Extended Forecast Discussion NWS Weather Prediction Center College Park MD 246 AM EDT Tue Sep 20 2022 Valid 12Z Fri Sep 23 2022 - 12Z Tue Sep 27 2022 ...Guidance Evaluation/Predictability Assessment... Model and ensemble solutions are well clustered through medium range time scales over the lower 48, bolstering forecast confidence despite some lingering local embedded system timing/strength differences. The WPC medium range product suite was mainly derived from a blend of the 18 UTC GFS, 12 UTC ECMWF/UKMET/Canadian and 01 UTC National Blend of Models Friday-Sunday, increasingly gravitating to the compatible GEFS/ECMWF ensemble means into early next week. Overall, guidance differences seem well mitigated by the composite blending process consistent with a pattern with above normal predictability. WPC product continuity is well maintained in this manner and remains in line with latest 00 UTC models and ensembles. ...Pattern Overview and Weather/Hazards Highlights... Ample cool Canadian high pressure will settle across much of the central to eastern U.S. Friday into the weekend in the wake of a lead system/cold front. The lingering front may focus some showers across Florida. Meanwhile upstream, initially amplified upper trough ejection out from the West and surface system translation should focus modest convection coverage over the north-central U.S/Midwest by Friday/Saturday. A warming upper ridge with upwards to 10F+ above normal maximum temperature anomalies is expected to build back over the drier West in the wake of this system Sunday into early next week. This ridge amplification should favor the downstream digging of reinforcing northern stream shortwave energies/frontal systems that is forecast to rejuvenate lead convective rainfall potential that may offer some local runoff issues from the Great Lakes/Ohio Valley/Appalachians Sunday through the Northeast/Mid-Atlantic Monday. The trailing frontal push across the South early next week seems to only offer isolated shower activity, but will usher in another refreshing surge of Canadian high pressure down across much of the central-eastern U.S.. 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, 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