Extended Forecast Discussion NWS Weather Prediction Center College Park MD 300 AM EDT Wed Sep 16 2020 Valid 12Z Sat Sep 19 2020 - 12Z Wed Sep 23 2020 ...Guidance/Predictability Assessment... The WPC medium range product suite was created from a composite of well clustered guidance from the latest GFS/ECMWF/Canadian/UKMET and National Blend of Models Days 3-5 (Sat-Mon) in a relatively quite pattern with above normal forecast predictability. Forecast spread growth days 6/7 lent a change to a blend of the quite compatible GEFS/ECMWF ensemble means. ...Overview and Weather/Hazard Highlights... In the wake of Sally, strong high pressure settling into the East will bring well below normal temperatures including a few record values this weekend into early next week, with gradual moderation from west to east. The high pressure surge will also act to confine deeper moisture mainly to Florida and the Gulf of Mexico near a slow moving trailing front to linger over the next week. NHC is monitoring a slow moving tropical disturbance over the southwest Gulf of Mexico and broad deep moisture seems set to fuel widespread moderate to heavy rainfall that may feed into the western to west-central Gulf Coast. Elsewhere, amplified upper trough/embedded low ejection will spread some welcome rainfall and cooler temperatures out from the fire stricken Northwest and northern California to the northern Intermountain West/Rockies this weekend. Ahead of this system, the warmest temperature anomalies in the 10-15F range will focus into the northern-central states. Schichtel Additional 3-7 Day Hazards information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, 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/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml