Extended Forecast Discussion NWS Weather Prediction Center College Park MD 159 AM EST Fri Nov 11 2022 Valid 12Z Mon Nov 14 2022 - 12Z Fri Nov 18 2022 ...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 Northern Plains/Midwest states. Multiple reinforcing cold fronts/shortwaves will help to maintain this pattern. A Gulf Coast storm system is expected to bring widespread light to moderate rain from the Deep South to the East Coast for the middle of the week in association with a southern stream shortwave, and there is some potential for this to develop further as it emerges off the East Coast late in the week. ...Guidance and Predictability Assessment... In general, there is overall good synoptic scale agreement on the broad cyclonic flow expected over the north-central U.S. for most of next week. However, there is still significant model spread with the timing of individual shortwave features, especially regarding northern and southern stream shortwaves diving into the Western/Central U.S. on the east side of a building ridge over the East Pacific. One important feature involves a southern stream shortwave crossing the southern Plains on Monday, with the CMC a notably faster solution. It still remains to be seen on the level of potential phasing of this system with a northern stream shortwave across the north-central states around the same time. Meanwhile, another shortwave tracks southeast near the West Coast, with the latest 00Z ECMWF a bit slower compared to the model consensus. The WPC forecast used a blend of deterministic solutions through Tuesday, but then trended more towards the ensemble means for the second half of the period owing to greater model differences. ...Weather/Hazard Highlights... An upper trough crossing the Northeast states on Monday, along with cold low level cyclonic flow, will support some lake effect snow east of the upper and lower Great Lakes, mainly early in the week. Parts of the Rockies and Intermountain West will likely get some light precipitation, mainly in the form of snow, accompanying the upper trough and cold front going into the middle of the week. The disturbance exiting the Rockies and emerging across the Southern Plains on Monday is expected to result in broader coverage of precipitation from the southern half of the Plains to the East Coast. Rain could be locally heavy for portions of the central Gulf Coast, and it will be possible for some wintry precipitation to exist for the northern fringe of the moisture shield from northern Oklahoma/Kansas to southern Illinois. It will take additional time to resolve important system details that will determine the coverage/intensity/type of precipitation. Broad upper troughing in response to the strong ridge offshore the West Coast should keep a cold pattern in place through all of next week, especially west of the Appalachians. The coldest readings should be over parts of Montana and the Dakotas, with some temperatures on the order of 20-30 degrees below normal, including locally subzero morning lows. Coldest anomalies over the West should tend to be over the Great Basin with multiple days of highs 10-20F below normal. The Midwest to East Coast are also expected to be below normal all week, though with slightly less extreme anomalies. Maine and Florida could be exceptions with near to slightly above normal temperatures. 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