Extended Forecast Discussion NWS Weather Prediction Center College Park MD 208 AM EDT Wed Jun 09 2021 Valid 12Z Sat Jun 12 2021 - 12Z Wed Jun 16 2021 ...Much above normal temperatures and record heat this weekend into early next week across much of the interior West/Northern Plains.... ...Overview... Upper pattern is forecast to amplify along 105W this weekend into early next week, promoting warm/hot temperatures over much of the West and northern High Plains that may near or break daily records. Troughing will exit but then build back into the East where rainfall will focus over the Mid-Atlantic into the Southeast. A Pacific front will push into the Pacific Northwest early next week. ...Guidance/Predictability Evaluation... The latest model guidance for the medium range period (Saturday-Wednesday) is in reasonable agreement and offers average to above average predictability and consistency. The upper flow amplification driven by near +3 sigma height anomalies is well agreed by the most recent deterministic and ensemble guidance. The largest model spread exists with downstream troughing potential for the Great Lakes to Northeast. With such strong ridging, the deeper troughing has become a clearer signal and preferred pattern but the depth and progressiveness remains uncertain. Upstream energy and interactions with shortwave energy coming out of Hudson Bay lower confidence by the middle of next week. With this in mind, the WPC blend utilized the ECMWF/CMC/GFS followed by a ECENS led blend by days 6-7. ...Weather Highlights/Hazards... The amplification of the upper ridge over the central U.S. is expected to bring another round of much above normal to possibly record warm/hot temperatures to the northern Rockies and northern Plains late this weekend and early next week. Temperatures may be 10-25F above normal with some triple-digit readings possible across central/eastern Montana Monday and Tuesday. Nighttime lows will also remain warm for the region and likely stay 10F to 15F above normal for middle of June. Elsewhere across the CONUS, temperatures are expected to be near to slightly above normal. The strong/dominant upper ridge over the central CONUS will keep much of the area void of significant or heavy rainfall, the exception being possibly along the Gulf Coast to Southeast U.S. late this weekend into early next week where a frontal boundary stalls and lingers. 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