Summer 2024 Climate Outlook for northeastern SC and southeastern NC

Warm weather fans can rejoice: outlooks from the NWS Climate Prediction Center show an increased likelihood of above normal temperatures this summer across North and South Carolina.  This is on the heels of a spring that was the warmest in recorded history in Wilmington and the second warmest on record in North Myrtle Beach.

Temperatures, La Niña, and Climate Change

Climate change is tilting the odds in favor of warmer temperatures with each passing year.  Climate change over the past century is the result of the accumulation of carbon dioxide, methane, and other gases in the atmosphere from continued extraction and burning of fossil fuels like coal, oil, and natural gas.  These gases help trap heat that would normally radiate out into space.  NOAA announced 2023 was the warmest year recorded since systematic climate records began in 1850 with global temperatures 2.12° F above the 20th century average.

Wilmington's 2023 observed temperature averaged 1.9° F above 1991-2020 normals while North Myrtle Beach ran 1.0° F above normal.

  > > > Read more about Climate Change from NOAA

This summer will have another factor at work that could enhance our potential for above-normal temperatures: La Niña.  El Niño and La Niña are two extremes in a natural oscillation in ocean water temperatures across the tropical Pacific Ocean called ENSO - the El Niño Southern Oscillation.  A complete cycle from El Niño to La Niña and back again normally takes two to five years to complete. 

Last winter, El Niño occurred as water temperatures across the tropical east Pacific ocean were warmer than normal, setting into motion a series of atmospheric changes that normally provide the Carolinas with a wet winter.

 > > > Learn more about El Niño and La Niña from NOAA

Now in early June, El Niño is quickly fading and there is growing consensus that La Niña may develop later this summer.  La Niña occurs when tropical east Pacific Ocean waters become cooler than normal.  When a shift to La Niña occurs during our summer months, we usually see a tendency for above normal temperatures to develop across the Carolinas.

Over the past 30 years there have been five times where La Niña developed during the summer: 2020, 2016, 2010, 1998, and 1995.  The table below shows temperatures averaged warmer than normal during four of those five summer seasons, and temperatures observed during two of those years (2016 and 2010) were far above normal.  This reinforces the Climate Prediction Center's outlook for warm summer temperatures across the Carolinas.

Hot summer temperatures can increase heat stress to people, animals, and plants.  Warmer temperatures also increase the amount of energy needed for air conditioning, driving up costs to families and businesses.  Each one degree F increase in our summer average temperature roughly equals a six percent increase in energy costs.

Rainfall and Drought

NWS Climate Prediction Center summer outlooks show an increased likelihood of above normal rainfall across the Carolinas.  This forecast is based on a combination of above normal sea surface temperatures across the Gulf and Atlantic, plus input from long-range climate forecast models.  A warmer ocean evaporates water more quickly into the atmosphere, allowing thunderstorms to drop heavier rainfall.

NWS Climate Prediction Center outlook for rainfall this summer

Examining local precipitation observed during the past five summers (2020, 2016, 2010, 1998, and 1995) when La Niña formed, there is a wide variety in totals that reflects the random nature of rainfall from heavy summer thunderstorms.  An average calculated across all five of those years gives a near normal value, however individual cities observed widely differing totals during each of those years -- some well above normal and others well below. 

Fortunately, no drought currently exists across our portion of the Carolinas according to the U.S. Drought Monitor. 

Drought outlooks from the Climate Prediction Center also suggest no significant potential for drought to develop this summer.

Hurricane Season

NOAA's official Seasonal Hurricane Outlook calls for an exceptionally active Atlantic Hurricane Season featuring 17 to 25 named storms, 8 to 13 hurricanes, and 4 to 7 major hurricanes.  These numbers are well above long-term averages (14 named storms, 7 hurricanes, and 3 major hurricanes) and highlight the importance of remaining aware of the substantial threat this year's hurricane season poses to coastal residents of the United States.  Hurricane season officially starts on June 1 and continues through the end of November.

North Atlantic sea surface temperatures are well above normal, alarmingly so across the "Main Development Region" that spans the tropics between the African coast and the Caribbean Sea.  This is where many of our late summer and early fall hurricanes have originated -- storms like Bertha, Fran, Floyd, Florence, and Isaias.  The additional heat available in the ocean water there could help more storms to develop later this summer, and help those that develop become stronger.

With a La Niña climate pattern expected to develop by late summer, wind shear across the Atlantic should fall below normal levels.  Wind shear weakens hurricanes as it tilts the storm's vertical circulation and spreads its energy over a wider area.  Strong wind shear can destroy even a well-developed hurricane.  Less wind shear, like we anticipate this year, means hurricanes can more easily form and can reach stronger intensities.

During La Niña there is less thunderstorm activity across the cooler water found in the tropical East Pacific Ocean.  This allows an upper level trough to form over the east Pacific, inducing a ridge of high pressure to form downstream across the Caribbean Sea.  Low wind shear within this ridge is what can help supercharge the Atlantic Hurricane Season during La Niña years. 

Over the past 30 years there have been five times where La Niña developed during the summer: 2020, 2016, 2010, 1998, and 1995.  These five hurricane seasons produced a number of damaging storms across the Carolinas shown in the table below.

Another factor to consider for this hurricane season is the strength of the West African monsoon.  A monsoon is a component of some climates where seasonal wind shifts cause a significant portion of the year's rainfall to occur in only a few months.  A stronger West African monsoon typically means there are more easterly waves that cross the continent and move into the tropical Atlantic Ocean -- some of which become our long-tracked late summer and early fall hurricanes.

According to NOAA's outlook, models are suggesting this year's West African monsoon will be stronger than normal, implying a larger number of tropical disturbances may reach the warm waters of the tropical Atlantic.

 > > > Learn more about the West African Monsoon from Meteo-France

If we exhaust the entire Atlantic list of 21 names this hurricane season, there is a supplemental list of names approved by the World Meteorological Organization (WMO) that would be used.

Supplemental Atlantic Storm Names

The complete Atlantic name list is available from the WMO at https://wmo.int/content/tropical-cyclone-naming/caribbean-sea-gulf-of-mexico-and-north-atlantic-names

Coastal Flooding Risk

Astronomical tides will not run excessively high this summer and significant coastal flooding is not likely to occur in the absence of a nearby tropical cyclone or strong onshore winds.  Normally large tidal ranges will occur in the days surrounding new moons on June 6, July 5, and August 4, and full moons on June 21, July 21, and August 19.  Astronomical high tides will be largest during the August 19 full moon.

The Monthly High Tide Flooding Outlook from the National Ocean Service has more details about each month's flooding risk.

Wildfire Risk

Forecasters with the National Interagency Fire Center (NIFC) monitor trends in drought, fuel moisture, and plant growth to create maps highlighting the hazards posed by wildfire. Their outlook shows a near normal wildfire risk for this summer season.

Avoid outdoor burning on days when low humidity and gusty winds coexist.  Check our latest Fire Weather Forecast to see if weather conditions will allow safe burning.  

Other Links of Interest

• Climate Prediction Center Seasonal Temperature and Precipitation Outlooks
• Climate Prediction Center Seasonal Hurricane Outlook for 2024
• Average Temperatures and Precipitation for Wilmington, NC | Florence, SC | Myrtle Beach, SC | Lumberton, NC
• NWS Wilmington, NC North and South Carolina Historic Heatwaves

Research and Page Author: Tim Armstrong
Last Updated: June 2, 2024