Winter may bring snow and rain to some drought-stricken U.S. states

NOAA’s winter outlook covers U.S. temperature and precipitation from December through February. Its central message is a regional split. Much of the South may be wetter than average, while parts of the northern United States may be drier. Large areas may also be warmer than usual. El Niño is expected to shape these patterns strongly.

The southern band, including the Southwest, Southeast, and parts of the East Coast, has a higher chance of wetter-than-average conditions. Portions of the Great Lakes, northern Mountain West, Hawaii, and much of Alaska may be drier. Warmer-than-average temperatures are expected in parts of northern California, the Pacific Northwest, Midwest, Mississippi Valley, and eastern United States.

The forecast is not equally certain everywhere. Parts of the Intermountain West, northern Plains, and Ohio Valley have equal chances of below-average, near-average, or above-average precipitation. The outlook could ease drought in several southern regions, but heavy rainfall may also bring flooding and mudslides.

El Niño is a shifting climate pattern governed by ocean temperatures in the tropical Pacific Ocean. It is the warmer phase of the El Niño-Southern Oscillation cycle, opposite the cooler La Niña phase. Even though the name suggests warmth, El Niño does not make every U.S. location warmer or produce milder winter weather everywhere.

The pattern influences weather around the world by changing large-scale atmospheric behavior. In the United States, past El Niño events have been associated with stormier conditions across the South. That can increase the chances of rain and snow there. At the same time, the northern tier may experience drier-than-average conditions, according to NOAA’s outlook.

This winter’s El Niño is described as exceedingly strong and likely to play a major role. Still, its effects vary by region. Some areas, including parts of the Intermountain West, northern Plains, and Ohio Valley, have equal chances of below-average, near-average, or above-average precipitation.

The outlook describes a broad, uneven pattern rather than one condition for the entire country. The southern band, including the Southwest, Southeast, and portions of the East Coast, is likely to be wetter than average from December through February. This matters because several of those regions have faced drought and could receive useful rain or snow.

Drier-than-average conditions are expected in portions of the Great Lakes, the northern Mountain West, Hawaii, and much of Alaska. Warmer-than-average temperatures may cover parts of northern California, the Pacific Northwest, Midwest, Mississippi Valley, and eastern United States. Much of Alaska is also expected to be warmer than usual.

Forecast confidence is lower in some central regions. Parts of the Intermountain West, northern Plains, and Ohio Valley have equal chances of below-average, near-average, or above-average precipitation. Drought may ease across the Southwest, southern Great Plains, and East Coast, but it could develop or worsen in Oregon, eastern Washington, and parts of the northern Rockies.

El Niño often brings stormier, wetter winters to the southern United States because previous events have repeatedly produced that pattern. NOAA forecasters used decades of observations to shape this winter’s outlook. The pattern is not a guarantee for every town, but it raises the likelihood of more storms across the southern band.

The expected storm track includes the Southwest, Southeast, and portions of the East Coast. More frequent or stronger winter storms can increase total precipitation as rain or snow. This is especially important for areas that experienced drought earlier in the year. A strong El Niño can therefore bring both possible relief and serious weather hazards.

NOAA cautions that El Niño does not reduce the severity of winter risks. Southern communities may welcome additional water, but too much precipitation can create destructive flash floods and mudslides. The outlook also shows that El Niño’s influence is uneven, with drier conditions expected in several northern regions.

Drought means an area has gone too long without enough water, so additional winter precipitation can provide needed relief. Rain directly adds water to the landscape, while snow can contribute water as it accumulates and later melts. NOAA expects drought conditions to ease across large stretches of the Southwest, southern Great Plains, and parts of the East Coast.

For example, a drought-stricken area in the southern United States may receive several storms during an El Niño winter. Those storms could bring both rain and snow. If precipitation is spread across the season, it may improve local water conditions and reduce the area affected by drought. Forecasters said drought could even end in some places.

Relief is not guaranteed everywhere. The amount, timing, and location of precipitation matter. Heavy rain can run off quickly instead of helping deeply dried ground. Meanwhile, drier-than-average conditions could develop or worsen in Oregon, eastern Washington, and parts of the northern Rockies.

Drought does not make heavy precipitation automatically safe. After a long dry period, soil can be hard and unable to absorb intense rainfall quickly. Water may then move rapidly over the ground instead of soaking in. Steep or unstable terrain can make that runoff more dangerous, producing flash floods and mudslides.

NOAA’s Ken Graham warned that too much precipitation on dry soil can fuel these hazards. A drought-stricken southern community could therefore face a double-edged winter. Rain and snow may improve water conditions, but a sudden, powerful storm can overwhelm land and drainage systems. Snow can also add risk later if it melts quickly, although the article does not specify that process.

This is why NOAA urged communities in potentially affected regions to prepare. The outlook expects wetter conditions across much of the South because of El Niño, but it does not promise gentle rainfall. Relief depends on how much precipitation falls, how quickly it arrives, and how well the ground can absorb it.

Drought is a sustained period when available water is insufficient for an area’s needs. Precipitation is the main input: rain and snow can reduce drought, while below-average precipitation can deepen it. But the same amount of precipitation can have different effects depending on when it falls and whether the ground can absorb it.

Soil moisture shows how much water remains available near the surface. Snowpack stores water that may become available later, while little snow can leave supplies short. Water demand also matters. Higher demand from communities, agriculture, or ecosystems can worsen drought even when some precipitation occurs. After severe dryness, intense rain may run off and cause flooding instead of restoring soil moisture efficiently.

The article expects drought relief in the Southwest, southern Great Plains, and parts of the East Coast. It also warns that drought could develop or worsen in Oregon, eastern Washington, and the northern Rockies. The result will depend on precipitation amounts, timing, storage, and demand.