Extended Forecast Discussion NWS Weather Prediction Center College Park MD 238 AM EDT Mon Oct 21 2019 Valid 12Z Thu Oct 24 2019 - 12Z Mon Oct 28 2019 ...Guidance/Uncertainty Assessment and Weather Highlights/Threats... Guidance agrees that the active flow pattern will reload over the cooling/unsettled West Wed/Thu as digging upper impulse/jet energies support some enhanced Rockies snows. Height falls should then act to carve out an amplified central U.S. upper trough later week. Pattern evolution uncertainty grows quickly, resulting in low forecast confidence. Guidance continues to indicate two possible scenarios by this weekend: (1) A more amplified upper trough draws in deep moisture from the Gulf and results in a low pressure system that spreads heavy rainfall well inland, as indicated by recent ECMWF/UKMET and CMC solutions; or (2) less flow separation between the northern and southern streams will keep a cold front moving steadily across the southern and eastern U.S., as indicated by recent GFS runs. GEFS/EC/CMC ensembles are mixed, with ECMWF ensembles showing the most support for the first scenario. WPC progs modestly lean the forecast to show such potential. This considers upstream upper ridge amplitude and as the next main upper trough does not bring renewed cooling with enhanced precipitation/mountain snows through the Northwest then Rockies until next weekend, so wavelength spacing with the downstream system seems sufficient to allow for at least some southern stream separation. 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