textproduct: Topeka

KEY MESSAGES

- Scattered showers and isolated storms this afternoon/evening and again on Friday.

- Temperatures falling into the 30s tonight supports frost formation across portions of north-central Kansas and along the Kansas-Nebraska stateline. A Frost Advisory has been issued.

- Saturday morning's lows could favor frost formation again.

- Turning warmer Sunday with increasing precipitation chances next week.

DISCUSSION

Issued at 150 PM CDT Thu Apr 30 2026

Zonal flow continues across the Central Plains today with a closed low near the Great Lakes and another moving into Baja California. A shortwave moving through the flow has pushed a weak surface front into the area. This boundary may serve as a focus for showers and a few storms to develop this afternoon and evening. Instability and shear are weak, so not expecting any strong storms and this activity will wane through the evening as the shortwave and front push south of the area. Surface high pressure moves in tonight with clearing skies and light winds allowing temperatures to fall into the mid to upper 30s. Passing clouds may keep lows a degree or two warmer than forecast, but NBM has a 60-90% chance of temperatures falling to at least 36 degrees across portions of north central Kansas and areas along the Kansas-Nebraska stateline. Frost formation appears most likely in this area, so have issued a Frost Advisory for tonight into Friday morning.

Friday will be almost a carbon-copy of today with a stronger shortwave and weak front sparking some showers or isolated storms. A second surface high builds in Friday night into Saturday morning with slightly cooler airmass resulting in a more favorable frost scenario. A Frost Advisory may be needed, especially north of Interstate 70. Saturday looks dry, but cool again with highs in the 60s before shortwave mid-level ridging moves overhead for Sunday. Increased southwesterly winds will boost temperatures into the low 80s Sunday afternoon. Yet another shortwave/surface front combo is progged to move through Sunday night into Monday which could generate some light precipitation. Highs Monday may trend cooler than forecast if the front pushes south and clouds hold through the day. There is still some uncertainty into the middle of next week in how the energy diving south out of Canada interacts with the aforementioned closed low over Baja California as it ejects east. The majority of guidance (75%) favors the northern stream wave to dive far enough south to shunt the better moisture and instability into the southern Plains, limiting the severe thunderstorm potential across northeast Kansas. The other 25% of guidance has the southern stream wave a bit farther north with the better shear/instability environment still in northeast Kansas by Tuesday afternoon. Even with the cooler and less favorable severe environment scenario, the passage of the wave will increase chances for rain Tuesday into Wednesday. The front is likely to be south of the area by Wednesday with decreasing rain chances through the day and highs in the 60s.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 629 PM CDT Thu Apr 30 2026

Reduced visibility due to fog could occur early Friday morning at KTOP, so included a brief mention of IFR visibility. Confidence is not high in how low visibility could get, so updates may be needed. Otherwise, winds turn nearly calm overnight, then increase out of the northwest Friday afternoon. There is a 15 to 20 percent chance for isolated TS again near airports, mainly between 18Z Friday and 00Z Saturday.

TOP WATCHES/WARNINGS/ADVISORIES

Frost Advisory from 1 AM to 8 AM CDT Friday for KSZ008-KSZ009- KSZ010-KSZ011-KSZ020-KSZ021.