304 FXUS02 KWBC 050800 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 300 AM EST Mon Jan 5 2026 Valid 12Z Thu Jan 08 2026 - 12Z Mon Jan 12 2026 ...Overview... The pattern over the CONUS will be increasingly amplified by the start of the medium range period on Thursday as a southern stream upper low/shortwave phases with strong northern stream energy into the Northwest. This will develop a deep trough that moves from the West Thursday into the Central U.S. Friday and more slowly toward the East next weekend. The pattern will allow for an increase in precipitation coverage across the Central to Eastern U.S., with well above normal temperatures ahead of it from the East-Central U.S. to the East. ...Guidance/Predictability Assessment... There remain some minor timing and detail differences regarding the phasing of this shortwave over northern Mexico and the larger scale trough/northern scale energy over the West on Thursday, but a multi-model blend seemed to be a good starting point. This progresses as an amplified trough through the Central U.S. on Friday, and the main outlier is the UKMET which is slower and pulls troughing farther west (something the ECMWF was doing yesterday). There is better consensus for a more progressive trough, as shown by the EC, GFS, and CMC. Differences in the timing of this trough however do increase by Sunday-Monday, seemingly due to additional energy that drops into the trough next weekend. Through the 12z guidance, the GFS and CMC were both noticeably faster than the ECMWF (and the AI-guidance and ensembles), exiting the East coast by Monday, while the ECMWF kept it over the East longer. However, both the new 00z CMC and GFS slowed down, while the ECMWF sped up quite a bit. So, very low confidence forecast and a lot of variability on this which would impact how quickly the front and associated precipitation clear the coast. The 01z NBM seemed to serve a good starting point for this right now amidst the uncertainty. The WPC forecast tonight used a non UKMET blend for Days 3 and 4. By day 5 and beyond, gradually increased the ensemble mean weighting to 70 percent of the blend to help mitigate late period differences. ...Weather/Hazards Highlights... Precipitation across the West will be ongoing as the period starts, but should wind down Friday. Some heavy snow is possible in the higher terrain. As the shortwave and the larger scale trough over the West phase into Thursday, the combined trough should tap into Gulf moisture, allowing for widespread precipitation from the Mississippi Valley into the Ohio Valley. A favorable upper jet, moisture anomalies over the 90th percentile for this time of the year, and some instability reaching as far north as the Ohio Valley will support convection in this region. Model 24-hourly QPFs show 1-3 inches of rain, with locally higher amounts, supporting at least a Marginal risk for the Thursday/Day 4 ERO. Rain rates will need to overcome the antecedent dry conditions, which may limit the overall risk, at least initially. The system will track into the Tennessee Valley/Mid- Atlantic/Ohio Valley on Friday, and another marginal risk is placed across the Tennessee Valley where model QPFs are highest right now and where the front may be slightly slower to progress through. Precipitation moves into the East by Saturday, likely clearing the coast in time for Sunday. Much of the country looks dry by Sunday, with the exception of maybe Florida and lake effect snows across the Great Lakes. On the backside of this system, wintry precipitation remains possible. While the details are still uncertain depending on the track and timing of the surface low pressure system, accumulating snow chances are increasing across portions of the northern/central Plains into the Midwest Thursday night into Friday and for the Upper Great Lakes region Friday into Saturday. It is not looking like a particularly hazardous event at this time, but at least a few inches of snow is possible. Temperatures are likely to be well above average across the entirety of the country east of the Rockies by midweek. Temperature anomalies of 15 to 25 degrees above average will be widespread from the Central U.S. to the East Thursday and Friday. Daily records for warm lows and highs could be set across the southern tier. Meanwhile the West/Southwest should be nearer to normal or slightly below as the pattern turns more amplified and troughing develops, and temperatures are likely to moderate back to normal into the Plains and Mississippi Valley by Saturday and the East next Sunday behind a potent cold front just ahead of the upper trough. A building ridge behind this may bring above normal temperatures back into the north-central U.S. by next Monday. 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 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 $$