Tuesday, April 20, 2010

The Perfect Spring of '10

* Tuesday was Day 2 of Severe Weather Awareness Week in Minnesota - for some timely information on watches, warnings, the limitations of the emergency sirens, and the cheapest life insurance you'll ever buy (NOAA Weather Radio) click here to read a great summary from the NWS.

* Monday's NWS post deal with severe thunderstorms, hail and some great lightning factoids (and myths). Click here to read more, you'll be the life of the next party (if you happen to be partying with Al Roker).

* Tornadoes in the metro area? 5 tornadoes in the metro area just in 2009, a total of 8 in Hennepin county since 2000. Last year small tornadoes touched down on the Lake Minnetonka area and in South Minneapolis, proof positive that tornadoes CAN hit the immediate metro area. No watches/warnings were in effect at the time, a blunt reminder that you have to (always) be on guard - situation awareness is key. If skies turn threatening, clouds lower and begin to rotate (or large hail begins to fall - evidence of an especially severe storm) you need to head to safety, even if the sirens are not sounding, even if an official warning hasn't been issued for your county. One of our (amazing) WeatherNation meteorologists, Kristin Clark, was installing a weather instrument at her home in South Minneapolis. She could literally SEE the pressure falling before her eyes (!) - she turned around, only to see a wall cloud dropping a tornado over South Minneapolis. She grabbed her iPhone and started videotaping the tornado. I'll never forget the call to the weather center at WN. "There's a tornado over South Minneapolis Paul! I'm watching it right now!" Have you been drinking Kristin? "NO, it's really happening." I turned on the Doppler and sure enough there was a tiny, almost insignificant "couplet" on the radar screen, evidence of a small, compact area of rotation over S. Minneapolis. Here is the video she captured, courtesy of Conservation Minnesota.

BTW, I went to college with Kristin's dad, Tom Clark, who has been doing TV weather for 30 years at WNEP in northeastern PA, where I worked from 1979-1982. He's married to an amazing woman, Noreen, who is also a TV "met". It's only natural that they would have a daughter who has meteorology running through her veins. BTW, Tom is a dear friend, was best man at my wedding....he could tell you stories...I'll stop now.

Tuesday Almanac Data. Highs yesterday ranged from 48 at Grand Marais to 71 in the Twin Cities, a balmy 73 at St. Cloud, 74 at Redwood Falls. These readings are consistently 10-15 degrees above average.

Week's Worth of Records. Officially: 1,311 weather records from coast to coast in just the last 7 days. Record highs across the Pacific Northwest, Ohio and Tennessee Valley, record rainfall amounts over Texas, record warm "low" temperatures over the Upper Midwest. Click here for an interactive map from Ham Weather (division of WeatherNation) to see all the pertinent details.

Another day in Meteorological Paradise, the new Palm Springs of the Great North, the state (of weather bliss) formerly known as Minnesota. A generation ago the mere mention of the word would leave Americans in other, lesser, partly-boring cities around the nation trembling. Land of 10,000 Weather Extremes, chin-deep drifts, they test batteries up there don't they? So cold it could almost freeze the purple out of Prince.

No more. With a few notable exceptions our winters have pretty much been neutered, especially since 1998 or so. Sure it snows, it gets cold, but not the hair-freezing, headline-generating arctic fronts that turned us into a punchline on Letterman and the Tonight Show 20 years ago. Welcome to the earliest spring on record, pioneer records date back to the 1830s. I look at the statistics (no snow since Feb. 23, no frost since March 26, April temperatures soaring 10.4 F above average). And it just goes on and on and on, like the Energizer Bunny after a triple grande no-whip quad-shot cappuccino. Minnesota meteorologists are dazed and amazed, grappling for things to talk about, no storms, nothing even close to severe weather - thank God we have that annoying volcano in Iceland to babble about, or there would be an awful lot of dead air on the TV tube.

And just when you think it can't get better - it does. 71 yesterday, a postcard-perfect sky, virtually no wind. Yes, allergy-sufferers are not amused, and the air quality stinks (quite literally). Winds have been so light near the ground, an inversion aloft trapping pollutants, we had a touch of smog in the air yesterday, but I didn't hear too many people complaining. It is the PERFECT SPRING of '10, something we'll be telling our grandkids about...."do you remember the year we had 6 MONTHS of boating in Minnesota?" Remarkable.

A Potential Climate Factor? This was the eruption from Mt. Pinatubo back on June 12, 1991 in the Philippines. The ash cloud reached 70,000 to 80,000 feet into the atmosphere, a thin veil of sun-blocking ash swept around the entire planet. The result: a global cooling of 1-2 F for the next year or two. So far the eruption in Iceland has been minor, by comparison, the ash reaching no higher than about 30,000 feet. A geological, meteorological and aviation story to be sure, but so far, not a climate factor. That could change if the nearby "Katla" volcano on Iceland begins to erupt, which has happened the last 3 times that Ejyafjallajokull volcano blew it's top. Stay tuned..

A Temporary Reprieve? The volcano is still spewing ash and smoke, but a number of European airports were able to open up, at least temporarily, on Tuesday. For the very latest on the eruption, and the implications downwind, click here to read more from the BBC, which is one of your best sources for global news & information. Click here for a very good summary from the Star Tribune (with a local angle). New high-res imagery can be found here.

Supercell. Here is a 3-D cross-section of the "supercell", the rotating thunderstorm that spun up a tornado near Bushland, Texas Tuesday evening. Note the storm leaning away from the wind, evidence of powerful wind "shear", strong changes in wind speed and direction rising up through the atmosphere. Under these conditions horizontal wind shear can become translated into vertical wind shear, focused in a rapidly rising updraft with air shooting straight up at over 100 mph. The precise mechanisms that convert horizontal spinning into vertical spinning is still something of a mystery - something pulls the rotation down to the ground, probably the RFD, the rear flank downdraft, a downward rush of cooler, denser (but buoyant) air that pulls the circulation down to the earth.

"Tornadogenesis" Here was the end result: what appeared to be an EF2 tornado touching down on the Texas panhandle. This is the heart of tornado-chasing country - you can SEE 40-50 miles in every direction, no hills, powerlines or buildings to get in the way.

Latest Warnings. Here is a good site to see the very latest warnings from around the USA. It refreshes in your browser every 2 minutes, so you always have the latest, greatest warnings. This one is bookmark-worthy. Thanks to the College of Du Page Meteorology department for a great/useful site.

Fireball! Here is another webcam that captured the meteor that streaked across the sky around 10 pm. Be patient - it shows up about halfway through the YouTube clip.

"TV Weathercasters know which way the wind is blowing." Really? Click here to learn more.

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

Today: Plenty of sun, breezy, a bit cooler. Winds: NE 10-15. High: 66

Wednesday night: Clear and cool. Low: 43 (upper 30s in the outlying suburbs).

Thursday: Partly cloudy, still mild. High: 68

Friday: Fading sun, showers/T-storms may arrive by Friday night. High: 65

Saturday: Showery rains, thunder possible - damp breeze (few hours of rain). High: 61

Sunday: Showers taper, some PM sun possible. High: 62

Monday: Lingering clouds, slight chance of showers far southern/western MN. High: 61

Tuesday: More sun, drier statewide. High: 64

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