Extended Forecast Discussion NWS Weather Prediction Center College Park MD 311 PM EDT Sat Oct 24 2020 Valid 12Z Tue Oct 27 2020 - 12Z Sat Oct 31 2020 ...Record cold in the central US Tue before relenting... ...Heavy precipitation threat from the Southern Plains to the southeastern third of the CONUS next week... ...Guidance Evaluation/Preferences... In general, the longwave pattern is in agreement given the usual spread in timing features and placement of precipitation. Consensus favored a combination of the 00Z ECWMF/EC mean, 00/06 GFS and GEFS mean, and the 00Z UKMET/CMC. The ECWMF favored precipitation further north and heavier across the Plains and Midwest while the was a little lighter and south. The CMC was very wet along he eastern Gulf Coast and later into the Southeast. A combination of he above provided a middle of the road approach at this time. ...Weather/Hazard Highlights... An early season cold spell occurring over much of the West, Rockies and Plains during the short range periods will linger into Tuesday; the cold airmass is expected to moderate and move eastward during extended period. Numerous daily low records, as well as low maxes, will be possible Tuesday-- especially for locations across the Southern/Central Plains were temperatures will average 20 to upwards of 40 degrees cooler than normal for late October. As the airmass moderates, daily values will still hover around 5 to 15 degrees cooler than seasonal normal. Outside of this cold airmass, temperatures will be roughly 5 to 10 degrees warmer for parts of the Pacific Northwest, California and into the Great Basin region. Most of the active weather will be across the southern half of the country. Warm, moist air will be transported north from the Gulf ahead of a tropical disturbance drifts west/northwest. Meanwhile, a series of waves along a frontal boundary will lift/track east across the Southern/Central High Plains early on and then progress toward the Southeast and Mid-Atlantic regions. Within the warm sector, scattered to widespread heavy rain will be possible Tuesday and Wednesday primarily for parts Texas and Oklahoma, but also the surrounding area. In the cold sector, snow along with sleet and/or freezing rain near the transition zone is expected. As the system moves across the Midwest/Mississippi Valley it will spread the heavy rain/wintry precipitation along with it. Heavy precipitation will be possible for the Southeast, Appalachians and the Mid-Atlantic region this weekend as the front pushes across the East Coast. Campbell 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