Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
028 FXUS02 KWBC 010810 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 410 AM EDT Mon Jun 1 2026 Valid 12Z Thu Jun 04 2026 - 12Z Mon Jun 08 2026 ...Overview... The medium range, beginning this Thursday, will be active for the Central U.S. and northern tier of the country, where weak mid- level vortices will generate warm temperatures, scattered thunderstorm activity and potential flash flooding for the Eastern half of the country. A broad ridge over the East will flatten beneath some of the aforementioned vortices moving through the Great Lakes and Northeast this weekend. A deep upper- level trough will bring renewed precipitation chances to the Northwest this weekend. ...Guidance/Predictability Assessment... Models are in relatively good agreement on the mid-level disturbances over the Central U.S. and ridging in the Southeast. There are uncertainties around the amplitude and timing of small scale vortices propagating through the Southern Plains as well as the speed of a surface cold front moving through the Northeast late this weekend. There`s also some spread as to how the West Coast trough evolves this weekend, with the Euro and Canadian models developing a split flow pattern by next Sunday and Monday. A general model blend is used on day 3 followed by an early introduction of the GEFS on day 4 to due to the Euro`s slow moving trough in the Western Atlantic. The Euro and Canadian ensemble means are introduced to the blend on days 5 and 6 and are gradually increased in weighting especially due to the emerging spread with the trough in the West and ridge over the Central U.S.. ...Weather/Hazards Highlights... A quasi-stationary front draped across the northern tier of the country may act a focus for scattered showers and thunderstorms beginning on Thursday. Marginal risks (at least 5% chance) of excessive rainfall are in effect across much of the Great Plains and Middle/Upper Mississippi Valley, due, in part, to the forcing caused by mid-level vortices propagating along a north-south axis through the Central/Southern Plains. Elsewhere, a deep trough will bring rainfall back to the Northwest beginning on Friday and continuing through the weekend. Showers and thunderstorms may develop along a cold front extending from the Mississippi Valley to the Northeast on Sunday. Temperatures will be average to above average over much of the Eastern U.S. during the medium range period due to troughing over the Plains and ridging over the Midwest. Temps in the upper 80s to 90s with overnight lows struggling to drop below 70 degrees could lead to increased heat risk concerns along the Mid-Atlantic Coast this weekend. 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, 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 $$