Extended Forecast Discussion NWS Weather Prediction Center College Park MD 155 AM EST Wed Feb 9 2022 Valid 12Z Sat Feb 12 2022 - 12Z Wed Feb 16 2022 ...Weather Pattern Overview... A rather significant pattern change is coming early next week as a strong trough, originating over the Gulf of Alaska, drops southeastward across the West Coast region. This will abruptly replace the long-standing upper ridge (positive PNA pattern) that will be over the western third of the nation through the end of this week and into this weekend, which is expected to lead to surface cyclogenesis by the middle of next across the western High Plains. This will tend to displace the ridge axis farther east across the Plains, although less amplified than before, and resulting in more of a quasi-zonal flow pattern across much of the central and eastern U.S. as the deep upper trough over the East Coast region lifts out by early-mid next week. Additionally, there will likely be an offshore low that develops off the East Coast for late Sunday and then lifts northeastward to Nova Scotia and Newfoundland. ...Guidance Evaluation/Predictability Assessment... The 00Z deterministic model guidance has come into much better agreement on the expected synoptic scale evolution of the western U.S. trough that builds in for early next week. However, there are still some model differences with shortwave energy crossing the eastern U.S. through early Monday and its role in offshore surface cyclogenesis. At this time, this southern stream shortwave is not expected to phase with the next Great Lakes disturbance until after the cold front exits the East Coast, and this will limit the chances of an offshore low forming close enough to the coast to cause issues, but future model trends will continue to be monitored, especially if the stronger GFS solution comes to pass. The WPC fronts/pressures forecast was primarily derived from a deterministic blend through the weekend, and then gradually increasing percentages of the means through early next week. 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. and lake effect snow for the weekend. ...Weather Highlights/Threats... A strong but progressive clipper type low pressure system will cross southern Quebec and far northern New England by Saturday, with the potential for light to moderate lake effect snow across portions of Michigan and upstate New York in its wake. There will also be breezy to windy conditions across the Great Lakes region and the Northeast as this low moves through the region. Another Canadian surface high drops southward across the central U.S. and delivers dry conditions to much of the nation for the upcoming weekend. It appears likely that a oceanic low will develop off the East Coast by Sunday evening, but is currently expected to be far enough offshore to keep most of the precipitation and wind away from land, although some light snow is possible for the Delmarva and coastal portions of New England. Depending on the eventual evolution of the western trough and accompanying surface low, precipitation is forecast to increase in coverage across portions of the Rockies and Pacific Northwest by next Tuesday, and an increase in showers and some storms across the central/southern Plains by Wednesday and beyond along with gusty winds. In terms of temperatures, there will a brief warm-up for the East Coast on Saturday, followed by a return to below average readings by Sunday and into early next week as the strong cold front ushers in a renewed round of cold weather. Highs up to 20 degrees below normal are possible for portions of the Great Lakes region this weekend. It should be mild once again across most of the Plains for Sunday and into Monday with the West Coast region beginning to cool down with the trough building in, after anomalous warmth across portions of California this weekend. 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