Skip Talbot
EF5
Looks like a nocturnal tornado event shaping up over Dixie Alley. I'm not considering chasing this event given the location and timing, but thought it would be worth starting a forecast thread for those considering taking the plunge or for the local chasers who will be out anyway.
Both the GFS and NAM have been fairly consistent bringing in an impressive negatively tilted trough and ejecting a 90 knot shortwave over the southern states tomorrow evening. Surface temps and dews in the 60's will lead to modest instability, but the NAM has been trending on advecting more moisture and pushing it further north in recent runs. Some pockets of 1000 J/Kg MLCAPE being plotted on the NAM will be more than enough for supercells and tornadoes given the strongly sheared environment and dynamic lift associated with the trough. The GFS is less bullish on the instability, but still brings in ample moisture and pockets of 500 J/Kg MLCAPE. Also interesting is the 0-3km CAPE really surges in the evening and overnight hours as strong moisture advection continues after dark. Coupled with the low level jet ramping up to 50-60 knots, we may have a dangerous combination favoring a nocturnal tornado event.
Storm mode looks like it could be a mix with models showing initiation on a cold front over eastern AR and south by 6pm. Forcing on the front and surface winds that are fairly veered may lead to rather solid, linear line, but the speed and directional shear is more than strong enough to support embedded supercells. As that low level jet and helicity ramps up overnight, the tornado thread will probably increase.
I wouldn't consider this a chase-able event unless you're a gluten for punishment or already live down there and have a few good spotting locations. The fast storm speeds from the very strong mid and upper level flow, the trees and terrain of northern MS and AL, and that this is going to be mainly after dark will make for an extremely difficult if not impossible chase. The only real shot I see at a chase is perhaps catching initiation in eastern AR, where the terrain is flat and treeless and there might still be some light in the sky before the early sunset. The appreciable tornado threat might not come until later, however, so that's going to be a real gamble. However, spotters and chasers will need to be on their toes from early evening to after midnight over MS, AL, TN, and points north.
Both the GFS and NAM have been fairly consistent bringing in an impressive negatively tilted trough and ejecting a 90 knot shortwave over the southern states tomorrow evening. Surface temps and dews in the 60's will lead to modest instability, but the NAM has been trending on advecting more moisture and pushing it further north in recent runs. Some pockets of 1000 J/Kg MLCAPE being plotted on the NAM will be more than enough for supercells and tornadoes given the strongly sheared environment and dynamic lift associated with the trough. The GFS is less bullish on the instability, but still brings in ample moisture and pockets of 500 J/Kg MLCAPE. Also interesting is the 0-3km CAPE really surges in the evening and overnight hours as strong moisture advection continues after dark. Coupled with the low level jet ramping up to 50-60 knots, we may have a dangerous combination favoring a nocturnal tornado event.
Storm mode looks like it could be a mix with models showing initiation on a cold front over eastern AR and south by 6pm. Forcing on the front and surface winds that are fairly veered may lead to rather solid, linear line, but the speed and directional shear is more than strong enough to support embedded supercells. As that low level jet and helicity ramps up overnight, the tornado thread will probably increase.
I wouldn't consider this a chase-able event unless you're a gluten for punishment or already live down there and have a few good spotting locations. The fast storm speeds from the very strong mid and upper level flow, the trees and terrain of northern MS and AL, and that this is going to be mainly after dark will make for an extremely difficult if not impossible chase. The only real shot I see at a chase is perhaps catching initiation in eastern AR, where the terrain is flat and treeless and there might still be some light in the sky before the early sunset. The appreciable tornado threat might not come until later, however, so that's going to be a real gamble. However, spotters and chasers will need to be on their toes from early evening to after midnight over MS, AL, TN, and points north.
