There will be a threat for severe thunderstorms and flash flooding as we move into Christmas Eve. This is due to an already existing storm system that is backed by powerful upper-atmospheric winds, and this cell will continue to affect the eastern half of the country as we move into Christmas Day.
This storm has already packed a powerful punch in the south, causing widespread damage and several deaths on Tuesday when the storm hit Columbia, Mississippi and the whole part of southern Mississippi.
A big concern with this system is flash flooding along the Gulf Coast. Tallahassee, FL broke the record for the most rainfall in December when almost eight inches of rain fell, annihilating the record of 5 inches that was set on December 2, 2009. Widespread street flooding ensued due to the heavy rains.
Even though tornadoes aren’t very common around Christmas time, two years ago a tornado outbreak tore through the Gulf Coast region on Christmas Day, producing about 28 tornadoes.
There is a very powerful plunge in the jet stream that is moving into the East, and as this moves warm air surges ahead towards the north creating a cold front. This has made the perfect conditions possible for severe weather, and these conditions will continue to favor severe storms into Thursday from the eastern Carolinas to the central and southern Florida Peninsula.
A limited severe weather threat may also develop farther to the west ahead of the cold front from parts of southeast Michigan and Ohio to eastern Kentucky, western Virginia, and far western Pennsylvania. There are very strong winds that are located just above the ground and any thunderstorms could bring brief damaging gusts down to the ground level and cause some downed power lines and trees.
As we move into late Christmas Eve and early Christmas morning, bands of rain with embedded thunderstorms will move into the Mid-Atlantic and the Northeast. There is a possibility of some strong wind gusts due to a sharp cold front moving through the area, and this could also cause some power outages and downed trees.
Along with the severe threat, locally heavy rain may trigger some additional flash flooding in some areas of the Deep South through Christmas Eve night. The greatest risk of flooding will be over parts of southeast Alabama, southern Georgia, and northern Florida due to the heavy rainfall that has already fallen from previous storms. New England and much of the northeast could also experience flash flooding due to the possibility of more rain heading their way.
Flood watches are in effect for much of Upstate New York and New England because the meltwater from the existing snowpack is rising, and combining this with rainfall may raise the levels on some smaller streams and rivers, leading to the possibility of some flooding.
Check with your local weather authority for updates on these systems in your area.