Extended Forecast Discussion NWS Weather Prediction Center College Park MD 149 PM EST Mon Feb 07 2022 Valid 12Z Thu Feb 10 2022 - 12Z Mon Feb 14 2022 1900 UTC update... The latest 00z/06z model guidance continues to show a similar evolution and thinking compared to previous runs and so no major changes were needed from the overnight WPC forecast package. The 06z GFS continued to be an outlier with very little to no support from other pieces of guidance with a cut off closed low over the Southwest U.S. this weekend and so it was excluded from the WPC blend after day 4. However, the 12z GFS did come in without that feature so that is something to note. After day 5, the timing of systems within the mean East trough as well as amplitude and timing of an incoming Pacific Northwest shortwave on day 7 continue to present forecast issues. Therefore, a blend away from the deterministic solutions with more emphasis towards the ensemble means seemed a safe starting point for the updated forecast and also provided excellent continuity with the previous WPC progs. See previous discussion below for additional information and details regarding model guidance and sensible weather impacts. Santorelli Previous discussion issued at 0700 UTC... ...Weather Pattern Overview... It remains the case that a rather amplified upper level pattern will be in place for this forecast period with a synoptic scale ridge centered near the West Coast through Sunday, and a broad trough with multiple embedded shortwaves/fronts over the eastern half of the nation. There is some signal of a potential pattern change by early next week as a more active storm track over the northeast Pacific tries to break down the West Coast ridge. ...Guidance Evaluation/Predictability Assessment... Models and ensemble means remain generally in reasonable agreement with the larger scale upper-pattern this week, albeit with some timing and focus differences noted with many of the individual shortwaves. By Saturday, the 00Z GFS becomes quite amplified with the trough dropping south across the Rockies and forms a closed low that lacks ensemble support, but the 18Z was able to be incorporated into the fronts/pressures forecast. By next Monday, the ECMWF becomes very strong with a closed low off the Oregon Coast, whereas the GFS/CMC favor a more modest shortwave trough. For the large scale trough developing over the eastern U.S. this weekend, it still appears that the axis will be positively tilted and little in the way of phasing regarding northern/southern stream energy, and this will limit the potential for surface cyclogenesis off the East Coast as it stands right now. The WPC fronts/pressures forecast was primarily derived from a deterministic blend through Friday, and then gradually increasing percentages of the means through next Monday. For QPF, more of the ensemble biased corrected model, along with some of the CMC/GFS/ECMWF, was used since the NBM appears too light with its QPF across the north-central U.S. for the end of the week. ...Weather Highlights/Threats... The majority of the continental U.S. will enjoy dry weather and little in the way of disruptive weather through the weekend. There has been a gradual increase with expected snowfall totals across the Upper Midwest and Great Lakes region with the strong clipper system for the end of the week, with some potential for 3-6 inch accumulations across portions of northern Minnesota, northern Michigan, and downwind of Lakes Erie and Ontario. Farther south, there will likely be an emerging area of showers from the central Gulf Coast and the Florida Peninsula to the Southeast U.S. coast over the weekend as moisture flows northward ahead of an approaching cold front. In terms of temperatures, the majority of the nation should be near to slightly above average for highs to close out the week, with the greatest warm departures on the order of 15-25 degrees for portions of the Northern Plains on Thursday. With the trough building in across the east-central U.S. in time for the weekend, expect a return to reality with highs running up to 15 degrees below average from the Great Lakes to the Ohio Valley and Northeast. It should be mild once again across most of the Plains for Sunday and into Monday. Hamrick 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