Sunday, June 14, 2009

A Cooler Summer?

Here is the latest CPC (Climate Prediction Center) Outlook for the entire summer season, June, July and August. There's a better than 50/50 chance that the Dakotas and Minnesota will wind up cooler than average, with significantly hotter weather predicted for much of the west, far south and eastern seaboard. The extended (way-out-on-a-limb) forecast is based on trends in the Pacific Ocean, as well as blocks and "oscillations" setting up over the Northern Hemisphere, that all seem to point to an unusual amount of Canadian air emptying southward into the Upper Midwest the next couple of months. Is this proof that global warming is hogwash? No. This is still "weather", not "climate". Even if the forecast verifies (comes true) for Minnesota, it doesn't say anything about what's happening globally. We rely on a constellation of satellites and ground-based climate observations worldwide to help us get a global snapshot over time. We can't use a cool day, or even a cool summer, to disprove climate change any more than a resident of Phoenix or Washington D.C. can use a string of 90 or 100 degree days to "prove" that climate change is, in fact, a reality. It's tempting to look out the window and - assume - that the entire planet is feeling the chill (or the heat) but reality is a bit more complicated. Even meteorologists, who study day-to-day changes in weather patterns have a difficult time gauging what's happening worldwide over a span of months, years and decades. That's why we rely on climate scientists to give us insight into the big picture, and a majority of those scientists continue to believe that the (global) temperature trend is ever-upward. For more stories about climate change check out my ClimateSpot blog, which I try to update daily with new stories. It's a big puzzle, and no one weather event, storm, heatwave or cool front proves anything. Stepping back and trying to take in the big picture is challenging and time-consuming, but there is ample evidence for anyone truly taking the time to look. I HOPE global warming and subsequent climate change winds up being disproven; I hope another theory rises to the surface to explain the worldwide warming trend we're witnessing from the artic regions and Greenland southward to Antarctica, something else that accounts for shrinking glaciers, rising water levels and some of the truly baffling weather we're seeing in both hemispheres. There's plenty of incentive for a hot-shot Phd to find that smoking gun and convince other climatologists there's a better explanation for what we see all around us. I'm keeping an open mind - I hope you will too.

Sunday was extraordinary, summer the way we knew it could be here in the Land of 10,000 Weather Insults. Temperatures peaked in the mid 80s, a few chubby cumulus clouds strewn amidst cirrus blow-off from tall thunderheads poking up across the Dakotas. You may witness a few colleagues/friends/strangers sporting new sunburns today. A bubble of high pressure over the Great Lakes will turn our winds around to the southeast today, moisture creeping ever-eastward, fueling a shower/T-shower risk over southwestern Minnesota by late afternoon and evening. It should stay dry over the northeastern 2/3rds of Minnesota today, with enough dim sun for highs topping 80 in many towns, close to where we should be in the temperature department.

Tomorrow looks wet, with a much better chance of showers and T-storms statewide. There's a potential for a pretty good soaking, with some .25 to .50+" rainfall amounts. In fact Tuesday may very well wind up being the wettest day of the entire week. Considering that much of central and southern Minnesota is still too dry, and rain is scheduled for a weekday, we won't complain too much, ok? Just remind that whiny friend or office pest "hey, we need the rain." A damp start Wednesday should give way to some sun by midday and afternoon, but the next slow-moving trough of low pressure may spread more showery rains into town late Thursday and Friday.

The weekend forecast is tricky, especially Saturday. A persistent swirl of low pressure temporarily stuck over the Great Lakes may soak much of Wisconsin with a cool rain Saturday, and eastern counties of Minnesota may be close enough to this lingering storm for considerable cloudiness, the chance of showers increasing rapidly as you head east of the St. Croix. Sunday appears to be the safer, sunnier, milder day statewide as high pressure builds overhead, a dome of sinking, drying, warming air over Minnesota. So Saturday looks iffy, especially east of Mille Lacs and Twin Cities area lakes, although it should be fairly nice from St. Cloud on north to Gull Lake and the Whitefish Chain. My (strong) hunch is that Sunday will be the more popular outdoor day of next weekend.

WRF/NAM outlook for 7 pm this evening, showing regions of higher relative humidity (blue equates roughly with 70% RH) entering southwestern Minnesota. The best chance of late-day showers and embedded T-storms should remain southwest of the MN River Valley later today.

Rainfall (in inches) from June 7-13. Note that much of the northern half of Minnesota received less than .50" of rain (most lawns/fields/gardens require about 1" of water every week for sustained, healthy growth of flowers and crops in June). Southern Minnesota is in slightly better shape: 1.5 to 2" of rain fell there last week.

For the latest weekly rainfall estimates for the USA from the High Plains Regional Climate Center click here.

Weather Headlines

* Today: not as sunny as yesterday, still warm with highs topping 80.

* Best chance of showers/T-storms: south & west of the Minnesota River Valley.

* Tuesday looks wet statewide with a good chance of showers/storms.

* Break in the showery pattern Wednesday midday into Thursday afternoon.

* Next chance of organized showers comes late Thursday into Friday.

* Saturday rain may linger over Wisconsin, clouds and showers can't be ruled out over far eastern Minnesota.

* Sunday appears to be the sunnier, warmer, drier day of the weekend, statewide.

* Long-range guidance: highs mostly in the 80s the last full week of June. No more cold fronts in sight.

Paul's Outlook

Today: Fading sun, still seasonably warm. Winds: SE 10-15. High: 82

Tonight: More clouds, growing chance of a shower or T-shower. Low: 59

Tuesday: Mostly cloudy, showers likely, even a heavier T-storm or two. High: 73

Wednesday: Damp start, then becoming partly sunny. High: 74

Thursday: Sunny start, clouds increase PM hours. Some rain moving in late. High: 76

Friday: Unsettled with a few widely scattered showers. High: 74

Saturday: Mix of clouds and sun. Showers should stay well east of the St. Cloud area. High: 76

Sunday: Nicer day of the weekend. Sunnier and warmer. High: 82

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