Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1225 PM EST Mon Feb 28 2022 Valid 12Z Thu Mar 03 2022 - 12Z Mon Mar 07 2022 ...Heavy Rainfall Signal Emerging for the Mid-South and Ohio Valley Sunday/Next Monday along with heavy snow potential from the Upper Midwest/Great Lakes to northern Northeast... ...Overview... It remains the case that latest guidance continues to suggest that a steadily building eastern Pacific upper ridge from late this week into early next week will help to establish mean troughing from central Canada through the western U.S. This general pattern appears likely to persist beyond the medium range period. Ahead of the developing mean trough, eastward progression of an initial Rockies/High Plains upper ridge will eventually displace an eastern North American mean trough. By early next week a broad zone of southwesterly flow should exist downstream from the mean trough axis. Leading energy moving into and through the West will spread precipitation across the region and then bring a broad area of various precip types to the central U.S. as its northeastward ejection supports a Plains through Upper Great Lakes surface system late Friday through the weekend. The trailing front may become a focus for enhanced rainfall over parts of the east-central U.S. late weekend into early next week. Below normal temperatures will spread over an increasing portion of the western/central U.S. with time while above normal temperatures become more focused over the East. ...Guidance Evaluation/Predictability Assessment... Guidance overall shows good agreement and continuity for the expected large scale pattern evolution. Embedded smaller scale system variances remains run to run inconsistent though, mainly into days 5-7. The WPC medium range product suite was accordingly derived from a composite blend of compatible guidance from the 06 UTC GFS and 00 UTC ECMWF/UKMET/Canadian days 3-5 (Thursday-Saturday) along with the 13 UTC National Blend of Models (NBM). Blended the best compatible 06 UTC GFS/GEFS and 00 UTC ECMWF/ECMWF ensemble means along with the 13 UTC NBM for days 6/7 (Sunday-next Monday) amid growing forecast spread, albeit in a pattern with overall better than normal predictability. WPC product continuity is well maintained in this manner. ...Weather Highlights/Threats... The system moving into the West late this week will spread a broad area of mostly light to moderate (though perhaps locally heavier) rain and high elevation snow across the region. Some scattered precipitation may persist over the West through the rest of the period depending on shortwave details. Toward the end of the week through the weekend precipitation should become more widespread across the central U.S. as low pressure tracks from the central Plains through the Upper Great Lakes. The best potential for wintry precipitation types continues to extend from the northern half of the High Plains into the Upper Great Lakes and eventually New England. Highest probability of significant snowfall currently exists over the Upper Midwest, just to the northwest of the surface low track. There is still considerable uncertainty over the strength of the system so confidence in the precipitation/wind specifics is fairly low. Rainfall of varying intensity will be possible over the rest of the central/east-central U.S. ahead of the trailing cold front. Guidance is signaling the potential for heavier rainfall within an area from the southern Plains into the Ohio/Tennessee Valleys by Saturday night/Sunday into Monday, as the front decelerates while it becomes more aligned with flow aloft and interacts with low level Gulf moisture. The northern fringe of this late-period moisture shield will contain wintry weather with potential for a main axis of snow/ice from the Upper Midwest/Great Lakes to northern Northeast. Late this week expect above normal temperatures from the central/southern Plains through the Southeast, and including back to the Great Basin/Southwest on Thursday. Highest anomalies should be in the plus 15-25F range over the central Plains. On the other hand the northern tier may see readings up to 10-20F below normal. Colder air overspreading the West starting late this week will continue to expand into the Plains during the weekend into early next week, yielding a broad area of temperatures 5-15F below normal by next Monday. Meanwhile the eastern U.S. will see increasing coverage of warmer temperatures Saturday-Monday, generally plus 10-20F anomalies for highs and up to plus 20-25F anomalies for morning lows. Temperatures may challenge record highs over the Southeast. Rausch/Schichtel Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook 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