D2 tornado threat and current outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1146 PM CST Sun Jan 07 2024
Valid 091200Z - 101200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS TUESDAY ACROSS
PARTS OF SOUTHEASTERN ALABAMA...NORTHERN FLORIDA...PARTS OF THE
CAROLINA PIEDMONT AND THE CAROLINA COASTAL PLAIN...
...SUMMARY...
Severe thunderstorms may impact much of the eastern Gulf and southern Atlantic Coast states Tuesday, accompanied by a risk for very strong and damaging wind gusts and a few strong tornadoes.
...Synopsis...
Within the prevailing split flow across the eastern mid-latitude Pacific, it still appears that mid/upper ridging will undergo amplification through this period. As this occurs, mid-level is forecast to begin to dig across Pacific Northwest, and a strong downstream trough, initially approaching the Mississippi Valley, likely will remain progressive.
Strong cyclogenesis appears likely to proceed from the Mississippi Valley through much of the eastern U.S., with the center of the primary surface cyclone generally forecast to track from east central Missouri through lower Michigan by late Tuesday night.
Models indicate that the mid/upper trough axis will take on a negative tilt while pivoting northeast of the Mississippi Valley, with difluent flow aloft overspreading much of the Southeast.
Further intensification of lower/mid-tropospheric wind fields may include 50-90+ kt southerly to southwesterly flow in the 850-700 mb layer overspreading much of the eastern Gulf/southern Atlantic Coast region during the day Tuesday, accompanied by a moistening warm sector.
...Southeast...
Associated with the strong synoptic forcing for ascent, a strong to severe squall line, perhaps closely preceded by discrete supercell development, may be ongoing ahead of an eastward surging cold front across parts of central/southern Alabama into the north central Gulf of Mexico at 12Z Tuesday. With at least a continuing corridor of sufficient pre-frontal destabilization, the forcing for ascent likely will maintain this convective development across much of the eastern Gulf/southern Atlantic Coast region by Tuesday evening.
While inflow off the Atlantic into the Carolinas will contribute to pre-frontal low-level moistening even if the Gulf moist inflow becomes cut off, relatively warm layers aloft with weak lapse rates model likely will tend to at least limit the degree of boundary-layer destabilization. However, latest forecast soundings from both the 03Z Rapid Refresh and NAM do appear to suggest that thermodynamic profiles immediately ahead of the line will continue to become at least marginally sufficient to maintain a line of surface-based or near surface-based storms.
It is still possible that the line of convection may undergo at least some weakening across parts of Georgia and Florida during the morning or early afternoon, before intensifying once again across the Carolinas. However, given mean winds forecast on the order of 60-70+ kts in the lowest 6 km, downward mixing of higher momentum may remain sufficient to support widespread strong, damaging wind gusts. Given the strong to extreme low-level shear, developing meso-vortices within the line may pose a risk for tornadoes.
Within the moistening return flow off the Atlantic, there is at least some signal within convection allowing guidance of increasing potential for discrete supercell development across the Carolina coastal plain by late Tuesday afternoon, aided by large-scale ascent associated with warm advection ahead of the squall line. In the
presence of potentially very large, clockwise-curved low-level hodographs, this may be accompanied by the risk for a couple of strong tornadoes.
It remains unclear how much of a focus a remnant baroclinic zone, extending through much of the eastern Georgia and Carolina Piedmont, may become for severe thunderstorm development.
