2012-06-09 FCST: ND/MN/SD/NE/IA/KS

[Aaron Shaffer]

Figured I'd see what people are thinking a few days out... seeing many people citing the SPC's Day 6/7 outlook today got me looking myself. Looking like an interesting scenario developing... Saturday, obviously, is more reasonable to chase for the weekend (and distance wise).

Looks like great low-level directional shear, limited speed shear, and plenty of energy for storms. As of now I'd plan on heading to Fargo to chase (I'm in Minneapolis) and revising that launch spot as we get closer to "real" data. I don't really trust the long-term models for mesoscale chase days, but minus the impressive capping inversion this looks decent: http://www.twisterdata.com/index.ph...iew=large&archive=false&sounding=y&sndclick=y

Any other thoughts? I know there are plenty of people here who are either mets who are chasers or hobby chasers, so I'd be curious to hear people's thoughts this far out!

 

[Derek Weston]

Figured I'd see what people are thinking a few days out... seeing many people citing the SPC's Day 6/7 outlook today got me looking myself. Looking like an interesting scenario developing... Saturday, obviously, is more reasonable to chase for the weekend (and distance wise).

Looks like great low-level directional shear, limited speed shear, and plenty of energy for storms. As of now I'd plan on heading to Fargo to chase (I'm in Minneapolis) and revising that launch spot as we get closer to "real" data. I don't really trust the long-term models for mesoscale chase days, but minus the impressive capping inversion this looks decent: http://www.twisterdata.com/index.ph...iew=large&archive=false&sounding=y&sndclick=y

Any other thoughts? I know there are plenty of people here who are either mets who are chasers or hobby chasers, so I'd be curious to hear people's thoughts this far out!

Has potential. Want a play to emerge besides CF. (but CF behavior up north can different later in season) Hope the 500 flow syncs up better with the big CAPE and backed low levels. (otherwise it'll look like your typical summer CF setup)

 

[Andy Jackson]

This day has been holding steady for a while now. I think per the GFS the moisture looks fabulous, whether it actually occurs is another story. The upper-level trough moving into the region should allow for some good shear and cool temperatures especially at the 700mb level. Depending on the overnight convection storms could fire from Brandon, MB into ND.

 

[Scott Weberpal]

The 12z GFS has the upper level support and surface features largely disconnected with the upper trof hanging west over MT while the surface front is much further east into the eastern Dakotas and Minnesota. I think it's fair to say the GFS is largely overdoing moisture thus boosting CAPE values. IF the upper support ends up further east or the surface features further west, there could be a great play in the northern plains, but as of right now, it looks less than stellar.

 

[Jeff Duda]

The 12z GFS has the upper level support and surface features largely disconnected with the upper trof hanging west over MT while the surface front is much further east into the eastern Dakotas and Minnesota.

I've noticed this with a lot of setups this year. I'm not exactly sure why the front always outraces the upper level support, but it probably has something to do with the "shape" of the vorticity field that is generating the lift. The 500 mb height/wind field shows a trough that is positively tilted with strong flow on the eastern side of the trough axis, thus promoting a lifting of the trough with time and more of a vorticity ribbon (elongated and parallel to the mid-level jet) rather than a ball. Setups in which the vort max has a more even aspect ratio (i.e., closer to 1:1) seem to have more favorable orientations of surface boundaries.

 

[Derek Weston]

I've noticed this with a lot of setups this year. I'm not exactly sure why the front always outraces the upper level support, but it probably has something to do with the "shape" of the vorticity field that is generating the lift. The 500 mb height/wind field shows a trough that is positively tilted with strong flow on the eastern side of the trough axis, thus promoting a lifting of the trough with time and more of a vorticity ribbon (elongated and parallel to the mid-level jet) rather than a ball. Setups in which the vort max has a more even aspect ratio (i.e., closer to 1:1) seem to have more favorable orientations of surface boundaries.

Interesting. Noticed this too. Perhaps I'm remembering incorrectly, but notice these patterns more often later in the season... so it seems we've had more of a towards-summer pattern for a while now. (well into June towards July)

 

[Logan Karsten]

As mentioned before, it seems as though the GFS is pushing the surface CF very quickly, almost ahead of the upper-level features. I would prefer if the upper level features either sped up or slowed down, or the surface front slowed down in it's movement. If the front can hang back, eastern South Dakota, western Minnesota would be in play on Sunday. However, if the upper level features can speed up just a bit, Saturday would be the obvious play in South Dakota. At the moment, I don't like the disconnection between the surface front and upper level features on Saturday, and by Sunday afternoon, the CF is way to the east with veered flow at the surface. Time will tell.

 

[Andy Jackson]

Looking at the recent 12z runs it looks like temps aloft may not be so cool but at least there is a narrow area of cooler 700mb temps. I think Friday has better tornado potential but I'm pretty sure both days are good for severe weather.

 

[samuel stone]

might as well throw in SD,IA,NE,KS into the FCST title, 12z GFS breaks out precip all the way to Kansas as the front sags back SW and meets a triple point. yeah LCL heights dont look good down there right now along with a number of other red flags, but dont count out Kansas(I.E. 5/19 EF3 landspouts). Its way to far out for me to want do a real forecast, so I wont. Ill be too busy to post any further on this setup but ohters can take over.

 

[Brett Nickeson]

Well, after several days of good agreement between the GFS and Euro of a positively tilted trough ejecting over west-central to central ND, the NAM has come in and has been borderline off the reservation with its surface features. The location of the surface low and cold front is around 200+ miles east of where the 0Z GFS and 12Z Euro place it. NAM also has much stronger mid and upper level winds ejecting over the northern plains, and, as would be expected, cooler mid level temps.

Normally I would put my trust in the NAM and almost completely ignore the GFS 72 hours out, but it's hard to ignore the vast differences between the two sets of models and how consistent the long range models have been over the last several days. As of right now I'm wishcasting that the NAM is overdoing the speed at which this system will move through and I'm targeting north-central ND. However, if the models begin to trend towards where the NAM currently is I'll likely call off the chase, as hunting for storms in the woods of northern Minnesota doesn't sound like much fun.