Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1200 PM EDT Wed Jun 26 2019 Valid 12Z Sat Jun 29 2019 - 12Z Wed Jul 03 2019 ...Overview and Weather Highlights/Threats... Deep troughing/low pressure over the Pacific Northwest and weaker troughing over the northeast CONUS with a broad upper ridge in between as well as an inverted trough over Texas summarizes the overall flow pattern this weekend into the middle of next week. The northern stream will waver along the US/Canadian border with rain potential through the four day period over portions of the northern Great Plains to the northern Great Lakes along a slow moving front. No clear signal exists for organized heavy rainfall though the potential is there on a local level. Temperatures will be well above average in the northern Plains/Upper Midwest (80s to upper 90s, warmest on Saturday) with a daily risk of showers/storms and locally heavy downpours in the vicinity of a warm front Saturday and a stationary front Sunday onward. The Southeast and lower MS Valley/Gulf Coast region will see a daily chance of showers/storms in typical summertime fashion that may be enhanced via the upper trough over Texas and lower-level moisture increases from the Gulf. ...Guidance/Predictability Assessment... The deterministic models mostly clustered together for days 3/4 before uncertainty in timing/evolution (mostly with the Pacific Northwest trough/low) resulted in decreased confidence in specifics. Trended to a majority ensemble mean weighting by Tue/Wed. Largest question remains west of the WA/OR and how the positively-tilted (and latitudinally-elongated) trough evolves downstream of a significant positive height anomaly over southern Alaska. A blended mean continued to suffice for now which maintains troughing over the Pacific Northwest (downstream of the persistent strong western Alaska/Aleutian ridge) that does not favor any singular deterministic model. Jackson 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