Extended Forecast Discussion NWS Weather Prediction Center College Park MD 149 AM EST Tue Feb 8 2022 Valid 12Z Fri Feb 11 2022 - 12Z Tue Feb 15 2022 ...Weather Pattern Overview... A rather significant pattern change is likely in the works for 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 will probably lead to some form of surface cyclogenesis by the end of the forecast period across the southwestern U.S. 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. ...Guidance Evaluation/Predictability Assessment... The deterministic model guidance has a good overall depiction of the synoptic scale pattern across the U.S. through the weekend. The 00Z CMC is a bit slower with the shortwave crossing Texas on Sunday, whereas the GFS/UKMET/EC all suggest a more progressive solution. At this time, this southern stream shortwave is not expected to phase with the next Great Lakes disturbance before 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. Things become more uncertain with the digging trough from the Gulf of Alaska that will herald a pattern change to much of the western U.S. next week. The ECMWF and its ensemble mean are faster with the upper trough/closed low through Tuesday, compared to the slower GFS and the well offshore 00Z CMC (the 12Z CMC was closer to the 00Z ECMWF and is more favored than its newest 00Z run). Teleconnections with the positive 500mb height anomaly (50N 140W) on February 16th suggests the upper level trough axis would be over the Desert Southwest and central Rockies, which is closer to the 12Z CMC/00Z ECMWF compared to recent runs of the GFS that are slower and farther northwest over Oregon. The WPC fronts/pressures forecast was primarily derived from a deterministic blend through Saturday, 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. for the end of the week and into Saturday. ...Weather Highlights/Threats... A strong but progressive clipper type low pressure system will cross the northern Great Lakes on Friday and then northern New England by Saturday, with the potential for several inches of snow from northern Minnesota/Michigan to portions of upstate New York. There will also be breezy to windy conditions across the Upper Midwest and Great Lakes region 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. Depending on the eventual evolution of the western trough and accompanying surface low, precipitation may increase in coverage across portions of the Rockies and Pacific Northwest by next Tuesday along with increasing winds. 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 15-20 degrees for portions of the Central Plains on Friday, and a brief warm-up for the East Coast on Saturday. 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 by Sunday. 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. 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