Extended Forecast Discussion NWS Weather Prediction Center College Park MD 233 AM EDT Sat Jun 05 2021 Valid 12Z Tue Jun 08 2021 - 12Z Sat Jun 12 2021 ...Much Above Normal Temperatures Continue Into Next Week Across the Northern Plains to Northeast.... ...Locally Heavy Rainfall Possible Next Week Across Lower/Mid Mississippi...Tennessee...and Ohio Valleys... ...Overview and Guidance Evaluation/Preferences... The weather overview for the CONUS next week will be the continuation of much above normal to near record warmth across the northern tier of U.S., particularly across the northern Plains to Northeast and New England. The other weather highlight will be the threat of locally heavy rainfall throughout next week over portions of the lower to middle Mississippi River Valley and gradually spreading toward the Tennessee and lower Ohio River Valleys. The latest model guidance is in fairly good agreement with the upper level pattern remaining amplified across the CONUS featuring the western longwave trough while the strong Bermuda ridge holds. Early on in the forecast period, a weakness in the trough over the central U.S. will be the focus for some unsettled weather but that is forecast to become absorbed or dissipate by the end of the upcoming work week. The greatest model differences are after Wednesday with the evolution of various shortwave troughs moving through the longwave trough over the eastern Pacific into the western U.S.. There are considerable timing issues between the various deterministic models and the downstream effects reach the Rockies and northern Plains as storm systems eject out. The WPC blend incorporated the latest ECMWF/GFS/CMC early on then transitioned over to mainly the latest GEFS/ECENS means to account for some of the greater uncertainty out West. ...Weather Highlights/Hazards... The interaction of deep/moist flow from the Gulf of Mexico with weakening surface boundaries up from the western/central Gulf Coast and lingering upper troughing will continue to provide episodes of heavy rainfall and possible flash flooding across the ArkLaTex and Lower/Mid Mississippi River Valley where the greatest risk area for several inches of rainfall totals exists. Over time next week, the associated surface trough is forecast to weaken and lift northward which will bring numerous to widespread showers and thunderstorms to portions of the Ohio Valley and Great Lakes regions, which could produce some locally heavy rainfall. The much above normal to near record warmth will continue across the northern Plains to Northeast over the course of next week. After Wednesday, some moderation is possible across the Northeast, but the ridging over the Southeast U.S. and western trough should provide additional periods of much above normal temperatures across the Northern Plains through the week. The South will see normal to even slightly below normal temperatures thanks to increased cloud cover and precipitation chances while the West Coast will experience slightly below normal readings in response to the troughing in place over the region. Taylor 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