Extended Forecast Discussion NWS Weather Prediction Center College Park MD 200 AM EST Wed Nov 16 2022 Valid 12Z Sat Nov 19 2022 - 12Z Wed Nov 23 2022 ***It will continue to feel like the middle of winter through the weekend across the east-central U.S. along with continued lake effect snow*** ...Synoptic Overview... A highly amplified upper level flow pattern will be in place across the country for the weekend with a deep trough extending from Hudson Bay to the Northeast. An arctic front is progged to clear the East Coast and result in a continuation of the January-like temperatures for a few more days. The deep trough will likely begin lifting out by Monday as a more zonal flow pattern commences across much of the country. Out West, a couple of weak pacific storm systems will likely move inland as the upper ridge axis decays by Sunday and into Monday. ...Guidance and Predictability Assessment... The 00Z deterministic guidance continues to have an excellent synoptic scale depiction of the broad upper trough over the central-eastern U.S. for the weekend. The models also agree well on this deep trough lifting out starting Monday and heralding a pattern change, with more quasi-zonal flow across the nation. Similar to yesterday, the greatest model differences are apparent across the Western U.S. going into early-middle part of next week as a pair of Pacific shortwaves approach the central-northern West Coast region. By Wednesday, it appears the ensemble means are generally a little faster than the deterministic guidance as the shortwave energy reaches the Rockies and western High Plains. The WPC forecast was primarily based on a multi-deterministic model blend through the weekend, with a gradual increase in use of the EC and GEFS means going into the first part of next week. For the QPF forecast, particularly in the vicinity of the Great Lakes, the NBM 4.0 was blended with some of the ECMWF and GFS to increase overall totals, and preferred more of a ECMWF/CMC solution for West Coast QPF. ...Weather/Hazard Highlights... Widespread well below average temperatures for this time of year are expected to continue into the weekend across a majority of the country, with the coldest readings expected across Minnesota, North Dakota and northern Wisconsin where highs will only reach into the middle 10s to lower 20s, and lows in the 0s or even slightly below zero for this same general area. Parts of the Rockies may also have subzero overnight lows Saturday morning. It will also be quite chilly extending southward to Texas and the central Gulf Coast through Monday, with highs generally running 10 to 20 degrees below mid-late November averages. Looking ahead to early next week, there will likely be some abatement in the cold weather pattern as the deep upper trough begins lifting out with a more zonal flow evolving. In terms of precipitation, much of the nation should be relatively dry as a sprawling surface high governs the overall weather pattern. Some light to moderate rain is likely for portions of southern Texas and Louisiana on Saturday. Lake effect snow is likely to be persistent downwind of the Great Lakes through Sunday owing to strong cold air advection over the warmer waters, and then abating going into Monday. Showers and mountain snow are likely to make a return to the West Coast states early next week as the Pacific storm systems move inland. Hamrick 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, experimental excessive rainfall outlook, 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/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml