Thursday, September 30, 2010

More Floods (and why we may have to adapt to climate change)

Invasion! Do you have any Boxelder bugs swarming around your place? We are in the process of being INVADED out here at WeatherNation - they're everywhere! These harmless bugs don't bite, they aren't a risk to people, pets or plants - they tend to spend their summers munching away contentedly up in nearby trees - but in the autumn they try to get ready for the winter to come by getting INSIDE homes or buildings (or cars for that matter). Sunny, southern exposures tend to be more vulnerable to these pests - more tips from the University of Minnesota Entomology Department here.

Ah, The Memories! What a September: 5.53" of rain, nearly twice as much as normal, an unusual number of severe weather outbreaks, a handful of tornadoes, and last week's historic flooding over southern Minnesota, the worst flooding since 2004. See a recap of the month from NOAA here.

October Preview. There is no such thing as "average" weather. You know that already, but if you're interested in the normal highs/lows/precipitation and the records for October, day by day, you're in luck. We should see our first frost within the first 10 days of October, our first snow flurries by the third week of October, maybe a little accumulating snow up north by the end of the month. Something to look forward to. Data courtesy of the MN State Climate Office.

Holding Their Breath. The New York City subway system has 700 pumps to keep water off the tracks - on a sunny, dry day these pumps pull at estimated 13 million gallons of water out of the subway system! The pumps can handle up to 1.5"/hour, but the tropical remains of "Nicole" were forecast to dump as much as 2-4"/hour on metro New York Thursday. More from Gizmodo here.

Fore! Gurgle Gurgle. My dad (Volker) took this picture of a nearby golf course (Bent Creek) outside Lancaster, PA - reeling from as much as 6-8" of rain yesterday. The small stream running through the course became a raging river - there were hundreds of reports of flooded intersections and underpasses, stranded motorists - much of the east picked up 2-3 MONTH'S worth of rain in less than 18 hours. Thanks Dad.
Jamaica Flooding and Tornadoes. The tropical wave that went on to become Tropical Storm Nicole delivered a soggy, windy blow to the island of Jamaica several days ago - home video showing what 8" of rain in less than 36 hours can do here.

More Tornadoes In Unusual Places. The soggy remains of Tropical Storm Nicole raced up the east coast Thursday, drenching many coastal regions with 3-6" or more of rain, and a few (rare) late-season tornadoes. This funnel was spotted near Norfolk, Virginia - courtesy of Twitter.

Better Than Advertised. It's generally ok when the forecast turns out better than expected. We got the "sunny" part right, but temperatures were a good 5 degrees warmer than expected, peaking at 72 in St. Cloud and the Twin Cities, 73 at Redwood Falls. Not a bad way to end the month of September.

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

Today: Clouds increase, slight chance of a PM shower/sprinkle, especially north/east of the Twin Cities. Winds: N 10-20. High: 64

Friday Evening: Gradual clearing, dry with a chilly breeze (jacket weather). Temperatures falling through the 50s.

Saturday: A mix of clouds and sun, breezy and cool. Winds: N 10-15. High: 55

Saturday night: Mostly clear with diminishing winds. Potential for the first frost of the season in the outlying suburbs. Low: 38

Sunday: A better day. Bright sun, light breeze, a few degrees warmer. Winds: S 8-13. High: 62

Monday: Blue sky, beautiful! High: 67

Tuesday: Sunny and spectacular - one of the nicer days of autumn. High: near 70

Wednesday: Hanging on to sunshine - still dry and lukewarm. High: 71

Thursday: Sun fades a bit behind increasing high clouds, still balmy. High: 69

"Paul, why does the forecast change?" It's one of the well-known frustrations of tracking the weather here in Minnesota, or anywhere for that matter. You check out the 7-Day on a Tuesday and the weekend forecast looks promising. Check back in 2 days later and - what! - how did a shower get into the Saturday outlook? The accuracy rate for the "Tomorrow Forecast" is holding at about 87% (nationwide average), and that hasn't improved much in the last 30 years, in spite of Doppler radar and supercomputers. Although there is some skill out to about 15-20 days (better than 50/50, better than the flip of a coin) there is no doubt that by the time you get to the 7th day of a 7-Day Outlook the accuracy is closer to 60% (or even lower than that, especially during the winter months, when systems move faster, increasing the potential for a "busted outlook").

The reality: we get new computer data from the NAM/WRF 4 times a day, 4 new computer runs, based on the latest, greatest (real-time) conditions. Our confidence level goes up when the computer models all pretty much agree, but oftentimes there are big discrepencies from one model to the next, or one model RUN to the next. We look for trends ("each computer run takes the storm farther and farther south") - that can be helpful. But in the end it comes down to "which model do you trust the most - which computer tends to do the best job in a given scenario?" All computers have weakenesses and biases (because, after all, they're only as good as the people programming them). The physics in the computer models is good, long-range accuracy is improving by about 1% every year, but there are problems. The math that describes how the atmosphere SHOULD work isn't a perfect representation of how the atmosphere really works, the "fluid" of air floating overhead. And there are limits to how accurately we can input the current (initialization) data - a snapshot of what is happening right now - worldwide. Over oceans we rely on satellites for much of the data - even over land areas weather balloons are only launched twice a day. In other words there are gaps in the data. I tell people it's a little like doing a crossword puzzle with many of the pieces missing! Junk in - junk out. If you put incomplete or erroneous data into the supercomputer you're going to get a flawed forecast.

The USA still has the best weather service in the world. We see more severe weather than any nation on Earth (China and Russia are #2 and #3).  Yes, we are #1! In spite of that less than 100 people in a given year will lose their lives to hurricanes and tornadoes, which is pretty miraculous when you think about it. Flooding and heat claims more lives, but most Americans have access to a continuous stream of weather forecasts and warnings that most people around the globe could only dream of. We shouldn't take that for granted (our tax dollars are put to pretty good use, in my humble opinion). Some meteorologists believe that the Europeans have a more accurate weather model, the European "ECMWF" may be a bit more accurate than NOAA's "GFS" global model, but that's open to some debate.

Predicting the future is complex. Ask any economist, stock broker or CIA analyst. Billions of variables - computer help to sort through all these variables, but they're not perfect, and never will be. That said, I'd like to believe that the odds of getting caught flat-footed by another "Armistice Day Blizzard" are small - I don't think you could have an EF-4 tornado roaring through the suburbs of Minneapolis without some sort of warning being issued in advance. All this newfangled technology IS saving lives every year, but there is a limit (financial and mathematical) as to how accurate the 7-Day Outlook will ever get. Sounds depressing seeing this on paper, but it's the truth.

Disclaimer aside, today won't be as spectacular as Thursday was, an approaching "Alberta Clipper" (it's baaaack!) pushing a canopy of clouds and a few embedded showers and sprinkles across the state, from northwest to southeast, as the day goes on. The best chance of 15-30 minutes of rain will come this afternoon, skies probably starting to clear in time for evening high school football games, but grab a jacket: temperatures will quickly fall through the 50s, and a stiff north wind will make it feel cooler than that.

By Saturday there will be NO doubt in your mind that it's October. In spite of some "in and out" sunshine temperatures will be stuck in the low to mid 50s, the wind will make it feel like 40s, and the stage may be set for the first frost of the season by Sunday morning, especially in the outlying suburbs, well away from the 494-694 beltway around the Twin Cities, well away from the warmth of the "urban heat island" which can keep the downtowns and close-in suburbs as much as 5-10 degrees warmer on a clear, calm night. Concrete and asphalt retains some of the sunny warmth of the daylight hours, slowly releasing or re-radiating the warmth during the nighttime hours, keeping Crystal, Edina and Maplewood as much as 10 degrees warmer than Elk River, Delano, Lakeville and Stillwater. As the center of a high pressure bubble drifts directly overhead late Saturday night winds should diminish, setting the stage for a frosty coating of white on many suburban lawns Sunday morning. If you live in an area that normally sees an early frost (at least 15-25 miles away from the downtowns) you may want to cover up any tender plants before you hit the sack Saturday night - it's going to be a close call.

Sunday should be brilliant, fewer scrappy cumulus clouds, more sun, a southerly breeze coaxing the mercuy above 60, the nicer day of the weekend. And right now all the computer models keep us dry and increasingly mild all of next week, a run of 60s, even a shot at 70 by the middle of next week. Not a bad way to kick off the cool, blustery, changeable month of October. CPC is still predicting a warmer-than-average October, and studying the maps I tend to believe them.

September was roughly 1 degree cooler than average in the Twin Cities, with nearly TWICE as much rain as average (5.53") vs. a normal amount of 2.62". We have some catching up (and drying out) to do over the next few weeks.

Vast Potential In the Discomfort of Howling Winds. Any well-traveled tourist or (professional) golfer will attest to the fact that the winds over Scotland HOWL much of the year, in fact there is thought to be enough renewable wind power potential lurking offshore to meet more than 6 TIMES Britain's current demand for electricity, according to this New York Times article. Those same fowl winds that can make the U.K.'s weather so dreadful much of the year could help to power and energy windfall - and much of northern Europe is now waking up to the opportunity.

Harvest Time. This satellite comparison shows the rapid maturation and ripening of the crops over Iowa and southern Minnesota in just the last month, the landscape going from a lush green to a dull brown in roughly 30 days. More from the Iowa State University Department of Agronomy here.

Before The Flood. High-res "MODIS" 250 meter resolution satellite imagery of Wisconsin on September 13, before the flood.

After The Flood. An image taken on September 29 shows the Wisconsin River out of it's banks - the 2 cities highlighted in blue (Arcadia and Portage) were largely evacuated at the height of the floods late last week. Data courtesy of the University of Wisconsin, more information here.

A Wild Sky - Over LA? Towering thunderheads over Los Angeles, and a spectacular rainbow hinting at better weather to come. Is this Kansas or beautiful downtown Burbank? Los Angeles has been hammered with strange weather in recent days, Monday's all-time record high of 113 F. giving way to midweek thunderstorms. An unlikely sky over LA on YouTube here.
Conservation Minnesota's Environmental Election Scorecard. Which candidates for office (from all parties) are truly looking out for Minnesota's environment? Quoting their web site: "The Conservation Minnesota Voter Fund endorses and works to elect candidates who are true conservation leaders.  Our goal is to elect leaders of all parties who understand the importance of natural resources to our health, our economy, and our lives." You might want to check it out before heading off to vote in a few weeks.

Climate Change And The Limits Of Skepticism. From an editorial in the Daily Princetonian: "Science is inherently uncertain. When scientists test a hypothesis, they can reject the hypothesis or support it, but they can never prove it. There is always the possibility that future research will qualify or even nullify previous work. But if I were to tell you that gravity is just a theory, you would laugh at me. The theory of gravity may have its limitations, but the understanding we gain from not rejecting its implications is vastly beneficial. The uncertainty of science is no reason to stand paralyzed in inaction." But a debate last week at Princeton between Fred Singer (one of the world's most prolific climate change deniers and a couple of bonafied climate scientists set off a debate about the "debate."

* 5 Steps To Help Keep Science Straight On Global Warming. This is one of the better explanations of the state of the science, what we know, what we suspect, where there is remaining uncertainty.

Top UK Science Agency Releases Climate Change Guide. The UK's National Academy of Science, the Royal Academy, has just released a new guide focusing on the science of climate change - where confidence in the scientific community is high, and where "substantial uncertainty" remains. The story is here - the actual pdf document "Climate Change - A Summary Of The Science" is here.

New Report Says U.S. Must Adapt To Climate Change Now. A National Climate Adaption Summit was held in Washington D.C. earlier this year, a pragmatic look at how we can adapt to a rapidly changing climate over North America (recognizing that a certain amount of change is already "baked" into our future). Some of the key points:

• The Summit report states that the United States must adapt to a changing climate now and prepare for increasing impacts on urban infrastructure, food, water, human health, and ecosystems in the coming decades.

• It urges local, regional, and federal decision makers to develop and coordinate climate change adaptation measures across these scales of government and with the private sector.

• Measures that increase resilience to climate change can include changes in technology, management practices, or institutions.

• The report also states that proactive adaptation planning can help minimize negative impacts of climate change on our Nation's communities, businesses, ecosystems, and citizens.

• The Federal Government must help to set priorities and share information about relevant programs and best practices.

The entire article is here.

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