624 FXUS21 KWNC 131919 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EST January 13 2026 SYNOPSIS: A weakening area of mid-level low pressure over the eastern contiguous U.S. (CONUS) is expected to bring a lingering threat of much below normal temperatures over the Northeast early in the period. As this mid-level low pressure shifts westward and strengthens, there is an increased risk of multiple weather related hazards over the Interior West, anomalously cold winter temperatures along the northern tier of the CONUS, along with one or more surface lows developing in the lee of the Rockies which could bring heavy precipitation and low elevation heavy snowfall to portions of the Midwest during the period. In the central Pacific, there is an increased chance of Kona low development potentially impacting parts of Hawaii, with enhanced precipitation and occasional high wind gusts. HAZARDS Slight risk of much below normal temperatures for portions of the eastern Great Lakes and the Northeast, Wed, Jan 21. Slight risk of much below normal temperatures for portions of the Northern Intermountain, Northern Rockies, Northern Plains, Upper Mississippi Valley and Great Lakes, Thu-Tue, Jan 22-27. Slight risk of heavy snow for portions of the Great Lakes and Central Appalachians, Wed-Tue, Jan 21-27. Slight risk of heavy snow for the higher elevations of the Northern Intermountain, Great Basin and Rockies, Thu-Tue, Jan 22-27 Slight risk of high winds for much of the Interior West, Thu-Tue, Jan 22-27. Moderate risk of heavy precipitation for portions of the Middle and Lower Mississippi, Ohio and Tennessee Valleys, and Southern Appalachians, Fri-Sat, Jan 23-24. Slight risk of heavy precipitation for parts of the Mississippi, Ohio, and Tennessee Valleys, Appalachians, and Southeast, Wed-Sun, Jan 21-25. Slight risk of heavy snow for portions of the Central and Northern Plains, Middle and Upper Mississippi and Ohio Valleys, and western Great Lakes, Thu-Sun, Jan 22-25. DETAILED SUMMARY FOR FRIDAY JANUARY 16 - TUESDAY JANUARY 20: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR WEDNESDAY JANUARY 21 - TUESDAY JANUARY 27: Heading into week-2, there is good agreement between the GEFS and ECMWF ensemble mean 500-hPa height forecasts featuring anomalous ridging centered over the western CONUS with downstream troughing over eastern U.S. and Canada. As much of the shortwave energy lifts out of the eastern U.S. early in week-2, dynamical models continue to advertise a retrogression of the mean troughing over south-central Canada and extending into the western CONUS, with building mid-level heights over the southern tier and southeastern U.S. towards the end of next week. This pattern transition is expected to bring a moderation of temperatures throughout many parts of the east, however the potential for weather related hazards shifts westward where there is more model support for anomalous troughing aloft over the Interior West. This also increases the risk of surface low development in the lee of the Rockies to potentially trigger heavy precipitation and heavy snow downstream across portions of the Midwest in the updated outlook. Tied to the deamplifying trough early in week-2, raw tools show a substantial reduction in the negative temperature departures forecast over the eastern CONUS from day 7 to day 8. As a result, the slight risk of much below normal temperatures is discontinued over the southeastern U.S., however a corresponding temperature hazard remains posted for Jan 21 over the northeastern CONUS where the anomalous cold may be slow to moderate. Within the highlighted area, both the GEFS and ECMWF Probabilistic Extremes Tools (PET) maintain elevated chances 20-40% for minimum temperatures falling below the 15th percentile and below -10 deg F. As the mean troughing shifts westward after day 9 (Jan), the accompanying temperature responses are well reflected in the PETS with emerging cold signals in percentile space focused over the north-central CONUS. Compared to the GEFS, the ECMWF PET is stronger with the hazardous cold potential, particularly over the Upper Mississippi Valley, but both PETs agree in regards to the timing of the cold threat, with both ensembles featuring more mean surface high pressure descending from the Canadian Prairies by late next week. These ensembles also depict rebuilding surface high pressure over the Northern High Plains, suggestive of another shot of anomalous cold air later in week-2. Therefore, a slight risk of much below normal temperatures is posted from the Northern Intermountain to the Great Lakes for Jan 22-27.The potential for multiple shots of cold air over the northern tier of the CONUS also favors a combination of pure lake effect snow and lake enhanced snow over the Great Lakes, and a slight risk of heavy snow remains posted downwind of the Lakes and into the Central Appalachians for all of week-2. Due to better agreement between ECMWF and GEFS ensembles in regards to anomalous mid-level troughing over the Interior West late next week, slight risk areas of heavy snow are posted over the higher elevations of the Rockies, Great Basin, and Northern Intermountain region for Jan 22-27. This is supported in the GEFS Snow Water Equivalent (SWE) PET and raw snow tools, which depict an uptick in chances for amounts exceeding a foot over the highest elevations of the West during week 2. In addition, a slight risk of high winds is also posted for much of the Interior west at the base and ahead of the mean trough axis where PETs show at least 20% chances for wind speeds exceeding the 85th percentile. The mid-level pattern transition towards more mid-level troughing (ridging) the western (eastern) CONUS supports surface low development in the lee of Rockies with moist return flow from the Gulf of Mexico to increase risk of heavy precipitation. While the details of timing and storm track remain unclear based on the daily ensemble guidance, one or more surface lows are favored through the middle of the period, and there is good agreement in raw and calibrated PETs showing the greatest precipitation threat over portions of the Tennessee and Ohio Valleys. Although PETs are more supportive of a slight risk designation, deference is given to the more recently skillful raw precipitation tools over this part of the country, and a moderate risk of heavy precipitation is posted where both the GEFS and ECMWF indicate >40% chances for 3-day amounts exceeding an inch, with highest daily amounts occurring on days 10 and 11 (Jan 23-24). Within this moderate risk area, localized flash or small stream flooding is possible during the period. A broader slight risk area remains posted for Jan 21-25, where PETs depict 20-30% chances for 3-day amounts exceeding the 85th percentile and 1 inch. With anomalous cold air expected over the northern tier of the CONUS, the enhanced moisture is expected to be conducive for accumulating snowfall on the backside of any transient low pressure system. A slight risk of heavy snow is posted from the Central and Northern high Plains extending eastward to the Great Lakes where there is greatest convergence of evidence in the GEFS and ECMWF ensembles with 10-30% chances for 3-day amounts exceeding 4 inches. Some deterministic solutions favor a more southerly storm track with higher snowfall amounts further south, however any further expansion of the corresponding snow hazard will be revisited in upcoming hazard outlooks. No hazards are issued over Alaska. There is better agreement between the ECMWF and GEFS in regards to strong ridging over the north Pacific with a ridge axis extending northward across the Mainland. This pattern remains favorable for the above-normal temperatures with a tilt in the odds for above-normal precipitation. Should the mid-level ridge axis remain amplified and shift westward, this would allow for more cross polar flow with colder temperatures developing across the Mainland and any temperature trends will continue to be monitored. With persistent troughing favored underneath strong ridging forecast over the northern Pacific, one or more Kona lows may develop and impact parts of Hawaii during week-2. There is considerable uncertainty regarding the location, evolution, and magnitude of any hazardous conditions, but there is general agreement that precipitation over most of the state will be above normal for week-2. Potential impacts include periods of heavy precipitation, high winds, and significant waves. FORECASTER: Nick Novella $$