A quick-moving Northeast US shortwave and associated cold front brought a brief period of snowfall to higher elevation areas of W MD/E WV/S PA during the early morning overnight hours of 25 Jan 2022. Radar beam blockage and distance results in slightly degraded radar coverage in parts of this region. NWS Baltimore/Washington forecasters leveraged the NESDIS Snowfall Rate product to diagnose snowfall across the higher terrain in western areas of their forecast area during the evening. SFR is available in AWIPS at some NWS offices, and can also be found online here (and with more info) and here.
In the overnight near-term forecast update, the NWS forecaster wrote the following, with corresponding imagery included as Fig 1: “NESDIS snowfall rate product from Suomi NPP and NOAA-20 satellites from 0722Z and 0813Z respectively showed snow falling across the mountains west of Frostburg with liquid equivalent rates of around 0.05 in/hr. Another inch of snow is possible before snow ends later this morning behind Arctic frontal passage currently analyzed over southwestern PA.”
A version of the SFR product merges the satellite-based SFR with MRMS radar-based, helping to fill in gaps where radar coverage might be unavailable. That product surrounding the period of discussion is shown in Fig 2.
Observed snowfall reports later that morning confirmed up to a few inches of snow total had fallen in the region overnight. This event exemplifies how the NESDIS Snowfall Rate product can be leveraged to boost confidence in a nowcast/short-term forecast of snowfall, particularly in regions of less-than-ideal radar coverage.
Bill Line, NESDIS and CIRA