textproduct: Topeka

KEY MESSAGES

- Hot conditions are expected to continue through Saturday. An Excessive Heat Warning remains in effect through Saturday.

- Isolated showers and storms could develop this evening. Better chances for storms are forecast Saturday night.

- A break from the heat is forecast for Sunday and Monday with highs mainly in the 80s.

DISCUSSION

Issued at 230 PM CDT Fri Aug 14 2026

19Z water vapor imagery showed a shortwave lifting through the middle MO river valley while the longwave upper trough remained over the Pacific Northwest. Surface obs showed an inverted surface trough bisecting the forecast area with CNK showing a northeast wind and FOE with a southeast wind. Cloud cover and limited mixing of the boundary layer has kept temps in the 80s and lower 90s so far today.

Models show the airmass over the forecast area remains conditionally unstable with MU CAPE values 3000 J/kg. But think some subsidence on the back side of the shortwave over eastern NEB has limited vertical motion so far this afternoon with some modest inhibition for a surface parcel. Think there are a couple mesoscale features to watch for that could spark convection. The first would be continued destabilization along the surface boundary and weak convergence. As the shortwave continues to move east subsidence will weaken. Mid level lapse rates remain steep at around 8 C/km and forecast sounding prog around 1200 J/kg of downdraft CAPE. Meanwhile overall bulk shear is progged to weaken. So for the late afternoon and early evening there could be a pulse storm or two develop mainly along the surface boundary. Damaging winds could occur with a collapsing thunderstorms, and with precipital water values near 2 inches torrential rainfall will remain possible. The second mesoscale feature to keep an eye on is the potential for a convectively induced vort max lifting out of the high plains late tonight. Already seeing convection developing over CO and models show a compact vort max lifting through north central KS towards sunrise Saturday. There should be quite a bit more inhibition with any shower activity being well elevated. Bulk shear is expected to be week overnight, so again pulse storms could bring some brief heavy rainfall. Lows tonight are forecast to fall into the middle and upper 70s for most locations.

For Saturday models show the upper ridge sliding south with the surface boundary remaining in the area. Have held onto some slight chance POPs across north central KS through the morning thinking that elevated shower activity may be able to linger similar to the past couple days. Confidence in the temp forecast is below normal as some of the short term guidance is coming in with a more southerly position to the surface boundary. This brings into question the heat warning. Think that some of the northern counties may struggle to reach the 105 heat index. But if it clears out and we get a southerly wind we may still see heat indices of 105 to 110 for areas along and south of the KS river. So have opted to leave the excessive heat warning as is. Models show improving storm chances Saturday night, and given the pattern over the last several days it is hard to argue with. The central plains should be under more of the westerlies and the persistent nocturnal convection seen to the north of the area the last couple nights will have a better opportunity to develop over northern KS. So have stuck with the likely POPs across the northern counties that the NBM has.

There is pretty good agreement from the operational models and ensembles for there to be a break from the excessive heat Sunday and Monday. The good news is highs look to be in the 80s. The bad news is the humidity doesn't look that much better with dewpoints expected to still be around 70 degrees on Monday. Shortwave energy within northwest flow aloft is progged to bring chances for shower and storms to the area Wednesday. By the end of the forecast period, the consensus from the ensembles is for the upper ridge to redevelop over the Rockies. There is a lot more spread in the ensembles (around 15 degrees between the twenty fifth and seventy fifth percentiles) overall for Thursday and Friday, so haven't made any changes to the forecast from WPC/NBM. I would anticipate adjustments to the forecast temps for the back half of next week. Overall the signal from the ensembles is for scattered precip chances that lines up with climatology.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1157 AM CDT Fri Aug 14 2026

There are differences in the models in when the weak boundary moves south overnight with some potential for MVFR CIGS north of the boundary. The majority of solutions tend to keep it north of the terminals through Saturday morning. So will keep a VFR forecast going. CAMs continue to show SHRA coverage being isolated or widely scattered. Confidence in impact to the terminal is to low to include in the forecast for now.

TOP WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning until 7 PM CDT Saturday for KSZ020-KSZ021- KSZ022-KSZ023-KSZ024-KSZ026-KSZ034-KSZ035-KSZ036-KSZ037-KSZ038- KSZ039-KSZ040-KSZ054-KSZ055-KSZ056-KSZ058-KSZ059.