Tuesday, June 30, 2009

In Search of Summer

Well, this is a first. Just when you think you've seen everything Mother Nature can dish out on an unsuspecting populace, along comes the Crazy, Illogical Summer of '09. It is summer out there, right? The calendar on the wall insists that it's July 1. They why are Minnesotans up north wandering the streets in light jackets and sweatshirts? This makes no sense, I admit. A few weeks ago the mercury brushed 100 degrees - now we're all walking around in an early-October funk. Look at it this way: we're getting the coolest, cloudiest, lousiest weather out of the way, so skies can clear and temperatures can recover in time for the biggest holiday weekend of summer. That's how I'm rationalizing all of this. It could be worse. Under the center of a stalled Great Lakes storms daytime highs never climbed out of the 50s across northern Michigan, a rare summer wind chill making it FEEL like upper 40s! This is the first, and hopefully the last time I will ever subject you to a windchill map in mid summer.

So what does this mean for climate change Paul? Ready to concede - toss in the towel? No. And it's not because I have a streak of German stubbornness deep in my DNA. It's easy to confuse "weather" with "climate". It's the difference between CNN Headline News and the History Channel. Even for meteorologists it's exceedingly difficult to keep a global perspective. Yes, it was unusually cool today across the Great Lakes and Midwest, but did unseasonably warm weather across Siberia and Scandinavia more than compensate for this cool spell? The only way to track global temperatures trends is via satellite observations - distilling an accurate global perspective is difficult using airport observations taken at the top of every hour. Thousands of climate scientists have examined "peer-reviewed" research and come to the same conclusion: overall, over time, the planet is warming, in fact it's accelerating. Don't rely on blogs and regurgitated talking points to get solid science: these climatologists have already taken a close look at the sun, and whether fluctuations in the "solar constant", the amount of energy reaching the Earth, might be responsible for this observed warming trend. Compared to the 38% spike in greenhouse gas, most of that in the last 50 years, the sun's effect is thought to be minimal. Many of the skeptics aren't even climate scientists, they're economists, or researchers funded by special interests with a vested interest in the status quo. I'm fairly conservative in my politics, but this has nothing to do with politics or think-tanks or Heritage Foundations and everything to do with pure science, peer-reviewed science. On that score there remains a very solid, unwavering consensus. These men and women haven't flip-flopped, the evidence continues to mount, and greenhouse gas emissions remain the most likely cause of some of the symptoms we're witnessing worldwide. If another, better theory emerges to explain what we're seeing, the rise in ocean sea levels, shrinking glaciers and rapid changes in the arctic regions, I'll be the first to jump ship and admit that anthropogenic warming is a crock. That hasn't happened yet. Beware of blogs for a straight, unbiased, scientific perspective. I rely on the National Science Foundation, the National Academy of Science, the American Meteorological Society - and thousands of professional PhD climate scientists around the world for reliable, accurate, unbiased, apolitical news on what the climate is really doing. I hope you'll keep an open mind - and consider the source.

Tuesday's highs, courtesy of the Plymouth State Weather Center. Notice the Great Lakes, where highs held in the 50s and low 60s, more typical of late April than late June. Much of the rest of America is baking in the 90s, but we were lucky (?) to enjoy some free air conditioning.

The stubborn, unusually strong storm that has kept Minnesota in a cool, gusty stranglehold since the weekend will finally get an eastward nudge today, the clearing line will shift eastward, and sunshine should be on the increase statewide as wind finally begin to ease up. Thick clouds can make a 10-20 degree difference in temperature during the summer months, and with more sun the mercury will get a much-needed kick, meaning low 70s today, upper 70s to near 80 on Thursday. Thunderstorms will rumble across the central Plains, staying well south of Minnesota through the end of the week.

One computer model (NAM/WRF) is hinting at a few random T-storms marching across Minnesota early Monday, but the majority of computer simulations keep us basically dry, sunny and lukewarm through most of the holiday weekend. No sign of anything resembling hot weather anytime soon - we're expected mid to upper 70s Friday and Saturday, a few degrees cooler on Sunday as a weak bubble of high pressure remains in control. Can I PROMISE or GUARANTEE a perfect holiday weekend, weatherwise? No, it's still a little early - I want to see a couple more model runs before I bless the holiday forecast (no room for cockiness when a major holiday weekend is on the horizon!) Storms, given a choice, prefer to come on weekends, they get extra points when they foul up the 4th. So I'm still cautiously optimistic, but not yet overly confident. I'm fairly sure that temperatures will run a few degrees below average. But the latest model run has me a little spooked, printing out about .10" of rain late Friday night and Saturday morning. It may be a fluke, an aberration, a mistake, but I can't discount it altogether, not yet.

GFS Outlook for Saturday morning, July 4, showing dry weather across Minnesota, showers and storms staying to our south/west across the Dakotas and central Plains. Looking at this you'd be tempted to say, "great news, a dry, mild 4th of July is likely!" Not so fast...

WRF/NAM Outlook for the same period, Saturday morning at 7 am, July 4. Yes, this looks dramatically different than the GFS solution for the same time, showing bands of showers and T-storms, some heavy, tracking across Minnesota. On paper this model is the more reliable, accurate model, with more refined physics. That said, I sincerely hope it's dead wrong.

Paul's Outlook

Today: Partly sunny, less wind than yesterday. Winds: North 10-20. High: 73

Tonight: Clearing, cool for early July. Low: 55

Tomorrow: More sun, noticeably warmer. High: near 80

Friday (July 3): Mix of clouds and sun, stray T-storm or two far north. High: 78

Saturday (July 4): Partly sunny, slightly more humid. A T-storm or two can't be ruled out. High: 77


Monday: Plenty of mild sunshine. High: 79

Tuesday: Sun fades, clouds increase. Growing chance of late-day T-storms. High: 81
Sunday (July 5): More sun, probably dry. High: 75

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