Sunday, July 18, 2010

Isolated T-storms (a quieter week on tap)

* 7-8 tornadoes reported across Minnesota on Saturday, total for the year: close to 40.

* July: 4.4 F. warmer than average in the Twin Cities.

* 4 days above 90 so far in July, 7 days above 90 so far in 2010.

* Cooling degree data: summer season running warmer than average - we've spent nearly 24% more than usual cooling our homes and offices so far this summer season.

Superb Sunday. After Saturday's atmospheric rock and roll it was nice to get a break Sunday, highs in the low to mid 80s statewide, morning cloud cover giving way to sunshine by afternoon. 24-hour rainfall amounts ranged from nothing in Alexandria to 1.38" at Eau Claire, WI (most of that shortly after midnight).

Sunday Flashback. After Saturday's ugly sky it was nice to go through an entire day without consulting the Doppler radar screen or tilting your head to find out if the emergency sirens are sounding (again). The sunset was remarkable, a reminder of why we live here, why we stay (in spite of our challenging winters). If only we could pause time RIGHT NOW.


Severe Saturday Recap. SPC has 8 separate tornado touchdowns on Saturday across Minnesota, although I suspect the Anoka tornado may have been the same one that hit the Dayton area. We may know more later today or tomorrow, but there is no doubt that Saturday's outbreak was probably second only to the June 17 tornado swarm. Look for more details on the local NWS web site here.

"Hailer" Here is video of the supercell thunderstorm that swept from northwest to southeast, tracking over 100 miles from near Long Prairie to St. Bonifacius, where this video was captured. It's the same cell that spawned 4 1/2" hail near Cold Spring, that's larger than baseball size. Yes, that could put a bit of dent in your vehicle (or your skull, for that matter).



Well, we're 0 for 1. After a tormented Saturday, sprinkled with tornadoes, funnels, baseball-size hail and bow echoes, we enjoyed a pretty phenomenal Sunday. A gray start (residual moisture leftover from Saturday night's soaking rains) giving way to afternoon sunshine, a fresh northwest breeze and a welcome drop in humidity levels. Highs peaked in the low 80s, pretty close to "normal" for the 18th day of July. It was atmospheric redemption after Saturday's sinister sky, blaring sirens and Doppler-speak. Yes, I'm sorely tempted to test whether Doppler radar floats. I think it could be a worthy scientific experiment.

We hang onto sunshine much of today, although a close proximity to a troubled frontal boundary may spark a few late afternoon T-storms - mainly over far southern Minnesota, the chance spiking higher the closer you drive to Iowa. So avoid Iowa at all costs. A few storms from Waterloo to Des Moines may turn severe later today, but I think any rough storms will probably pass well south of the area. An instability shower or T-shower can't be entirely ruled out up north (best chance of a quick 20 minute shower between 4 and 7 pm, when the atmosphere is most unstable).

Popcorn T-showers. NAM/WRF output valid around dinnertime today, showing expected rainfall between noon and 6 pm. Conditions aloft are ripe for a few isolated (instability) showers and T-showers by late afternoon, but any severe storms should sail off to our south across Iowa. We may actually go an entire week with no (widespread) severe weather outbreaks.

The cycle will repeat itself again Tuesday: morning sun, a few stray PM T-showers sprouting up, probably garden-variety storms, the odds of severe weather slim. We may get a break Wednesday before that frontal boundary makes another northward pass, kicking up more widespread T-storms (some strong to potentially severe) from Thursday afternoon into Friday morning.

The good news? Computer models sweep most of the storms to our south and east during the day Friday - skies should clear as the day goes on, with a weak bubble of high pressure drifting right over Minnesota Saturday, implying generous sunshine, light winds and highs in the 80s pretty much statewide. It's early, but if I had to gamble I'd bet on Saturday as the nicer day of the weekend. Although Sunday doesn't look too shabby either, a little more haze and humidity as that fair-weather-bubble drifts toward Chicago, turning on a southerly breeze statewide.

Last week the long-range (and admittedly unreliable) GFS 15-day model was hinting at a spell of real heat here, starting late this week, spilling over into the last week of July, possibly the first few days of August. The last few runs don't look nearly as ominous, keeping daytime highs mostly in the 80s into next week, close to normal, no big weather surprises lurking out there anytime soon.

Have a great Monday - hopefully weather will be something of an afterthought this week. We're due for a quiet spell.

July Stats. So far at MPX temperatures are running 4.4 F. above average, 4 days above 90 F. A total of 1.92" of rain has fallen, .45" less than average, to date. Based on cooling degree data from the National Weather Service we've spent about 24% more than during a typical summer season to cool our home and offices. Here is a link to the latest data for the Twin Cities in July.

Kentucky Floods. At least 2 deaths have been blamed on severe flooding in the hills of eastern Kentucky over the weekend. 5,000 locals were impacted, an estimated 200 homes damaged or destroyed. The story is here.

North Pole Cam. I've seen plenty of webcams, but this is the first time I've seen a webcam transmitting images from the top of the world. Pretty impressive. Check out NOAA's Arctic Theme page here.

"Our Beaker Is Starting To Boil" Think climate change is a hoax? Try telling that to residents of Tibet, where most of the local glaciers are in full-retreat. This is the "Kyetrak" glacier, the photo on the left taken in 1921, the one on the right snapped in 2009. Click here to see an interactive image, a before and after sequence that puts things into perspective. Mountaineer David Breashears has climbed throughout the world, and lately he's noticed some astonishing changes on the mountains he's scaled, and the glaciers surrounding those mountains. He's documented some of the changes he's witnessed in the article. You don't have to travel to the Himalayas to see these transformations. Glacier National Park had approximately 150 glaciers a century ago, at least count that number was down to 25. Coincidence? Possibly, but on a global scale? The story in the New York Times is here.

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

Today: Sunshine giving way to a partly sunny afternoon, slight chance of a late-day T-shower. Winds: S 8-13. High: 77

Monday night: Partly cloudy. Low: 64

Tuesday: Still unsettled, morning sun giving way to a few scattered (late PM) T-storms. High: 81

Wednesday: Mix of clouds and sun, more humidity - probably dry. High: 86

Thursday: Sticky with a growing risk of T-storms, some potentially heavy. High: 88

Friday: Stormy start, then gradual clearing, getting better as the day goes on. High: 86

Saturday: High pressure overhead: lot's of sunshine, light winds. High: 85

Sunday: Hazy sun, more humid, probably dry. High: 86

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