The unsettled pattern in the Midwest will continue with widespread severe storms Tuesday. Ongoing thunderstorms Tuesday morning in parts of the Central US will leave a warm, sticky air mass in their wake that will spawn several additional bouts of thunderstorms throughout the afternoon and overnight into early Wednesday morning. Many of these thunderstorms could become severe, especially over parts of Missouri and Kansas where they are expected to be widespread.
These ongoing storms will be capable of producing damaging winds and possibly hail up to 1 inch in diameter throughout the afternoon in most of Kentucky and Tennessee and southern parts of Illinois, Indiana and Ohio. Scattered storms from this morning will become organize into linear structures by late in the afternoon, by which point the hail risk will lessen.
Further west, a slowly propagating shortwave trough will enhance lift over a hot, soupy air mass with a robust low-level moisture feed from the Gulf of Mexico. South of the upper-low’s center, a warm front will be draped across the southern Plains northeastward into the Midwest. These dual sources of lift will support the development of strong and widespread thunderstorms over much of the Midwest into Tuesday night.
The most widespread severe storms will develop over eastern Kansas and western Missouri. The primary threats here will be powerful straight-line winds and colossal hail. Several rounds of thunderstorms will develop over this area throughout the day, but the most damaging storms will form late in the afternoon through sunset. Additional storms may develop into the overnight hours along the warm frontal boundary but these are not expected to be as severe.
The severity of the storms over eastern Kansas and western Missouri is due to highly favorable environmental conditions. A corridor of vigorous low-level winds on the southern periphery of the upper-level low will result in strong wind shear. In conjunction with extreme instability, this environment will be capable of supporting supercells and multicellular clusters. Hailstones with diameters in excess of 2″ are possible over this area, which could result in significant damage to cities like Springfield and Joplin in Missouri. Golfball-sized hail is possible in cities surrounding this corridor including Kansas City and Wichita. Tornadoes are also possible but will be more likely to the northeast where conditions will be more favorable for their development.
Further north towards the Great Lakes, residual debris from Tuesday morning’s storms will limit the instability that develops in the afternoon. Clearing in the afternoon will trigger more storms associated with lift ahead of the upper-level low and weak surface low. Scattered storms in the afternoon may become supercellular and will join to form clusters by the evening. Damaging straight-line winds are the primary threat with these storms, but some of the supercells will be capable of forming tornadoes.
With a lower ratio of instability to wind shear, tornadoes are most likely to develop over the northern half of Illinois, northeast Missouri, and far eastern Iowa. Cities that may experience a tornado include Springfield, IL, Davenport, IA and the suburbs of Chicago. Lake breezes may thwart the tornado risk in Chicago proper.
The same upper-level low responsible for much of today’s severe storms will continue its trek further east, bringing bouts of showers and thunderstorms to the Northeast Wednesday and Thursday. Rain showers are expected to be widespread, but the storms are not expected to be severe.