8/3 NOW: Upper Midwest

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Intense bow echo continues near FSD currently. Reported gusts near 90 mph and numerous other svr wind reports. Radar shows a relatively compact convective system now, though radial velocities from FSD are very intense! SPC just issued a PDS Severe weatch for widespread winds to 90mph... RUC indicates extreme CAPE will build into northern IA through the afternoon, ahead of the current complex. This instability should maintain and strengthen the system with time... Additionally, the system will likely increase in size as it tracks into far southern MN and into northern IA.
 
There is also increasing convective coverage along the outflow boundary from the SD/MN MCS extending south and southwestward toward the surface low just east of Broken Bow. Convection was also starting to develop southeastward along the other residual outflow boundary that runs from ~ SUX to SPI. SPC RUC Mesoanalyses suggest the atmosphere is still capped strongly in these areas - so convection could currently be elevated in nature - but sufficient shear exists along the northern extent of this convection to allow for storm organization, and persistent upper level divergence over eastern NE should continue to promote additional convective development and cap erosion - perhaps allowing a few cells to tap into the boundary layer by early afternoon. Areas from SUX to Ft. Dodge look worth watching for the next few hours. Anyone else have thoughts on this?

Glen
 
TOR warning up for what appears to be a tail-end charlie storm riding an OFB (maybe?). Strong velocity couplet seen on radar and a hint of a hook on BREF. This storm is currently WNW of Ames, IA.
 
Interesting Severe Weather Statement out of Des Moines at 4:02pm CDT
this is for Greene County Iowa, currently has a tornado warning for it.
AT 356 PM...NWS SPOTTERS REPORTED A FUNNEL CLOUD NEAR CHURDAN...BUT
AS OF 402 PM AMATUER RADIO SPOTTERS DID NOT SEE A FUNNEL.
WW 698 TORNADO IA IL 032125Z - 040300Z
WW 699 SEVERE TSTM WI LM 032145Z - 040300Z just been issued.

Mike
 
Level II data shows 64.5dbZ up to 28K just over Dana so there's plenty of hail ready to fall out... Rotation not as good as before with outflow racing ahead of storm. Temps dropping nearly 20 degrees with passage.
 
So, SPC just issued a T box for much of e IA into nw IL - bit of a surprise move in my opinion - I don't really see much of a tornado threat developing in that area. Plenty of instability - but still somewhat capped, and heating for the day is coming to a close. Helicity is currently pretty lame in the region boxed - though the RUC forecast suggests this will change over the next few hours. Upstream convection is looking pretty linear already, so it will be interesting to see if this box verifies.

Glen
 
So, SPC just issued a T box for much of e IA into nw IL - bit of a surprise move in my opinion - I don't really see much of a tornado threat developing in that area. Plenty of instability - but still somewhat capped, and heating for the day is coming to a close. Helicity is currently pretty lame in the region boxed - though the RUC forecast suggests this will change over the next few hours. Upstream convection is looking pretty linear already, so it will be interesting to see if this box verifies.

Glen

I agree - The southern most storm (tail end charlie) just threw out an outflow, so I don't see any significant potential there (its weakening now, probably due to the cap you mention - which is probably weakening the cold pool)... The middle storm (between the tail end charlie and the stuff in extreme northern IA/southern MN) looks like its now beginning to bow out...
 
Plenty of CAPE (I'm looking at SBCAPE of 7000+ on SPC's hourly meso analysis page on the border between IA and MO) with a weak to non-existant CIN can do amazing things, even with little to marginal helicities/shear. If some storms can fire along that OFB that tail-end charlie just laid out, we might be seeing something...
 
Updated: 508 PM CDT

-Report of 80 mph winds out of Iowa Falls in Hardin County
-Tornado warning: Iowa for Marshall County
-Tornado warnings Wisconsin for Sauk Counties
nice little boundary moving west on MKX radar

-Storms just popped up in Dodge County Nebraska
WW 700 TORNADO IA NE 032200Z - 040300Z

Mike
 
I decide to take a look at the weather cause im bored and look what i find, a CAPE of 4885 and a CINH of 0029 wow. I hope these stormes get going before sunset so that I can use my camera some more... and my roommates Rav4 hehe.
 
The cell just west of OMA - if you are within an hours drive from it I'd seriously consider giving this cell a visit. the intersection of the outflow with the line in IA might get it done - but the motion of E @ 55 would make for a difficult chase.....

Glen
 
That storm just west of Omaha, that just popped up within
the last hour, a severe thunderstorm warning was issued
for Dodge County at 459 PM CDT, in neighbor Saunders
County at 520 pm CDT now has a tornado warning and
a tornado warning just issued for Dodge County at 543pm.

Storm formed along the warm front.
http://mgweather.com/OAX.SRMV1.gif Time:2235Z

Mike
 
According to MikeH, the merger of that storm west of Omaha and another smaller cell that was behind the southern end didn't help things and it now looks outflow dominant. Radar trends indicate it may be trying to reorganize and propogate along the boundary however.
 
Storm Spreading

Indeed there is a outflow boundary! NWS radar out of OMA is showing a nice trail of OFB streching from Columbus toward Wahoo and Fremont. Also the storm system is enlarging toward the north in Washington County in NE. Got word that Sarpy County in NE is under a SWW and that includes the city of Omaha.
 
We've had two tornado warnings so far in Wisconsin with the developing storms this afternoon, one in Grant County and another in Dodge County. Some pretty intense rain reported on the radio, 2 inche downpours. The Wisconsin Dells report streets flooded now with over 10 inches of water.

It was interesting to watch the lake breeze collide with the storms in the middle of the state. It looked like outflow heading due west, meeting the storms heading due east. Where they met, the storms grew in intensity.

Storms still developing west of Madison.
 
There was 2 tornadoes reported in Iowa today earlier:

-453 pm CDT 8 miles southwest of Hubbard in Hardin County, Iowa
A breif touchdown, it moved a camper

-455 pm CDT 6 miles south of Radcliffe in Hardin County, Iowa
Tornado touchdown. Outbuildings and house damaged. No injuries

Mike
 
I don't see a reports thread so I'll put my thoughts on this thread. Turned into a real wind chase in EC Nebraska. Our group spent the afternoon swleltering on the Osceola courthouse lawn in central Nebraska before towers started going up around 4:15. Were initially hesitant because the south tower closest to us appeared very soft. Decided though they were our pursuit and headed after them as they moved into Saunders county. Caught up to the them quickly enough and from our vantage point, saw one wall cloud under a sloppy meso. We felt tornadogenesis possible with the storm for less than 5 minutes. Never saw the storm recycle and as the two cells merged, it became a wind event quickly. Major wind damage occurred along the Platte River near Fremont. Large trees down, power lines down, a general mess. Urban flooding in Fremont after the storms moved through. It was never difficult for me to drive but at times near Mead, the car was being pulled. And for all of the action, it just seemed to be a horribly non-photogenetic day. The towers were soft. We wanted to head east during the only appearance of any wall cloud. The later squall line moving south had no shape. Even the sunset was somewhat dismal by Nebraska standards.

James
 
I was very bored so i went after the saunders county storm with hopes to get some structure pics or just use my camera. I left around 5:15 pm around the time the cell went torn warned. I stopped a few miles north of Ceresco and took some shots of what i believe is the inflow base of the newer southern storm just before the two cells merged. I could see the meso of the northern cell but did not want to burn that much of my roommates gas since he is on vacation.
 
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