Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1158 AM EDT Tue Jun 18 2019 Valid 12Z Fri Jun 21 2019 - 12Z Tue Jun 25 2019 ...Weather Highlights/Threats... An unsettling southeast Canada/Northeast U.S. upper trough and coastal low will support lingering wrapping moisture/rainfall into northern New England Friday into Saturday. The closed trough is expected to slowly give way to a warming upper ridge building from the east-central U.S./Southeast up into the Great Lakes into early next week. Expect hot warm sector temperatures under this ridge including a risk of record warm minimum values mainly for the eastern southern Plains and lower MS Valley. This ridge builds ahead of a series of upstream troughs that drift/reform from the Northwest/West to the Rockies and Plains/south-central Canada. The systems present an emerging threat of strong to severe/MCS convection and locally heavy rains with frontogenesis/cyclogenesis, pooling moisture/instability and repeat cells. There is also a risk of some northern Rockies June snows. ...Guidance/Predictability Assessment... The WPC medium range product suite was derived from a composite blend of compatable guidance from the 06 UTC GFS and 00 UTC ECMWF/Canadian/UKMET days 3-5 then GFS/ECMWF and GEFS/ECMWF ensemble guidance days 6/7 in a timeframe with increased but manageable forecast spread. This maintains good WPC continuity, albeit with most uncertainty still associated with the focus for localized summertime convective weather and hazards. Schichtel 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