The National Weather Service has issued a Tornado Watch until 7:00 pm for western Kentucky. The watch is part of a larger advisory from NWS that includes the 22 Kentucky Counties as well as 7 Arkansas Counties, 19 Illinois Counties, 20 Missouri Counties, 6 Indiana Counties, and 9 Tennessee Counties.
The Watch was issued ahead of a line of storms that the Storm Prediction Center in Norman, Oklahoma is forecasting will develop over parts of the Mid-Mississippi and Ohio Valleys into Michigan through early Sunday night. The areas most likely to experience the strong, long-track tornadoes includes Northern and Western Kentucky.
A potent jet stream disturbance with wind speeds in excess of 120 knots will sweep east across the central Plains today and across the Ohio Valley and northern half of the Appalachians tonight. As this occurs, a surface low now over the mid-Mississippi Valley will rapidly intensify and accelerate northeastward, reaching northern Michigan early tonight and western Quebec Monday morning.
East of the low, increasingly warm and humid air at the surface will spread north across the Tennessee and Ohio Valleys, contributing to very unstable conditions over a large part of the east central United States. Coupled with daytime heating and ascent provided the jet stream impulse, the environment will become very favorable for severe thunderstorms, especially along and ahead of fast-moving cold front trailing southward from the low into the mid-Mississippi and Ohio Valleys.
Given the degree of thermodynamic instability, and the strength and character of the winds through the depth of the atmosphere, many of the storms will become supercells. Some of these will be capable of producing strong tornadoes, in addition to large hail and swaths of damaging surface winds.
The storms are expected to consolidate into one or two extensive lines later today into tonight, extending the threat for damaging winds and isolated tornadoes eastward into the Appalachians by early Monday.
State and local emergency managers are monitoring this potentially very dangerous situation.
The National Weather Service has also issued a Wind Advisory for the entire area until 5:00 pm Sunday evening. South winds will increase during the daytime hours Sunday as the weather front approaches, with the strongest winds and the highest gusts occurring from midday until the cold front passes late this afternoon. South winds will average 20 to 30 mph with gusts to 40 to 50 mph at times. These winds will not be associated with thunderstorms or precipitation.
Officials say winds of this magnitude can make driving difficult, especially for high profile vehicles as well as small crafts on rivers or lakes with treacherous waves. The winds are expected to shift to the west or northwest behind the front late this afternoon and at that time will be substantially weaker than the south winds ahead of the front.