Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
038 ACUS02 KWNS 211731 SWODY2 SPC AC 211730 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Tue May 21 2024 Valid 221200Z - 231200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHERN TEXAS AND SOUTHEAST OKLAHOMA ACROSS THE OZARKS AND TOWARD THE MISSOURI BOOTHEEL... ...SUMMARY... Severe thunderstorms posing a risk for damaging gusts and hail will be possible from central Texas into the Ohio Valley and lower Great Lakes area on Wednesday. The greatest threat of damaging hail and wind is forecast from north Texas across the Ozarks. ...Synopsis... A broad zone of moderate to strong southwest flow will stretch from the Plains to the Great Lakes, with the primary shortwave trough affecting the upper MS Valley and Great Lakes through 00Z. This wave will eject northeastward into Ontario and Quebec thereafter, with various convectively enhanced disturbances trailing southwestward within the southwest flow toward Texas. At the surface, low pressure near Lake Superior early Wednesday will fill as it occludes into Ontario, with a cold front roughly from lower MI into southern MO and into northwest TX by midday. Ahead of this front, ample moisture will exist from TX into the lower OH Valley, with various rounds of severe thunderstorms throughout the period. ...Southern Plains into the Ozarks and Mid South... Severe regimes are forecast on both sides of the synoptic front, beginning early on Wednesday. Scattered storms are expected early Wednesday morning over parts of OK, and expanding into southern MO. Here, forecast soundings show extreme elevated instability, along with very favorable hodographs supporting splitting elevated hail storms. Northeast winds north of the front beneath moderate southwest flow will result in lengthy hodographs and good effective-layer storm relative inflow. While the precise corridor is difficult to place, it will likely be just north of the surface front, with potential swaths of significant damaging hail. Western portions of the front into northwest TX will also favor relatively early development, with steep lapse rates aloft and lengthy hodographs again favoring damaging hail. As heating occurs ahead of the boundary, additional storms will develop across northern TX, producing damaging hail and areas of damaging winds. A couple tornadoes will be possible, especially if the boundary briefly stalls or robust cells develop along old outflows. Given that the boundary is roughly parallel to the flow aloft, a prolonged splitting hail storm event will be possible, from the Red River region across the Ozarks. Additional clusters of storms are likely to develop and translate south/southeast across AR and into western TN/MS where ample moisture and instability will favor areas of damaging wind and hail. ...OH Valley into PA/NY... Although the region will be well ahead of the main upper wave, gradual height falls are forecast to occur atop the moistening air mass ahead of the cold front. Strong heating will lead to an uncapped air mass, with weak but sufficient lift timed with peak heating. Scattered cells are forecast from the OH River toward the southern shores of Lakes Erie and Ontario by around 21Z, and modest veering with height may support a few longer lived cells capable of hail spreading east. ..Jewell.. 05/21/2024 $$