January 16th, 2020 by WCBC Radio
Canadian high pressure will settle overhead Friday through Friday night, causing dry but cold conditions across the area. Low pressure will develop over the Plains and track toward the western Great Lakes Friday night before intensifying as it tracks through the Great Lakes Saturday. The high over our area will weaken and shift well off to the northeast. Usually, this type of track with low pressure means that the main p-type would be rain. However, there will be plenty of cold and dry air in place ahead of the system. Therefore, as precipitation develops from isentropic lift (warm advection) and frontogenetical forcing there will be an evaporative and dynamical cooling effect that offsets the strong warm advection for a bit. Precipitation is expected to move into the area (especially northern VA, eastern WV, central and northern MD) very late Friday night into Saturday morning. Temps should be cold enough to support mainly snow during this time. However, there is some uncertainty as to how much precipitation there will be during this time due to model divergence in solutions. For now, did lean toward the solutions with a little lighter QPF (ECMWF, EPS, GFS), and this is because there will be plenty of dry air to overcome and the main forcing mechanism for this precip will be frontogentical forcing at the mid-levels. This forcing will be outrunning the main upper-level system over the Great Lakes. Having that been said, accumulating snow is likely across many areas Saturday morning and even if amounts are light, it will be impactful due to the cold conditions leading up to the event.