SAVANNAH, Ga. (WSAV) — Now that we are finally in fall, temperatures have been cooling off and have largely been below average in Savannah.
Overall, the first part of October is expected to continue the below-average temperature trend across the southeast. With colder and drier air settling in, we can also expect below-average rainfall amounts.
Late in the month, the expectation is that conditions will gradually warm up and will be slightly above average.
One of the main reasons for the cooler than average temperatures is due to the position of the jet stream. The jet stream is a current of air that is usually about 30,000-40,000 ft above sea level.
During the summer, it is usually oriented in what is called a zonal pattern which promotes a west to east flow of air across North America.
Starting in the fall and into the spring, the jet stream usually is in what is called an amplified pattern and that allows cold Canadian air masses to move southward and often varies position a lot. That often leads to large swings from warm and then cold periods.
For the beginning of October, the amplified pattern is what will be setting up where the jet stream dips well to our south. The average high for the beginning of October in Savannah is 82°F. We will be looking at highs likely in the 70s.
Even though colder and drier air usually means a greater chance of less precipitation. We often do have showers and storms ahead of cold fronts before the colder air moves in and we can expect that to be the case on and off, however, amounts of rain received will remain below seasonal averages.
The drier pattern that will be setting up will actually be beneficial for the Coastal Empire and Lowcountry.
2020 has been a wet year. Early on, there was a lot of rain in February and March that led to some river flooding and very soggy ground. Which is never good for the planting season.
In Savannah so far for the year, 42.59″ of rain fell at Savannah-Hilton Head International Airport. Normally to Sept. 24, we can expect 37.98″ of rain. This means we are over 4.61″ for the year.
A few spots have along the Savannah River are abnormally dry at the moment, no long term drought conditions are expected to develop during the season. Overall though, we’re in good shape and do not expect a drought to develop in the Coastal Empire or Lowcountry.
In the western U.S., extreme and exceptional drought conditions are expected to stay in place.