Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1100 AM EST Mon Feb 04 2019 Valid 12Z Thu Feb 07 2019 - 12Z Mon Feb 11 2019 ...Overview... Upper ridging will dominate the area just west of the Gulf of Alaska as well as across the Florida Straits. This will favor renewed troughing along the West Coast with a storm track northeastward through the Great Lakes/St. Lawrence Valley. ...Guidance/Predictability Assessment and Preferences... There is close agreement between the 00z ECMWF/06z GFS and their ensembles Thursday-Saturday with deep troughing ejecting into the Plains and eventually lifting into eastern Canada this weekend, while at the same time a trough/closed low drops southward along the West Coast. For this period (day 3-5), a majority deterministic blend between the latest runs of the ECMWF/GFS and the parallel FV3-GFS worked well for a starting point. This weekend, there is also good agreement with Canadian high pressure sliding southeastward into the Mid-Atlantic, while a week system attempts to lift into the Great Lakes by Monday. The biggest differences in the medium range arise by days 6 and 7, mainly in the details of an interaction between the Western U.S. trough, and shortwave energy dropping into the Eastern Pacific. The ensemble mean solutions (GEFS/ECENS) comprised the majority of the blend for the WPC fronts/pressures days 6 and 7, with smaller contributions from the deterministic ECMWF mainly due to slighty better agreement with the means, and overall better run-to-run continuity. Only minor adjustments were needed to the previous WPC cycle of medium range progs. ...Weather Highlights/Hazards... Well above average temperatures in the Southeast/East (with record highs possible) Thursday will be replaced by nearer to average temperatures as the cold front clears the East Coast. From MT to the Upper Midwest temperatures will remain well below average on the north side of an arctic front that will linger near the Divide. The rest of the West will mostly see below average temperatures due to the persistent troughing. A swath of heavier precipitation (mostly rain but perhaps northern fringe snow) will spread east of the Plains through the OH/TN Valleys and into the northern Mid-Atlantic/Northeast on Thursday. Frontal/warm-sector rains may be locally heavy on Thursday but trend lighter on Friday as the system weakens and looses support. To the north, some light accumulating snow is possible across the Upper Great Lakes, with lake-effect snows resuming Friday into Saturday with cold air advection behind the main surface low and ahead of the high pressure. Late this weekend and into early next week, another round of potentially heavy precipitation will spread out of the Plains into the mid-MS and TN Valleys via another weak impulse out of the Rockies and to the north of a warm front along the Gulf coast. Santorelli/Fracasso WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation and winter weather outlook probabilities are found 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