Thursday, April 8, 2010

The United States of Extreme Weather

America the Beautiful. America the (Increasingly Severe). Are we really seeing more extreme weather, more wild swings of the weather pendulum - or is it simply a function of more people outdoors, commuting, working, exposed to the weather, NOTICING the weather, more people armed with camera-phones and Twitter accounts? Good question: personally, I think it's a little of both. We are seeing a gradual upward trend in extreme weather episodes around the planet (a recent research project showed a spike in 1"+ rainfall amounts in New England in the last 10-15 years). Last winter brought some 30-40" snowfall amounts near Washington D.C. and Baltimore, from 2 separate storms in less than a week! Lately it's been epic floods and mudslides in Peru and Brazil, while Australia and southern China are struggling through the worst drought in over a century.

Weather has always been extreme, weather variable, especially over far northern latitudes, but even though we're doing a better job of spotting, tracking and predicting these crazy atmospheric tantrums - experts point out that we're increasingly putting ourselves in harm's way: more people building homes in tornado alley, more retirees moving to the beach - in the potential path of hurricanes. We see a 1-in-500 year flood every 5 years somewhere in the Upper Midwest, yet the people who evacuate to higher ground almost always move back.

We've transformed into a nation (a world) of "sitting ducks." When severe weather does (inevitably) strike, chances are there's a subdivision in the path of the tornado (instead of farmland), a retirement community smack dab in the middle of the hurricane landfall, a town at the bottom of the mudslide, a neighborhood threatened by a rapidly expanding brushfire. As cities grow, suburbs expand, we put ourselves increasingly at risk. It's an unpleasant symptom of growth, development and success, and we're only going to see more weather extremes in the years ahead. The biggest concern? Although severe rainfall (and snowfall) events are spiking, much of the world is forecast to dry out as it slowly warms; water for drinking and agriculture will be increasingly difficult to find. It's more than just a warming trend - the symptoms and side-effects will be worst for the poorest people on the planet - people who don't take access to water for granted.

Record Heat. 291 record highs east of the Mississippi since Wednesday morning. 90 in Boston, 92 in New York, both record highs, the earliest 90s in modern-day records dating back to the mid 1800s. Amazing. Click here to go to Ham Weather (a division of WeatherNation) for an interactive map - you can click on each icon to get details of the record that was set in that city.

An Extreme Greenhouse Effect. I saw this Twitter photo on (just plug in a search keyword and you can see some amazing photos). Granted, the car was probably in the sun, black upholstery (?) This is why you should never even think about leaving a child (or a pet) in your car, even for a few minutes - temperatures can be 10-40 degrees hotter than the outside air temperature, with potentially tragic results.

A Very Close Call. 4" of snow in Green Bay? Madison picked up a slushy 2", as much as 6" of snow piled up over eastern Wisconsin, enough to shovel, plow, and irritate the heck out of Wisconsinites. We feel their pain, don't we? Let me think about that....

Severe Recap. Check out the data from 1980 to 2006, a fairly short time span to reach sweeping conclusions. The plot shows major tornadoes (F2 or stronger), wind reports > 70 mph, and hail 2" in diameter or larger. In general, the risk of tornadoes increases the farther south/west you travel across the state of Minnesota. The raw data is here, click here to see similar severe weather summaries for other cities around the USA.

Troubling Trends. Again, it's a 26 year span of data, but the numbers are curious, a 224% increase in severe storm reports over a 20 year period. Is it just more people outside - exposed - reporting severe weather that has always been there, or are we really experiencing an upward tick in tornadoes, floods, hail and extreme weather events in general? Truth: it may be a little bit of both...

White Bay, Wisconsin. Nothing very green about Green Bay in the last 36 hours. Folks there are still fuming about Brett Favre joining the Vikes; now they have the weather to compound their lingering anst. Good grief: I almost feel sorry for the locals, digging out from 4" of snow - most of it already gone. Almost. Could have been us. These things tend to even out over time. Have a friend in Green Bay? Send them a quick note and tell them Minnesota is greening up, ice came off the lakes 2-3 weeks early, no more snow or frost in sight. Man, we got off easy this year....

Today will be a big step in the right direction, a touch of frost in the outlying suburbs early, jackets required for the trek to work or school, but lukewarm sun will tug the mercury into the low and mid 60s by late afternoon, about 10-15 degrees warmer than average. A fizzling cool front will stall over Minnesota over the weekend - can't rule out an isolated shower or T-shower Saturday, but a weak bubble of high pressure moving in Sunday should ensure sunshine much of the day, temperatures still poking into the 60s. Sunday looks like the nicer day of the weekend. That stagnating front will do a U-turn and surge north as a warm front early next week as Minnesota breaks out into the "warm sector", a fetch of warm, moist southerly air blowing directly from the Gulf of Mexico fueling a few scattered thunderstorms Monday and Tuesday. If the sun peeks out, even for a couple hours, we may see some low 70s close to home. Not sure we'll have all the ingredients necessary for a severe storm outbreak, but there's a small chance of isolated severe storms, large hail, even some damaging winds by Tuesday evening. An eastbound cool front should clear us out Wednesday, drier weather the latter half of the week. I can't believe our good fortune. The other shoe has yet to drop. I've been holding my breath since mid February. Maybe it's time to exhale...

First Severe Storm Episode Next Week? By midday Tuesday (GFS run) a steady stream of moisture from the Gulf, dew points in the 50s to near 60, sufficient wind shear in the lowest 1-2 miles of the atmosphere, and moderate instability aloft - may spark a few isolated severe storms across Minnesota. Tornadoes are more likely to form along or near warm frontal boundaries than cold fronts - a fairly vigorous warm front will be draped over Minnesota - if you believe the model. It's pretty far off, but I could see some watches & warnings by Tuesday of next week.

Climate Smackdown. A TV meteorologist in one corner, a PhD climate scientist in the other. Watch the clip, reach your own conclusion. We report - you decide. Who do you believe?

April Burn? Today the sun will be as high in the sky as it was back on September 2. Keep in mind the potential for sunburn has nothing to do with the air temperature, everything to do with the sun angle, the intensity of the sun. Lucky enough to be spending a lot of time outside? Apply sunscreen liberally - you'll be glad you did.

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

Today: Bright sun, light winds - beautiful! Winds: S 8-13. High: 64

Tonight: Patchy clouds, not as chilly. Low: 44

Saturday: A mix of clouds and sun, slightly cooler. Winds: W/NW 10-15. High: 61

Sunday: Plenty of sun, even nicer. High: 65

Monday: More clouds, humidity, chance of a shower or T-storm. High: 63

Tuesday: Warm and humid with a better chance of T-storms (some strong?) High: 73

Wednesday: Showers taper, rapid clearing by afternoon. High: near 70

Thursday: Lot's of sun, another raging case of spring fever. High: 64

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