Extended Forecast Discussion NWS Weather Prediction Center College Park MD 159 PM EST Thu Jan 30 2020 Valid 12Z Sun Feb 02 2020 - 12Z Thu Feb 06 2020 ...Overview and Guidance/Predictability Assessment... An dynamic upper-level trough is forecast to track off the Eastern Seaboard Sun as a deepening surface coastal low spins past the Canadian maritimes. The western and central U.S. will be the more active regions of the lower 48 states for much of the remainder of the extended forecast period. Models still show good consensus with potent shortwave trough forecast to reach the Northwest Sun. The trough is forecast to further amplify as over the Great Basin Mon and then cross the Rockies to the central U.S. by Tue. This feature should eject/shear northeastward over the north-central U.S then Great Lakes/Northeast day 6/7 along with packets of northern stream energy. This occurs as reinforcing/amplified trough energy digs again through the West and emerges out across the U.S. southern tier in amplified and active flow. Recent GFS/GEFS runs have trended increasingly toward the last few ECMWF/ECMWF ensemble runs at these time frames, bolstering forecast confidence. A composite blend of these seemingly reasonable and well clustered guidance pieces was primarily used as the starting point for production of the full WPC medium range product suite. ...Weather/Hazard Highlights... Onshore flow persisting across the Pacific Northwest will keep rain/mountain snow in place across western Oregon/Washington on Sun before potentially (briefly) drying out on Mon. Farther inland, the shortwave/cold front will bring rain/snow Sun-Mon, from the Great Basin to the central/northern Rockies. There is a threat of heavy snow over favored terrain. Additional rain/snow, potentially heavy at times, is forecast to reach the Pacific Northwest next Wed-Thu as a low pressure system moves from the North Pacific into western Canada, bringing a plume of increased moisture to Washington/Oregon and eventually the interior Northwest. Farther east, moisture return ahead of the upper trough and surface front will bring showers and thunderstorms from the lower Mississippi Valley to the Southeast and Mid-Atlantic Tue-Thu. Frontal wave development and leading/increasing Gulf moisture inflow suggest some threat of heavy rainfall. Farther north, sufficient cold air may be in place for some wintry precipitation Tue-Wed from the Midwest/Mid-MS Valley to the Northeast with as per series of frontal lows. Temperatures are forecast to be well above average across the central U.S. Sun-Mon, and the eastern U.S. well into next week. High temperatures of 15 to 30 deg F above average are possible across the Plains on Sun, then shifting toward the eastern U.S into next midweek. Meanwhile, the trough/cold front expected to reach the western U.S. this weekend will bring an end to above average temperatures, with highs 5 to 15 deg below average forecast to spread across the West Sun-Mon and persisting into the middle of next week for the interior west. Ryan/Schichtel Additional 3-7 Day Hazards information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, 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/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml