Extended Forecast Discussion NWS Weather Prediction Center College Park MD 513 PM EDT Tue Jun 09 2020 Valid 12Z Fri Jun 12 2020 - 12Z Tue Jun 16 2020 ...Overview and Guidance/Predictability Assessment... The medium range period is expected to begin Fri 6/12 with a trough/ridge/trough pattern across the CONUS, which should flatten out somewhat early next week except in the East. While model agreement was generally pretty good for the overarching pattern, one area where model differences were present was the West early on. While most deterministic and ensemble guidance split energy in the western trough into northern and southern components and held the southern part back, the 00Z GFS combined the energy and the 06Z run was faster/farther east with the southern energy. So the deterministic GFS runs were not generally favored there, with the 00Z ECMWF, CMC, and UKMET creating a large proportion of the model choices for late this week. This western trough along with a surface frontal system ahead of it should move slowly eastward through Sun before the upper low moves eastward across south-central Canada and the troughing flattens across the Great Basin, while another upper low approaches from the northeastern Pacific Mon/Tue. Model differences are present with both upper lows in terms of placement and strength, so went with a general GFS/ECMWF/CMC model and GEFS/ECENS ensemble blend there, which also worked for the persistent but reorienting trough in the East. ...Weather/Hazard Highlights... Temperatures 10 to 20 degrees above normal will shift out of the Rockies toward the High Plains this weekend ahead of the western front. Behind this system, temperatures will be 5 to 15 degrees cooler than average across the Pacific Northwest and surrounding area this weekend before moderating. Cooler than normal temperatures around the Great Lakes Fri/Sat should shift east-southeastward to the Mid-Atlantic next week. Over the Southern Plains, hot temperatures will focus from west Texas northward to western Kansas where temperatures approaching or exceeding 100 F can be expected next week. Rainfall should be light over most of the CONUS during the period. The upper trough in the Northeast may keep the best moisture offshore Fri/Sat, but could remain along the Southeast coast. There is an increasing signal for rain northward Sunday into Monday through the Mid-Atlantic, but this will depend on the upper trough location/strength/orientation and available moisture. Over Florida, increased moisture over the northern Caribbean may enhance rainfall next week. Front into the Pacific Northwest will bring some light to modest rainfall to especially the higher elevations, and some light snow is possible for the highest peaks, but snow levels should be higher than the event early this week. The precipitation will spread eastward and diminish a bit as the best dynamics are expected to lift into Canada. Tate/Fracasso Additional 3-7 Day Hazards information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php Hazards: - Heavy rain across portions of the Southeast, Sun-Mon, Jun 14-Jun 15. - Heavy rain across portions of the Central/Southern Appalachians, and the Mid-Atlantic, Tue, Jun 16. - Flooding possible across portions of the Upper/Middle Mississippi Valley, the Great Lakes, the Northern Plains, and the Ohio Valley. - Flooding occurring or imminent across portions of the Mississippi Valley, the Northern Plains, the Northern Rockies, and the Southeast. - Flooding likely across portions of the Central Plains, the Central Great Basin, the Northern Plains, the Northern/Central Rockies, and the Middle Mississippi Valley. - High winds across portions of the Northern/Central Great Basin, and the Southwest, Fri, Jun 12. - High winds across portions of the Northern/Central Plains, the Central Great Basin, the Southern Rockies, and the Southwest, Sat, Jun 13. - Enhanced wildfire risk across portions of the the Central Great Basin and the Southwest, Fri, Jun 12. - Enhanced wildfire risk across portions of the the Central Rockies, the Central Great Basin, and the Southwest, Sat, Jun 13. 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