Today’s setup featured a typical high plains return flow pattern with low-level moisture upslope evident on surface observations and both the synthetic WVT & 5.15um channel imagery. One feature that caught my attention initially in the synthetic imagery was a dry pool over the Cheyenne Ridge, spanning from Weld County, CO up into Kimball County, NE (highlighted with yellow circle in the image below). Observed surface dew points in this area were in the mid to upper 40s in southeasterly flow, likely on the leading edge of the plume of higher moisture in KS and CO. I did not see this level of detail on any other satellite imagery.
With this feature, I was curious on two fronts: the placement of this feature compared to reality, but also how would this dry pool affect convection later in the day. Compared with surface obs, the dry pool seemed to be slightly displaced to the east from reality, but not by far. My gut was telling me that convective initiation on the Cheyenne Ridge itself would be nil due to the dry pool (perhaps with a hint of subsidence?), and that any established convection moving through the drier air would not exhibit explosive growth and would overall be weaker, and/or perhaps we’d see an enhanced downdraft wind threat.
See below the loop of synthetic imagery highlighting the 5.15um imagery that covered the majority of our test period. Reality played out pretty close to the evolution of convection as seen in the loop. A left split fired off the mountains near Fort Collins and persisted northeast up into Wyoming. This storm produced severe hail slightly larger than quarter size in Cheyenne, but then appeared to weaken on visible satellite as it progressed further east-northeast along the Cheyenne Ridge where the drier air was forecast to reside.
This case shows the utility of highlighting moisture content, or lack thereof, that you cannot necessarily see on traditional satellite imagery.
Astrophage
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