textproduct: Topeka

KEY MESSAGES

- Widely scattered showers are possible again this afternoon.

- Temperatures should trend warmer through Monday. Afternoon heat indices are forecast to be around 105 degrees Monday.

- A slight cool down is expected by the middle of next week with a chance for showers and storms late Wednesday and Thursday morning.

DISCUSSION

Issued at 223 AM CDT Sat Jul 18 2026

07Z water vapor imagery showed little change to the overall pattern. An upper low remained over west TX under a broad upper ridge over the central plains as the mean westerlies stayed well north of the forecast area. The surface pattern with high pressure over the southern MS river valley and low pressure along the lee of the central Rockies maintained southerly low level flow and humid conditions.

With no real change in the pattern or airmass, there isn't a lot of change to the forecast. So a moist and conditionally unstable airmass remains across the forecast area. And the latest RAP and NAM progs show a weakness in the upper ridge over northeast KS in the form of a weak shear or deformation axis. A general lack of or only weak subsidence is not expected to be enough to prevent the diurnally driven showers once again. Have included some 20 to 30 percent chance POPs for isolated to scattered showers from midday through the afternoon.

The upper ridge is still forecast to strengthen through Monday, but the better height rises look to stay across the Rockies. This has caused the blend to pull back slightly on highs for Sunday and Monday. But the 00Z operational solutions still support highs in the upper 90s and around 100 for Monday. So have kept the forecast close to what it has been the last couple days. Then focus shifts to the dewpoint forecast where the NBM is mixing out the moisture on Monday with dewpoints falling into the lower 60s. With a south and southeast wind, this seems to optimistic and may be a result of the GFS influence and a lack of short term guidance. So kept dewpoints a little closer the the seventy fifth percentile given the pattern. All of this to say heat indices are expected to hit triple digits with values up to 103 degrees for Sunday afternoon and around 105 degrees Monday afternoon.

For Tuesday and beyond, models continue to show the upper ridge shifting to the southern plains. Cluster analysis points to continued uncertainty in the amplitude of the upper ridge/trough pattern over North America. This potentially has a greater impact on temps as a more amplified pattern could allow stronger surface ridging to hang on. However a less amplified pattern may allow warm air to advect north quicker. All of this points to greater spreads in temps and the potential for some fluctuation in the forecast through the end of the workweek. There remains reasonable confidence in a slight cool down by Wednesday as a frontal boundary move south on Tuesday. The pattern should also allow for potential perturbations to affect the forecast area and operational solutions continue to point to some shortwave energy rounding the upper ridge Wednesday night and Thursday morning. Chance POPs look reasonable for this time period.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 555 AM CDT Sat Jul 18 2026

An uncapped airmass with some weak deformation aloft is expected to allow for widely scattered SHRA to develop this afternoon. Outside of the SHRA, VFR conditions should prevail with just some temporary MVFR conditions if precip moves over the terminals. Predictability of location and timing remains low given a lack of surface feature to focus convection. So will just keep a PROB30 group which has some support from the MOS guidance.

TOP WATCHES/WARNINGS/ADVISORIES

None.