Extended Forecast Discussion NWS Weather Prediction Center College Park MD 255 AM EDT Sat Oct 8 2022 Valid 12Z Tue Oct 11 2022 - 12Z Sat Oct 15 2022 ...General Pattern Overview... An anomalous mid-upper ridge axis across the eastern Pacific is expected to be nearly anchored in place for much of next week, and this will tend to result in an amplifying downstream trough over central Canada and into the north-central U.S. going into the middle of the week, and this will be accompanied by another strong cold front east of the Rockies. This will help reinforce the autumnal airmass across much of the eastern U.S., while still remaining mild to warm across the northwestern U.S. and the southern tier states. ...Model and Predictability Assessment... In terms of the building northern stream upper trough for the middle of next week, the models continue to agree on a strongly amplifying trough in the northern stream flow with less signal for a cut-off low breaking away across the western U.S., and the CMC is starting to slowly trend towards the model/ensemble consensus in depicting less of a western U.S. upper low. Teleconnections with the positive height anomaly over the eastern Pacific and the negative height anomaly north of Hawaii suggest a non-CMC solution, and this would not support a well-defined upper low breaking off from the main trough. Similar to yesterday, the forecast was primarily derived from a UKMET/GFS/ECMWF/WPC continuity composite through Wednesday, and then some of the GFS and past two runs of ECMWF and increased use of the ensemble means for the Thursday through Saturday time period. ...Sensible Weather and Potential Hazards... An amplifying upper trough and a strong cold front reaching the Northern Plains and Upper Midwest by early Wednesday will likely produce showers and some thunderstorms from the Central Plains to the Great Lakes, although rainfall totals should be light to moderate. There will likely be an uptick in showers and thunderstorm coverage as the front approaches the Ohio Valley and then Northeast U.S. towards the end of the week, and also for the Gulf Coast region as the front taps into deeper moisture. The latest NBM has some areal 2-4 inch rainfall totals from upstate New York to Maine for the Thursday to Friday night time period as deeper Atlantic moisture is advected towards the northern Appalachians. Elsewhere, the monsoonal convection across the southern Rockies and Arizona is finally expected to subside going into the middle of the week as the upper low/trough weakens, although some isolated storms might remain through Wednesday. Some high elevation snow showers are also possible for the highest terrain of the central and northern Rockies on Tuesday and Wednesday. Much of the northwestern U.S. should have above normal temperatures next week with the upper ridge just off the coast, and a warm-up is likely across the central/northern Plains Tuesday/Wednesday ahead of the front. This will likely be followed by highs about 5-15 degrees below average to close out the work week from the Upper Midwest to the Ohio Valley and Great Lakes, and potential for some frost/freeze conditions at night, mainly north of the Ohio River. Hamrick Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, experimental excessive rainfall outlook, 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/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml