MattPetrulli
Member
SPC has put out a day 4 risk for 3/25/21
NAM, GFS, Euro all paint some type of significant severe risk however there are some big timing and location differences for Eastern LA through southern AL.
Here's SPC discussion
...DISCUSSION...
...Day 4/Thu - Eastern TX to the Central Gulf Coast States...
An upper shortwave trough over the Rio Grande/northern Mexico will
strengthen and become negatively tilted as it ejects northeast
across the Arklatex through Thursday evening, and to the Ohio Valley
by Friday morning. Intense shear will overspread the south-central
and southern U.S. ahead of the trough. Furthermore, strong low-level
warm advection will result in a broad warm sector ahead of a
deepening surface low and eastward-advancing cold front from the
Sabine Valley eastward across the central Gulf coast/TN Valley
vicinity.
Differences in the evolution of the surface low across the lower MS
and OH Valleys are still apparent in medium-range guidance. This is
mainly resulting in uncertainty in the position of the surface low
and cold front Thursday morning, and how far east each of these
features progresses by Friday morning. As a result, changes in
severe probabilities, especially on the western and northeastern
edges, are likely in the coming days. Nevertheless, weak to moderate
instability will overlap with favorable shear parameters and an
overall supportive pattern for severe convection. A couple of rounds
of severe storms could be possible, as some warm-sector development
may occur across the Lower MS Valley before a QLCS develops along
the surging cold front during the evening/nighttime hours. All
severe hazards will be possible with discrete warm-sector
supercells. Potential for damaging gusts and tornadoes will becoming
preferential with any upscale development along the cold front.
NAM, GFS, Euro all paint some type of significant severe risk however there are some big timing and location differences for Eastern LA through southern AL.
Here's SPC discussion
...DISCUSSION...
...Day 4/Thu - Eastern TX to the Central Gulf Coast States...
An upper shortwave trough over the Rio Grande/northern Mexico will
strengthen and become negatively tilted as it ejects northeast
across the Arklatex through Thursday evening, and to the Ohio Valley
by Friday morning. Intense shear will overspread the south-central
and southern U.S. ahead of the trough. Furthermore, strong low-level
warm advection will result in a broad warm sector ahead of a
deepening surface low and eastward-advancing cold front from the
Sabine Valley eastward across the central Gulf coast/TN Valley
vicinity.
Differences in the evolution of the surface low across the lower MS
and OH Valleys are still apparent in medium-range guidance. This is
mainly resulting in uncertainty in the position of the surface low
and cold front Thursday morning, and how far east each of these
features progresses by Friday morning. As a result, changes in
severe probabilities, especially on the western and northeastern
edges, are likely in the coming days. Nevertheless, weak to moderate
instability will overlap with favorable shear parameters and an
overall supportive pattern for severe convection. A couple of rounds
of severe storms could be possible, as some warm-sector development
may occur across the Lower MS Valley before a QLCS develops along
the surging cold front during the evening/nighttime hours. All
severe hazards will be possible with discrete warm-sector
supercells. Potential for damaging gusts and tornadoes will becoming
preferential with any upscale development along the cold front.
