Extended Forecast Discussion NWS Weather Prediction Center College Park MD 255 PM EST Fri Nov 08 2019 Valid 12Z Mon Nov 11 2019 - 12Z Fri Nov 15 2019 ...Record cold next week with an inland Northeast heavy snow threat... ...Pattern Overview and Guidance/Predictability Assessment... The general pattern across the CONUS next week is expected to feature upper ridging over the western U.S. and Canada with downstream troughing over much of the central/eastern CONUS. A slow moving upper level low will gradually move across Mexico and into the Gulf toward of the end of next week. Overall, forecast models and predictability were average to slightly above average in the large scale with the usual timing/track/strength differences noted. The anomalous deep trough mid-week will induce a surface low along the U.S. East Coast and bring a threat of heavy snow for interior/northern New England. Model guidance has come into enough of an agreement that for Day 3-4 (Mon-Tue), a blend of the available deterministic guidance was used. Beyond that time frame, the 00Z ECMWF and 06Z GFS offered enough utility to be incorporated, with increasing percentages of the latest ECENS/GEFS means toward Day 7. ...Weather Highlights/Threats... Cold Canadian high pressure will spill out of eastern Montana Monday morning through the Central Plains and into the Ohio Valley by Wednesday, bringing in well below average temperatures that will likely break daily records across a sizable area of the eastern half of the CONUS Mon-Wed. Conversely, some record highs are possible on Monday over northern California under the upper axis. Front in the east will carry low pressure just off New England with a swath of snow to the northwest of the track and lake-effect snows for the Great Lakes with very cold temperatures aloft over still warm water. Temperatures will moderate for later in the week as the high moves offshore and weakens, but highs will remain about 10-15 degrees below average along and east of the Mississippi into next Friday. West of the Rockies, temperatures will stay above average by about 5-10 degrees. By the end of the week, the upper low once over Mexico reaches the Gulf and its interaction with a stalled/lingering frontal boundary could spread precipitation along the Gulf Coast with possible low pressure developing. Fracasso/Taylor 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 - Heavy snow across portions of the Upper Great Lakes, Mon, Nov 11. - Heavy snow across portions of the Northeast and the Lower Great Lakes, Mon-Tue, Nov 11-Nov 12. - Flooding occurring or imminent across portions of the Middle Mississippi Valley and the Northern Plains. - Flooding likely across portions of the Northern Plains. - Much below normal temperatures across much of the Great Plains to East Coast, Tue-Thu, Nov 12-Nov 14. - Much below normal temperatures across portions of the Northern Plains and the Northern Rockies, Mon, Nov 11. 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