339 FXUS21 KWNC 011902 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EST January 01 2026 SYNOPSIS: There is still considerable uncertainty in the details among the various ensemble mean models during week-2. In general, the ECENS, GEFS, and CMCE, support mid-level low pressure over the western half of the contiguous U.S. (CONUS) and mid-level high pressure over the eastern half. The mid-level low will bring elevated chances of high winds over the Four Corners region, heavy precipitation from the Lower Mississippi Valley to the Ohio Valley, and heavy snow from the eastern Dakotas eastward across the Great Lakes region. In Alaska, the mid-level height pattern continues to evolve bringing warmer surface temperatures into the state by week-2. HAZARDS Slight risk of heavy precipitation over portions of the Mississippi, Tennessee, and Ohio Valleys, and in parts of the Southeast, Fri-Tue, Jan 9-13. Slight risk of heavy snow from the eastern Dakotas eastward across the Upper Mississippi Valley and Upper Great Lakes region, Sat-Mon, Jan 10-12. Slight risk of heavy snow over the Lower Great Lakes region, Sun-Tue, Jan 11-13. Slight risk of high winds over much of the Four Corners states, Fri-Sun, Jan 9-11. DETAILED SUMMARY FOR SUNDAY JANUARY 04 - THURSDAY JANUARY 08: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR FRIDAY JANUARY 09 - THURSDAY JANUARY 15: Mid-level ridging is generally predicted over the eastern CONUS and the Pacific Northwest, while mid-level troughing is favored from the Southwest towards the Central Plains. The GEFS is a little stronger with these circulation features than the ECENS and CMCE. A large mid-level ridge and positive 500-hPa height anomalies are also forecast over the far northeastern Pacific, with the maximum height anomaly center close to the southern portion of Southeast Alaska. The mid-level trough over the southwestern CONUS enhances chances for high winds over the Four Corners states early in the week-2 period. The ECENS Probabilistic Extremes Tool (PET) is very supportive of these chances while the GEFS PET is more subdued but in fair agreement with the pattern. Therefore, a slight risk of high winds (>85th historical percentile and >20 mph) is posted for much of the Four Corners states, Jan 9-11. Surface high pressure predicted off the Southeast coast will bring south-southwesterly low-level flow across much of the central and east-central CONUS, along with an increase of Gulf moisture. As the southwestern CONUS trough approaches the Central CONUS, a significant surface low is most likely to form in the general vicinity of the central Plains, but the models disagree on its expected position. Though the details are uncertain, the big picture still focuses on a developing low which tracks towards the Great Lakes region, bringing increased chances of heavy precipitation and heavy snow to many areas. The GEFS solution is significantly slower than the ECENS solution, with the GEFS forecasting the associated cold front extending from the Lower Mississippi Valley northeastward to the Ohio Valley by day 10 (Jan 11), whereas the ECENS already has moved the front off the Atlantic coast by that time. Uncertainties in the timing of this storm system will also affect how long the main precipitation shield and subsequent lake-effect squalls will influence portions of the East. A slight risk of heavy precipitation is posted from the Lower Mississippi Valley northeastward to the Ohio Valley from Jan 9-13, where the GEFS PET depicts precipitation amounts in excess of the 85th historical percentile and actual amounts greater than 1-inch. The ECENS PET also predicts amounts greater than the 85th percentile, but shows a slight southeastward displacement of the heavier precipitation amounts. However, the raw ECENS precipitation amounts and distribution are more in line with the GEFS solution. Across the Northern Plains, Upper Mississippi Valley and Great Lakes, snow is the most likely precipitation type. This may be the most uncertain aspect of today's hazards outlook. The main uncertainties include the predicted spatial distribution and amounts of snow. The GEFS predicts accumulating snow from central portions of the Dakotas and Nebraska northeastward across the Upper Peninsula of Michigan. The ECENS, being the faster solution, focuses the snow farther east, primarily over the Great Lakes region. Raw snow total predictions from both models (including the AI version of the ECENS) are in the 4-6 inch range over this widespread region, with locally higher amounts possible in climatologically favored areas downwind of the Great Lakes. Therefore, a slight risk of heavy snow is posted from the eastern Dakotas eastward across the Upper Mississippi Valley and Upper Great Lakes region, Jan 10-12. A second slight risk area for heavy snow is indicated over the Lower Great Lakes region, Jan 11-13. No temperature hazards have been posted on today's map. However, the GEFS model in particular, is forecasting an Arctic incursion into the north-central states during the second half of week-2, in the wake of the aforementioned storm system. The GEFS Superensemble predicts a surface ridge axis of high pressure extending southward across the Canadian Rockies and High Prairies. The associated northerly surface flow (just east of the ridge axis) is directly from near the North Pole across west-central Canada to the north-central states, with forecast temperatures of -10 deg F and wind chills in excess of -20 deg F. The ECENS is not quite as cold, and keeps the coldest air just north of the border. As this scenario is largely GEFS-based and is predicted to occur during the second half of week-2, it was decided to hold off on the inclusion of a hazardous temperature shape on the map today, and reassess the model guidance tomorrow. In Alaska, the ECENS continues to have high chances for temperatures to fall below the 15th climatological percentile over southwestern Mainland Alaska. However, the temperature pattern is rapidly evolving over Alaska, with much warmer temperatures, relative to much of December, overspreading Mainland Alaska. Therefore no temperature hazards are posted today. FORECASTER: Anthony Artusa $$