7AM Day 1 Convective Outlook for Monday, August 18. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL/NORTHERN PLAINS AND OVER PARTS OF THE MIDWEST .
SUMMARY
Strong to severe storms capable of damaging winds are possible in parts of the Midwest today. Widely scattered storms with large hail and severe winds are possible in parts of the central/northern Plains through tonight.
IA/WI/IL
A long-lived MCS continues to track eastward across central IA this morning. Visible satellite imagery shows the potential for considerable daytime heating ahead of this activity across parts of eastern IA/southern WI/northern IL, where temperatures will warm into the 90s. Ample low-level moisture will yield afternoon MLCAPE values around 3000 J/kg, along with sufficient westerly flow aloft for some convective organization. It is unclear whether current activity will intensify, or new storms will form later today. Regardless, this region will see the potential for strong/severe storms capable of damaging wind gusts. A tornado or two is also possible, given the backed low-level winds and east-west baroclinic zone along the WI/IL border. Have added a SLGT risk for this scenario.
Northeast CO into SD/NE/KS
Strong heating and ample low/mid level moisture will promote the development of scattered thunderstorms by mid-afternoon over the foothills and plains of central/eastern CO. Other more isolated storms are expected farther north across western NE into the Black Hills region. All of these storms will be relatively high-based, posing a risk of damaging wind gusts. Sufficient westerly flow will also aid in a few transient supercells capable of large hail. These storms may persist into the evening, tracking into central NE before weakening.
MO/AR
Clear skies are evident this morning across central/southern MO and much of AR. Hot and humid conditions will ensue with temperatures reaching the upper 90s. Most CAM solutions suggest widely scattered afternoon thunderstorm development in this environment of steep low-level lapse rates and 1500-2000 J/kg of MLCAPE. The strongest storms will be capable of locally damaging wind gusts.