299 FXUS02 KWBC 211955 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 355 PM EDT Sun Jun 21 2026 Valid 12Z Wed Jun 24 2026 - 12Z Sun Jun 28 2026 ***Additional heavy rain for the Central Plains and very hot conditions for the Desert Southwest through Friday*** ...General Overview... A couple of shortwaves are forecast to move across the northern tier states within broad troughing that dips into the eastern two- thirds of the country through the medium-range period. An upper level ridge will maintain the heat across the Desert Southwest into portions of the Intermountain West before a more pronounced trough dips into the Pacific Northwest by next weekend. A lingering frontal boundary draped across the Mid-South to the central Plains, coupled with some shortwave energy aloft, will fuel the development of multiple thunderstorm complexes that will bring episodes of heavy rainfall. By next weekend, the upper trough will herald the arrival of colder weather into the northwestern quadrant of the country with a double-barrel low-pressure system developing on the lee of the Rockies. ...Guidance/Predictability Assessment... Within the broad troughing across the eastern two-thirds of the country, model guidance is showing a gradual slowing trend and with less amplitude for the two shortwave troughs moving across the northern tier states, which is uncharacteristic for the medium- range period. Overall agreement is good for the upper trough/closed low reaching the Pacific Northwest by the end of the week with a slightly earlier arrival time. Across the central U.S., the ECMWF has been favoring a more southern QPF axis from D5/Friday onward across the central U.S. versus the GFS cluster, which shows a more northern and progressive QPF axis across the Midwest. There has been a general consensus to trend toward the GFS cluster as the warm front ahead of the double-barrel and elongated low-pressure system develops over the High Plains. Over the Pacific Northwest, models are signaling colder post- frontal environment next weekend, with rain/snow mix or wet snow across the higher-elevations of central Idaho and northwestern Wyoming. In addition, there is good agreement on the placement of the moderate to perhaps locally heavy rain across the northern Plains preceding the elongated low-pressure system over the High Plains. ...Weather/Hazards Highlights... The weather pattern will remain quite unsettled from the central Plains across Arkansas and southwestern Missouri through the middle of the week with multiple rounds of thunderstorms and locally heavy rainfall. This is in association with a frontal boundary that will be in place across this region, with anomalous moisture surging north and fueling the convection that develops. A marginal excessive rainfall is depicted for this area in the outlook map. Going into the end of the week, the heaviest rainfall is expected from eastern Kansas to central Illinois where additional thunderstorm complexes are expected to develop and lead to periods of heavy rainfall, and this will likely be the case for the Ohio Valley going into Saturday. Temperatures are expected to be very pleasant by late June standards across a large expanse of the north-central states through much of next week, with highs generally in the 70s and comfortable humidity levels given the overall dip in the jet stream and broad upper trough in place. Most of the Mid-Atlantic and Northeast should be close to seasonal averages with highs mainly in the upper 70s to upper 80s. With the upper ridge over the West through Friday, heat is expected to build from the Desert Southwest to the Pacific Northwest, with highs generally running 5 to 10 degrees above normal in many cases. A pattern change is expected to arrive next Saturday as a cold front drops south across the Pacific Northwest and brings an end to the heat wave there. Portions of south-central Oregon as well as the higher-elevations of central Idaho and northwestern Wyoming could cool below freezing by next weekend, with rain/snow or wet snow possible over the higher elevations. Moderate to perhaps locally heavy rain and embedded thunderstorms are forecast across the northern Plains preceding the elongated low-pressure system over the High Plains. Meanwhile, hot and humid conditions will continue unabated across the Deep South and Gulf Coast region. Kong/Hamrick 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 $$