Bob Hartig
EF5
I've been eyeballing the area from Louisiana into Alabama for a few days. It looks poised for a Christmas Day severe event, with low-level helicity in excess of 200 m2/s2 and SBCAPE around 1,000 J/kg suggesting the possibility for tornadoes. A slightly negatively tilted trough brings a potent 500 mb jet core into LA, with diffluence overspreading from LA into AL as the system progresses. This morning's NAMM forecast sounding shows 0-3km CAPE approaching 200 J/kg in Alexandria, LA, migrating eastward.
Bottom line: With the sun setting early, this isn't a long-distance chase event. But it is a concern for the folks in southern and central LA, MS, and perhaps AL--particularly, I think, in a line across central LA into western MS. Where the southeast side of the H5 jet kisses better instability--especially higher 0-3km CAPE--curving hodographs could spell trouble, and I see that the SPC has now issued a moderate risk for part of the area. I'm not sure which Dixie Alley diehards are up for chasing on Christmas Day, but this could be an opportunity, albeit a fast one, with storm motions ranging from fast to screaming, aoa 45 kts.
Frankly, I don't like the thought of Dixie Alley lighting up on Christmas. Besides the fact that people will be travelling, families' guards are apt to be down. No one expects to sustain storm damage, or perhaps worse, on Christmas.
Bottom line: With the sun setting early, this isn't a long-distance chase event. But it is a concern for the folks in southern and central LA, MS, and perhaps AL--particularly, I think, in a line across central LA into western MS. Where the southeast side of the H5 jet kisses better instability--especially higher 0-3km CAPE--curving hodographs could spell trouble, and I see that the SPC has now issued a moderate risk for part of the area. I'm not sure which Dixie Alley diehards are up for chasing on Christmas Day, but this could be an opportunity, albeit a fast one, with storm motions ranging from fast to screaming, aoa 45 kts.
Frankly, I don't like the thought of Dixie Alley lighting up on Christmas. Besides the fact that people will be travelling, families' guards are apt to be down. No one expects to sustain storm damage, or perhaps worse, on Christmas.
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