textproduct: Paducah

KEY MESSAGES

- Daily chances of showers and thunderstorms will persist into the weekend. A stronger gusty storm cannot be ruled out on Saturday, especially in the northeast across southwest Indiana.

- Hot and humid conditions will continue into next week with heat index values peaking nearing 105 degrees on Tuesday, with relief from the heat arriving Wednesday.

- Any sustained northerly flow (the best chance of which is Wednesday behind the cold front) could bring in unhealthy air quality conditions due to the Northwestern Ontario wildfire smoke.

UPDATE

Issued at 637 AM CDT Fri Jul 17 2026

Updated the aviation section for the 12Z TAF issuance.

DISCUSSION

Issued at 242 AM CDT Fri Jul 17 2026

Broad upper-level ridging remains across most of the country today. Calm winds and yesterday's rain will result in some fog formation early this morning. Remnants of a weak disturbance, along with plenty of moisture (PWs near 2 inches) will help produce scattered showers and thunderstorms today, mainly in the afternoon. Some nuisance flooding is possible with slow moving storms. Higher chances are located near the Evansville Tri-State as a front is positioned NW to SE across Indiana. MLCAPE values peak around 2000-2500J/kg, with shear of 15-20kts holding back severe weather.

Tomorrow, in addition to the peak heating afternoon convective potential, there is also a late evening-overnight frontal passage. An SPC slight risk extends through Central Indiana for this front but, with an unfavorable overnight timing, and being far from the low pressure center speeding from the Great Lakes to Quebec, severe weather potential is limited to a marginal risk for straight-line winds for the Evansville Tri-State. Shear and lapse rates will be a little more favorable than today. Troughing digs into the northeast as this system moves through, bringing northwesterly flow aloft through the Quad State. Precip chances are trending higher Sunday as a disturbance moves around the western ridge.

The NBM trends drier early next week with dry to slight chance PoPs Monday and Tuesday. This might be an underestimate Tuesday as low pressure moves through the Great Lakes. Regardless of positioning, northeastern portions would be more favored for rain Tuesday vs southwestern areas. Today through Tuesday, highs slowly tick upward with 90s becoming widespread early next week. Heat indices around 100 rise to 105 on Tuesday. Cooler air arrives Wednesday following the Tuesday/Tuesday night cold front.

One potential issue would be with any sustained northerly flow as massive active wildfires in Canada have produced extremely high PM2.5 concentrations. Currently, PM2.5 readings of 400+ug/m3 are located in northeastern Minnesota, 250-400 in Michigan/Chicago, and 150-300 in OH/PA/NJ, For context, the NAAQS air quality standard for PM2.5 is 35.5 ug/m3 (the threshold level for the Unhealthy for Sensitive Groups category), while unhealthy is 55.5-150.4, very unhealthy is 150.5-250.4, and hazardous is 250.5+. Those traveling north/northeast of the Quad State should check air quality information and take precautions, especially if you have a health condition that puts you at higher risk.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 637 AM CDT Fri Jul 17 2026

Localized vsby drops should clear up within an hour. Winds become westerly today at 5-8kts. Afternoon showers and storms are forecast, mainly in the east, with MVFR cigs/vsbys accompanying storms. Winds calm in the evening with rain tapering off.

PAH WATCHES/WARNINGS/ADVISORIES

IL...None. MO...None. IN...None. KY...None.