Extended Forecast Discussion NWS Weather Prediction Center College Park MD 201 AM EST Thu Nov 10 2022 Valid 12Z Sun Nov 13 2022 - 12Z Thu Nov 17 2022 ...Overview... Amplified troughing over the East on Sunday should lift out by Monday with some weak ridging returning early next week over the Southeast. Meanwhile, a strong and block ridge over the Eastern Pacific will force various systems southward into the north to north-central CONUS which promotes overall cyclonic flow and below normal temperatures over much of the lower 48 through at least the middle of next week. Confidence in embedded details is still on the lower side, with particular focus on an upper shortwave/surface system that could spread precipitation of varying types over parts of the central/eastern U.S. in the early-mid week time frame. ...Guidance and Predictability Assessment... In general, there is overall decent agreement on the large scale braodly cyclonic flow expected to maintain over the CONUS during the medium range period (Sunday-Thursday). However, there remain some significant differences in the details, particularly surrounding northern and southern stream shortwaves diving into the Western/Central U.S. on the east side of a building ridge over the East Pacific. The guidance continues to show quite a bit of run to run variability, but there may be some sort of trend towards a consensus given the decrease in overall spread of the various ensemble solutions. One particularly impactful feature involves a southern stream closed low diving across the Great Basin on Sunday into the southern Plains on Monday. There is a lot of uncertainty by Tuesday-Wednseday next week on details surrounding phasing of this system with a northern stream shortwave into the north-central states at the same time. Another system dives into the Northwest mid next week with again a lot of questions on both speed and amplification. The WPC forecast used a blend of deterministic solutions early on, amidst better agreement, but then trended more towards the ensemble means the second half of the period in an attempt to mitigate the differences. ...Weather/Hazard Highlights... An upper trough crossing the East along with cool low level cyclonic flow will support some lake effect snow within the typical snow belts over the upper and lower Great Lakes, mainly early in the week. The West may see some light precipitation accompanying the upper low expected to track from Oregon southeastward this weekend. Latest consensus is maintaining stronger definition of this feature as it opens and continues east-northeast from the southern Rockies early-mid week, leading to more surface waviness from the Gulf Coast to East Coast. This yields broader coverage of precipitation from the southern half of the Plains through the East. Rain could be locally heavy along the Gulf Coast and it will be possible for some wintry precipitation to exist in the northern fringe of the moisture shield. 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 Sunday-Thursday, and likely beyond per the Climate Prediction Center week 2 forecast. The coldest air should be over parts of Montana and the Plains Sunday-Tuesday with some readings at least 20-30F 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 10-25F below normal. The midwest to East Coast are also expected to be below normal the whole period, though with slightly less extreme anomalies. Maine and Florida could be exceptions with near to slightly above normal temperatures. Santorelli 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