Extended Forecast Discussion NWS Weather Prediction Center College Park MD 259 PM EDT Sat Jun 05 2021 Valid 12Z Tue Jun 08 2021 - 12Z Sat Jun 12 2021 ...Much Above Normal Temperatures Continue Into Next Week from the Northern Rockies/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 nation into 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 Rockies/Plains to Northeast and New England. Uncertain energies to work into the West/Northwest offers modest rainfall across that region and a possible stronger/wetter downstream convective focus for the northern Rockies and north-central U.S. near a wavy front. Another highlight will be some threat of locally heavy rainfall next week for the lower to middle Mississippi River Valley that will gradually spread to the Midwest/Mid-Atlantic during the week. Latest model guidance is in fairly good agreement with the upper level pattern over the lower 48 featuring a West Coast cooling longwave mean trough and a strong Bermuda ridge. Most short range energy with a ridge embedded upper trough over the south-central U.S. should lift to the Midwest and slowly lose focusing influence for unsettled weather through the end of the upcoming work week. Meanwhile, hot upper ridging gradually builds up over the west-central U.S. as downstream upper troughing digs over the heat moderating Northeast and Midwest/Great Lakes. The greatest model differences are evident mid-later next week with the evolution of various shortwave troughs moving through the longwave trough over the eastern Pacific into the western U.S.. Differences have recently become more of a run continuity issue between 00/06 UTC guidance and more amplified and less progressive 12/18 UTC guidance, but the latest differences are smaller than yesterdays. The WPC medium range product suite was primarily derived from a GFS/ECMWF/UKMET/Canadian composite model blend days 3/4 (Tue/Wed) before transitioning to mainly the compatible GEFS/NAEFS/ECMWF ensemble means by days 6/7. ...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 system 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. Additional energies digging into the region may act to further organize activity later period. Activity will also spread downstream in this pattern into the Appalachians and Mid-Atlantic as aided with advance of a temperature moderating backdoor cold front. 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, 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