Extended Forecast Discussion NWS Weather Prediction Center College Park MD 200 AM EST Wed Jan 19 2022 Valid 12Z Sat Jan 22 2022 - 12Z Wed Jan 26 2022 ...Pattern Overview and Guidance/Predictability Assessment... Guidance remains in good agreement with the mean flow over the lower 48 highlighted by an amplified upper ridge off/along the West Coast and an amplified and unsettling upper trough over the central to eastern U.S. that coincides with several short and medium range Arctic blasts with periods of much below normal temperatures. The models have been less than stellar with the run to run continuity of embedded shortwaves rotating through the mean upper trough position and surface system reflection, but seem to be slowly improving. Given lingering model variance issues however, the earlier released WPC medium range product suite was primarily derived from the 12 UTC GEFS mean and especially the ECMWF ensemble mean along with the 01 UTC National Blend of Models. The 00 UTC models seem to be converging on better clustered solutions that have overall trended favorably toward the WPC composite solution, bolstering forecast confidence. ...Weather Highlights/Threats... 00 UTC forecast guidance is better clustered with an important shortwave trough exiting the Mid-Atlantic Saturday that offers potential for coastal storm development. The 00 UTC models better agree with development of an organized low off the Mid-Atlantic and New England. The WPC Winter Weather Outlook holds a lingering chance for coastal snows into Day 4/Saturday with the exiting low given the threat of a few more robust ensemble members. Upstream, models generally agree to carve out a Southwest U.S/northern Mexico closed low by Saturday that offers terrain enhanced snow potential from the Mogollon Rim to the southern Rockies/High Plains. The system remains slated to be ejected eastward across the U.S. southern tier early next week. Lead moisutre return from the Gulf of Mexico will overrun a trailing/wavy front to fuel a decent swath of precipitation within a cooled airmass from Texas eastward across the Gulf Coast. Schichtel Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, winter weather outlook probabilities and heat indices are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml