Extended Forecast Discussion NWS Weather Prediction Center College Park MD 253 AM EDT Tue Jun 07 2022 Valid 12Z Fri Jun 10 2022 - 12Z Tue Jun 14 2022 ...Dangerous/Record heat for the Southwest/Central Great Basin to Texas Friday into the Weekend... ...Overview and Model Guidance Evaluation/Preferences... Lingering zonal flow will trend toward increased troughing into the East/Northeast and western Canada/Northwest U.S. as upper ridging builds into the Southwest late this week into the weekend. This will favor a cooler and wetter period for much of the East late this week into the early part of the weekend with extreme heat for portions of Texas to the Southwest/Central Great Basin, and a generally warm/hot pattern for much of the rest of the West. A frontal boundary over the Southeast and Mid-South will act as a focus for more organized rain/thunderstorms in addition to a weekend wave of deepened low pressure moving along the Mid-Atlantic/Northeast. The guidance remained in overall good agreement with a blend of the 12Z/18Z GFS/ECMWF/UKMET/Canadian forming a reasonable starting point and details that has good ensemble support. By early next week, there remain differences in how quickly moderating upper troughing moves into the West, with best clustered guidance from the GFS/ECMWF and GEFS/ECMWF ensemble mean emphasized. The 01 UTC National Blend of Models also offers an adequate middle-ground solution overall, especially with temperatures. Newer 00 UTC guidance remain in line with this scenario, but have overall trended a bit more amplified with the flow and that may be reasonable. ...Sensible Weather/Threat Highlights... For Fri, heavy rain potential will lie over the Mid-South (where SPC highlights a chance for severe weather) as moisture intersects the frontal boundary over some areas that have been relatively wet the past week. The system will progress eastward then northeastward to the coast, spreading rain and most organized heavy storms into the Mid-Atlantic and Northeast Fri-Sat where it has been relatively dry as of late and also along the trailing front over the Southeast. Meanwhile, much of the West should stay dry until late week and the weekend when Pacific system energies work inland to bring some enhanced moisture and rainfall to the Pacific Northwest and onward across the northern Intermountain West/Rockies. Downstream system progression would add enhanced convective potential to the northern Plains/Upper Midwest into early next week. Temperatures will be near to below normal over much of the East due to clouds and increased rain chances, but it will be hot and dry over Texas and the Southwest/central Great Basin. With strong ridging in place by Friday, temperatures will soar into the 100s and 110s over the lower deserts which will be 10-20 degrees above normal at what is typically near the hottest time of the year in that part of the CONUS. This will challenge daily records for many locations from I-80 southward and especially focused over southern Nevada into Arizona and southeastern California. Excessive Heat Watches are in place for parts of this region for later this week through the weekend. Low temperatures will be quite warm as well, only dipping into the 70s and 80s for many locations in the Southwest. Schichtel 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, experimental excessive rainfall outlook, 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/#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