June 17, 2019

From my morning storm chasing forecast email list: "SPC has defined a nice small target for us right on I-76 in northeast Colorado. CAPE max has been plotted there with nice surface winds wrapping around the top of the low developing in se CO. I agree it looks like the spot. But the HRRR says no storms. Fires a giant circle of storms around but not in this area. Of course. So what happens is you're sitting in Sterling under clear skies looking at tornado warnings near Cheyenne and Colorado Springs or DIA. Then how long do you sit there before you make a mad dash for one of those.

But seriously, some discrepancy on the morning model runs. We'll probably see the front range up and down fire early as soon as it warms up. Might be a tornado warning in the mix there. NAM loves that I-76 corridor around Sterling with a wide open cap and low level instability pool, backed surface winds and decent moisture advecting in from the east. Mid to upper 50s dews should make for pockets of moderate instability.

HRRR says Cheyenne to Laramie is in play with a nice CAPE pool and fires a supercell in the area, while keeping the 76 corridor quiet.

Otherwise Fort Morgan might make a decent starting point, get storms earlier before they start to form clusters and cold pools as I'm not sure they'll make far up in the 76 corridor in the undersheared environment.

Secondary targets: Eastern New Mexico with what looks like more robust instability, and you'd be closer to the Day 2 target. High T/Td spreads, some warm 700mb temps, and surface winds that aren't as backed may limited the tornado potential, which isn't saying much as it's already pretty meager across the region. Could be structure and lightning again with perhaps a more robust updraft, whereas Colorado may yield smaller, cooler looking storms.

Storms look to fire off a line of confluence on the moisture pool across Nebraska. HRRR has a supercell track in the nw Nebraska Panhandle right on the edge of the CAPE gradient. Be a gamble going after that, but you could HRRR chase that for sure. Otherwise I think today is a crapshoot, like finding a needle in a haystack and not knowing if there actually is a needle in the haystack. I'm hemming hawing about this setup because I'm actually playing it. I think we'll make for I-76 in ne Colorado and hope something goes between Sterling and Fort Morgan as I don't think we'll make one of the early targets in time."

Brindley and I made a High and Northern Plains run in mid June. The first day out looked to be a pretty marginal play in the Cheyenne to Sterling to Fort Morgan area. After arriving in Sterling, CO, we got on a developing supercell on the NE/CO border. Roads are sparse here and we meandered down gravel and dirt roads for miles, watching the storm from afar.

Wall Cloud:

This is about where the storm peaked: a pretty low precipitation supercell with a robust looking base.

We stair stepped on the grid to track the storm for a bit, but it withered away. We called the chase and made for Burlington for some Mexican and a room.