Sunday, September 19, 2010

Troubling Trends in the Arctic (and unusually warm nighttime lows in the USA this past summer)

* Warming trend: a string of 70s likely this week.

* Passing shower today, but Thursday looks like the wet day (1-2" rains possible).

* Early word on next weekend: partly sunny and mild, highs in the 70s.

* Summer temperatures: nighttime "lows" were exceptionally warm east of the Mississippi River. More in the blog.

Soggy End To The Summer Season. This map shows estimated rainfall for the last 30 days, based on Doppler radar. The south metro picked up 2-3", while the north metro has been soaked with 3-5" amounts. Every county shaded in red has seen at least 5" of rain in the last month, some 8-10" estimates over southwestern Minnesota! See the NOAA rainfall data for yourself by clicking here.

Heavy Jackets in mid September? Wake-up temperatures Sunday morning dipped into the upper 30s over the far northern suburbs of the Twin Cities, including Cambridge and Princeton, the "urban heat island" (more asphalt/concrete) retaining heat in the immediate Twin Cities, keeping temperatures 10-15 degrees milder.

Autumnal Equinox. It's hard to believe that autumn officially arrives Wednesday night, when the sun's direct rays will pass directly over the equator (heading south, I might add). The autumnal equinox means roughly equivalent levels of daylight & darkness. As far as the atmosphere is concerned fall really arrived closer to September 1. Historically the warmest 90 day period comes from June 1 to September 1, so "Meteorological Autumn" really kicked off about 20 days ago. More on the equinox here.

A "Live" Hurricane. Check out this live, streaming webcam from Bermuda. Thigh-high water was reported on the western end of the island Sunday evening - Category 1 Hurricane Igor's eye is passing just west of Bermuda, lashing the island with 70-90 mph gusts and a storm surge over 5 feet.

* Yes, Sunday was cloud-cluttered and cool, but it could have been considerably worse. On September 19, 1927 a "trace" of snow flurries was observed in the Twin Cities. Not a great day to be a weatherman in the state of Minnesota.

Sunday Numbers. No rain reported anywhere in the state, high temperatures about 5-10 degrees cooler than normal, ranging from 61 at Alexandria to 62 in St. Cloud, 64 in the Twin Cities.


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

Today: Mostly cloudy, windy and milder - chance of a brief shower (steadier light rain expected up north). Winds: SE 15-25. High: 74

Monday night: Showers, possible thunder - milder than recent nights. Low: 60

Tuesday: Unsettled start with an AM shower or T-shower, then PM clearing. High: 73

Wednesday: Plenty of sunshine - a beautiful fall day! High: 68

Thursday: Gray and soggy with rain likely, potentially heavy (models hinting at some 1-2" amounts). High: 72

Friday: A mix of clouds and sunshine, still lukewarm. High: 74

Saturday: More clouds than sun, probably dry (brief shower up north?) High: 73

Sunday: More sun, still balmy - probably the nicer day of the weekend. High: 71

September can be a beautiful month, arguably one of the nicest months of the entire year with hazy-blue skies and highs reaching the 70s, even the 80s. It can also be a volatile month as the first jabs of winter invade on harsh, northwest winds. We can see frost, accumulating snow, tornadoes, even 90s - all in the convenient span of one single (eye-opening) month.

Anything is possible in September, but with less humidity there's far less fuel for severe thunderstorms, and roughly half as many wet days as we endure during June. September temperatures are running 2.5 F. cooler than average, we've had 10 days with highs in the 60s, one day in the 50s (no 80s....yet). The jet stream, the main superhighway for storms, has dipped unusually far south, more typical of late September or early October, meaning more rain (1.95" so far, about a tenth of an inch wetter than average, do date), and more frequent changes....storms and fronts stacked roughly 2-3 days apart. No rest for the weary. It's as if Mother Nature has grabbed a remote control and pressed the fast-forward button on fall. It's been too cool....too soon. In an attempt to maintain some sense of equilibrium temperatures will mellow considerably this week - every single day through next Monday should be in the 70s, except for possibly Wednesday, when a fresh outbreak of Canadian air may keep us in the 60s. that's right - we should average a couple degrees above normal for the next 7-10 days, a little cosmic payback for early goosebumps.

Forgettable Thursday? The GFS model is printing out anywhere from 1.8 to 2" of rain on Thursday, in all probability the wettest day of the week. Severe weather is doubtful, but a few embedded T-storms can't be ruled out, especially over southern MN, where dew point temperatures may be close to 60.

The approach of a vigorous warm front sparks more clouds today, a passing shower can't be ruled out, with more widespread light rain expected over parts of central and northern Minnesota. A showery start Tuesday gives way to a clearing trend by afternoon as winds turn around to the northwest, a dry spell late Tuesday into Wednesday. The wettest day of the week looks like Thursday, when some 1-2" rainfall amounts may result as a storm tracks east. Have a Plan B (and C) for Thursday. The sun punches more holes in our cloud deck Friday, and in spite of a brief instability shower Saturday next weekend looks pretty nice right now - highs mostly in the 70s, Sunday probably the sunnier, nicer day to take in some ripening leaves, toss a football, or make one last (?) pilgrimage up to your favorite lake. Not sure we'll see 80, but I'm banking on at least 5-7 days above 70 through the first few days of next week.

September is about to mellow out a bit (fewer grumpy neighbors and colleagues mumbling about the "cool, gray, lousy weather"). Yes, we got off to a chilly, October-like start, but my hunch is that the last week or so of September may wind up being the nicest week of the entire month, restoring some of your temporarily misplaced faith in a Minnesota Fall. We're due for a break...

The Worst Summer Ever? Dark Side of Climate Change Seen in Record-Setting Nighttime Temperatures. The NRDC, the National Resources Defense Counsel, has released data about summer temperatures around the USA - specifically the pronounced trend toward much water nighttime low temperatures, especially east of the Mississippi River. Nighttime lows were the warmest ever recorded at nearly 1 in 4 weather stations in NOAA's Climate Network. This means that at 278 stations the average nighttime low temperature for June, July and August were warmer than any time since 1895. More than half the 1,218 climate stations recorded nighttime lows among their 5 hottest on record. According to NRDC "nighttime temperatures are more sensitive to the buildup of heat-trapping pollution in the atmosphere than daytime temperatures because increases in aerosols and cloud-cover have counteracted some of the warming effect of greenhouse gases during the day. Hot, stagnant nights can prove even more harmful than daytime highs as vulnerable populations (particularly the elderly) are unable to cool down and get some relief from the stress of daytime heat." More here.

Arctic Region Is Continuing Down In A Death Spiral: Every Bit Of Evidence We Have Says The Ice Is Thinning. There is a fair amount of disinformation out there right now about what's happening in the arctic: "no worries - ice is getting thicker again!" That's not the case. In 2009 average ice volume between June and September fell to a record low of 8,000 cubic kilometers, 55% lower than the 1979 to 2000 average. This year is forecast to be even lower - the story is here.

Troubling Trends. Last week we brought you a story about tens of thousands of walruses washing ashore over northwestern Alaska (because the ice they normally rely on has melted - leaving them nowhere to stay and breed). More from CBS News here.

Arctic Sea Ice Volume Anomaly. The trends since 1959 are fairly evident - the shrinkage of arctic ice even more extreme since 2006. Something is happening up north - and to believe otherwise is to ignore a large and growing body of scientific evidence. More from the Polar Science Center here.

Aren't We Clever. St. Louis Park's Thomas Friedman (of New York Times fame) wrote a Sunday editorial which struck a chord. He argues that the USA is missing a golden opportunity to reinvent itself into a green economy - acknowledge the obvious: the climate is changing, and some of the symptoms are most unpleasant - and by going green and encouraging non-carbon-based technologies we can not only clean up the air, but PUT AMERICANS BACK TO WORK. This is about jobs, plain and simple. It's ironic - while Congress dithers and sits on their hands - the Chinese have no illusions about the future. "There is really no debate about climate change in China," said Peggy Liu, Chairwoman of the Joint U.S. - China Collaboration on Clean Energy, a non-profit group working to accelerate the greening of China. "China's leaders are mostly engineers and scientists, so they don't waste time questioning scientific data." Read Friedman's editorial here. The Chinese are taking the lead - manufacturing a majority of the world's solar panels and (soon) wind turbines. We could retool Detroit and the rest of the Rust Belt to manufacture green technology - what we need is a vision and the political will to move forward. But with the current polarization and finger-pointing going on in Washington D.C. I wonder if and when we'll get back on track. The Chinese aren't waiting - it's our game to lose.

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