685 FXUS21 KWNC 181804 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT March 18 2026 SYNOPSIS: Mid-level high pressure favored across much of the western and central contiguous U.S. is expected to bring a continuation of above-normal temperatures into week-2. While excessive heat conditions are less of a concern during the period, the anomalous warmth is likely to continue driving early springtime snowmelt for the higher elevations of the West, where many locations have registered well below normal snowpack over the winter. Surface low development in the lee of the Rockies is expected to bring an elevated risk of high winds over the Central and Northern High Plains. HAZARDS Moderate risk of high winds for the Northern and Central Plains, Thu, Mar 26. Slight risk of high winds for the Central and Northern Plains, Upper Mississippi Valley, and Great Lakes, Thu-Fri, Mar 26-27. Slight risk of much above-normal temperatures for the Desert Southwest, Rockies, Great Basin and the Central and Southern Plains, Thu-Sat, Mar 26-28. DETAILED SUMMARY FOR SATURDAY MARCH 21 - WEDNESDAY MARCH 25: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR THURSDAY MARCH 26 - WEDNESDAY APRIL 01: At the start of week-2, both the 0z GEFS and ECMWF ensemble mean 500-hPa height forecasts continue to feature an amplified anomalous ridge center over the Central and Southern High Plains, with a broad coverage of negative height departures over the higher latitudes in Canada. Over the past few days, ensembles have become more reluctant to weaken this ridge anomaly, which implies more persistence of anomalously warm week-1 temperatures favored over the western CONUS into week-2. By later next week, models maintain an eastward expansion of the anomalous mid-level ridging towards the mid-Atlantic and the Southeast, while also amplifying a mean trough over eastern Canada with a trough axis extending into Great Lakes and Northeast. This pattern evolution supports an increased potential for the intrusion of colder air over the northeastern CONUS, while keeping anomalous warm and dry conditions mainly confined to the west of the Mississippi. Tied to shortwave energy propagating above the anomalous ridge center in the West, surface low development remains favored in the lee of the Rockies, where models remain in agreement depicting a mean surface low tracking into the upper Midwest early in week-2. Although there is not much of a precipitation response associated with the storm track, likely due to ample moisture being mostly cut off from the Gulf, tools continue to point to an increased potential for elevated winds. A moderate risk of high winds remains issued (Mar 26) over the Central and Northern High Plains where Probabisitic Extreme Tools (PETs) show elevated chances of wind speeds exceeding the 85th percentile. A broader slight risk area also remains issued and is expanded eastward into the upper Midwest to capture the potential storm track in the updated outlook. Gusty winds combined with above-normal temperatures and dry fuels may support enhanced risk of wildfires across parts of the Southern and Central Plains. In the wake of the departing surface low, potentially strong surface high pressure is favored to descend into the Canadian Prairies and bring a shot of colder air into the Plains and Mississippi Valley. Based on both raw and calibrated temperature tools, however, there is a good amount of disagreement between the GEFS and ECMWF in regards to the strength and extent of the anomalous cold air. Due to weaker ridging in the GEFS, a colder temperature response is seen digging as far south as the Tennessee Valley and parts of the Southeast, whereas the ECMWF is relatively weaker with the anomalous cold and limits its reach to the Ohio Valley and Mid-Atlantic by days 9-11 (Mar 27-29). While forecast temperatures are not cold enough for winter hazards criteria, any early spring cold snap inducing nighttime frost and/or freezes may adversely impact emerging springtime vegetation over the eastern CONUS such as what is being felt now across the southeastern U.S. A slight risk of much below normal temperatures was considered for addition, however due to the model disparities in the southern reach of the cold, this precludes any cold hazard in the latest outlook. This potential will continue to be monitored in the coming days. As the mean low lifts out over the Canadian Maritimes, periods of elevated winds are possible over the Northeast however there is less support in the tools, resulting in the removal of the corresponding wind risk over northeastern CONUS. Upstream, the prevailing positive 500-hPal height departures are expected to bring a prolonged period of above-normal temperatures throughout many parts of the central and western CONUS. However, similar to the east, the ECMWF favors stronger ridging than the GEFS particularly through the middle of week-2, resulting in differences in the strength of the anomalous warmth in the raw temperature tools. Complicating the picture are the PETs, which show a cooling (warming) trend of the warm signals in percentile space in the GEFS (ECMWF) since yesterday. Based on the National Blend of Models (NBM) showing a lower number of locations approaching record breaking temperatures compared to yesterday, there is more of a lean towards the cooler GEFS to reduce confidence of much above normal temperature risk. Given this and the general discrepancies in the tools, the corresponding moderate risk is discontinued in the outlook. However, a slight risk of much above normal temperatures remains posted where both the GEFS and ECMWF PETs show at least a 20% chance for maximum temperatures exceeding the 95th percentile through day 10 (Mar 28). While tools are unsupportive of temperatures reaching excessive heat thresholds, the anomalous warmth is likely to continue driving early springtime snowmelt for the higher elevations of the West, where many locations have registered well below normal snowpack over the winter. Over the northwestern CONUS, differences also exist between the GEFS and ECMWF along the western periphery of the anomalous ridge center. The GEFS features more troughing beginning to unfold toward the middle of the period, whereas the ECMWF maintains more ridging through late March. Regardless, precipitation tools from these models are rather scant in terms of any heavy precipitation or heavy snow potential over this part of the country, and the slight risk of heavy snow over the northern Cascades is removed. Over Alaska, models have been impressively consistent in maintaining amplified ridging to the west of the Bering Strait and downstream troughing over the Mainland and Southeast. This stable pattern has brought and continues to bring below-normal temperatures throughout much of the state. While PETs maintain elevated chances for minimum temperatures falling below the 15th percentile, actual temperatures look to remain above advisory thresholds due to rapidly increasing springtime sun angles at the higher latitudes, and no temperature hazards are posted. Over Hawaii, persistent Kona low activity has led to heavy rainfall and flooding throughout the state. Ensembles do not show much change in the mid-level pattern with troughing favored to persist over the Central Pacific later in March. PETs continue to indicate elevated chances for 3-day amounts exceeding the 85th percentile, with some locations expected to receive over an inch throughout week-2. The continuation of above-normal and potentially heavy precipitation is likely to worsen already saturated ground conditions and may trigger additional localized flooding in the state. FORECASTER: Nick Novella $$