Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
098 FXUS02 KWBC 252004 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 304 PM EST Tue Nov 25 2025 Valid 12Z Fri Nov 28 2025 - 12Z Tue Dec 02 2025 ...Moderate to heavy snow becoming likely across the northern Plains to Midwest Friday-Saturday... ...Overview... Cold high pressure settling into the east-central U.S. will lead to lingering lake effect snow, gusty winds, and chilly temperatures into Friday. The cold high will contrast with low pressure developing in the High Plains under a strong shortwave aloft, leading to increasing chances of impactful snow across the northern Rockies and out into portions of the northern Plains into the Midwest for Friday-Saturday. Farther south, moisture streaming in will allow for moderate to heavy rain in eastern portions of the Plains into the Mississippi Valley over the weekend, likely focusing closer to the Gulf Coast and Southeast into early next week. Additional rounds of troughing should bring continued colder than average temperatures to the central U.S. for the weekend into early next week. ...Guidance/Predictability Assessment... Recent model guidance has come into better agreement in showing a potent shortwave trough moving through the northern tier late week into the weekend, enhancing QPF (in the form of snow in the northern tier). The main outlier with that was the faster 00Z GFS, but the 06Z and 12Z run were more agreeable with the other guidance. Then, models over the past couple of days have been waffling significantly with the pattern as additional energy was set to dive through the eastern Pacific/western U.S. this weekend. Some guidance, such as several GFS runs including the 00Z, had been pulling this energy well southwest to form a southern stream low of varying depths and positions. Meanwhile the ECMWF has been steady the past few runs with a more phased trough with sometimes some minimal separation. The GFS, starting with the 06Z run, started to become more phased like the ECMWF guidance. The 06Z GFS was not favored though with how quickly it pushed the troughing eastward compared to other guidance though. CMC runs have been a nice middle ground solution, showing some limited energy separating into the southern stream, but still phased enough for the northern stream trough to guide it eastward. 00Z cluster analysis and ensemble members still showed ample spread. But the 12Z models are maintaining this pattern of showing only a small separation of streams by Monday, so hopefully guidance has settled on this for future runs. The WPC forecast was based on a multi-model deterministic blend favoring the ECMWF and CMC early in the period, with increasing proportions of the ensemble means as the period progressed, reaching half the blend Day 6 and more Day 7 given the increasing spread. ...Weather/Hazards Highlights... Moderate to heavy lake effect snow will be ongoing at the start of the extended period Friday, with an additional 6-12 inches of snow possible in the most favored areas. The lake effect precipitation should slowly taper off by Saturday. Meanwhile, low pressure developing across the northern Rockies and High Plains and moisture overrunning the arctic airmass over the northern Plains is likely to lead to widespread snow chances for those areas Friday and spreading east over the weekend. The possibility for impactful snow has risen over the past day or two as model guidance comes into better agreement. Moderate to heavy snow is forecast to stretch from portions of South Dakota across southern Minnesota and Iowa Friday into Friday night, reaching the Midwest Saturday. Travel may be impacted; see WPC`s soon to be issued Key Messages for more information. Some snow is possible in the Interior Northeast Sunday. Farther south, Gulf moisture ahead of a southern Plains low pressure system will allow for showers and thunderstorms to develop in the south-central U.S. late week. Rain should be light to moderate in intensity Friday, but by Saturday should increase in intensity across eastern parts of the southern Plains and Middle/Lower Mississippi Valley with increasing upper level support and instability. The Day 5/Saturday Marginal Risk in the Excessive Rainfall Outlook still looks good. By Sunday-Monday there is more model uncertainty, but the low pressure/frontal system is generally forecast to move east and spread precipitation to the Eastern Seaboard. But the front should stall closer to the central Gulf Coast and enhance rain totals there Sunday, and possibly across the Southeast Monday. Light to moderate precipitation is possible across the Intermountain West over the weekend, with a generally southward trend from day to day. Some higher elevation areas like the central Rockies could receive heavy snow. Colder than average temperatures by 10-20 degrees will be common from the north-central U.S. into the eastern half of the lower 48 late week as cold high pressure settles in behind a strong cold front. Temperatures in the East will gradually raise closer to average into early next week. But meanwhile an even colder arctic airmass is forecast to spill into the High Plains Saturday and across much of the central U.S. by Sunday and Monday. Multiple days of below 0F lows and highs in the teens are likely in the Dakotas to Minnesota. Tate 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 forecast (QPF), excessive rainfall outlook (ERO), winter weather outlook (WWO) probabilities, heat indices, and Key Messages can be accessed from: 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 https://www.wpc.ncep.noaa.gov/#page=ovw $$