Extended Forecast Discussion NWS Weather Prediction Center College Park MD 255 PM EDT Fri Oct 07 2022 Valid 12Z Mon Oct 10 2022 - 12Z Fri Oct 14 2022 ...Pattern Overview... A mid-upper ridge is currently forecast to keep a strong hold over the eastern Pacific to Gulf of Alaska through next week, while its exact placement and axis may meander a bit from day to day. With that feature in place, potent energy is forecast to spill southeastward to its east, creating and amplifying a trough downstream in the north-central U.S. initially and then tracking into the East. The trough will push another fairly strong cold front eastward with cooler temperatures behind it and rain chances becoming widespread ahead of it across the central U.S. Tuesday-Wednesday and into the East Thursday-Friday. ...Guidance and Predictability Assessment... Most model guidance has been more consistent for the past few cycles regarding the Pacific ridge/high directing energy currently developing over the Bering Sea to the ridge's east, with most if not all of this energy remaining in the northern stream and forming a strong upper low in central Canada with its troughing influence extending into the central U.S. by midweek and shifting eastward late week. The CMC runs remain a holdout in maintaining what some other models were also showing a day or two ago, namely, some energy splitting off from the northern stream trough to help form a cutoff low over the West for the latter half of the week. A handful of ensemble members from the CMC/EC/GEFS suites display some indication of this, but the majority lean toward the better GFS/ECMWF/UKMET consensus. This latter guidance does show some troughing perhaps separating into a weak closed low Wednesday-Friday, but this arises from a different shortwave that dives south across the West Coast states during the short range period. With teleconnections with the positive height anomaly over the Gulf of Alaska and the negative height anomaly north of Hawaii also leaning toward a non-CMC type solution, the WPC model blend was initially composed of the 00Z and 06Z GFS runs and the 00Z ECMWF and UKMET. Within the tentative agreement for the troughing, there remains considerable variability in placement of the centroid of the upper low for midweek and beyond, with models from the 00Z/06Z and newer 12Z cycles showing a variety from north-central Canada into the north-central CONUS. The 12Z GFS and ECMWF deterministic models are generally on the southern side. This affects the exact frontal position/timing and development of low pressure waves along the front. The latter part of the WPC model blend increased the proportions of the GEFS and EC ensemble means to just over half by the end of the period to reduce individual model differences. Though there has been some forecast/model convergence, forecast confidence still remains a bit below average at this time given the model variability. ...Sensible Weather and Potential Hazards... The amplifying upper trough and a strong cold front reaching the Northern Plains and Upper Midwest will likely produce showers and some thunderstorms from the Central Plains to the Great Lakes, with light to moderate totals possible through Tuesday. Rain is forecast to become more widespread in coverage as the front progresses across the Mississippi Valley and Ohio/Tennessee Valleys midweek and toward the East in the latter part of the week as the front taps into deeper moisture. Currently, the heaviest rainfall totals are expected for the interior Northeast as the front may slow there as it pivots. Elsewhere, the 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. Some high elevation snow showers are also possible for the highest terrain of the central and northern Rockies on Tuesday and Wednesday. Showers remain possible over Florida in the vicinity of a front as well. Above normal temperatures are now forecast to persist through much of next week across the northwestern U.S. with the upper ridge just off the coast. In the East, temperatures should be moderating early in the week after a relatively chilly weekend for most locations. Temperatures ahead of the main cold front will be warm across most of the Plains and Midwest states ahead of the front passing through Tuesday-Wednesday. Behind the front, highs are likely to be about 5-15 degrees below average to close out the workweek for the Ohio Valley and Great Lakes, with potential for frost at night. Tate/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