Skip Talbot
EF5
What a roller coaster ride this system has been to watch on the models, eh? We're finally getting some run to run consistency and the ECMWF and GFS are in general agreement on the placement, orientation, and intensity of a large trough moving into the plains on Sunday. The setup is a far cry from what the GFS was showing in earlier runs, however. At the surface we've got an extremely impressive pattern: 984 mb surface low, 65 degree dewpoints backing up to a sharp dryline with 15 knots of backed surface winds. Wow, what more could you ask for? It gets ugly above the surface, however. A very robust EML looks like it's going to be in place across the whole warm sector leading to a stout cap. The past several runs of the GFS have shown it barely eroding and significantly strengthening after 0z. Midlevel temperatures look sickly warm leading to dismal mid level lapse rates and cape except south of OKC where the richest moisture is bumping cape up to 2000 J/kg. The cap looks menacing even with a good source of lift, and that's our next problem. Both the ECMWF and GFS are holding that trough back over the southwest until it ejects overnight across the plains. Without that upper level support, and the strong cap, it's probably going to be a nice sunny day across much of the plains, and maybe a stormy night over areas to the east. North of OK into KS and the upper midwest, the dryline takes on a northeast to southwest orientation along the elongated area of low pressure. Shear profiles are less impressive as is instability and the EML extends even to the northern reaches of this region. I'm not seeing much of a chase at this point, but am throwing this forecast out here as this setup looked huge a few days ago. The timing on that trough seems to be the main culprit. Without it ejecting over the plains by Sunday evening we just won't have the height falls, colder temps aloft, and lift for a major severe weather event. We'll see what the NAM says tomorrow morning, but if it holds the trough back to the west like the GFS and ECMWF are currently showing, we probably don't have much of a chase setup.