Extended Forecast Discussion NWS Weather Prediction Center College Park MD 241 AM EDT Wed Jul 04 2018 Valid 12Z Sat Jul 07 2018 - 12Z Wed Jul 11 2018 ...Overview... An upper high will continue to dominate the lower 48 this coming weekend into the middle of next week. Troughs in the Northwest and Northeast will flatten with time as a more zonal flow takes shape along the US/Canadian border as heights become above average from coast to coast. A front in the east will sink into the Southeast this weekend and dissipate next week as a western front tilts across the Upper Midwest/Great Lakes and eventually moves into the Northeast. ...Weather threats/highlights... Temperatures will be near or below average in much of the east this weekend but trend back to above average by the middle of next week. The Deep South will lie south of the upper high and subject to easterly mid-level shortwaves that, coupled with the surface front, will maintain a daily chance of showers/storms and cooler than average max temperatures. The west will see near to above average temperatures, especially Saturday in southern California with 90s likely to the coast and 100s inland which should tie/break daily records. Moisture is forecast to gradually increase into the Southwest out of Mexico, first into New Mexico and then into Arizona. This will keep daytime temperatures near or a couple degrees below average. ...Guidance evaluation/preferences... Models/ensembles remained in very good agreement and a consensus blend was used through the period. The 12Z ECMWF may be too aggressive in its forecast of a forming upper low in the Northeast next Wednesday as the consensus lied offshore in a weaker state. Fracasso WPC medium range forecasts of 500 mb heights, surface systems, weather grids, quantitative precipitation, and winter weather outlook probabilities are found at: http://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif http://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif http://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html http://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml http://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4