Dowdy interviews UGA climatologist Pam Knox, who explains that the polar vortex, which usually stays up in the polar north through the winter, is an area of cold, strong, high winds and low pressure.
Knox said, “Usually it [the polar vortex] sits on top of the globe like a hat, but this year it has slid forward over the U.S.” This year, she added, also has been a year of "high swings in temperature conditions."
Dowdy explains, "This unpredictability could cause havoc for Georgia farmers and gardeners this spring ... For instance, if Georgia fruit trees begin to flower and a late frost hits the state, the fate of peach, blueberry and other fruit crops will be threatened."
Knox also cautions gardeners to not plant too soon, since the chance of a late frost is increased this year.
How late is a "late" last frost?
Here in Cobb County, we have become accustomed in recent years to the last frost's occurring in March, and warm enough temperatures for planting tender crops like peppers and eggplants in early April. UGA's Automated Weather Stations show, though, that the last frost has fallen in April in some years within the past decade or so.
These are the data for the last frost date from the two nearest UGA Automated Weather Stations for Cobb County -- one in Dallas, GA, at the Paulding County High School, and one in Dunwoody, at The Cherokee Town & Country Club:
Last Frost Date
Notice that in 2005, the two stations show very different last frost dates. Also, the weather station in Alpharetta (data not listed hear) showed a last frost date for 2012 of April 12, somewhat later than the Dunwoody and Dallas stations. The charts show that, not only can the last frost date shift by several weeks from year to year, but it also can vary across the metro area, and "late" can be very late indeed!
For Dowdy's complete article, with additional information provided by Pam Knox, click on the link here.