Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1202 PM EDT Tue Jun 25 2019 Valid 12Z Fri Jun 28 2019 - 12Z Tue Jul 02 2019 ...Overview and Guidance/Predictability Assessment... An initially deep closed upper low over the Pacific Northwest is forecast to shear apart and send most of its energy into British Columbia Friday through Saturday before remnant energy rounds a deep ridge up the central CONUS and Canadian Prairies this weekend. Meanwhile a trough will persist over the Pacific Northwest into Sunday. Global guidance diverges with the Pacific Northwest trough on Sunday with the 00Z NAEFS and its deterministic components shifting the trough/closed mid-level low farther west offshore while the 00Z ECMWF/ECENS maintains a trough along the Pacific Northwest coast into the middle of next week. Excellent agreement with deterministic solutions resulted in a general model blend into Sunday. Starting on Sunday, a preference was for the 00Z ECENS over the 00Z NAEFS given preferences to a stronger trough over the Pacific Northwest (which agrees with a teleconnection to persistent ridging over the Aleutians and western Alaska). There is good agreement on the upper ridge amplifying up High Plains/Canadian Prairies into Saturday and the resultant deep low ejecting southeast from Hudson Bay and crossing New England Sunday. Global guidance again diverges at this time with the 00Z/06Z GFS maintaining a closed low off the New England coast early next week while the 00Z ECMWF has an open trough with similar position. A preference for this weaker trough off the northeast also warranted inclusion of more 00Z ECENS than 00Z NAEFS starting on Sunday. Along the Gulf Coast, an inverted trough will drift west from the western Gulf of Mexico Friday and stall over Texas through the weekend. ...Weather Highlights/Threats... The amplified upper low and lingering troughing will favor cooler than average temperatures in most of the West (especially Pacific Northwest into the Great Basin/Intermountain West) and scattered rain/storms with some very high elevation snow in the Cascades Friday into Saturday. Temperatures initially 5-15 deg F below average should moderate some, but remain below normal as the trough persists in the wake of the closed low. Temperatures in the northern Plains/Upper Midwest will be 5-10 deg F above average (80s to mid 90s), but with a daily risk of showers/storms with locally heavy downpours in the vicinity of a warm front trough Saturday and a persistent surface trough/stationary front Sunday to Tuesday. The Northeast will see cooler temperatures showers/thunderstorms this weekend followed and a drier air mass next week as a front and low pressure sinks through the region. 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 as it moves westward and lower-level moisture increases from the Gulf. 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