Extended Forecast Discussion NWS Weather Prediction Center College Park MD 214 PM EST Thu Feb 02 2023 Valid 12Z Sun Feb 05 2023 - 12Z Thu Feb 09 2023 ...Overview... A wavy and fairly progressive upper-level pattern will be present over the contiguous states initially before an upper trough treks across the central and eastern U.S. early in the week with fairly dry conditions. A trough entering the West Coast Sunday will spread some precipitation to the West. As that trough tracks into the central U.S. by Tuesday-Wednesday, it should transition into a much a wetter pattern. Much of the central and eastern U.S. looks to see above average temperatures through next week, with near normal conditions in the West. ...Guidance/Predictability Assessment... The beginning of the extended forecast is well clustered as a trough moves through the East by Monday and a stronger trough nudges into the West, with ridging in between. With overall agreement a multi-model blend was utilized for days 3 and 4. AS noted from the previous forecast discussion, differences persist with the evolution of the western trough. GFS runs have been showing run to run stream separation leading to an upper low closing off in the Southwest/northern Mexico Tuesday-Wednesday and slowing down, with some ejection east by Thursday. The ECWMF has been persistent in depicting a trough with a bit of separation that has a steady eastward progression. The 00Z run of the ECWMF has a more notable departure from the clustered upper trough/low over the Southwest and wants to quickly shunt the feature eastward keeping it more progressive than the rest of the guidance. The CMC once again seems to be the middle ground solution between the ECWMF and the GFS/UKMET as the closed low/trough shifts eastward toward the Southern/Central Plains. Again, the ensemble members by and large were similar to their parent models. While the ECWMF was not ruled an outlier for being much faster than other solutions, it did have a reduced weighting when compared to the previous forecast. Likewise, WPC did not prefer the slowest/west placement of the GFS but rather a closer to middle ground. Similar weighting was used to maintain some forecast continuity but trended less of the ECWMF. ...Weather/Hazard Highlights... A couple of rounds of light precipitation are expected to pass over the Midwest/Great Lakes into the Northeast next week. Areas downwind of the Lakes may have higher amounts than surrounding locations due to lake enhancement. Showers are possible along the Eastern Seaboard with some moisture return by Sunday from Florida into the eastern Carolinas and eastern parts of New England, but any heavier amounts look to remain offshore. For the western states, moderate precipitation is expected to overspread Coast to portions of the Intermountain West by early next week. In general lower elevations will have rain while areas of higher elevation will receive snow; with typical terrain enhancement across the coastal ranges and the Sierra Nevada. Then precipitation could overspread the central U.S. by Monday-Tuesday along and ahead of a low pressure/frontal system. The details of this precipitation including placement and precipitation type remain uncertain given the model differences. The current forecast shows enhanced rainfall amounts centered across the Lower Mississippi Valley and surrounding areas by Tuesday-Wednesday, with some potential for wintry weather across portions of the Plains to Midwest, but this is subject to change with future forecasts. Meanwhile, additional rounds of energy coming into the West will keep precipitation chances likely in the Pacific Northwest and the Northern Rockies through midweek. The exact location of the precipitation and amounts are of lower confidence given the spread in model solutions. Another cold morning is expected Sunday across northern New England, but with temperatures below zero more limited in scope than in the short range period, and highs should warm up close to normal there during the day. Above average temperatures of 10 to 20F (15-25F above average for the daily highs) will continue to expand through early next week, with some shift into the eastern half of the U.S. by Tuesday-Thursday. For the West, maximum temperatures are expected to hover around 5-10F below normal, though with lows about average. Campbell 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, experimental excessive rainfall outlook, 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/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml