Wednesday, July 14, 2010

Tornado & Heat Recap (and news of a real heat wave?)

What a day. You survived/endured one of the more unusual days of the summer - a free sauna in the comfort of your own back yard, coupled with a turbulent, violent sky mutating, minute by minute, overhead. Blast-furnace levels of heat and humidity (at one point the heat index in Fairmont reached an unimaginable 113 F - that's what it FELT like across far southern Minnesota). The dreaded dew point reached 78 at MSP and St. Cloud, over 80 from New Ulm to Rochester, similar to the humidity levels one might encounter in Abu Dhabi or the Philippines. Heat advisories, tornado watches and warnings - all capped off by an awe-inspiring sunset, the result of a massive thunderstorm anvil spreading north into the metro area, a thunderstorm helmet illuminated by the setting sun.

Fine Finish. This shot, taking shortly after 9 pm, shows a setting sun illuminating the underside of a massive cirrus cloud-shield, a thunderstorm anvil expanding north from storms bubbling up over extreme southeastern MN - it was an amazing site.

Beauty and the beast...

Northfield Tornado. These images were snapped shortly after 2 pm Wednesday near Northfield, the sun illuminating the tornado funnel, giving it a white appearance. Photos courtesy of KYMN Radio in Northfield.

Wednesday Madness. Highs reached 93 at St. Cloud, the Twin Cities and Redwood Falls, 01 at Rochester (where the dew point topped 80). Rainfall amounts reached nearly 2" at Grand Marais, only .08" at St. Cloud and .27" in the Twin Cities.

* 93 degree high in the Twin Cities Wednesday, 5th day above 90 this year (but factoring in a dew point of 77-78 F it FELT more like 100-105 around late afternoon).

* Heat index of 113 reported at Fairmont, dew point reaches 81 (!)

* At least 5 tornado touchdowns from Wednesday's storms, possibly more.

* 38 tornadoes so far in 2010 in Minnesota? As of Tuesday Pete Boulay from the MN State Climate Office reported a running tally of 33 tornadoes + 5 (preliminary) tornadoes yesterday.

* Reports of 4"+ rains in Barron county, Wisconsin on Wednesday.

Tornado Reports. SPC reports at least 4 separate tornado touchdowns, near Lakeville, Randolph, Northfield, and Cloverdale, up in Pine County. More possible tornadoes were spotted in western Wisconsin, the local NWS office in Chanhassen is dispatching a damage assessment team Thursday to determine the size and scope of these tornadoes - expect preliminary findings as early as Friday. See the latest reports from SPC here.

Touchdowns. Storm reports are automatically plotted on the "GR2 Analyst" software from Gibson Ridge. The main zone of tornado reports (and subsequent damage) was between Lakeville and Northfield, between 2 and 3 pm. The south metro went from blue sky to tornadic "supercell" thunderstorms in less than 45 minutes.

Wednesday Storm Reports. The NWS reported 4 touchdowns near Lakeville/Northfield, another in Pine County, with an additional 5 tornadoes reported across western Wisconsin. Click here for a detailed text report of all the severe storm reports out of the MPX office.

On Monday and Tuesday we tried to pinpoint the counties of Minnesota most likely to experience tornadic thunderstorms, and the models (coupled with gut feel) worked pretty well. On Tuesday we predicted the greatest risk would be "just south/east of the Twin Cities, probably east of I-35". It's impossible to predict tornadoes more than 30-60 minutes in advance, but all in all the forecast worked out pretty well (relieved that there were no reports of injuries or widespread damage, although we won't know the full extent of damage until teams arrive on the scene).

It was a turbulent Wednesday, no question. The day started with an MCS (mesoscale convective system) arriving, right no schedule, sweeping across central and northern Minnesota during the early morning hours, whipping up 2-3" rains, frequent lightning and winds over 50 mph. After a brief pause the main event kicked in shortly after 2 pm, a combination of extreme instability, wind shear and dew points near 80 sparking explosive thunderstorm development just south of the metro area - Northfield and Lakeville hardest hit, reports of vehicles swept across highways and damage to some homes and barns. Funnels were spotted near Glenwood, a lowering, rotating wall cloud causing quite a stir near Sauk Center, sparking more funnels north of St. Cloud between 3 and 4 pm. More severe storm watches were posted, but by that time winds were already swinging around to the west, drier air sweeping the worst of the storms across southeastern MN into Wisconsin.

Rainfall Recap. The first batch of storms that swept across central and northern MN Wednesday morning dropped some 1.5 to 2" rainfall amounts from near Wadena to Brainerd to Sandstone. The severe storms that erupted during the afternoon dumped even heavier amounts of rain on extreme southeastern MN and western WI, Doppler radar estimates suggesting some 3" amounts near Wabasha, maybe as much as 5-6" closer to Black River Falls, Wisconsin.

So now we exhale, enjoy a couple of phenomenal days, blue sky, more reasonable humidity levels (dew points in the 50s have never felt better) and wait for another warm-up coming Saturday. The weekend looks pretty good right now, hardly meteorological perfection (it's 'gonna be stinking hot on Saturday with a gusty south wind, maybe a few late-day and nighttime storms, especially up north). Sunday looks better, drier statewide, and just a couple degrees cooler. But the vast majority of the weekend should be dry - perfect weather to check out the Hopkins Raspberry Festival, or the million and one other things to do around the state.

How (on earth) did it get to be "mid summer"? That's the problem with our fleeting warm weather season here in Minnesota, if you blink, sneeze, change the channel, it's already Minnesota State Fair Time, you're already being annoyed with back-to-school commercials. Please let time stand still for a few more weeks...

"Heat-pump High" Long-range models show an expansive bubble of high pressure temporarily stalling over the Ohio Valley the latter half of next week, forcing the main belt of westerlies, the core of the jet stream, north of Minnesota. The result? As many as 7-12 days or more of highs above 90 from roughly July 21 through the first few days of August. We're due for an extended stretch of heat, and it's finally showing up on the maps. To track the progression of the 500 mb winds (roughly 19,000 feet above the ground) over the next 10 days, click here (data courtesy of Unisys).

Now, at the risk of burying the lead, news of impending heat. We've been pretty lucky so far, just a few brief, fleeting glimpses of summer heat, nothing prolonged (or controversial). That may change next week. The GFS model is strongly hinting at 1-2 weeks of 90s, starting next Wednesday, going through the end of July, possibly the first few days of August. That's hardly surprising, considering our hottest weather routinely comes in late July. Enjoy today's slightly-cooler-front - I have a hunch with 8-10 days friends, neighbors, colleagues will all be griping about the Dog Days of Summer (in unison). Something to look forward to huh?

Hammond, Wisconsin Damage. Here is a YouTube clip showing one example of the wind damage from recent storms in Hammond, impossible to tell if it was straight-line winds or tornadic.

Typhoon Conson. Here is footage from the recent typhoon (same thing as a hurricane) that slammed into the Philippines, causing massive flooding.

Daily Oil Impact Assessment. If you're interested in a blow-by-blow, day-by-day accounting of clean-up efforts in the Gulf click here to see the very latest initiatives and projects underway. Another tracking tool, showing fishing closures, the size and direction of the spill - an amazing interactive site that packs in a lot of relevant, current information.

Tracking Ocean Currents in the Gulf of Mexico. Here is a link explaining the intricate currents in the Gulf, and the possible impact on the growing oil slick - where will it go next?

Oily Waters - Is NOAA Hoarding Key Data On Oil Spill Damage? It appears that real-time observations from the Gulf (above and below sea level) are getting to BP much faster than they're getting out to the general public. An interesting development here.

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

Today: Mostly sunny, breezy and pleasant (a big drop in humidity from yesterday). Winds: W/NW 15-25. High: 84

Thursday night: Clear and comfortable. Low: 66

Friday: Sunny, heating up again. High: 88

Saturday: Hazy sun, sticky and hot with a stiff south wind. T-storms possible late, especially central and northern MN. Winds: S 10-20+ High: near 90

Sunday: Drier and sunnier with a slight dip in humidity - probably dry. Winds: W/NW 10-15+ High: 87

Monday: Lot's of sun, beautiful. High: 85

Tuesday: Partly sunny and seasonably warm. High: 86

Wednesday: Blue sky, sticky and plenty hot. High: 91

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