparking more extreme precipitation events: flash floods, river flooding, and potentially increasing the odds of major snowfalls. Proving cause and effect with the atmosphere is never straightforward, and many factors may be involved, including a moderate to strong El Nino causing the storm track to temporarily "lock" over the southern and eastern USA. A complicated puzzle? You bet.

Paul's Conservation MN Outlook for the Twin Cities

Today: Plenty of sun, still milder than average. Winds: NW 5-10. High: 32

Tonight: Partly cloudy, still quiet. Low: 15

Friday: Less sun, more clouds, dry. High: 29

Saturday: Mostly cloudy, a few flurries possible. High: 27

Sunday: Overcast, more flurries, nothing more than a dusting. High: 26

Monday: A period of very light snow/flurries, maybe a coating. High: near 30

Tuesday: Flurries giving way to partial clearing, gusty winds. High: 26

Wednesday: Mostly sunny and chilly. High: 22

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