textproduct: Topeka

KEY MESSAGES

- Storms expected (50-90% chance) to develop across the area this afternoon and into the evening. Severe storms are probable with large hail, damaging winds, and a tornado or two all possible.

- Elevated fire danger this weekend across north central Kansas.

- Low temperatures in the 30s could support frost/freeze headlines Saturday and Sunday morning.

DISCUSSION

Issued at 232 AM CDT Fri Apr 17 2026

Southwest flow aloft exists across the Plains early this morning ahead of a trough currently over the Intermountain West. A 994mb surface low over southwestern Nebraska has kept a tight pressure gradient overnight, allowing the boundary layer to remain mixed which has held temperatures in the 60s. As the western trough ejects towards the Plains through the day, a strong cold front will dive southeast across the area. Forcing along the front and from the approaching wave will be sufficient to generate thunderstorms by early afternoon as the capping inversion erodes. Guidance still varies in exact location of the front when convection is likely to initially develop. The most likely timeframe for convective initiation is between 1-3 PM along and east of a line from Seneca to Council Grove. Storms may form as far west as Marysville to Abilene if the front is slower and/or storms develop earlier. Regardless of timing and exact location, the severe parameter space will be very conducive to severe storms, featuring 3000-3500 J/kg of SBCAPE and effective shear of around 50kts. Initially discrete storms will have the best potential at producing all hazards including very large hail (2-2.5" in diameter), damaging wind gusts (60-70 MPH), and a tornado or two. Given the forcing along the boundary, upscale growth into a linear complex of storms is likely to occur, transitioning hazards to mainly a damaging wind threat. 0-3km shear vectors of 30-35kts from the west would support mesovorticies forming along the leading edge of a line of storms as well. There have been some indications from CAMs in a few isolated storms developing ahead of the cold front. This signal has been inconsistent leading to lower confidence in this scenario occurring, but any storms that do form ahead of the front could be able to remain discrete supercells for longer and have an increased risk for very large hail and a tornado. There is also some potential for several rounds of storms producing heavy rainfall across east-central Kansas. HREF members suggest some spots could see 1-4 inches of rain with the better signal for heavy rainfall farther east and southeast. Considered a Flood Watch for areas along and south of I-35, but will hold off for now given lower confidence in widespread flooding issues. Will see if subsequent model runs suggest a higher flooding potential.

There are a couple of things to note from an environmental standpoint for this afternoon and evening. Firstly, forecast hodographs from some models show a weakness in the 1-4km layer, which may prevent storms from reaching their peak intensity and limit the upper-end severe potential. Secondly, low-level hodographs do depict some curvature in the lowest 1km, but become rather straight above this layer. This could still result in tornadoes, but may require interactions with other storms or mesoscale boundaries to achieve enough streamwise vorticity for tornadogenesis.

Storms exit the area tonight with breezy north winds ushering in much cooler air. Lows tonight will fall into the 30s for most, including some near-freezing temps near the KS/NE stateline. A Frost Advisory and/or a Freeze Warning may be needed. Sunny skies dominate the day Saturday, but highs will be much cooler than recent days, topping out in the low 60s. There is a very low chance (<10%) for some high-based showers Saturday afternoon, but think dry conditions are likely to hold. Surface high pressure moves overhead for Saturday night with light winds and clear skies allowing temperatures to be a few degrees cooler than tonight. Again, frost/freeze headlines may be needed.

Southwesterly surface winds will bump temperatures back into the 70s on Sunday before mid-level ridging advances east across the Central and Southern Plains by Monday. Expect warming temperatures Monday through the middle of next week. Guidance differs in the progression of the next western trough, but the approach of this trough brings increased precipitation chances by Wednesday-Thursday.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1234 AM CDT Fri Apr 17 2026

Gusty south winds persist overnight and are expected to mitigate LLWS concerns, but increasing winds with height and gradually veering direction will likely lead to low-level turbulence. Chances for MVFR cigs overnight and into Friday morning have lowered, so have removed mention from TAF. A cold front will spark thunderstorms between 18-20z with some uncertainty in exactly where these storms form. Storms are most likely to develop east of KMHK, but could impact KTOP/KFOE for a few hours before pushing southeast of these terminals. Winds become northerly and remain gusty behind the boundary Friday evening.

FIRE WEATHER

Issued at 232 AM CDT Fri Apr 17 2026

A dry airmass builds in behind today's front, leading to elevated fire danger across north-central Kansas this weekend. For Saturday, northwest winds sustained at 10-15 MPH with gusts of 20-25 MPH are expected as relative humidity values fall to 15-20 percent. Winds are lighter on Sunday (5-15 MPH), but do become southwesterly and lead to warmer temperatures and slightly lower relative humidity. Green-up has progressed enough to limit fire danger for the majority of the area with the exception of Cloud and Ottawa Counties which have not received much rain over the past 30 days.

TOP WATCHES/WARNINGS/ADVISORIES

None.