Extended Forecast Discussion NWS Weather Prediction Center College Park MD 246 PM EDT Fri May 01 2020 Valid 12Z Mon May 04 2020 - 12Z Fri May 08 2020 ...Record heat for parts of the southern tier of the CONUS lingers into next week... ...Guidance/Predictability Assessment... Quasi-zonal and progressive flow across the CONUS at the start of the medium range period is expected to evolve into more amplification featuring a western US ridge and troughing over the central/eastern CONUS. Low pressure organizing over the south-central Plains on Day 3 will quickly move east through the Ohio Valley and Southeast/Mid-Atlantic and its wake, stronger high pressure originating from Canada builds southward over the CONUS. Model guidance shows average to slightly above average agreement on day 3 with a fairly equal blend of the latest available deterministic guidance (00Z ECMWF, 06Z GFS, 00Z UKMET, and 00Z CMC). The 00Z/06Z GFS trended faster and deeper with shortwave energy on day 4/5 coming out of the northern Plains and seemed a bit of an outlier compared to the reasonably clustered ECMWF/UKMET. Toward day 6/7, most of the deterministic guidance showed trends toward a more amplified upper level pattern and sprawling surface high pressure, with varying degrees of position and strength. Given some of the uncertainty, higher percentages of the 00Z ECENS/06Z GEFS means were incorporated but some deterministic ECMWF/GFS were kept for maintaining detail. ...Weather/Hazard Highlights... Record heat will continue to be the main impact into at least early next week. Temperatures 10-20F above normal over the Southern Plains will migrate westward through the Southwest and into California by the end of the week as the upper ridge builds along the West Coast/120W. By contrast, much of the east, and especially around the Great Lakes/Northeast, will see cooler than normal temperatures more typical of early April (about 5-10F below normal). Cold front may push all the way to southern Florida by the end of the week though in a very modified state. Precipitation will generally be limited to around the lead system out of the Rockies/Plains Monday-Tuesday as it flattens into the Southeast and streaks eastward. Weakening area of low pressure over the Northern Plains will carry an enhanced area of showers through the Great Lakes Tue before diminishing in favor of the southern portion over the central Appalachians eastward. Exiting low out of Maine Monday will maintain a showery/breezy pattern for the start of the week in northern New England. Some snow showers are still possible in the highest elevations. Precipitation will be rather scant by the end of the week CONUS-wide. Fracasso/Taylor Additional 3-7 Day Hazards information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, winter weather outlook probabilities and heat indices 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/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml