SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0804 AM CDT Mon Jun 12 2023 Valid 121300Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS CENTRAL/NORTH TEXAS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTH-CENTRAL HIGH PLAINS AND MID-ATLANTIC... ...SUMMARY... Severe thunderstorms capable of large hail and damaging winds are expected mainly this afternoon and evening across the southern Plains to middle Gulf Coast, with additional severe thunderstorms possible this afternoon across the Mid-Atlantic States. ...Central/North Texas... Surface cyclogenesis is expected today across the Edwards Plateau vicinity toward central Texas, with a triple point evolving near a west/east-oriented front and as a dry line advances eastward. This will be as the upper ridge modestly abates and westerlies strengthen across the region, with the net impact of enhancing very strong mid/high-level westerly winds and seasonally robust effective shear /50-60 kt/. Strong destabilization is expected near/south of the west/east front, and particularly in vicinity of the surface triple point where MLCAPE is likely to exceed 4000 J/kg just ahead of the bulging dry line. Near the triple point, the potential for intense thunderstorm development should be focused across the Texas Big Country and parts of the Low Rolling Plains late this afternoon. One or more large, intense supercells are expected to develop with a threat for very large to potentially giant hail, with some tornado potential as well, particularly with any storms interacting with the west/east front. These storms are likely to persist east-southeastward across the region through the evening before weakening/diminishing into the overnight. ...South-central High Plains... Thunderstorms, including some locally strong storms, will continue early today mainly across far southeast Colorado and northeast New Mexico. Lingering convection and cloud cover should largely relegate the primary corridor of later-day destabilization to relative proximity of the higher terrain/Raton Mesa vicinity, where additional afternoon thunderstorm development is expected. MLCAPE around 1000 J/kg with effective shear of 50 kt, accentuated by high-level winds of 80-100 kt will support supercells capable of very large hail. ...Louisiana/Mississippi to southern Alabama/Florida Panhandle... To the south of a west/east-oriented front, extreme instability will develop by midday across central and southern Louisiana into southern Mississippi/Alabama as temperatures rise into the low 90s F with dewpoints in the low to mid 70s F. A seasonally strong belt of west-northwesterly winds aloft will contribute to effective shear of 35-45 kt. This scenario should yield some initial supercells as well as the gradual evolution of intense southeastward-moving clusters/linear segments capable of severe hail as well as damaging winds. ...Southern Oklahoma/ArkLaTex... A few strong to locally severe thunderstorms are possible today along the southern edge of lingering overnight convection. Later today, a southwesterly low-level jet will strengthen to 30-40 kt across eastern Texas this evening. Amid very strong buoyancy, this may provide ample isentropic ascent for thunderstorm development late this evening into the overnight. Forecast soundings depict 2000-3000 J/kg of MUCAPE and effective shear in excess of 60 kt. This would support a threat for large hail late tonight from southeast Oklahoma into northeast Texas, southern Arkansas, and northern Louisiana. ...Mid-Atlantic States/Eastern North Carolina... A moist airmass will be present east of a cold front along the eastern seaboard this afternoon. Some surface heating will lead to 1000-2000 J/kg of MLCAPE in conjunction with 30-35 kt of effective shear. Multicells along with some transient supercells are possible from eastern North Carolina into eastern Virginia and the Delmarva this afternoon/early evening, with a primary threat of severe hail and damaging wind gusts. ..Guyer/Smith.. 06/12/2023
