Extended Forecast Discussion NWS Weather Prediction Center College Park MD 138 AM EDT Tue Jun 09 2020 Valid 12Z Fri Jun 12 2020 - 12Z Tue Jun 16 2020 ...Overview and Guidance/Predictability Assessment... A trough/ridge/trough pattern will attempt to flatten out by next week with the exception of the Northeast. An upper low may slowly move through the region as heights rise over the rest of the CONUS. Through the 12Z/18Z cycle, the models and ensembles were in good agreement overall on the pattern evolution. Differences remained over the PacNW where the GFS was farther south than the other guidance Fri/Sat with a northern upper low at the expense of a quicker/weaker southern trough through NorCal. To the east, upper trough over Ontario/Quebec will split into two segments with the southern portion splitting off a weak upper low over the eastern Great Lakes. Models have varied on how long to meander this upper low but generally have trended a bit weaker by splitting it into two pieces. Preferred to stay near the ensemble consensus best represented by the 12Z Canadian and 18Z GFS as the ECMWF was slower/farther west (possible but without a lot of ensemble support). Back to the west, 12Z ECMWF was preferred in its handling of the unfurling upper system as the GFS was farther south. 12Z ECMWF ensemble mean served well overall. ...Weather/Hazard Highlights... Temperatures 5 to 15 deg F above normal will shift out of the Rockies and 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 on Fri will east southeastward to the Mid-Atlantic next week. Over the Southern Plains, hot temperatures will focus from west Texas northward to western Kansas where 100F will be possible next week. Rainfall will be light over most of the CONUS during the period. Upper trough in the Northeast may keep the best moisture offshore Fri/Sat but along the Southeast coast. This may attempt to lift 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 (still some snow at the peaks) which will spread eastward and diminish a bit as the best dynamics may lift into Canada. 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 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