Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1123 AM EDT Fri Sep 06 2019 Valid 12Z Mon Sep 09 2019 - 12Z Fri Sep 13 2019 ...Record heat to continue for the Lower Mississippi Valley/Gulf Coast next week... ...Overview... Upper ridging will remain anchored over the Lower Mississippi Valley and Southeast next week, with a ridge extending up to the western Canadian Shield through the middle of next week before shifting east. Low pressure over the Pacific Northwest amplifies into a trough extending down to the Great Basin Monday through Wednesday before shifting across the northern Great Plains through Friday. Downstream of the ridge axis, a trough shifts southeast from Hudson Bay Thursday, developing into a low over the Canadian Maritimes Friday. ...Guidance Evaluation and Preferences... A typical general model blend of the 00Z/06Z GFS (favoring the 06Z) and 00Z ECMWF/CMC/UKMET formed a good consensus through Day 5 with good clustering near the ensemble means. Inclusion of the 06Z GEFS and 00Z ECENS increased Day 6 into Day 7 as is typical. The 06Z GFS is generally deeper with lows developing late in the week over the northern Great Plains and Canadian Maritimes and it more progressive by Day 7 as the Canadian Maritime low ejects north to Labrador. ...Sensible Weather... The southeastern CONUS from the lower MS Valley eastward to the Southern Appalachians will see well above average temperatures in the upper 90s to lower 100s F that are forecast to tie or break record highs at least into the middle of next week with above normal temperatures persisting through Friday. Much of The West and Northern Rockies/High Plains will see below average temperatures with a generally stormy/wet pattern for the northwestern CONUS. Warm conditions, about 5-10F above average, are favored for the mid-Mississippi Valley eastward through the Ohio/Tennessee Valleys to the south of a frontal boundary. Rainfall will be mostly confined to northern areas along the storm track of both an initial shortwave trough crossing the northern Plains Monday into Tuesday and the low pushing east from the Pacific Northwest Tuesday and crossing the northern Plains Thursday and Friday. Pockets of heavier rain may be possible across the High Plains into the western Great Lakes region around the surface low and in advance of the warm front Mon-Tue. Another chance of widespread rain with embedded heavier elements will be possible next Thu/Fri from eastern Montana into Minnesota as low pressure deepens over the Plains. In the Southwest, moisture out of Mexico will likely lead to a daily chance of mountain showers/storms mainly over southern portions of Arizona/New Mexico/and extreme western Texas through Wednesday before drying out under the next building ridge. Jackson 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