Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1205 AM EDT Thu Jul 08 2021 Valid 12Z Sun Jul 11 2021 - 12Z Thu Jul 15 2021 ...Excessive Western Heat Persists into Next Week... ...Heavy Rainfall Threat Returns to the Midwest by the Middle of Next Week... ...Pattern Overview with Weather Highlights/Hazards... The ongoing heat wave under the upper ridge will continue for the Great Basin to the Coastal Ranges and lower CO River Basin into next week with temperatures 10-20F above normal through Tuesday with locally higher readings possible. Several daily high temperature records are likely through Tuesday primarily over the Great Basin through interior California to Arizona. Meanwhile, expect a heavy rainfall threat to persist over the Midwest and focus over the lower MS Valley on Sunday as fueled by return/pooling Gulf Moisture and instability along with lingering upper trough support and surface frontal system passages. Then, by the middle of next week the next Midwest system looks to bring heavy rainfall to the upper MS Valley which has been rather wet over the past few weeks. ...Guidance/Predictability Evaluation... Model and ensemble forecast spread into next week are low in a slowly evolving pattern with mean Midwest trough/low and the western ridge suppressing south and west to southern Cal early next week. The WPC medium range product suite was primarily derived for Days 3-5 from a blend of the 18 UTC GFS and 12 UTC ECMWF/UKMET/Canadian with Days 5-7 then focusing on the 18Z GEFS and 12Z ECENS means. This broad composite mitigates smaller scale guidance differences for shortwave activity over the Northwest coming into the mean Midwest trough. Jackson 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, 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