* Clouds roll in today, heavy rain likely from this evening through much of Thursday, latest models printing out 2-3" for the Twin Cities, a "tropical rain" likely (more typical of June than September).
* Flood watch issued by the NWS for much of Minnesota from tonight into Friday morning.
* Unsettled Saturday - passing shower or two possible, temperatures holding in the 60s.
* Sunday still looks like the sunnier, milder day, chance of sampling low to mid 70s.
* 8-14 Day Outlook keeps Minnesota significantly milder than normal through the first week of October.
* New summertime record for the Twin Cities: nighttime lows for June, July and August were the warmest ever recorded, nearly 5 degrees F. warmer than "average."
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Gulley-Gushing, Window-Rattling Rain? The latest NAM/WRF model prints out 2.65" of rain for the Twin Cities by Thursday evening. Some 2-4" amounts may set up over parts of central MN (looks like the north metro could see as much as TWICE as much rain as the south metro). Watering optional until further notice.
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Paul's Conservation MN Outlook for the Twin Cities and all of Minnesota:
Today: Some sun early, then increasing clouds - rain possible by late afternoon/evening. Wind: East 10-20. High: 67
Wednesday night: Cloudy with rain likely, heavy at times. Low: 59
Thursday: Rain, heavy at times - a few T-storms possible (some 1-3" amounts possible). High: 72
Friday: Windy and cooler with more clouds than sun - drying out (dry for evening football games). High: 65
Saturday: Still unsettled, more clouds than sun with a passing shower possible. High: 66
Sunday: Much better. Probably the nicer day, plenty of sun, breezy and mild by afternoon. High: 73
Monday: Blue sky, still lukewarm. High: 74
Tuesday: Clouds increase - slight chance of a shower or sprinkle late. High: 69
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What a strange September we're muddling through. I was pretty pumped up in late August, anticipating a mostly-sunny, mostly-dry September with a spell of lukewarm days, and a rapid drop-off in thunderstorms. We should be worrying about foggy mornings, tracking hurricanes in the Atlantic and Caribbean - instead we're tracking significant storms every 2-3 days, still tormented by bouts of severe weather. Burnsville picked up quarter-size (1" diameter) hail late Monday night, right after the metro area experienced a high of 80 close to midnight. What the heck is going on here?
We salvaged a good-looking Tuesday with a welcome dip in humidity - no weather complaints yesterday. Expect a dry commute this morning, but any fleeting sun will get snuffed out by increasing clouds by midday, a good chance that rain may streak into town by late afternoon or evening. Not sure about after-school activities later today - odds favor some rain after 4 or 5 pm. That rain may fall (heavy at times) tonight into a portion of Thursday - some of the computer models still printing out some 1-3" rainfall amounts for the metro area by Thursday evening, even a band of 3-5" from near St. Cloud and Monticello into the far northern suburbs of the Twin Cities. If that verifies we may have some minor flooding problems across parts of central MN by tomorrow, some swollen streams, wet basements, flooded intersections. That's typical of June, but September?
What strikes me about the summer of '10? A couple of things: humidity levels significantly higher than long-term normals. 145 tornadoes, Minnesota still leading the nation in that unlikely count, and a warmer than normal summer than lead to a much greater consumption of electricity to keep us cool. Based on "cooling degree days" we spent an estimated 35% more money than usual cooling our homes and businesses than normal. Where we're really seeing much of the warming (during the summer as well as the winter) is in the observed nighttime lows. As I mentioned up top nighttime lows in the Twin Cities during June, July and August ran almost 5 degrees F. warmer than average. The reason? Consistently higher dew points, more moisture in the air (the temperature can't fall below the dew point). If you have a day where the dew point is 70 you limit how cool it can get during the nighttime hours. More moisture in the air also provides more potential fuel for severe storms, flash flooding, hail and tornadoes. According to Pete Boulay at the MN Climate Office we had 252 hours of dew points > 70 F. this summer - that's 80 hours more than usual! Yes, it was an unusually sticky summer - that kept us warmer at night (and stormier than average, whatever "average" is these days).
So a pouring, soaking rain is expected from tonight into much of Thursday, maybe an inch or two for the metro, with some 2-4" amounts not out of the question across central Minnesota. A wind shift to the northwest on the backside of this area of low pressure begins to punch a few sunny holes in our stale cloud deck Friday - we begin to dry out, but scrappy stratocumulus clouds may linger much of the day (although I expect dry weather for Friday evening football games).
The weekend outlook? A bit more muddled than it was yesterday, I'm afraid. Models are hinting at a cold wrinkle of air drifting over Minnesota Saturday (one of those 'dang-blasted "upper air disturbances" that increasingly torment us during the fall months). If the sun is out for a few hours Saturday morning (likely) the airmass overhead may become unstable enough for a few instability clouds, even a passing shower or two Saturday afternoon. It won't rain all day - it should NOT be as runny & muddy as tomorrow - but a 20-30 minute shower can't be ruled out Saturday afternoon. By Sunday this cold twist aloft pinwheels over the Great Lakes, a warming trend aloft promising a more stable atmosphere floating overhead. That should mean more sun, enough blue sky for low to mid 70s across much of Minnesota with a light southwest breeze. Sunday should be a classic September day across the state - without a doubt the nicer day of the weekend.
We can't (officially) call it Indian Summer - yet. The reason? Most of central and southern Minnesota has yet to experience the first killing frost of the season. Up north locals can safely call it Indian Summer, without reproach or some weather know-it-all gently correcting you. North of Brainerd and Mille Lacs most areas HAVE seen the first frost, even the first killing freeze with a few hours colder than 28 up on the Iron Range.
Sunny, mild (dry) weather should spill over into Monday, possibly Tuesday, before the next clipper-like system whips up a few showers or sprinkles late Tuesday.
The foulest day in sight: Thursday. No redeeming qualities whatsoever, at least weatherwise. the best day in sight? Sunday. Blue sky, low humidity, highs topping 70s across most of central and southern Minnesota. By Monday a few towns south and west of the MN River may approach 80. That's more like it. Hey, the 8-14 Day Extended Outlook from the Climate Prediction Center has us considerably warmer than average through the first week of October.
Hope springs eternal...
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