Extended Forecast Discussion NWS Weather Prediction Center College Park MD 235 AM EDT Mon Jun 07 2021 Valid 12Z Thu Jun 10 2021 - 12Z Mon Jun 14 2021 ...Locally Heavy Rainfall Thursday and Friday from the Tennessee/Ohio River Valleys to the Central Appalachians and Mid-Atlantic... ...Much Above Normal Temperatures for the North-Central U.S Late This Week and Weekend.... ...Guidance/Predictability Evaluation... The latest model guidance offers average to above average predictability for the Nation during the medium range period (Thursday-Monday) and is driven by the amplified upper level pattern featuring a western U.S. trough with ridging across the southern to central U.S. and some troughing becoming established over the Northeast this weekend. This puts the primary storm tracks from the northern Rockies into the northern Plains while some waves of low pressure will work through portions of the eastern U.S. before settling down closer to the Southeast by early next week. The main model differences were noted across the West with the progression of shortwave energy rounding the base of the mean trough. Some of the typical biases were noted, with the GFS on the faster side of the model spread. Across the East/Northeast, some uncertainty on how a deepening low could force the wavy stationary boundary in place further south this week and allow sprawling high pressure to settle over the Great Lakes. The consensus is for this front to push southward into the Southeast before washing out/stalling. Overall, the medium range blend consisted of the 12Z ECMWF/CMC/UKMET and 18Z GFS for days 3-5 followed by mostly ECENS/GEFS means with some deterministic ECMWF included for days 6-7. The pattern overall offers above normal forecast predictability and continuity. ...Weather Highlights/Hazards... Upper level ridging building through the central U.S. will favor much above normal to possibly record warmth across the northern Rockies and northern Plains Thursday and then again later in the weekend to early next week (brief reprieve expected Friday/Saturday). Departures above normal could reach 15F to 20F with highs well into the 90s. Locally heavy rainfall capable of producing flash flooding will be possible Thursday and Friday across portions of the Ohio Valley to the Mid-Atlantic as moisture and lift associated with a weak upper level feature traverses the region. Its eventual interaction with a more substantial cold front dropping south will shunt the moisture southward this weekend. For this upcoming weekend, unsettled weather and higher precipitation chances will be confined to the Southeast U.S. along the residual frontal boundary as well as portions of the Pacific Northwest as a few waves of low pressure move onshore. 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