Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1156 AM EDT Wed Jun 19 2019 Valid 12Z Sat Jun 22 2019 - 12Z Wed Jun 26 2019 ...Weather Highlights/Threats... Deep layer southerly flow under an upper ridge over the central CONUS continues to advect warm air east across the southern Mississippi Valley and the Southeast/TN Valley/Oh Valley/Appalachians over the weekend, and continuing into the Northeast early next week. Expect high warm sector temperatures under this ridge including a risk of record warm minimum values mainly for the eastern southern Plains and lower MS Valley Saturday. Forcing ahead of the trough crossing the Rockies this weekend presents a threat of strong to severe/MCS convection and locally heavy rains in areas with pooling moisture/instability. The rainfall focus Sunday and Monday is forecast to be from eastern Kansas and Oklahoma across the Mississippi Valley into the Great Lakes and the Midwest. On Tuesday/Wednesday the showers/storms are expected to focus from east Texas across the Arklatex to the lower MS Valley, Ohio and TN Valleys and the Northeast. ...Guidance/Predictability Assessment... The WPC medium range product suite was derived from a composite blend of compatible guidance from the 06 UTC GEFS and 00 UTC ECMWF/UKMET and 00 UTC ECMWF ensemble mean guidance. The 06 UTC deterministic GFS continued a trend of strengthening a shortwave rounding a trough over the western CONUS and closing off as a mid-level low over the Desert Southwest by Saturday which is not in agreement with the preferred consensus. The preferred models agree on the large scale pattern of the initial northern Rockies closed low moving north into Canada by early next week and a high amplitude southeast ridge persisting. Next week, a new closed low develops and moves southeast from offshore British Columbia into the Pacific northwest or adjacent coastal waters by the middle of next week. This persistent and slow moving circulation allows the deep layer ridge to rebuild over TX and NM. There is less spread than normal for this consensus, lending the situation to a consensus based approach. 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 Hazards: - Heavy rain across portions of the Central and Southern Plains, the Mid and Upper Mississippi Valley, the Great Lakes, and into the Ohio Valley, Sat-Sun, Jun 22-Jun 23. - Heavy rain across portions of the Lower Mississippi Valley and the Southern Plains, Mon-Tue, Jun 24-Jun 25. - Flooding possible across portions of the Central and Southern Plains, the Middle Mississippi Valley, and the Ohio Valley. - Flooding occurring or imminent across portions of the Central Plains, the Lower and Middle Mississippi Valley, the Ohio Valley, and the Tennessee Valley. - Flooding likely across portions of the Central Great Basin and the Ohio Valley. - Excessive heat across portions of southern Texas, Sat-Mon, Jun 22-Jun 24. - Much below normal temperatures across portions of the High Plains, the northern and central Rockies, and into much of the Great Basin, Sat-Sun, Jun 22-Jun 23. 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