Saturday, October 17, 2009

An historic first half of October

What's that old saying, "may you live in interesting times?" Yeah. Thanks a lot. If it's any consolation (doubtful) you just survived/endured a very unusual, statistically significant first half of October. According to our friends at the local National Weather Service in Chanhassen high temperatures the first half of October averaged 47 degrees (again, that's the high temperature averaged over 15 days!) It should have been closer to 63. That makes the first half of October the coldest on record - a distinction which extends to St. Cloud as well. Yes, we still have boasting rights for North America (some things never change). High temperatures averaged about 16 degrees colder than normal, whatever that is - the chilliest weather over southwestern Minnesota. It wouldn't be an exaggeration to say that the first 2 weeks of October were more typical for the kind of weather we normally experience in early November. Does this mean a nasty, nose-numbing, shovel-bending, harsher-than-usual winter is imminent? In a word: no. In fact the National Weather Service Long Range Prediction Group is sticking to their guns and forecasting a milder winter than usual, thanks to a strengthening El Nino (warming of equatorial Pacific water). The fact that we got slapped with harsh, cold and snowy weather so much earlier than usual actually bodes well for a few more episodes of Indian Summer. Yes, I think we'll experience a few more 60s, a few more days of shirtsleeve weather and jumbo smiles over the next few weeks. In fact a few towns close to home may sample 60 later today and again Monday of this week. Today doesn't look to shabby, with dim sun through high clouds, a southwesterly breeze whipping up, and highs reaching well into the 50s - typical Autumn weather for Minnesota.

Departure from Normal for high temperatures, Oct. 1-15. Southwestern Minnesota saw the biggest swings away from normal, readings averaging 18-20 degrees colder than normal for the first half of the month. Statistically this is very significant, but doesn't necessarily mean a colder winter is a sure bet.

Computer models show a fairly impressive storm approaching from the high Plains by midweek, the chance of a cold rain increasing Tuesday, the wettest period coming Wednesday into a portion of Thursday. I think it should be just warm enough aloft for a rain event, at least for the southern half of Minnesota. Some wet snow may wrap into the storm, especially north of Brainerd, but I don't think we'll have to worry about any more slushy accumulations piling up close to home, at least not this week. My comfort level with the Climate Prediction Center's mild outlook for most of the winter isn't high, to be honest. Even though we have an El Nino brewing only 2 out of 3 El Nino events result in warmer winters for Minnesota and Wisconsin. The lack of sunspots on the sun has me a bit distracted/concerned. There's a strong correlation between a lack of sunspots and colder than normal weather, and this could be another important factor. Frankly I HOPE the CPC is right, and we do, in fact, experience fewer arctic outbreaks (and plenty of snow). I sure wouldn't bet the farm on the long, long-range outlook. Too many variables, too many things which can go wrong. Frankly, we have our hands full with the 7-Day Outlook, which is tough enough most weeks.

Enjoy the fading sun, try to sneak outside for an hour or so tomorrow, and get ready for a soggy midweek, heavy jackets returning within 48-72 hours. After what we've just muddled through we can be forgiven for celebrating 50s and 60s!

Precipitation for the first half of October. More than 3-4" of rain soaked much of central and southern Minnesota from October 1-15. Snowfall so far in October: 2.5" in St. Cloud and a whopping 2.8" in the Twin Cities.

* A big thank you goes out to my friend and colleague Todd Nelson, who's been filling in for me for well over a week. I went on a short Caribbean cruise earlier this week (when the flakes were flying across Minnesota, and yes, I do feel some guilt for being away. It'll go away - I hope). I'm at Penn State right now, where I got my meteorology degree many, many years ago. We have season tickets, and we try to get back for a few games every year - my son, Walt, also attends PSU. He's a senior this year, and I'm sure he LOVES it when his parents drop in to say hello! Today was a slushy adventure, Penn State digging out from the earliest heavy snowfall on record, a good 4-6" of snow fell Thursday and Friday, making for especially challenging conditions for Saturday's football game with the Gophers. For the first time ever tail-gating was canceled, which is a little like postponing Christmas. Thousands of revelers in RV's had nowhere to go (normally they all camp out in adjacent fields next to the stadium, where they set up their grills and celebrate until gametime). Not this year - it was mayhem. Anyway, you've been in very capable hands with Todd at the helm, and I want to thank him for doing such a great job while I was away.

NOAA's Winter Outlook. Based on a strengthening El Nino in the Pacific warmer than normal temperatures are predicted for most northern tier states, including Minnesota. A chiller-than-normal winter is forecast for much of the south and southeast. Stay tuned.

Normal Jet Stream position during an El Nino winter. The prevailing westerlies tend to be suppressed to the south during most El Nino episodes, favoring a storm track mostly south/east of Minnesota, milder Pacific air crossing the Rockies into the Upper Midwest. Roughly 2 out of 3 winters tend to trend warmer than average for Minnesota, with considerably less snow than usual (normal snowfall is 50-55"). For more detail and a great explanation of El Nino's impact on Minnesota winters click here for more information from the National Weather Service.

Paul's Outlook for the Twin Cities

Today: Partly sunny, breezy and milder. Winds: S/SW 10-20+ High: near 60

Tonight: Partly cloudy. Low: 44

Tomorrow: A mix of clouds and sun, turning slightly cooler later in the day. High: 62

Tuesday: Clouds increase, chance of a shower late. High: 53

Wednesday: A cold rain likely. High: 46

Thursday: More rain (mixing with wet snow over northern MN). High: 44

Friday: Intervals of sun, a drier day, still cool though. High: 48

Saturday: Some sun, a few degrees warmer. Not bad. High: 52

Sunday: More clouds, a light rain-snow mix possible. High: 45

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