223 FXUS02 KWBC 011924 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 324 PM EDT Sat Aug 1 2026 Valid 12Z Tue Aug 04 2026 - 12Z Sat Aug 08 2026 ...Heat wave likely to continue across the Southwest and Intermountain West through next week... ...Overview... The upper ridge currently dominating the weather pattern across the western half of the country will weaken slightly and get suppressed south early next week as a strong cold front is forecast to bring much cooler air through the Northwest and into the northern Plains the first half of the week. However, excessive heat will be persistent across the southwestern quadrant of the country, and should gradually spread northeast into the central Rockies/Plains as the upper ridge re-intensifies, as well as farther east across the South as it could join with subtropical Atlantic ridging coming in for later week. Meanwhile, a handful of frontal systems in the central and eastern U.S. will trigger scattered showers and thunderstorms through the week. Monsoon convection is possible in the Southwest as well. ...Guidance/Predictability Assessment... The first system of note at the start of the period Tuesday will be a likely closed upper low atop the eastern U.S. This low has trended farther south in most 00Z and now 12Z guidance compared to a day ago, yielding more QPF and PoP coverage in the Southeast. Will note that the AIGFS and EC-AIFS were the first to catch onto this southern trend. The low should gradually open up and erode as it lifts north/northeast into midweek, and the frontal pattern at the surface seems rather uncertain and complex. However, the base of the north-central U.S. trough, the cold front ahead of it, and thus the rain axis are fairly agreeable through midweek. Into late week, there are increasing differences in the positions of energies aloft within the persistent broad north-central U.S. trough. The flow pattern in the Northwest also shows some uncertainties, with questions on timing of Pacific energy coming in, and no real consensus emerging yet. The WPC forecast used a multi-model blend for the early part of the forecast period, with ensemble mean weighting gradually increasing to half by Day 7 amid increasing spread. ...Weather/Hazards Highlights... Though much more suppressed compared to the short range, widespread Major to Extreme HeatRisk will continue for much of the Southwest through much of next week. Then, heat should build again gradually northward across the Intermountain West and Rockies to the High Plains, as well as eastward in the Mid-South and Southeast as the upper ridge expands. See Key Messages issued by WPC for this event for additional information regarding this long lasting and dangerous heat wave. Temperatures across the East should be generally near average. A reasonably strong front will push through the Midwest and central Plains Tuesday-Wednesday and trigger a corridor of potentially heavy rain and thunderstorms along and ahead of it. Meanwhile, weak frontal boundaries will allow for showers and thunderstorms to be scattered across the East, with some locally heavy to excessive rainfall possible there as well. These interacting features should allow for additional rounds of rain and storms across the north- central to eastern U.S. through late week. Elsewhere, monsoonal convection is likely for Arizona and New Mexico in particular, with scattered convection occasionally reaching portions of Utah and Colorado. Tate/Santorelli 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 $$