6/14/06 NOW: MT / WY

[Andrew Khan]

Storms are moving over the mountains in Wyoming, we're sitting in Sheradin, WY waiting for the storms to move over the mountains, and get it's act together. Right now, the recent radfar scans are showing disorginazation, likely due to the elevated topography, disrupting the updraft. We can kind of make out the base now. Dew points are 60-61 and temps 83...so decent gradient....headed up to MT..NOW.......north. The storms are looking sick to me...I am getting upset now, the storm yesterday had such a high base, it was spining high with LCL's...this year is very dissapointing..

 

[nickgrillo]

The 18z Rapid City sounding looks pretty bad... With deep-layer/significant CINH (and associated high LFC height) and high LCLs across much of the region owed to the knee-deep moist layer (with very low mean boundary layer RH) evident on the sounding. Sfc mesoanalysis places the (deepening) sfc low near Buffalo, WY -- with strong isallobaric forcing backing the near-ground flow east-northeast of the strongest pressure falls (increasing storm-relative inflow). I'd probably head north from Sheridan... The supercell southwest of Colstrip doesn't look too bad -- and it's currently in a crap environment (with very large SBCINH per RUC mesoanalysis) with an elevated inflow parcel source. Nonetheless, once it moves northeast into the better air (into a more backed low-level flow) and approaches the low-level moist axis (with the 60F isodrosotherm poking all the way into Wolf Point, MT) and weaker static stability, then perhaps its inflow layer will lower (particularly when further afternoon insolation diabatically heats the sfc layer -- and further mixes out more CINH) and ingest the richer SRH air northeast of the low. I'm not too surprised by the 5% TOR given the kinematic profiles (with strong 0-6km shear supporting supercell and bow echo modes) and sufficient instability, but the widespread static stability (and high LCLs) as a result of the very shallow moisture could prove to be a killer today.

The supercell hasn't looked terribley bad -- and perhaps once its inflow layer could lower some (IF it does) it could further strengthen and perhaps gain stronger low-level rotation (if it can ingest the richer near-surface vorticity further east). Nonetheless, this storm should still be packing some very large hail (with 2-4" inch hailstones reported from the storm thus far).