876 FXUS02 KWBC 040606 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 206 AM EDT Mon May 4 2026 Valid 12Z Thu May 07 2026 - 12Z Mon May 11 2026 ...General Overview... A broad upper-level closed low over eastern Canada will continue to drive broad cyclonic flow and repeated trough reinforcement through the period. This pattern will bring a stretch of cool, unsettled weather across central/eastern U.S. The progressive cold front will continue to move across eastern U.S. by late week, bringing showers and thunderstorms across eastern U.S. Although the main front moves offshore by the weekend, the embedded shortwave troughs will continue shower activity along parts of eastern U.S. into the weekend. The remnants of the front will linger across lower Mississippi Valley into Southeast, bringing additional rainfall across the area. Below normal temperatures will continue across the Great Lakes into the Northeast through the weekend, while a warming trend spread across much of western/central U.S. ...Guidance/Predictability Assessment... Latest model guidance continues to show good agreement of the upper- level trough/low over eastern Canada with some differences in timing and amplitude of a few shortwave energies toward Day 5, especially with the GFS showing a faster progression than the CMC and ECMWF. Over western U.S., the GFS also shows some larger differences with the ridge over Pacific Northwest and the low/trough over the Southwest compared to CMC and ECMWF. The ensemble means does a decent job with smoothing some of these differences. Therefore, the WPC forecast was based on a multi-model blend with the GFS/CMC/ECMWF/UKMET and ECAIFS for the the first portion of the period. Later in the period, the ensemble means were incorporated to account for some of the timing and amplitude differences. ...Weather/Hazards Highlights... The broad upper-level low hovering over eastern Canada will continue to eject shortwave energy near the base of the mean trough across much of eastern and southern U.S. The low will serve as an anchor for maintaining cyclonic flow and reinforcing cooler air southward into eastern U.S. At the surface, the primary cold front associated with this trough will move eastwards and stretch across the lower Mississippi Valley into the Northeast on Thursday. The boundary will interact with moist Gulf moisture, which will lead to additional showers and thunderstorms across the Southern Plains into Southeast. In addition, the increasing deep-layer shear and modest instability will support organized convection and chances for heavy rainfall along the frontal boundary, particularly over Southeast. With flooding concerns over the area, a Marginal risk has been introduced for Day 4/Thursday across southern Alabama. In addition, gusty northwest winds may develop behind the front from Thursday into Friday. Heading into Friday, the trailing end of the cold front will stall over near the Gulf Coast and Southeast, bring additional showers and thunderstorms through the weekend. Furthermore, as the front exits off the coast, wraparound moisture and embedded shortwaves will bring occasional showers across the Great Lakes, Interior Northeast, and Central Appalachian through the weekend. Meanwhile, below average temperatures will continue across eastern U.S. behind the cold front from Thursday through Friday. Frost/freeze conditions will continue across the Upper Midwest/Great Lakes and Northeast through Friday morning and the northern borders of New England through Saturday morning. With the cold temperatures, there is a slight chance for some mixed precipitation over isolated high-elevation areas over the Northeast, but impacts will be minimal. Over western U.S., a shortwave energy will push a frontal boundary into northern- central Rockies/Plains on Thursday, bringing a chance for low-elevation showers and high-elevation snow through the weekend. In addition, deep boundary layer mixing will bring gusty winds across the area on Thursday. The front will continue to strengthen as it moves eastward, expanding the chances for light precipitation across central U.S. by Sunday. Over into the Pacific Northwest/West Coast, a ridging pattern continues to push inland early in the period and will gradually move southeastward into central U.S. through the weekend. This will bring 10-15 degrees above average temperatures with highs mostly in the 80s and 90s. Oudit 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 $$