Sunday, May 23, 2010

Hot - Steamy - Thundery

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

Today: Hazy sun, very humid with a few strong/severe storms by late afternoon. Winds: S 10-20. High: near 90

Tonight: Thunderstorms, some locally heavy rain possible. Low: 73

Tuesday: Still unsettled with more clouds than sun, a few more showers/storms around town. High: 88

Wednesday: Slight relief, more sun, just an isolated shower as a cool front moves through. High: 86

Thursday: Plenty of sun, noticeably less humid. High: 85

Friday: Lot's of sun, comfortable - beautiful May day. High: near 80

Saturday: Probably the better day of the weekend as sun gives way to increasing clouds. High: 81

Sunday: Showers and storms, locally heavy rain possible. High: 76

Memorial Day: Getting sunnier, less humid. High: 78

Sunday Almanac. There was just enough sun for a record-tying 88 degree high in the Twin Cities Sunday, St. Cloud registered a respectable 85, only 54 in Grand Marais, where there will NOT be a run on air conditioners anytime soon.

Even with the (stubborn/obstinate) cloud deck that hung around WAY too long on Sunday the mercury was able to soar to a record-tying 88 in the Twin Cities, just enough PM sun for temperatures to brush 90 on some bank thermometers late in the day (with humidity levels and dreadful dew points that made you want to evacuate to your favorite lake or pool). Instant-summer. A severe storm watch was issued for northeastern and parts of east central MN, there were some reports of quarter-size hail over the MN Arrowhead, but no tornado reports that I could find.

Lightning Tracker. Vaisala has a free site here that allows you to see where cloud to ground lightning is being reported. The only hitch: it's delayed 20 minutes. If you need more recent data they'll be happy to sell you a premium service!

Today will be just as hot, sticky and unsettled, an even better chance of nicking 90 by mid afternoon (if the sun is out for at least 3-5 hours, which sees likely). The atmosphere is still explosively unstable, enough juicy air from the Gulf of Mexico to fuel another spirited round of strong to potentially severe storms by late afternoon. Severe weather is most likely around the dinner hour, between 4 pm and 8 pm, right after the daytime "high", when surface temperatures are warmest, the differential between hot air at ground-level and chilly temperatures aloft most extreme. This is when warm, rising thermals, bubbles of sun-warmed air, can punch through an inversion and mutate into swirling thunderheads, towering cumulonimbus clouds, CB's.

Breathing Easier. One or two more days of stuffy, steamy air direct from the bayous of Louisiana, then some relief by midweek as winds swing around to the west/northwest. By Thursday dew point temperatures dip into the 50s, possibly even the 40s, meaning HALF as much water in the air - much more comfortable air is just a few days away.

The fickle frontal boundary wavering back and forth over Minnesota will finally get an eastward nudge on Wednesday, the showers dry up, and sunshine increases the latter half of the week with a welcome drop in humidity. No dew point-babble by Thursday and Friday, a surge of fresh air is about 72 hours away.

Sunday Soaking? I hope the GFS is dead-wrong, but right now long-range models (admittedly shaky) are predicting 1-2" rainfall amounts next Sunday, as a slow-moving cool front limps across the state. Saturday looks ok, sun giving way to increasing clouds - too early to make a semi-educated guestimate about Memorial Day. What can possibly go wrong?

What about the weekend? It will fall on a Saturday and Sunday, in fact next weekend is super-sized, Memorial Day weekend, when most of us will be up at the cabin, entertaining family or guests, hoping and praying to be able to salvage some quality outdoor-time fishing, boating, grilling, soaking up some late May sun. It's early but right now Saturday appears to be a decent day, some sun giving way to increasing clouds, highs topping 80 in southern Minnesota, possibly holding in the 70s up north. The GFS model brings a significant front into the state Sunday, printing out 1-2" of rain. I hope the model is off - WAY off, and the weekend forecast will undoubtedly change in the coming days as new data comes in, as we fine-tune that all-important holiday weekend forecast.

The GFS is indicating that this next (Sunday) front is progressive, meaning it should keep sailing to the east, it probably WON'T stall out overhead, meaning a fairly good chance of sun returning Monday with a drop in humidity, highs in the 70s to near 80. Right now Saturday and Monday look like the best outdoor days.

Too early to panic (or celebrate). Hey - no snow, no frost, the odds of an all-day washout are pretty small this time of year (the front would have to stall for us to see a true rain-out Sunday). Can't rule that out, but let's force ourselves to stay optimistic - I'll keep you posted as best I can, right here. For now dress light, and watch for some rough storms brewing by late afternoon - it's ripe for more watches and warnings, and this time it may be closer to the metro area. To say we're long overdue for a severe weather outbreak would be a grotesque understatement. So I won't say it.

Volcano Update. I'm relieved that this is one thing we won't have to worry about (unless you're planning a flight to Europe anytime soon). For the very latest on the (fickle) Icelandic volcano click here.

Time Lapse. O.K. I realize a volcano is not "beautiful" in the classic sense. Impressive? Awe-inspiring? Yes, without a doubt. To see some amazing time-lapse footage click here.

* Scientists Reassert Man's Role in a Changing Climate: a story in the Wall Street Journal here.

* America's Climate Choices: recent papers from the National Academy of Science here.

Interactive Weather. Ham Weather, a division of WeatherNation, has a free service that allows you to see an interactive map with radar, watches/warnings, satellite imagery, even nearby webcams. You can zoom into a specific metro area, animate the maps, see radar in motion - pretty good stuff. And it won't cost you a nickel.

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