SPC Mar 14, 2025 1730 UTC Day 2 Convective Outlook
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Fri Mar 14 2025 Valid 151200Z - 161200Z ...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS IN CENTRAL/SOUTHERN PARTS OF MS/AL... ...SUMMARY... A tornado outbreak is likely on Saturday across the central Gulf Coast States and Deep South into the Tennessee Valley. Numerous significant tornadoes, some of which should be long-track and potentially violent, are expected on Saturday afternoon and evening. The most dangerous tornado threat should begin across eastern Louisiana and Mississippi during the late morning to afternoon, spread across Alabama late day into the evening, and reach western parts of the Florida Panhandle and Georgia Saturday night. ...Central Gulf Coast/Deep South/TN Valley... After collaboration with WFOs BMX/JAN/MOB, an upgrade to a level 5-HIGH risk appears warranted for the most likely corridor of potentially violent tornadoes, peaking tomorrow afternoon and evening. A broader level 4-MDT risk has been expanded somewhat eastward for the nocturnal significant tornado threat. An intense mid-level jet, 100-110 kts at 500 mb, will eject through the basal portion of a broad southern Great Plains shortwave trough. This will induce secondary cyclogenesis along an initially slow-moving baroclinic zone from the Ark-La-Tex to the central Great Lakes. Another day of air mass modification ahead of this wave will yield a pronounced plume of rich northwest Gulf moisture that should be pristine across southeast LA and southern MS through late morning. As mid-level height falls overspread the diurnally warming air mass, increasing convective development is expected along the deepening baroclinic zone, as well as residual outflows to its northeast in the TN Valley from prior late D1 convection. Steep mid-level lapse rates atop the richly moist boundary layer will yield at least moderate MLCAPE from 1500-2500 J/kg across eastern LA into central MS. Vertically veering wind profiles with strong anvil-level divergence amid the favorable instability should support robust updrafts and intense supercells. Low-level shear will strengthen midday through the afternoon, yielding potential for a tornado outbreak. The most probable convective corridor will be along the effective outflow boundary across central/northern parts of MS into north AL and south TN. Along and south of this will be the most favored corridor for long-tracked, discrete supercells. These will likely develop within north/south-oriented confluence bands as increasing large-scale ascent becomes coincident with the peak heating cycle. A volatile combination of kinematic/thermodynamic parameters will support potential for long-track, EF3+ tornadoes. The overall spatial extent of this threat will be modulated by the degree of boundary-layer heating within the mid to upper 60s dew point plume, along with where exactly the large-scale outflow boundary sets up from late D1/early D2. Significant tornado potential, along with very large hail and destructive damaging wind gusts, should persist into Saturday night. Greater potential for a broken to linear band of thunderstorms is anticipated by this time, but wind profiles will still strongly favor supercells. As such, a mix of all three hazards may continue with sig severe hail potential favored south and sig severe wind favored north as the convective band spreads towards the southern Appalachians and the northeast Gulf Coast. ...OH Valley to central Great Lakes... Forecast confidence remains low with regard to severe potential north of the TN Valley. Guidance continues to differ on the degree of diurnal destabilization in the wake of the D1 shortwave trough and deep cyclone tracking into northern Ontario. With increasingly widespread Mid/Deep South to TN Valley thunderstorms during the day Saturday, the northward extent of appreciable surface-based instability appears highly questionable within a predominately meridional deep-layer wind profile. Given the fast flow regime though, even weak convection late afternoon through Saturday night will pose some risk for locally strong gusts and a tornado. ..Grams.. 03/14/2025
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