Deadlier than Tornado Alley: "Dixie Alley"

Weather Headlines

* Slight severe storm risk later in the day Thursday and Thursday night.

* NAM computer model prints out nearly .25 to .50" of rain tonight into the breakfast hour Friday.

* Drier wind kicks in late Friday & Saturday behind the cool front (few pop-up showers far northern Minnesota Saturday?)

* Slightly cooler Sunday, highs hold in the 50s with intervals of sun - drier statewide.

* Another chance of showers next Tuesday; no widespread, sustained soaking rains in sight.




Dixie Alley. It turns out the most violent, long-lasting EF3+ tornadoes have not touched down on the Plains States, the traditional "tornado alley" that runs from Texas to Iowa, but farther east, across the Lower Mississippi Valley. I was surprised by the new findings - most meteorologists were amazed to learn that the nation's worst tornadoes tend to form farther east, in "Dixie Alley", one of 4 pronounced "local" tornado alleys that arose from an exhaustive study.


Four Distinct Tornado Alleys. Southeastern Minnesota can be (roughly) grouped into the traditional tornado alley that runs from Texas and Oklahoma on north. The most intense tornadoes formed in "Dixie Alley", with two separate clusters of (frequent) tornadoes in "Hoosier Alley" and "Carolina Alley." Researchers examined data from 1950 to 2006, looking at the frequency and spatial occurrence of EF3+ tornadoes with a track length of 20 miles or more. The eye-opening report from msnbc.com is here.

Slight Severe Risk. SPC has much of Minnesota under a "slight risk" of isolated severe thunderstorms, the best chance around the dinner hour, right after the high temperature for the day (low 70s?) - when the atmosphere overhead is most unstable, most ripe for rising thermals of warm air to mutate into towering cumulonimbus, thunderstorms. Keep an eye on the western sky later today, stay tuned to local media (and your favorite web sites) for possible watches and warnings. Have you purchased a NOAA Weather Radio yet? You won't regret it...

To say we're getting hopelessly spoiled in the weather department would be a grotesque understatement - so I won't say it. I will think it, but I won't say it (out loud). Day after day of lukewarm sun, gentle breezes, low humidity, lonely bugs, big smiles. At some point the weather honeymoon will come to a grinding halt (although I probably said something similar back in early March). Whether it's El Nino, a whiff of climate change, or just good 'ol fashioned Lady Luck, the pattern across North America has become locked in a pattern that favors major Pacific storms detouring across the southern and eastern U.S. - a tendency for high pressure bubbles to set up shop over the Great Lakes, protecting Minnesota from any wild (or violent) weather. That's pretty much been the weather story since MID FEBRUARY (with only a few fleeting exceptions).

Unsettled Saturday? Although a sunny start is expected Saturday across southern and much of central Minnesota, a lingering pool of unusually chilly air aloft will leave the atmosphere over Minnesota unstable enough for a few pop-up showers by midday and afternoon, especially up north. The farther north you drive - the cloudier the sky, and the greater the chance of 1-3 hours of showers.

The sky draped over Minnesota slowly sours today, gusty winds from the south pumping moisture from the Gulf of Mexico - fueling a few heavy showers and thunderstorms later today and tonight. Conditions for a severe outbreak are marginal (dew points < onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhqWYt3wlJH6eE1ESRuPJdKVwFM8IlSSnK4pLRp_2YbUgMViZp3m_xAWr1xnoPXbV_G_nZpUmCpNG1_qk15J9BeINNCifRscB990V0kOcfa9QerC3qux3ivpKMv10XptcXy6DOHQDZsUKg/s1600/yazootwister.png">Yazoo City Wall Cloud. This photo was taken immediately after the mile-wide tornado passed near Yazoo City - the circulation so wide and vast that it appeared that the ENTIRE thunderstorm had descended to the surface of the earth - it was so big it didn't look like a classic tornado, a phenomenon known as a "wedge", mercifully rare.

Tracking a Killer. The large, violent, long-lasting tornado that hit Yazoo City, MS Saturday was on the ground for 149.25 miles, with a maximum intensity of EF-4, about as strong as tornadoes ever get. It had a maximum width of 1.75 miles! 10 people were killed, 146 injured. Had the tornado struck after dark (difficult to impossible to spot) the death toll would have been far higher. More on the Mississippi tornado outbreak from the NWS here.

Unlucky Weather. Check out what 50-70 mph. wind gusts did to the Mirage sign on the Las Vegas strip - damage across the city was extensive from straight-line winds as a powerful Pacific storm blew across Nevada.

More Damage. This (picfog.com) image came from Salt Lake City, where the same violent front caused considerable damage to businesses and homes, winds gusting past 60 mph. Peak winds from this Pacific front: 120 mph, reported near Lake Tahoe, strong enough to blow 18-wheel trucks off I-80.

Weather & Climate Stories

Every day I try to include a few stories that caught my eye - hope there's something here you find interesting.

Pollution Speeding up Snow Melt? Over the last 30 years spring snowmelt and warming seems to be happening at a faster rate across Eurasia than North America - and man-made pollution may be a factor, according to NCAR, (National Center for Atmospheric Research), based in Boulder, Colorado - one of the world's preeminent research centers. The article is here.

Flowering Plants Bloom Earlier With Warming. Project "Budburst" has been tracking the dates that certain species of plants have been blooming in the ChicagoLand area over the last 4 years - compared with a long-term 50 year average. Many plants are going into full bloom weeks ahead of schedule. A blip/fluke? Possibly, but the bloom of plants and migratory habits of animals (especially birds) can be effective markers of a climate in transition. DiscoveryNews looks at the project and initial results.

Climate Change Indicators in the United States. The EPA examines 24 different "indicators" to track some of the changes underway across America - a very comprehensive examination of the slow-motion transformations underway. The study findings are here.

U.S. Losing Trees Faster Than Other Industrialized Nations. From 2000 to 2005 the USA lost about 9% of it's forestland, 46,000 square miles, roughly the size of Pennsylvania, a faster rate of forest depletion than any other industrialized nation. One theory? Warmer winters are allowing pests/beetles to live longer, resulting in more diseases and dying forests. Anyone interested in preserving the beauty and health of the BWCA will want to check out this article in USA Today.

Jon Stewart. Ready for a little comic relief? Me too. Recently Jon Stewart interviewed Lisa Jackson, Administrator for the EPA, about a recent report focusing on climate change and new evidence that has surfaced - again, the result of peer-reviewed science. The resulting interview was funny, and illuminating.

The Vaccine War. Not sure if you saw the hour-long Frontline special on PBS Tuesday evening, but it was must-viewing, especially if you have an infant or small child and you're worried about vaccines, concerned about some of the urban legends (?) that vaccines may increase the risk of autism and other neurological ailments. I'm still not sure what to think after watching this thorough, thoughtful look at the vaccine controversy, but it's worth your time to check it out.

Tilting Against the Wind. The Utne Reader interviewed me about my (outspoken/public) views about climate change, from the standpoint of a meteorologist deferring to the work of professional, lifelong climate scientists. A significant percentage of TV meteorologists continue to believe that climate change is a "hoax", that there is insufficient proof that man has a role in the changes we're witnessing worldwide. Everyone is certainly entitled to their opinion - as I've been saying for years, it wasn't an overnight epiphany for me - the pieces of the climate puzzle began accumulating during the 90s, by 1998 I was fairly convinced that SOMETHING had changed, that there were simply too many coincidences taking place for the nearly 40% spike in greenhouse gases not to be a factor in what we've been witnessing around the planet (melting glaciers, rising sea levels, thinning arctic ice, more drought, more flooding, and a northward shift of about 150 miles in climate patterns across the USA). How much is natural vs. man-made? I don't pretend to know, but I continue to believe that this will be one of the big stories of the 21st century. Our grandkids will want to know what we knew - when - and what we did about it. I continue to believe that within 5-10 years any lingering doubt will be erased, the skeptics will come around (and probably pretend they were onboard all along). Science is a sloppy process, scientists can be fickle and human (as ClimateGate demonstrated). But a concerted effort among the 4,000+ climate scientists to deceive the public - an orchestrated conspiracy to misinform a global population about what is going on all around us? I don't buy it. Time will tell, the truth will come out, however unpleasant and unpopular. The question: when the final piece of the climate puzzle falls into place, and all reasonable doubt has been removed, will there still be time to DO anything about it? Doubtful. That's the paradox. If there's even a 30% risk that the majority of climate scientists are right, do we wait another 10-20 years, or take a series of steps today that lower our dependence on oil from Saudi Arabia, and invent new technologies that make the U.S. more energy-independent in our lifetime? The Chinese are already producing most of the wind turbines and solar panels exported to other nations. Quality of life? It's real, we have something very special in Minnesota - I want to do everything I can to make sure my kids and grandkids get to enjoy the same Minnesota I've fallen in love with. I'm a naive optimist, but on this subject I'm growing increasingly worried that the doubt, confusion and (politically-motivated) denial showing up from Main Street to Capitol Hill will put us in a bad way, environmentally and economically. As I've said all along, I hope the climate scientists are wrong - I'm keeping an open mind (and hope you'll be just as open-minded and skeptical as I am). If a better theory arises that explains what we're seeing around the world - and why - I'm happy to change my tune. But for that to happen I won't be relying on TV meteorologists (who study weather over the next 7-15 days) but climate scientists, who study long-term (global) patterns for a living. TV meteorologists are routinely burned by computer models - there is a built in skepticism about computer models, which leaves many of my colleagues suspicious about climate models. There's a real disconnect here - I understand why it's happening, but I'm bummed that some of these on-air professionals, local science ambassadors in their respective cities, aren't digging into the science and deferring to PhD climate scientists who seem to have a much better grasp on the big picture. BTW, the AMS, the American Meteorological Society, is one of 700 professional organizations acknowledging climate change, and the probability that man has some role in the changes we're witnessing around us. That's good enough for me.

Paul's SC Times Outlook for St. Cloud and all of central Minnesota

Today: Fading sun, breezy and warm. A growing chance of showers, T-storms later in the day, a tiny percentage may be strong to severe. Winds: S 15-30. High: 68

Tonight: Showers and T-storms, locally heavy rain possible. Low: 53

Friday: Showers taper, some PM sun possible - drying out as the day goes on. High: 64

Saturday: Sunny start, patchy PM clouds (showers far north). Winds: SW 10-20. High: 63

Sunday: More clouds than sun, cooler. Winds: NW 10-15. High: 57 (holding in the 50s outside the metro area).

Monday: Partly sunny. High: 58

Tuesday: Less sun, risk of a few showers. High: 59

Wednesday: More sun, a bit milder. high: 63