Thus, I'll just pass along the NWS graphic, which oddly is missing the NOAA/NWS logo.
Prior records are based on soundings collected at Ogden and Salt Lake City from 1948-2014, although there are gaps in which no data is available. Thus, these upper-air records are perhaps not as impressive as a record at the surface where there is a much longer history available. Still, it provides some illustration that this is an unusually cold airmass for mid May in northern Utah.700 mb00z 18 May 2017: -9.1˚CPrior Record: -9.0˚C12z 18 May 2017: -9.5˚CPrior Record: -9.2˚C500 mb00z 18 May: -28.7˚CPrior Record: -27.8˚C12z 18 May: -27.7ºCPrior Record: -25.1˚C
|Source: Climate Reanalyzer|