8/3/05 TALK: Upper Midwest WI/MN/IA/SD

[Edward Ballou]

In a lackluster season, here we are again with our slight chance of severe weather in the upper midwest. Looks like LCLs levels aren't going to cooperate with the high CAPE over northern IA. I'm seeing best chances in eastern WI and then some possible pockets of development from Sioux City(if the cap breaks) to Sioux Falls to Worthington. The new models haven't run yet but it's something to keep an eye on throughout the day. Had thunder and rain here in Brookings on the way into work this morning. If anyone wants to meet up, send me a pm. I'll probably be headed out at 3 or 4 if conditions are right.

 

[Jayson Prentice]

I'll be watching northwest IA/southwest MN today. Looks like a cap may be a problem, but I'll hope for the best. Looking at the RUC, best bet would be around Pipestone, MN... They actually show the cap breaking and a good increase in shear across there. Waiting for the rest of the NAM to come in to look at some of the severe weather parameters. It is local so I will be out and about...

 

[Tim Gonyo]

Just checked out the info today since I live in Eastern Wisconsin.... Helicity is 400 m2/s2, cape is decent, and EHI's are 7-8!!!!! SPC is only outlooking the area at a marginal 2% tornado risk though.... I'm curious to see what develops later today. I will definitely have my eye to the sky.

 

[Bill Schintler]

Chase target for August 3

Chase target:
Brookings, SD

Timing:
Storm initiation 3 PM CDT.

Storm intensity:
Low-end severe storms, with isolated hail to golf-ball size, and winds to 70 MPH.

Discussion:
A fairly complicated WX setup is in place across the upper-Midwest this morning. At the surface, a synoptic surface trough extends along an ADC/YKN/LXN line; the CF appears to extend along an ABR/9V9 line in SD; while numerous mesoscale boundaries are in place throughout the area as a result of ongoing and decaying convection and MCS’s. Ongoing convection in the HON and ULM areas will produce outflow boundaries that will be key in this afternoons convection. By 20Z, an E-W oriented boundary should extend from ULM/BKX/9V9 line, with locally backed surface flow north of this feature. This should serve to produce more favorable low-level shear then 12Z guidance suggests, although the RUC hints at this feature.

Upstairs, SWRLY flow is spreading into the Dakotas, with a couple of embedded S/WV’s and increasing vorticity advection throughout the region. WV imagery suggests a small-scale region of UVV along an MBG/DO7 line, and another near PIR/PHP in SD. Ample instability (SBCAPE’s to 5000J/kG/MLCAPE’s to 3500J/kG) by mid-afternoon, coupled with decent deep-layer shear of 30kts and SFC-1km SRH’s locally to 200m^2/s^2 along and just N of the aforementioned outflow boundary will support storm organization. Dewpoint spreads in excess of 20F will keep cloud bases on the high side, minimizing tornado threat.

- bill

 

[Edward Ballou]

I-90 corridor is home to the highest MLCAPE values. Area of highest anticipated intensity is Sioux Falls to Marshall. Hopefully we can see something nice today. Looks like the initiation window as moved from 4 to 6 pm today.

Continued target, east from Brookings and down in Worthington direction... Key to this system will be getting ahead of it in time to watch things develop. Seems like I always leave too late.

 

[Jayson Prentice]

Yes, I believe I have made my decision for today. I will be hanging around I90 as well, probably worthington or Jackson, MN. It looks like quite a bit of features come together along there and then make there way into northwest Iowa and actually increase in some aspects. I'm hoping for something!! Good luck...

 

[Andy Wehrle]

Definitely one of those boom or bust days. Little mesoscale caveats everywhere. Will be keeping an eye on it but not getting my hopes up unless these cloud debris clear pretty fast.

 

[nickgrillo]

Cold Front is still hauling south... VERY visable as on RAD.

Well, after several weeks of complaining, numerous threads (LOL...), I have GEMPAK/LINUX working totally fine...

 

[Andrew Khan]

Nick, what radar are you using their?