Extended Forecast Discussion NWS Weather Prediction Center College Park MD 155 PM EST Sun Jan 19 2020 Valid 12Z Wed Jan 22 2020 - 12Z Sun Jan 26 2020 ...Overview... A developing system in the Southern Plains will spread modest to perhaps locally heavy rainfall from the Lower Mississippi Valley northeastward next Thu-Sun. In the Pacific Northwest, a steady stream of systems will bring periods of wet weather to parts of the Northwest. Overall, a warming trend over most of the CONUS is expected. ...Guidance/Predictability Assessment... The models/ensembles were in generally good synoptic agreement in showing a progressive and modestly amplified longwave flow pattern across the CONUS during the medium range period. Compared to just 24 hours ago, models have come into much better agreement with placement of the low pressure system traversing the Midwest. The GFS, however, still lies a bit farther north than the ECMWF/CMC and the better ensemble clustering. A general model compromise, with more emphasis on the ECMWF/CMC was preferred for this system. This would take the low northeastward towards the Midwest day 4-5, weakening on day 6 in favor of a second low pressure developing off the Mid-Atlantic coast, which tracks up the coast on day 7. Off the West Coast, ensembles have trended towards deeper troughing next weekend, at the expense of the leading systems east of the Rockies, with the typical spread one would expect at that longer time range. To mitigate this, increased usage of the ensemble means by next weekend. ...Weather/Hazard Highlights... Despite what is normally just about the coldest time of the year, temperatures will trend toward above average nearly CONUS-wide by the end of the week into next weekend. Highest anomalies will lie astride the Canadian border with near to slightly above average temperatures near the Gulf Coast. Precipitation will be non-continuous but quite repetitive in the Northwest as several systems push through. The generally mild flow will keep snow levels a bit higher too. Farther east, rainfall will expand over Texas to points eastward/northeastward with help from leftover mid/high-level moisture across the eastern Pacific/Baja Mexico. Gulf inflow will help realize modest rainfall totals along the NW Gulf coast but with continued uncertainty to its northward extent. Some amounts could be locally heavy. The system will likely have some wintry weather on its northern side from the Central Plains to the Great Lakes but with amounts contingent on the precipitation structure and system evolution. Santorelli/Fracasso 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