Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
959 ACUS48 KWNS 120901 SWOD48 SPC AC 120900 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Wed Jun 12 2024 Valid 151200Z - 201200Z ...DISCUSSION... ...Saturday/Day 4 to Saturday/Day 5... On Saturday, an upper-level trough is forecast to move northeastward across the southern and central High Plains. An axis of instability is forecast to be further to the northwest across the western Dakotas. As a mid-level jet passes northeastward across the northern Rockies, large-scale ascent and deep-layer shear should be strong enough for an isolated severe thunderstorms in parts of the northern High Plains. Large hail and severe wind gusts will be possible, but uncertainty exists concerning the spatial distribution of the threat. The trough in the central Plains is forecast to move into the upper Mississippi Valley on Sunday, with a large pocket of instability located in its wake across the central Plains. Although large-scale ascent within this unstable airmass is expected to be weak, isolated severe storms could develop in the late afternoon and early evening. Further to the northwest, model forecasts show potential for storm development in parts of the northern High Plains Sunday evening. If this were to occur, MCS development, and an isolated severe threat, could occur across parts of the northern Plains Sunday night. ...Monday/Day 6 to Wednesday/Day 8... On Monday, a mid-level jet is forecast to move northeastward into the northern Plains, as a moist and unstable airmass remains in place across the Upper Midwest. Severe thunderstorms may develop across parts of the region during the afternoon and evening, in association with any shortwave trough that can translate through the flow. The models suggest there is enough potential on Monday for a more widespread severe threat, to add a 15 percent contour in parts of the eastern Dakotas and Minnesota. On Tuesday, an upper-level trough is forecast to move across the northern Plains. Isolated strong to severe thunderstorms would be possible ahead of the trough in parts of the upper Mississippi Valley. As the trough moves through southeastern Canada on Wednesday, severe storms would be possible in parts of the Northeast. However, uncertainty is considerable at this range in the forecast period. ..Broyles.. 06/12/2024