Extended Forecast Discussion NWS Weather Prediction Center College Park MD 130 PM EST Thu Feb 03 2022 Valid 12Z Sun Feb 06 2022 - 12Z Thu Feb 10 2022 ...Overview... The medium range period starts out Sunday with broad troughing across much of the CONUS, sandwiched between a building east Pacific ridge and a retreating ridge into the west-central Atlantic. Within the mean flow, several northern and southern stream shortwaves will act to reinforce the trough, allowing it to persist across the eastern two-thirds of the nation well into next week as the eastern Pacific upper ridge strengthens over the West. This pattern should keep the majority of the U.S. mostly dry and very quiet during the period, with no significant weather related impacts expected. ...Guidance Evaluation/Predictability Assessment... The latest guidance continues to show enough agreement during the day 3-5 (Sunday-Tuesday) time period for a general deterministic model blend. During this time, an elongated mean trough from the Upper Midwest to Southwest will split into a northern stream shortwave through the Northeast, and a southern stream shortwave into the Southern Plains, with a third shortwave rounding the top of the east Pacific ridge and dropping into the northern Rockies. After this, some significant run to run variability in details and timing of individual systems begins to creep in, including the southern stream shortwave moving through the Southeast and modest cyclogenesis off the East Coast. The most notable difference at this time involves the evolution of shortwave activity that slides down the western U.S. ridge toward the end of the forecast period, so went with an ensemble blend for days 6-7 (Wednesday-Thursday). 12z guidance was fairly similar to overnight runs, although do note the 12z GFS came in slightly faster progressing southern stream shortwaves compared to previous runs. In general however, the forecast retains good overall continuity from the overnight medium range forecast. ...Weather Highlights/Threats... Much of the CONUS should be uneventful and mostly dry through early next week at least in terms of any notable weather threats. Periodic shower activity is possible across the Southeast as eastward propagating shortwave trough activity spins up a few modest offshore frontal waves, with some return flow out of the Gulf of Mexico able to support light showers along the western and central Gulf coast by the middle of next week. Elsewhere, northern tier systems may bring periods of light and scattered snow from the upper Midwest to Great Lakes while mostly light rain/mountain snow should accompany a couple of systems brushing the Pacific Northwest and northern Rockies. Much below normal temperatures, with daytime highs 10-15 degrees below normal, will moderate but continue into early next week from parts of Texas and the lower Mississippi Valley into the Midwest. Lows in the teens over parts of the Southern Plains could challenge a record or two on Sunday. On the contrary, much of the West into the northern/central Plains should trend warmer during the medium range, under the influence of the eastern Pacific ridge building well inland. The warmest anomalies are expected over the northern/central Plains on Monday and Tuesday, where daytime highs near 20 degrees above average will be welcome relief after a very cold short range period. Asherman/Santorelli 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