SAVANNAH, Ga (WSAV) — The next week ahead is expected to be very warm and dry, and that is likely to be the trend well into the start of 2023.
For most of 2022, rainfall in the Coastal Empire and Lowcountry has been trending well below normal levels. The climate reporting station at Savannah-Hilton Head International Airport is indicating that Savannah is over 10 inches of rain behind what typically falls during a normal year as of December 3, 2022.
The continued rainfall deficit is becoming prolonged which is abnormally dry, which will lead to the development of a full-fledged drought situation. Drought conditions are expected to develop and continue throughout the winter months.
With droughts, you typically end up with warmer than normal conditions. Over the next week to two weeks, temperatures are expected to trend well above normal. In fact, some days Savannah’s highs will be nearing daily records. Most record highs for December are in the upper 70s to lower 80s, which is pretty close to our local forecast highs for the next seven days.
Part of the reason for the next several months looking to be warmer and drier than normal is the continuation of a La Nina pattern, a cold phase of a global-scale weather pattern, according to NOAA (National Oceanic and Atmospheric Administration) and the Climate Prediction Center.
The phase of the El Niño Southern Oscillation (ENSO) has profound effects on weather patterns across the world. ENSO is a variation of water surface temperatures and a variation of wind speed and strength over the equatorial Pacific Ocean. There are two phases of ENSO, El Niño which is a warm phase or La Niña which is a cold phase.
A La Niña pattern develops when there are stronger than normal trade winds over the equatorial Pacific Ocean. The trade winds blow from east to west. When the easterly trade winds are stronger than normal, they push the warm surface water toward Asia. That then leads to the upwelling of colder water from deeper levels in the ocean to the surface.
Colder water near the equator in the Pacific helps change where the jet stream, a current of fast-moving air that sets up between 5 and 10 miles above the surface that moves west to east. Usually with a La Niña pattern, the jet stream is farther north than normal in the winter.
When the jet stream is farther north, this typically leads to drought in the southern portion of the U.S. and heavy rain and flooding in the Pacific Northwest because of a change in storm tracks.
Locally in Georgia and South Carolina, we expect warmer than normal temperatures and less rainfall than normal.