textproduct: Topeka

KEY MESSAGES

- Storms redevelop this evening into the overnight, mainly along and south of Interstate 70. A few elevated supercells are possible with hail around quarter size and gusty winds.

- Locally heavy rainfall is the greater concern across east- central Kansas, where storms may train over the same areas that saw the heaviest rain last night. Cant rule out localized flooding concerns.

- Heat builds this weekend with heat indices near 100-105 degrees. Sunday and Monday look to be the hottest days, though confidence in the magnitude remains limited.

DISCUSSION

Issued at 226 PM CDT Thu Aug 6 2026

Current water vapor imagery and the 12Z upper air analysis keep the area under broad quasi-zonal flow along the southern periphery of the Westerlies and broad cyclonic flow regime across the northern CONUS into Canada, meanwhile the western CONUS anticyclone still anchored near the Four Corners. A slow-moving, modified frontal zone remains draped from south central Kansas into the Ozarks and continues to serve as the focus for convection. Embedded perturbations rounding the base of the broader cyclonic flow provide the only meaningful forcing for ascent, keeping the setup marginal but not negligible.

Attention turns to the overnight period as the LLJ strengthens generally after 03Z and isentropic ascent increases along its nose. Forecast soundings across east-central Kansas show MUCAPE near 2400 J/kg with CIN around 240, which points to elevated storms the likely outcome with the surface layer remaining capped. Hodograph structures tend to be somewhat elongated as the LLJ ramps up which could become supportive of rotating updrafts which may help storms persist allowing for at least quarter size hail as the primary threat. Gusty winds remain possible with the stronger cores but the elevated nature of the storms should limit any widespread wind threat.

The greater concern tonight focuses on locally heavy rainfall mainly across east-central Kansas. If the 850-300mb mean flow remains around 15-20kts with the moisture axis overlapping the area as the LLJ sets up then any training over the previously saturated areas would likely raise the flooding risk quickly. NBM guidance carries the highest QPF across some of the east-central areas into the overnight period around midnight into the early morning hours so these areas bear watching through the overnight hours.

Any lingering light rain exits Friday afternoon as the mid-level ridge expands eastward into the Central Plains. Temperatures climb steadily on Saturday, with highs in the low to mid 90s and dewpoints holding in the low 70s pushing heat indices near 100 degrees Saturday and peaking Sunday into Monday around 105 each day. Air temperatures reaching triple digits appear unlikely based on current trends and datasets, so the heat index remains the primary concern driven by the low level moisture return into the region and local impacts from the microclimate set up by agriculture production still in swing. Uncertainty in the warm forecast comes in the form of the northeastern flank of the ridge overall continuing to flatten with northwest flow displaced just north of the area. Subtle shortwaves within that corridor could produce enough ascent for either cloud cover to be higher than forecast or overnight precipitation to inhibit afternoon heating. The ensemble spreads through the weekend remain wide enough that headlines are premature at publish time for this forecast cycle. Ensembles favor the ridge flattening further by midweek, with a surface front and embedded shortwaves returning better precipitation chances to the area so overall uncertainty in the long range forecast is relatively high.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1239 PM CDT Thu Aug 6 2026

Marginal VFR conditions across the terminals early this afternoon gradually lift to VFR around 20-21Z. Attention then turns to shower and thunderstorm chances arriving overnight. Have carried -SHRA with VCTS as the best overall storm chances set up generally south of the terminals with variability in placement still evident past 12 hours out. The LLJ strengthens overnight but shear remains marginal outside of any thunderstorms, so have held off on any LLWS mention at this time. Trends point to possible IFR conditions as showers and storms exit toward the end of the period, but the best signal for this remains generally north of the terminals so have held cigs at VFR for now with potential for later change. Conditions otherwise improve with winds veering southerly around 10 kts or slightly higher to close the period.

TOP WATCHES/WARNINGS/ADVISORIES

None.