Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1200 PM EDT Fri Oct 04 2019 Valid 12Z Mon Oct 07 2019 - 12Z Fri Oct 11 2019 ...Another round of cold/snow for the Northern Rockies next week... ...Guidance/Uncertainty Assessment... The WPC medium range product suite was mainly derived from a composite blend of quite well clustered guidance from the 06 UTC GFS along with 00 UTC ECMWF/UKMET/Canadian and National Blend of Models Mon into Wed when forecast confidence remains above normal. Blended the 06 UTC GFS/00 UTC ECMWF and their respective ensemble means by Thu-Fri at these longer timeframes that offer less stellar run-run continuity with small-mid scale timings/amplitudes of systems embedded within the larger scale flow pattern. ...Weather Highlights/Threats... A lead and cooling cold front and supporting upper trough to approach the East Coast Mon will provide a focus for some locally modest-heavier rainfall from the central Appalachians into the Northeast. Rainfall should be mainly beneficial over areas currently experiencing drought of varying intensity. By Tue-Fri the front settles over the Florida Peninsula and possibly lead to some rainfall enhancement in its vicinity. Upstream, an amplifying upper trough set to dig southeastward from the Gulf of Alaska will bring a period of rain and initially higher elevation snow to the Northwest U.S. during the first half of next week with highest totals over favored westward-facing terrain. WPC Winter Weather Outlook snowfall probabilities are near 70% (> 2-3" snow) over higher elevations on Tuesday in western Montana around Glacier Park. The cold air behind the leading surface front will progress southward and eastward which will lower snow levels toward or into the valley locations of the rest of Montana. High temperatures are likely to be at least 10-20F below average over the northern Rockies/Plains on Wed and over much of the northern-central Plains by Thu. This will spread southward to Texas and eastward to the Mississippi Valley by Friday but perhaps with less intensity. Rainfall will expand and offers a risk to become locally heavy from the south-central Plains to the mid-MS Valley/Midwest later in the period with moisture inflow return from the Gulf. Fracasso/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