I’ve been keeping an eye on the upper air pattern trying to anticipate when we’ll get our next chase day. I actually made a long range forecast post yesterday, but for some reason it didn’t show up on my blog.

There have been some pretty serious changes in the upper air pattern over the last three runs of the GFS and it doesn’t agree well with the ECMWF, so it’s kind of hard to know what to expect.

I’ll forecast some later this morning because I want to take a closer look at the shortwave that should affect parts of the southern plains on Sunday and I also want to spend a little more time on the long range models.

Right now it looks like maybe, and that’s a big maybe you could get some chasing action on Sunday, but unless that shortwave slows down it’s progression (the GFS has sped it up in the past three runs) then the only area that would be worth chasing will be in unchaseable terrain with very fast storm motions due to a lack of directional shear and strong kinematics.
Saturday could be a sleeper day as the shortwave is still over the desert SW, but there will be a sharp dryline through Texas with good instability ahead of it, strong 850mb winds out of the south and just enough deep layer shear for supercells. I haven’t looked at this much, but if a storm or two could manage to form along the dryline Saturday it might do OK.

Beyond that there are some pretty significant differences in the models as I mentioned. On top of that I trust them about as far as I can throw them and I hear they’re pretty heavy. The GFS has continued to hint at a trough deepening over the west coast around next weekend time frame, but if the GFS can’t even get a surface boundary right 12 hours out who the hell knows how far it’s off when we’re talking about 220 hours out.

I’ll update a little later with some more details.

Below is a thumbnail of the 500mb chart for Sunday showing the shortwave over the southern plains.