374 FXUS02 KWBC 011836 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 236 PM EDT Wed Jul 1 2026 Valid 12Z Sat Jul 04 2026 - 12Z Wed Jul 08 2026 ...Significant heat wave expected to last into at least Saturday for the Midwest to Eastern U.S. before waning early next week.. ...Pattern Overview... It remains the case that the strong ridge supporting a significant and dangerous heat wave during the short range period should finally begin to weaken somewhat by the medium range period, however hazardous heat may still continue through the weekend, especially for parts of the East. Energy from the West should eventually work its way into the Northern Plains and Great Lakes suppressing the ridge completely by early next week. Ridging then looks to build back into the Four Corners region next week. Showers and storms will expand across the Ohio Valley and the South/East next weekend and into next week as the ridge weakens. ...Guidance/Predictability Assessment... Guidance solutions continue to be reasonably well clustered at mid-larger scales as is often the case during the warm season in the absence of organized tropical systems. Most lingering model, ensemble and machine learning guidance issues remain at smaller scales and especially with convective focus. A composite guidance blend favoring the models over the weekend and the ensemble means and machine learning guidance next week seems to best mitigate smaller scale variances as consistent with individual feature predictabillity that lowers over time. ...Weather/Hazards Highlights... The focus for a major ongoing heat wave will persist through the holiday weekend from parts of the Midwest into much of the East. Widespread and daily record breaking maximum temperatures into the 90s to low 100s, combined with high humidity, will result in heat indices approaching or exceeding 105-110 in many places, especially for Saturday. This equates to some widespread Major to Extreme HeatRisk threats. Overnight lows will linger and also be quite warm, with numerous record high minimums possible, bringing little to no relief from the heat in the nighttime hours. Heat may finally begin to abate by Sunday, with upper temperature limits through the weekend possibly restricted by increasing clouds/convection as ridge breakdown begins. Above normal temperatures should expand westward into the Southern and Central Plains as well, with temperatures out West near to below normal underneath of general/weakened troughing. Rain and thunderstorms should expand in coverage across much of the eastern half of the nation this weekend within a very warm, moist, and unstable air mass. Fairly weak overall flow may also help to support at least a localized flash flood threat across much of this region, with possibly some better convection focus near a wavy frontal boundary from the Midwest to the Mid-Atlantic. WPC Marginal Risks are in place from the north-central Plains into parts of the East for the Days 4/Saturday and 5/Sunday Excessive Rainfall Outlooks. Elsewhere, diurnally driven showers and storms are expected from parts of the central Gulf Coast to Florida most of the period with increasing moisture. Showers may refire again later in the period for parts of the Southern/Central Rockies and High Plains, as well as the northern tier ahead of additional shortwave energy. The rest of the West looks to remain mostly dry over this forecast period. Santorelli/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 $$