Extended Forecast Discussion NWS Weather Prediction Center College Park MD 240 PM EDT Tue Oct 8 2024 Valid 12Z Fri Oct 11 2024 - 12Z Tue Oct 15 2024 ...Desert Southwest record heat moderates/lingers into Saturday... ...Overview... A leading Northeast/Mid-Atlantic upper trough should push off the coast on Friday along with frost/freeze concerns, while a central U.S. ridge will continue to bring much above normal temperatures but with northern stream energy dampening the northern periphery. This energy should amplify as it reaches the East Coast this weekend setting up another round of Eastern U.S. troughing early next week along with an opportunity for some locally enhanced rains. This will also begin another period of cooling temps that should persist into week 2 as per CPC along with more frost/freeze concerns for the Northeast/Mid- Atlantic. Meanwhile out West, one shortwave into the Northwest this weekend will be followed by a much more amplified trough into the West Coast next week along with light to moderate rains for the Pacific Northwest. This will also act to amplify upper ridging downstream and another round of much above normal temperatures to the northern High Plains/Plains prior to the advent of much colder post-frontal temperatures and frost/freeze concerns in about a week. ...Guidance/Predictability Assessment... Models show good agreement on the overall pattern evolution across the CONUS during the medium range period, but with some typical details differences especially into early next week. Accordingly, the WPC med-range product suite was primarily derived a composite of best clustered guidance from the latest GFS/ECMWF and GEFS/ECMWF ensemble means along with the compatible 13 UTC NBM. This solution maintains good WPC continuity in generally benign flow across much of the nation in the wake of the now short range highlighted landfall of major Hurricane Milton into Florida. ...Weather/Hazards Highlights... It generally remains the case that a large part of the lower 48 will see fairly dry weather for a majority of the period. A compact eastern Pacific upper trough/low may bring a brief period of mostly light rainfall to the central West Coast around Friday- Saturday, with a little light precipitation possibly reaching farther eastward into the West thereafter. Then a front approaching the Pacific Northwest may bring some moisture and light to moderate rainfall into the region by the start of next week. The amplifying upper trough and accompanying surface evolution should bring some areas of locally enhanced rainfall to parts of the Great Lakes/Northeast by late weekend into the early part of next week. A central U.S. upper ridge will continue to promote a period of well above normal temperatures with northern stream troughing and a cold front pushing the greatest warm anomalies southeast with time from the central Plains and Mid/Upper Mississippi Valley to the Southeast Friday-Saturday. Temperatures around 10 degrees above normal in the Southwest could set additional daily records though the temperatures have moderated compared to recent days and the short range. The northern Rockies/High Plains may see temperatures reach up to 10-20F above normal by early next week. Meanwhile, some near to slightly above normal temperatures in the East this weekend should be replaced by temperatures generally 5-10 degrees below normal next week underneath amplified troughing. Later period cold frontal passage is also expected to provide a spread of much cooler temperatures from the north-central U.S. through the Midwest/Great Lakes and Northeast starting in about a week. Santorelli/Schichtel 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 forecast (QPF), excessive rainfall outlook (ERO), winter weather outlook (WWO) probabilities, heat indices, and Key Messages can be accessed from: 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 https://www.wpc.ncep.noaa.gov/#page=ovw