textproduct: Paducah

KEY MESSAGES

- Breezy south winds and lots of sun will allow temperatures to climb into the upper 80s and possibly lower 90s throughout the Quad State region Monday and Tuesday. Mild lows in the 60s and 70s are expected.

- A 40-70% chance of thunderstorms returns to the forecast Monday afternoon, with the best chances over southeast Missouri and southern Illinois. A few severe storms with a damaging wind and large hail threat are expected, especially across southern Illinois.

- More widespread showers and thunderstorms are expected Tuesday afternoon and night. At this time, severe storms cannot be ruled out, but locally heavy rainfall will definitely be a concern through the period.

- Cooler conditions with daily chances of showers and thunderstorms are expected for the end of the work week and the beginning of the Memorial Day weekend. It looks like it will be warming up through the holiday weekend, with daily chances of storms.

DISCUSSION

Issued at 150 PM CDT Sun May 17 2026

An elevated mixed layer has overspread the Quad State, leading to a warm and dry day. The humidity has taken the day off over west Kentucky and southwest Indiana where dewpoints have mixed down well into the 50s. The targeted Lake Wind Advisory looks good for today, and will likely be needed again Monday and possibly Tuesday.

The cap is likely to hold through much of Monday, despite some models generating some QPF over various parts of the Quad State. However, there is a strong signal for an MCS to reach the I-64 corridor in southern Illinois around 21Z, and the strong south winds running into its outflow boundary should allow it to develop southward into southern Illinois and southwest Indiana.

Moderate to strong instability is expected ahead of the storm complex, and shear will be healthy, too, so severe storms are a decent bet, per the Slight Risk from SPC. Given the instability, large hail will be a concern, but the 0-3km shear vector will be from the southwest, so development into our region will likely be upshear, which is not good for maintaining an intense squall line and damaging wind threat. Of course, there is already plenty of uncertainty just in getting the MCS here in the first place, so this is all very conditional. Subsequent changes to the expected path and timing of the MCS could change the severe outlook across the Quad State. If the MCS makes it and we are looking at upshear development, the slower progression southward could lead to a heavy rainfall and flash flooding threat given the highly anomalous precipitable water values expected.

Another MCS from storms that formed on the cold front will likely approach the area late Monday night, and should be weakening significantly. The remnant outflow is likely to be a focus for thunderstorm development in southeast Missouri and southern Illinois possibly before noon. Of course there could also be development on the cold front approaching from the northwest. The environment ahead of the boundaries over the Quad State should be at least moderately unstable, but the wind fields seem to be quite muddled which gives pause for organized severe potential. The precipitable water values Tuesday will be in the 90th percentile of climatology or higher, so heavy rainfall and possibly flash flooding may be a bigger concern Tuesday and Tuesday night.

The trend in guidance is to have the cold front through the entire area by early Wednesday, so temperatures will drop to normal levels or below for Wednesday through Friday. We will remain in southwest or west southwest flow aloft with plenty of disturbances in that flow streaming over the Quad State. This will result in daily chances of mainly afternoon showers and thunderstorms. There could be some steep mid-level lapse rates, so some elevated hail storms cannot be ruled out.

Looking ahead to the Memorial Day weekend, temperatures will be warming up to normal and above through the weekend, and diurnal thunderstorms are a decent bet.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1225 PM CDT Sun May 17 2026

South winds will gust 18-26kts this afternoon, with the strongest winds expected at KMVN. There is a small chance of low MVFR or even IFR ceilings in the morning, but confidence is much too low to mention in the forecast. An isolated shower or thunderstorm could impact any site by the end of the forecast. South winds will increase again in the morning and gust similar to this afternoon.

PAH WATCHES/WARNINGS/ADVISORIES

IL...Lake Wind Advisory until 7 PM CDT this evening for ILZ075-081- 085. MO...Lake Wind Advisory until 7 PM CDT this evening for MOZ100. IN...None. KY...None.