Thursday, September 9, 2010

A Spike in Extreme Weather Events? (and improving weekend weather)

* Rain likely later today and tonight, models hinting at a third of an inch.

* Damp, gray start to Saturday - skies start to brighten by afternoon (dry after 9 am).

* Sunday: warmer, sunnier day - highs should reach well into the 70s.

* 4th warmest summer on record across the USA, 10th wettest summer for Minnesota. More details in the blog.

Report Links Severe Weather With Global Warming. On Wednesday Environment Minnesota released a detailed report focusing on the (increasingly strange) weather we're witnessing worldwide, from record tornado counts in Minnesota to historical flooding in Iowa, it seems like every other day another region is experiencing historically significant weather. Connecting the dots is complex, and although no single event can be linked to climate change, a warmer, wetter atmosphere (4-5% increase in water vapor measured worldwide) seems to be loading the dice in favor of more numerous and extreme weather events. More from MPR here.

Report Links Extreme Weather to Global Warming. A different perspective from KARE-11, which stopped out to WeatherNation Wednesday for the Environment Minnesota press conference. Director Ken Bradley released the study to the public, pointing out that Iowa has experienced two "1-in-500-year" floods in just the last 15 years.

"Downtown" Tornado. Here's some visual ammunition for friends or family members who don't believe that tornadoes can hit major metropolitan areas. This YouTube clip shows a tornado forming close to downtown Dallas during evening rush hour Wednesday. As many as 250 homes were either damaged or destroyed by tornadoes and flooding across North Texas Wednesday as the soggy remains of Tropical Storm Hermine surged northward across the Lonestar State.

EF-2. The Dallas NWS office confirms EF-2 strength for the tornado that struck downtown Dallas late Wednesday, rare for early September. Some amazing video of the developing twister here, courtesy of Vimeo.

Nationwide we just muddled through the 4th warmest summer on record, according to NOAA. For the southeastern USA it was the warmest summer on record - across the northeast the January - August period was the warmest ever measured, temperatures running 3.4 F above long-term averages. Energy consumption (to cool homes/businesses) was the highest ever measured in 116 years of record-keeping.

Not much drought-babble this summer. It was the wettest summer ever recorded across Wisconsin (nearly 7" wetter than average, statewide), the 3rd wettest for Iowa, the 10th wettest since the late 1800s here in Minnesota. Another buried (and vaguely interesting) weather-nugget: NCDC's "Climate Extreme Index" or CEI, was 1.5 times it's historical average. The CEI takes into account several factors, including record and near-record temperatures, as well as unusually dry or rainy periods. It's the deviation from the norm.

And yes, even NOAA acknowledged the (crazy) fact that - at least this year - tornado alley took a 300-500 mile northerly detour, passing directly over the Gopher State. 145 tornadoes so far, twice as many as Oklahoma. This is a preliminary number - the final count will almost certainly break the old record of 74 Minnesota tornadoes set in 2001. I'm still waiting for confirmation from the NWS, but I suspect we also had a record number of days with tornado watches and warnings across the state. At least this summer, Minnesota was magically transformed into Kansas...with lakes.

* More details on August weather across the state from the MN State Climatology Office here.

Dreary Thursday. Clouds kept temperatures 5-8 degrees cooler than average statewide, highs mostly in the 60s. Rainfall ranged from a trace at MSP to .04" at St. Cloud, .19" at Rochester and a soggy .32" at Redwood Falls.


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

Today: Mostly cloudy, breezy and damp, a little drizzle, possibly some light rain by late afternoon. Winds: SE 10-20. High: 69

Friday night: A good chance of rain, fog possible. Low: 58

Saturday: Mostly cloudy. Wet start, drying out (possibly brightening up) during the PM hours. Some sun possible central/western MN. Winds: W 10-20+ High: near 70

Saturday night: Dry, partly to mostly cloudy with a touch of fog possible late. Low: 56

Sunday: Probably the nicer day. Plenty of sun, warming up. Winds: S 10-15. High: 75

Monday: Lot's of sun, turning cooler again. High: 65

Tuesday: Blue sky, comfortably cool. High: 63

Wednesday: Still cool and quiet with ample sunshine. High: 67

Thursday: Sunny start, clouds increase. High: 68

Nothing severe shaping up, just a mostly-gray Friday, with a growing chance of rain. The best chance of puddles comes tonight into a portion of Saturday morning. You'll probably stumble out of bed tomorrow morning, take one look at the sky, and be tempted to crawl back under the sheets and sleep in 'til the crack of noon. A drying westerly wind kicks in tomorrow, skies SHOULD clear from west to east during the day, a much better chance of afternoon sunshine in St. Cloud and Alexandria than the Twin Cities, but even here skies should brighten up during the PM hours - no rain or drizzle dribbling out of a slate-gray sky after 9 or 10 am. Your afternoon (outdoor) activities are not in grave peril.

Sunday looks better - any lingering morning fog/cloud cover or crud should burn off, revealing enough sun for at least mid 70s. If the fog dissipates quickly there's an outside chance we could see 80 by mid afternoon. A cooler front puffing southward out of Canada will probably sail through town (dry) Sunday afternoon/evening, although a stray shower can't be ruled out, especially up north. By Monday you'll feel that cool front, highs stuck in the 60s most of next week with low humidity and relatively light winds - September at its best.

Clouds may increase by the end of next week, some hints of a little rain next weekend. If you want to get out and take in the Renaissance Festival or maybe check out the 2010 Parade of Homes (a fall tradition) THIS is the weekend to do it. No mega-storms, nothing controversial. One more chance to hit the lakes (Sunday will be the better day) and soak up a respectable spell of weather.

A Flood of Hot Water? Just when you think you've seen everything, along comes a story about flooding near Guatemala City. An active nearby volcano ("Pacaya") heated the water which came flooding into the suburbs, leaving at least 45 dead. An estimated 50,000 local residents have had to flee their homes - more details here.

More Tornadoes in Unusual Places. A Twitter pic of a developing tornado near Providencia, Mexico.

A Little Early? Yes, it's a few days earlier than usual to be chatting about fall foliage, but the leaves are starting to turn near Bemidji, and along the North Shore of Lake Superior, where an estimated 10-25% of the foliage has begun to ripen. More from the MN DNR here.

Mega-Flare! Just when you thought it was safe to wander outside. No worries - this spectacular prominence, a "mass coronal ejection" is not racing toward Earth, which is a good thing (it would have triggered massive geomagnetic storms - possibly interfering with satellite and terrestrial communications systems, as well as the power grid). More from here.

Wind Turbine or Airplane? New Radar Could Cut Through the Signal Clutter. It's a real problem: wind turbines (up to 100 meters tall) show up on the same radar displays air controllers use to route private, commercial and military planes - creating a jumble of clutter that (some say) may compromise safety. Work is underway on a new generation of radar that can eliminate the on-screen clutter - the story from Scientific American here.

Weird Weather In A Warming World. Andy Revkin at the N.Y. Times has a story about "global weirding", the term being given to an apparent spike in the incidence of extreme weather events worldwide. Is it "subjective validation" - or seemingly random pieces of a much larger, and complex climate puzzle?

Climate Change: Are The Polar Ice Caps Melting Slower Than We Thought? Time magazine has an article about the complexities of trying to predict the rate of melting in Greenland and Antarctica, huge climate wildcards (that computer models have historically not handled very well). The rate of melting may be slower than previously thought, but the article points out an eye-opening fact: the National Geoscience study points out that 104 BILLION metric tons of ice in Greenland and Antarctica is still melting into the world's oceans every year; sea levels continue to rise. The question: how quickly? Is there a tipping point for Greenland?

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