Extended Forecast Discussion...amended NWS Weather Prediction Center College Park MD 305 AM EST Sun Nov 13 2022 Valid 12Z Wed Nov 16 2022 - 12Z Sun Nov 20 2022 ***It will feel more like January across much of the U.S. with widespread subfreezing high temperatures expected across the north-central states along with lake effect snow*** ...Synoptic Overview... A rather cold pattern is expected to be in place across much of the nation for the middle of the week into next weekend with broad cyclonic flow aloft around a deep upper level trough centered near the north-central U.S. and extending to Hudson Bay. Multiple reinforcing cold fronts/shortwaves will help to maintain this pattern, and a strong upper ridge axis should prevail just off the West Coast. A well organized storm system will be exiting the Northeast late on Wednesday, with coastal rain and inland snow expected, followed by lake effect snow downwind of the Great Lakes ...Guidance and Predictability Assessment... The 00Z model guidance suite is in good synoptic scale agreement for the Wednesday-Friday time period and agree on a strong reinforcement of the cold air mass across much of the northern tier states. However, more pronounced model differences emerge going into next weekend with Arctic shortwave energy diving south across central Canada and then the north-central U.S. The ECMWF is now much stronger and farther west with a polar closed low over the western Great Lakes, whereas the GFS has more of an open wave aloft and not as anomalous. The CMC also has a closed polar low, but it is farther east and closer to the GFS in terms of placement. This leads to lower than normal forecast predictability for the end of the forecast period. The WPC forecast was primarily based on a multi-deterministic model blend through about Thursday, followed by increasing the inclusion of the GEFS and EC ensemble means to account for the greater model differences going into the end of the week and into next weekend. In terms of QPF, a blend of about 25% GFS/25% CMC/50% NBM was used as a baseline for the Great Lakes region to add more detail to the expected lake effect snowfall. ...Weather/Hazard Highlights... There will be two main things making weather headlines going into next week. The first will be an organizing storm system near New England by midweek that is forecast to produce widespread rain across much of the Mid-Atlantic and into coastal portions of the Northeast, and accumulating snow for interior portions of New England. Strong cold air advection over the Great Lakes is expected to produce lake effect snow for several days, and some of this snow could be locally heavy at times. The other noteworthy aspect of the extended forecast will be the widespread anomalous cold weather across a great deal of the nation for the entire forecast period, especially from Montana and Wyoming eastward to the Midwest where afternoon highs could be running on the order of 15-30 degrees below typical mid-November averages. Some daily record lows are also within the realm of possibility for these areas. The exceptions to the cold weather will likely be across the Florida Peninsula with readings near or slightly above average. 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