205 FXUS02 KWBC 210804 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 404 AM EDT Sat Mar 21 2026 Valid 12Z Tue Mar 24 2026 - 12Z Sat Mar 28 2026 ...Anomalous early season heat wave across the Southwest abating somewhat early next week but will rebuild midweek... ...Overview... A series of shortwaves will propagate through the southern tier of Canada and northern tier of the CONUS next week. One of these waves will produce precipitation over portions of the Pacific Northwest, Great Lakes and Northeast/Mid-Atlantic between Tuesday and Friday. Meanwhile, an upper ridge will be responsible for a prolonged heatwave from the Southwest to the Great Plains before a Pacific trough shoves the ridge toward the Southeast late next week. ...Guidance/Predictability Assessment... Models tend to agree on the overall synoptic evolution across the CONUS outlined in the overview section. However, there's remains some uncertainty around the amplitude of the ridge trough axes in the West and East respectively beginning next Wednesday. A general model blend consisting of the deterministic Euro/GFS/Canadian, ECAIFS and GEFS models were utilized on day 3 due to run-to-run consistency and reasonable agreement on the timing of the East Pacific trough approaching the Pacific Northwest. The Canadian is replaced by the UKMET due to timing differences with the Pac NW energy. Cluster analysis reveals better clustering between the Euro and Canadian ensemble members compared to GEFS members beyond day 4. Therefore, the Euro, with some deterministic/ensemble Canadian, was favored in the days 5-7 blends. ...Weather/Hazards Highlights... While not quite as anomalous as this past week, the main story during the medium range period next week will remain another period of well above average, widespread daily-record level warmth across portions of the western and central U.S. A prominent upper-level ridge will support maximum temperatures that are 20-40 degrees above average, and widespread maximum and minimum temperature records are possible from the Southwest early next week to the Plains by midweek. This heatwave, combined with dry conditions and daily bouts of gusty, downsloping winds across the High Plains may lead to potential fire weather concerns on Tuesday and Wednesday. A more concentrated area of very strong winds is expected across the Northern Rockies and adjacent High Plains Wednesday as a deepening low in the lee of the Canadian Rockies passes by. A potent mid-latitude cyclone will move from the Northwest to the Canadian Maritime next week. This system will bring moderate to heavy rain over the Pacific Northwest Tuesday. Most of the precipitation from this will be in the form or rain since the shortwave aloft will be embedded within the broader Western ridge. Total amounts remain a bit uncertain but an upward trend would signal potential for at least isolated flooding concerns. Higher elevations of the Olympic and Cascade mountains will receive some snowfall, especially on the backside of the associated cold front. The low pressure system will weaken while it tracks across the Central U.S., before reinvigorating over the East and producing some rain south/snow north for parts of the Great Lakes/Ohio Valley/Northeast by late next week. Kebede 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 (QPF), excessive rainfall outlook (ERO), winter weather outlook (WWO) probabilities, heat indices, and Key Messages can be accessed from: 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 $$