Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
085 ACUS02 KWNS 271705 SWODY2 SPC AC 271703 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1203 PM CDT Thu Jun 27 2024 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL PLAINS INTO MISSOURI...IOWA AND SOUTHERN MINNESOTA... ...SUMMARY... Severe thunderstorms may develop from parts of the central Plains into parts of the Middle and Upper Mississippi Valley on Friday. Large hail, damaging wind, and a couple tornadoes will be possible. ...Northern/Central Plains to the Mid/Upper MS Valley... An upper trough over the northern Rockies will develop east to the Upper Midwest/upper Great Lakes vicinity. A convectively enhanced vorticity maxima also is forecast to be located over the lower/mid-MO Valley Friday morning. This feature will drift east toward Lake Michigan through evening. At the surface, an area of elongated low pressure will located near the international border in the vicinity of ND and southern Saskatchewan/Manitoba. This feature will shift east into northern MN and eventually the U.P. of MI and Lake Superior. At this occurs, a cold front will shift southeast across the northern Plains and Upper Midwest through the period. Isolated strong thunderstorms are possible ahead of the cold front during the afternoon/evening across parts of the Dakotas into MN. Locally strong gusts and a few instances of hail will be possible with this activity. Further south, a secondary surface low may develop in the vicinity of western/central KS on the nose of very strong heating over the southern Plains. Rich low-level moisture will be in place across the central Plains to the Mid-MS Valley. Morning convection will likely be ongoing in a strong low-level theta-e advection regime from northwest MO into IA/southeast MN/WI and northern IL. This activity poses some uncertainty in convective evolution into the afternoon as it may stunt destabilization, especially across parts of MO/IA/IL. If airmass recovery can occur, supercell wind profiles would support an all hazards risk, especially in the vicinity of any modified outflow from morning convection. Given uncertainty, only minor adjustments to the ongoing outlook have been made across the MO-Valley vicinity. Confidence is higher that strong destabilization will occur across parts of KS/NE. Convection will likely develop over southeast WY/northeast CO in a post-frontal upslope flow regime during the late afternoon. As this activity spreads east/southeast into NE/KS, isolated supercells and clusters will pose a risk for severe gusts. Steep low and midlevel lapse rates will be present, with a deeply-mixed boundary-layer evident in forecast soundings. Furthermore, dry air around 700 mb will further aid in strong downdraft potential. Isolated gusts to 80 mph will be possible. With any more discrete supercell activity, straight/elongated hodographs and large elevated instability and steep midlevel lapse rates will support isolated significant hail to around 2.5 inches in diameter. ..Leitman.. 06/27/2024 $$