Extended Forecast Discussion NWS Weather Prediction Center College Park MD 157 AM EST Sat Nov 12 2022 Valid 12Z Tue Nov 15 2022 - 12Z Sat Nov 19 2022 ...Synoptic Overview... A rather cold pattern is expected to be in place across much of the nation for next week with broad cyclonic flow aloft around a deep upper level trough centered near the north-central U.S. and extending into central Canada. Multiple reinforcing cold fronts/shortwaves will help to maintain this pattern, and a strong upper ridge axis should prevail just off the West Coast. There will likely be two separate Gulf Coast storm systems that develop in response to shortwaves tracking around the southern periphery of the deep trough, and these are expected to produce rounds of rain from the Deep South to the East Coast. ...Guidance and Predictability Assessment... The latest guidance is showing an active pattern with multiple shortwaves initially within the northern and southern streams that transition to a broad and phased trough over much of the nation. Overall, there is good synoptic scale agreement with the broad cyclonic flow expected over the north-central states, but there is still notable spread on the timing, location and strength of individual shortwave features that increase beyond Wednesday, with the 00Z GFS becoming stronger with the next southern stream system crossing the southern Plains and then the Gulf Coast region for late in the week. The CMC has trended closer to the model consensus compared to its previous 12Z run, which was an outlier solution across the western U.S. when compared to the ensemble guidance. The WPC forecast was primarily based on a mainly GFS/ECMWF/UKMET model blend through about Wednesday, 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 Saturday. ...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 the Gulf Coast early in the week that will likely widespread rain across much of the Deep South and Southeast, and perhaps the first snow of the season from Missouri to parts of the Ohio Valley, albeit light amounts. It then reaches the East Coast by Wednesday and may intensify further upon reaching the Northeast U.S. with potential snow for interior New England. Cold air advection over the Great Lakes is expected to produce lake effect snow at times, and some of this snow could be locally heavy. The other noteworthy aspect of the extended forecast will be the widespread anomalous cold weather across a great deal of the nation for basically all of next week, especially from the western High Plains to the Midwest where both highs and lows could be running on the order of 15-35 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 and portions of the West Coast states, 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