Extended Forecast Discussion NWS Weather Prediction Center College Park MD 243 PM EDT Sat Apr 16 2022 Valid 12Z Tue Apr 19 2022 - 12Z Sat Apr 23 2022 ...Weather Pattern Overview... An active northern stream pattern over the CONUS likely culminates in a large, closed low over the West Coast Thursday, perhaps into Friday. Two lows/troughs track ahead of this low, one that lifts north of New England on Wednesday and one that tracks from the Northern Plains to New England by way of the northern Great Lakes Tuesday night through Thursday night. Amplified ridging and above normal temperatures occur between these three lows/troughs. ...Model Guidance Evaluation... The overall synoptic depiction of the pattern is very strong in deterministic guidance until Thursday when the 06Z GFS opens the low off the Pacific Northwest, making it more progressive that other guidance with a shortwave trough that reaches the northern Plains by 12Z Saturday while the 00Z ECMWF/CMC keep a closed low over the Desert SW through that time. The 12Z GFS is a bit slower, but the trough still crosses the CO Rockies by 12Z Saturday. Otherwise, the global deterministic guidance is in good agreement. The WPC forecast was derived from a multi-deterministic blend through Day 5/Wednesday night before favoring the ECMWF/CMC and ensemble means from the GEFS/ECENS/CMCE. ...Sensible Weather/Threats... Far northern CA into OR have precipitation in the forecast for each of the four medium range days from back-to-back systems, the second one stalling and potentially working south through much of the rest of CA Friday into the weekend. This late season event will deliver highly beneficial rainfall/mountain snow to drought-stricken areas of California, with the potential for three inches of liquid for most northern CA terrain with a few feet of snow for the Sierra. Elsewhere across the continental U.S., the deep low lifting from New England Tuesday night will allow continued wrap around snow over Interior New England terrain into Wednesday. The next wave to cross the northern Plains looks to push most of its snow into the Canadian Prairies through midweek while another round of organized showers and storms are likely to develop across the central U.S. and extending northward to the Great Lakes as Gulf moisture is advected northward ahead of the organizing storm system. Heavy rain is possible, particularly over the Ozarks to Mid-MS Valley Wednesday/Wednesday night. Temperatures are expected to remain be below normal over the northern Plains through next week, slowing the recovery/melt from the recent blizzard as well as the expected snow tomorrow/Easter Sunday. On the contrary, above normal temperatures are expected across much of the interior western U.S. under ridging/south of the midweek low passages over the northern Plains before shifting east over the central/east-central portions of the CONUS into next weekend. Jackson 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