Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
557 ACUS03 KWNS 100730 SWODY3 SPC AC 100729 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Mon Jun 10 2024 Valid 121200Z - 131200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE MID MISSOURI VALLEY NORTHEASTWARD INTO THE UPPER MISSISSIPPI VALLEY... ...SUMMARY... Thunderstorms associated with large hail and severe wind gusts are expected on Wednesday from parts of the mid Missouri Valley northeastward into the upper Mississippi Valley. ...Mid Missouri and upper Mississippi Valleys... West-northwesterly mid-level flow will be in place across the north-central U.S. on Wednesday, as a mid-level jet moves eastward across the far northern states. At the surface, A cold front will advance southeastward through the northern Plains. Ahead of the front, a moist airmass will be in place from the mid Missouri Valley northeastward into the upper Mississippi Valley. Warming surface temperatures and destabilization will likely result in isolated to scattered thunderstorm development during the afternoon. Thunderstorm coverage is expected to increase across the region during the late afternoon and early evening, as low-level flow increases. The exit region of the approaching mid-level jet will also increase large-scale ascent and deep-layer shear, making conditions favorable for organized storms. By late afternoon, the strongest instability is forecast to be from eastern South Dakota into central Minnesota, where MLCAPE is forecast to peak in the 3000 to 4000 J/kg range. NAM forecast soundings along this corridor at 00Z/Thursday have 0-6 km shear in the 40 to 50 knot range, with steep low to mid-level lapse rates. Some soundings suggest that 700-500 mb lapse rates could approach 8 C/km. This environment will be favorable for supercells with large hail. Hailstones greater than 2 inches in diameter will be possible with the strongest of cells. A wind-damage threat will also become likely as the storms gradually grow upscale. Some models suggest that a severe threat could continue into the overnight period, as a cluster remains intact and moves eastward into the western Great Lakes. ..Broyles.. 06/10/2024 $$