Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1214 AM EDT Thu Jun 27 2019 Valid 12Z Sun Jun 30 2019 - 12Z Thu Jul 04 2019 ...Overview and Weather Highlights/Threats... A strong upper high near southern Alaska favors a positively-tilted trough lingering over the Pacific Northwest and near to above average heights for the rest of the Lower 48 with the exception of Texas where an inverted trough will meander. This typical summertime pattern will feature warm/hot temperatures for most areas east of the Rockies with scattered mainly afternoon showers/thunderstorms. Areas in the lower MS Valley/Gulf Coast may see some enhanced rainfall due to the combination of the upper trough over Texas and increasing lower-level moisture from the Gulf. Cooler than average temperatures are expected for much of the West. ...Guidance/Predictability Assessment... The deterministic models clustered well together for Sun-Tue despite some changes over/offshore the Pac NW. The ECMWF has led the way in this area but now the other models have joined in the chorus and a blend sufficed. Trended to a 50/50 deterministic/ensemble mean weighting for Wed/Thu via the ECMWF/Canadian. The GFS runs appeared to be too quick to move the trough out of WA/OR as can be its bias (even in the FV3 core). ...4th of July Forecast... Warm to hot temperatures for the central/eastern states with widespread 80s/90s. Mid 90s are possible in the Southeast where, combined with dew points in the 70s, will yield heat indices in the 105-110F range. Best chance of rain/storms will be over the High Plains/Upper Midwest (near an incoming frontal boundary), the Ohio Valley (near a wavy stationary front), lower Mississippi Valley (under the upper trough), and the Southeast. The West will be dry with near to below average temperatures in the upper 60s (northern coast), 70s (central/southern coast), 80s/90s (interior), and low 100s (deserts). Fracasso 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