Extended Forecast Discussion NWS Weather Prediction Center College Park MD 157 AM EST Sun Nov 04 2018 Valid 12Z Wed Nov 07 2018 - 12Z Sun Nov 11 2018 ...Guidance/Predictability Assessment and Weather Highlights/Threats... It remains evident that broad cyclonic flow aloft will remain anchored over most of the lower 48 this week as embedded systems pass through the large scale mean trough. A deep lead low reaches eastern Canada Wed as a trailing cold front/precipitation focus works into the western Atlantic and Florida/northern Gulf of Mexico. Forecast confidence is above normal for this scenario. Prefer a composite guidance solution. Guidance remains more varied later week into next weekend, but there is an increasing signal from the 00 UTC UKMET and 12/00 UTC ECMWF and ECMWF ensembles that upstream energies digging into the mean trough will dive more ernestly through the unsettled west to then eject and spin up another deepening low Thu/Fri over the east-central U.S. The GFS/FV3 and GEFS ensembles may in contrast be under amplified/too progressive with the pattern given recent trends and amplified flow upstream eminating from the Pacific. Prefer a solution closest to the ECMWF ensemble mean given lingering model variance. Accordingly, expect a threat for widespread heavier precipitation ahead/around this second main system, first with dynamics over the west into terrain and downstream with system genesis as fueled by influx of deepened moisture from the Atlantic and Gulf of Mexico. The main low would subsequently track up to eastern Canada by next Saturday as its trailing cold front progresses underneath across the central then eastern states. This may also spread some wintry weather/swath of heavier snow across the central Plains and onward to the north of the surface low track, especially Thu/Fri over the U.S. as cold post-system Canadian high pressure surges into/across the lower 48. Schichtel WPC medium range 500 mb heights, surface systems, weather grids, quantitative precipitation, winter weather outlook probabilities and heat indexes are found 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