200 FXUS02 KWBC 061927 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 327 PM EDT Mon Jul 6 2026 Valid 12Z Thu Jul 09 2026 - 12Z Mon Jul 13 2026 ...Major Heatwave focus over the Southeast U.S. also builds over the Southwest to West-Central U.S. through this week and beyond... ...Guidance/Predictability Assessment... Guidance seems in reasonably good agreement and continuity on the mid-larger scale flow pattern that portends above normal heat threat related predictability. However, there remains numerous and varied smaller scale differences, especially with impacts associated with local convective focus and translation over time. Overall, favor a broad compoiste blend of models, ensemble means and machine learning guidance to mitigate many of the smaller scale variances as consistent with individual predictability. This overall plan also acts to maintain good WPC product continuity. ...Pattern Overview and Weather/Hazards Highlights... An upper-level ridge will persist into the Southeast U.S./Florida and also build robustly this period from the Southwest/Central Great Basin to across much of the west-central U.S.. This will include anonamlous closed high development over the north-central U.S. later period. These will support a major heatwave initially over the South/Southeast and increasingly from the Southwest/Great Basin to the Rockies/Plains this week and beyond. No overnight relief from hot temperatures will affect anyone without adequate cooling/hydration as well as health systems and infrastructure. Meanwhile, transient shortwaves will propagate down from the U.S. northern tier on/into the northern periphery of the ridge. Upper troughing/weaknesses will promote showers and thunderstorms from the Midwest to the Mid- Atlantic where WPC Excessive Rainfall Outlook Marginal to Slight Risk areas have been issued. Wavy frontal system translation and enhanced rainfall/thunderstorm activity focus should shift southward and spread down over the east-central and eastern U.S. and the South into the weekend/early next week under a mean upper trough carved downstream of the aforementioned main upper ridge/closed high. Meanwhile, the guidance signal is growing that monsoonal moisture and rainfall is seasonally expected to begin and increase into the Southwest/Southern Rockies over the weekend into next week as the main upper ridge/high builds from the Southwest to the North- Central U.S.. Ridge amplification should also lead to scattered downstream strong Southern Plains convection given summertime airmass and growing upper diffluence/tucked weaknesses aloft. Kebede/Schichtel 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 forecast, excessive rainfall outlook, winter weather outlook probabilities, heat indices and Key Messages 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/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml https://www.wpc.ncep.noaa.gov/#page=ovw $$