Extended Forecast Discussion NWS Weather Prediction Center College Park MD 306 AM EDT Thu Oct 24 2019 Valid 12Z Sun Oct 27 2019 - 12Z Thu Oct 31 2019 ...Overview and Guidance/Uncertainty Assessment... Model spread remains significant during the extended period in an active pattern. For the last week or so the GFS has been consistently too progressive with energy tracking across the CONUS. This seems to be the case with the latest GFS runs and GEFS/NAEFS means are also in this camp to a lesser extent. Recent UKMET and especially Canadian runs have been closer to the ECWMF and the ECMWF ensemble mean and offer a deeper and slower progression of the low/trough exiting to the eastern U.S. by early next week and amplifying upstream upper troughing digging into the West then w-central U.S. next week. Accordingly, the WPC medium range product suite was primarily derived from a composite blend of the best clustered soltuions from the ECMWF/Canadian and ECMWF ensemble mean, with highest weighting applied to the ensemble mean for max continuity amid uncertainty. ...Weather Highlights/Threats... The resultant weather pattern may offer several significant hazards. Lead system ejection over the eastern U.S. Sunday and a wavy trailing front over the Southeast into early-mid next week should act to focus precipitation. Rainfall may be enhanced with potential entrainment of tropical moisture stemming from a tropical distirbance that the NHC is monitoring over the Gulf of Mexico. Meanwhile upstream, the deep digging of a series of potent systems favors an unsettled and cooled West then central U.S. next week with advent of a series of post-frontal high pressure surges. Some upwards of 15-30+ degree negative temperature anomalies may rival record values and upper support/modest moisture sets the stage for terrain enhanced snows over the West and especially the central Rockies with potential likely spreading northeast over the central Plains then Upper Midwest with gradual system progressions and cooling. Lead heavier rains may also be re-develop along/ahead of a reinforced low/frontal boundary with renewed return moisture influx from the Gulf of Mexico over the east-central U.S. mid-later next week. 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