2024-2025 Winter Outlook for Northeastern SC and Southeastern NC

For the fourth time in five years, La Niña is expected to be a factor in this winter's weather and climate across North and South Carolina. 

La Niña is natural, periodic cooling of ocean water across the tropical east Pacific Ocean that brings global impacts to temperatures, rainfall, wind, and pressure patterns.  La Niña is known during the summer and fall for its enhancement of Atlantic tropical cyclone activity - but also brings impacts to the Carolinas during the winter when it increases the potential for below normal rainfall across the southern United States.  La Niña is the cool (or negative) phase of the El Niño Southern Oscillation (ENSO).

Two of the past three La Niña winters brought below-normal rainfall across the coastal Carolinas.  A normal winter sees 9.5 to 11.0 inches of rain across the area, but rainfall during the La Niña winters of 2021-2022 and 2022-2023 ran about 25 percent below normal, leading the National Drought Monitor to declare "abnormally dry" conditions in February 2023 and "moderate drought" conditions in February 2022.

Given the moderate drought already in place over portions of the coastal Carolinas, an outlook of increased chances for below normal rainfall is concerning and could lead to increasing severity of drought over the next several months.

Learn more about La Niña and El Niño from the National Ocean Service...

Rainfall

Winter outlooks from the NWS Climate Prediction Center show an increased potential for below normal precipitation totals during the 2024-2025 winter season.  Based on their latest outlook, there is a 78 percent chance that this winter's precipitation totals will be near or below normal, and only a 22 percent chance they will fall within in the upper one-third of historic winters.

A decrease in rainfall totals is the single largest impact La Niña typically brings to the eastern Carolinas during the winter.

Moderate drought continues across large portions of the southeastern United States including parts of coastal North and South Carolina.  This has been due to persistent high pressure across the eastern U.S. since fall began, with temporary improvement in local drought from Potential Tropical Cyclone Eight and Hurricane Helene.  The U.S. Drought Monitor shows 11 percent of South Carolina and 35 percent of North Carolina is experiencing moderate drought conditions as of mid November.

Another aspect of this winter's La Niña is an increased risk of wildfire across portions of the Carolinas.  According to the most recent outlook from the National Interagency Fire Center, western portions of both North and South Carolina may experience an above normal fire potential during portions of the upcoming winter.  Here across the coastal Carolinas, the wildfire risk is expected to be near normal.

Temperatures

Unlike with precipitation, the difference in average seasonal temperature between El Niño, ENSO-neutral, and La Niña winters is not especially large. 

Historic correlation between ENSO (El Niño, neutral, or La Niña) conditions and our observed winter average temperature is very low. This implies that other factors beyond ENSO are primarily responsible for influencing winter temperatures across the Carolinas.

One of the most important weather patterns that influences our winter temperatures is called the North Atlantic Oscillation (NAO).  In its positive phase, a fast west-to-east jet stream keeps cold arctic air bottled up across Canada and the Carolinas tend toward warm weather.  However during the negative phase of the NAO the jet stream is free to undulate north and south, often allowing cold arctic air to more easily spread across the eastern United States.  Cold winter weather can result across the Carolinas during the NAO's negative phase.

Unlike El Niño and La Niño that are often predictable many months in advance, the NAO is only predictable into the future for a couple weeks, and can shift phases multiple times during a single winter season.  How the NAO may impact the coming winter is not known yet.

Learn more about the North Atlantic Oscillation from Climate.gov...

Snow

Snow is an uncommon occurrence across eastern North and South Carolina.  Not every winter sees anymeasurable snow, and when it does amounts are typically small.  Major snowstorms (six or more inches of snow) haven't occurred in Wilmington since December 1989 and since January 2000 in Florence, SC. 

Epic snowstorms where a foot or more of snow has fallen have occurred only three times in Wilmington's history:  February 17-18, 1896; February 9-11, 1973; and December 22-24, 1989.  In Florence, SC, where climate records only extend back to 1948, only the Feburary 1973 snowstorm has produced over a foot of accumulation.

Since 1959, there have been 22 winters when La Niña conditions were present like we expect for this coming winter.  Unfortunately for snow-lovers, the majority of those winters experienced below-average snowfall across the Carolinas. In addition, the most recent 30-year period used for climate normals (1991 through 2020) has the smallest average snowfall for any time in Wilmington's climate record, only 0.9 inches per year.  This is likely related to ongoing climate change which has led to warmer temperatures.

"How does La Niña affect snowfall over North America?" from Climate.gov

Tides and Coastal Flooding

Tidal ranges are naturally larger during full moon and new moons, and December's full moon on December 15 should produce water levels within one foot of minor coastal flood thresholds at the beaches.  Any nearby low pressure system or strong onshore winds occurring in the days surrounding this full moon could easily produce coastal flooding. 

Coastal flooding can occur even during low tides if onshore winds are strong enough.  A powerful winter Nor'easter that occurred in December 2023 produced significant coastal flooding with observed water levels of 9.97 feet MLLW at Myrtle Beach - almost 3 feet above flood stage.  This same storm system produced up to 14 inches of rain near Georgetown, SC accompanied by 50+ mph wind gusts along the beaches.

Hourly forecasts for water levels at Wrightsville Beach, Myrtle Beach, and the Cape Fear River at downtown Wilmington are available on the National Water Prediction Service webpage.  These forecasts are made by NWS meteorologists and include forecast storm surge and tidal anomaly factors. 

The National Ocean Service produces a Monthly High Tide Outlook that provides months of advance notice of periods when astronomical tides will be unusually high and could more easily produce coastal flooding.

Additional Links

• NWS Climate Prediction Center
• Current ENSO Status and Predictions
• Daily Climate Normals and Records for Wilmington, North Myrtle Beach, Florence, and Lumberton
• Historical snowfall for Wilmington, Myrtle Beach, and Florence
• U.S. Drought Monitor - Southeast

Research and Page Author: Tim Armstrong
Last Updated: November 19, 2024