The Storm Prediction Center (SPC) has issued a Slight Risk for the Northern High plains today.
Associated with the Slight Risk is no organized tornado threat.
To summarize the SPC: A pair of low pressure systems is expected to develop over western South Dakota and Nebraska. These lows will help draw Gulf moisture into the region. There will be some speed shear, which will support supercells, but they will remain high-based.
The visible satellite imagery shows clear skies over the threat area.
The surface observations show winds circling around the low pressure system in eastern South Dakota, but no strong, obvious frontal boundaries.
I did mark a subtle dryline and the location of the low pressure system.
The surface pressure chart shows low pressure over the threat area with no strong pressure gradients. The RAP shows this trend is expected to continue for the next six hours, as the primary low pressure system moves east. In the next six hours, the RAP is not showing these two low pressure systems developing.
No 12 Z soundings are available at this time.
The Nested NAM simulated reflectivity shows a discrete cells popping across western Nebraska and South Dakota by 22 Z or so. The cells eventually merge into a large bowing segment.
High temperatures will rise into the mid 90s in western Nebraska.
The Nested NAM shows that the dryline is tighter just south of I-80, with 50s F dewpoints on the wet side.
The Supercell Parameter shows a small peak near I-80 in western Nebraska.
Today is a warmup for tomorrow. There will be some marginally severe thunderstorms, but the chance of tornadoes is low. The big limiter today is the shear. While I was typing this post, the 12Z soundings were released, and all of them showed garbage shear- under 20 kts deep-layer.
We will not get out of position for tomorrow. The rookie mistake would be to chase the Slight Risk today and drive four hours north, to see nothing, try to outrun a blobby mess, and then have to come south for tomorrow’s threat. We will likely hang out in North Platte, maybe trend a little west or southwest towards the dryline.