206 FXUS21 KWNC 281745 PMDTHR US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM EDT March 28 2026 SYNOPSIS: Forecast mid-level low pressure is expected to promote cooler and more seasonable temperatures next weekend following an exceptionally warm March for many parts of the western and central contiguous U.S. (CONUS). However, a potentially strong frontal system brings an elevated risk for high winds and heavy precipitation early in week-2, with the potential for thunderstorm activity across the south-central CONUS. In Alaska, mid-level high pressure located over the Bering Strait is expected to bring a continuation of near to below-normal temperatures over the southern Mainland. HAZARDS Slight risk of heavy precipitation from much of the Southern Plains, Lower and Middle Mississippi, Tennessee, and Ohio Valleys, Southern Appalachians, Southeast, and Mid-Atlantic, Sun-Mon, Apr 5-6. Slight risk of high winds for much of the portions of Middle and Upper Mississippi and Ohio Valleys, Great Lakes and the Northeast, Sun, Apr 5. DETAILED SUMMARY FOR TUESDAY MARCH 31 - SATURDAY APRIL 04: https://www.wpc.ncep.noaa.gov/threats/threats.php FOR SUNDAY APRIL 05 - SATURDAY APRIL 11: By the outset of week-2, dynamical model 500-hPa height anomaly forecasts from the GEFS and ECMWF ensembles continue to favor shortwave troughing lifting out over the Great Lakes, bookended by a pair of anomalous ridge centers situated over the northwestern and northeastern CONUS. At the surface, a mean surface low tracking into southeastern Canada and an accompanying frontal boundary reaching into the southern tier of the U.S. looks to increase the risk of heavy precipitation across the Great Plains and Mississippi Valley next weekend. Consistent with previous ensemble guidance, the ECMWF is deeper with this mid-level troughing feature and favors a stronger precipitation response across the south-central CONUS compared to the GEFS. Beyond this lead, however, diverging mean solutions are increasingly evident between the GEFS and ECMWF ensembles. The GEFS remains eager to reload heights across the Interior West, implying a short respite to the unprecedented March warmth being felt across West, while also developing more of a deeper mean trough downstream across eastern North America. By contrast, the ECMWF is comparably more zonal and muted across the West, while favoring more ridging to persist over the western Atlantic and eastern Seaboard later in week-2. As a result of these variations in the height pattern, there continues to be high uncertainty in the hazard outlook later in April. Tied to the predicted frontal system across the Plains and Mississippi Valley, Probabilistic Extremes Tools (PETs) have become less supportive of a heavy precipitation risk early in the period, with much of this threat now timing off into the week-1 period. While the synoptic pattern looks to remain favorable next weekend, characterized by good forcing and ample low level moisture advection, the ECMWF has become an outlier with the heavy precipitation risk lingering into day 8 (Apr 5). The uncalibrated ECMWF shows 30-50% (20%) chances for 3-day amounts exceeding an inch (two inches), whereas the GEFS shows virtually no signal early in the period. Given the drier solutions in the uncalibrated GEFS and Canadian, as well as the weaker PETs, the moderate risk of heavy precipitation is discontinued in the updated outlook. However, a slight risk of heavy precipitation remains posted and valid through Apr 6, with its coverage adjusted to include (exclude) portions of the Southeast and Mid-Atlantic (northeastern CONUS) relative to the previous outlook. Within the highlighted risk area, the threat of thunderstorm activity remains, particularly across the ArkLaTex region where deterministic solutions show dewpoints reaching the upper 60s and lower 70s (deg F). The favored troughing and accompanying mean surface high pressure in the wake of the front is anticipated to usher colder temperatures across the western and central CONUS, while maintaining an increased risk of high winds next weekend. Similar to precipitation, the strongest signals for high winds appear to be timing off into week-1, and the corresponding moderate risk area is removed in the updated outlook. However, a slight risk remains posted over parts of the Mississippi and Ohio Valleys and the Great Lakes where there is ensemble support for wind gusts exceeding 34 knots behind the mean surface low early in week-2. With the high wind risk shifted eastward in the outlook and cooler temperatures favored upstream across the Interior West and Great Plains, this is expected to be less favorable for wildfire activity, at least initially in the period. Raw temperature tools depict warmer temperatures returning over this part of the country by the middle of week-2, but any subsequent wind and/or wildfire risk is uncertain in the absence of any organizing troughing features aloft over the West in the ensemble guidance. With the deeper troughing favored in the GEFS over the eastern U.S., the GEFS PET features increased chances for minimum temperatures falling below the 15th percentile dipping into the mid-Atlantic as the mean surface high settles east of the Mississippi towards the middle of week-2. However, there is little tool support for minimum temperatures falling below freezing south of the Ohio Valley that would adversely affect emerging springtime vegetation. Over Alaska, prevailing northwesterly mid-level flow downstream of a persistent 500-hPa mean ridge established over the Bering Strait is expected to lead to near to below normal temperatures for much of the southern Mainland, Aleutians and the Southeast. No temperature hazards are posted. Across Hawaii, persistent Kona Low activity brought heavy rainfall and flooding to the state during mid-March. Guidance shows a return to a more seasonable trade wind regime, and although above-normal precipitation is favored, any heavy precipitation risk looks to be kept to the south closer to the equator in the PETs, at least through the middle of week-2. FORECASTER: Nick Novella $$