SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Sat Apr 05 2025 Valid 052000Z - 061200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR NORTHERN MISSISSIPPI INTO WESTERN TENNESSEE... ...SUMMARY... Severe storms, capable of producing damaging wind gusts, large hail and several tornadoes are still expected from the Sabine River Valley northeastward into the Mid-South and lower Mississippi and Ohio Valleys. Strong tornadoes, very large hail, and severe wind gusts are all possible. ...20Z Update... The primary changes made to the 20Z Convective Outlook Update were to trim severe probabilities from the west to account for the passage of the ongoing QLCS over the Mid-South into the Lower MS Valley region. Severe hail may still accompany the stronger storms along southern extent of or immediately ahead of the QLCS. Otherwise, strong to severe surface gusts and tornadoes (a couple of which may be strong) may occur with embedded mesovortices and LEWPs within the QLCS, as well as with any storms ahead of the line. See the previous outlook (below) for more details. ..Squitieri.. 04/05/2025 .PREV DISCUSSION... /ISSUED 1140 AM CDT Sat Apr 05 2025/ ...East TX/ArkLaTex to Lower Mississippi Valley... Severe storms continue to increase through late morning into midday especially across parts of Arkansas, with the upscale-growing MCS/bow echo near/northeast of the Little Rock area as of 1130 CDT. A 60 kt wind gust was recently measured at KLRF/North Little Rock. This bowing MCS should continue to favor the zone near/immediately north of the effective boundary that precedes it (roughly parallel to I-40), likely taking it into western Tennessee this afternoon, potentially near the Memphis metro vicinity. See Mesoscale Discussion 411 for additional details. A Moderate Risk upgrade has been introduced for this scenario, as well as potential semi-discrete warm-sector development later this afternoon to its south. Within the axis of a strong low-level jet (south-southwesterly 50-60 kt across the ArkLaTex and ArkLaMiss), supercell longevity/tornado potential will be maximized with any diurnal warm-sector development that occurs away from (east-southeast of) the outflow-reinforced effective front, although the extent of that my tend to be somewhat curbed by persistent cloud cover and semi-mild mid-level temperatures (-9 or -10C at 500mb) into the warm sector. Additionally, deep-layer shear vectors will be largely parallel to the effective front regionally, suggestive of a mixed convective mode including HP supercells/smaller-scale bows in close proximity to the convectively modified effective front. The front will become more east/southeastward-progressive later this afternoon and tonight across east/southeast Texas, southern Arkansas, and Louisiana. Overall, some tornadoes are expected regionally, a few of which could be strong, aside from damaging winds and isolated large hail. ...Mid-South into the TN/OH Valleys... Farther north, the boundary will be less progressive throughout the morning/early afternoon, particularly north of a weak low currently over northeast Texas. The boundary will likely sharpen during this time, before then becoming more progressive once again as the convectively augmented shortwave trough currently moving into western Oklahoma progresses into the region. This will likely result in a bowing line segment with damaging gusts as the primary severe risk. However, given the strength of the low-level flow, some embedded tornado potential exists as well.
