Extended Forecast Discussion NWS Weather Prediction Center College Park MD 332 PM EDT Mon Jul 13 2020 Valid 12Z Thu Jul 16 2020 - 12Z Mon Jul 20 2020 ...A very hot summer pattern for much of the nation... ...Overview and Guidance/Predictability Assessment... Hot upper ridging will linger from the Southwest/Great Basin through much of the central and eastern U.S. A main storm track will remain closer to the Canadian border in progressive westerly flow as above normal temperatures rule for most areas of the lower 48. The Northwest should even warm into next week with the easing of a moderating upper trough. Ensembles remain in great agreement compared to varied model depictions of smaller scale weather features, especially QPF. The WPC medium range product suite was mainly derived from a blend of the 06 UTC GEFS mean and the 00 UTC ECMWF ensemble mean. Extra blend weight was applied to the ECMWF ensemble mean that maintains slightly more upper ridging. This seems more likely given pattern history and continuity. Hot ridges tend to persist. ...Weather Pattern/Hazard Highlights... I consolidated WPC forecast frontal structures to focus on main features that hold higher predictability. These will focus some locally strong to severe convection, with even more uncertain activity widely scattered in the expansive hot airmass. A leading cold front will focus convection and some locally heavy downpours across the Great Lakes/Ohio Valley/Mid-Atlantic/Northeast Thu into Sat. A second main front exiting an unsettled Northwest will favor activity over the northern Rockies/Plains and Upper Midwest/Great Lakes Fri-next Mon. Generally dry conditions, albeit with some scattered thunderstorms, are expected elsewhere over the lower 48. Florida though should see afternoon showers/storms with tropical wave passage later this week. Some convection may also build this period near the southern Rockies on the west side of the upper high. The relative lack of rainfall across the West and Plains during the next week in combination with summertime heat is overall expected to worsen/expand drought conditions in those areas. Temperatures remain near record highs over parts of New Mexico and Texas later this week with widespread 100+ readings, but a few degrees cooler than in the short term. Some much above normal temperatures are also likely from the south-central Plains through the Midwest and into the Northeast by the weekend (5-10+ degrees above normal). The WPC 3-7 Day Hazards Outlook shows an excessive heat and humidity threat area focus over the east-central states. Schichtel 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: - Flooding occurring or imminent across portions of the Northern Plains. - Flooding likely across portions of the Northern Plains. - Excessive heat across portions of the Central and Southern Plains, the Mississippi Valley, the Midwest, and the central Gulf states, Thu-Sun, Jul 16-Jul 19. - Excessive heat across portions of the Mid-Atlantic, Sat-Mon, Jul 18-Jul 20. 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