Extended Forecast Discussion NWS Weather Prediction Center College Park MD 227 PM EDT Sat Sep 23 2023 Valid 12Z Tue Sep 26 2023 - 12Z Sat Sep 30 2023 ...Overview... The pattern through the middle to late parts of next week features an amplifying upper trough over the Northwest through the entire western U.S. with a downstream omega high centered over Ontario before drifting east. ...Guidance Evaluation/Predictability Assessment... Reasonable agreement among global guidance continues through through Thursday with the 06Z GFS more amplified with the Northwest trough. Thereafter, the 00Z ECMWF and 06Z GFS maintain an amplified trough/becoming a closed low by the weekend. The 00Z Canadian continues to flatten out the mid-level flow and be more progressive to the northern Plains. The initial blend is a fairly even blend of the 00Z ECMWF/UKMET/Canadian, and 06Z GFS through Day 5. After Thursday morning, the blend increasingly relied on the 00Z ECENS/06Z GEFS. QPF grids are from the 13Z NBM enhanced with the ECMWF/GFS through about Day 5, then mainly the NBM for Days 6/7 given increased uncertainty. ...Weather/Hazards Highlights... No Excessive Rain Outlooks for Days 4/Tuesday or 5/Wednesday at this time. An early season storm system will bring active weather to the Pacific Northwest through next week. Rounds of heavier precipitation are expected, favored for the coastal regions and upslope areas of the Washington and Oregon Cascades. However, given current drought conditions and generally lower rainfall rates suggests no excessive rainfall outlooks are needed. A stalled front over the Florida Peninsula through much of next week will bring periodic heavy rains Tuesday into next weekend. A particular focus area will need to be looked for, but as of this time there is insufficient confidence to warrant an excessive rainfall outlook. Increased ridging over the center of the country and troughing farther west, will make for an increasing temperature trend in the Plains/Great Lakes and decreasing across the West. Below normal temperatures over the Mid-Atlantic States can be expected through midweek before moderating on approach of the ridge. Jackson/Roth 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, excessive rainfall outlook, winter weather outlook probabilities, heat indices and Key Messages 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 https://www.wpc.ncep.noaa.gov/#page=ovw