Area Forecast Discussion

KEY MESSAGES

- A few thunderstorms may develop overnight into early Saturday morning. Large hail, damaging winds, and locally heavy rainfall are the main hazards with any storms that form.

- Higher chances for thunderstorms (60-90%) come Saturday late afternoon through the evening. This brings a greater concern for severe weather and heavy rainfall. Flood Watch has been issued for portions of northeast and east central KS.

- Cooler and drier weather arrives early next week with highs in the 70s and 80s, warming up more by Wednesday.

DISCUSSION

Issued at 254 PM CDT Fri Jun 12 2026

We are within an area of zonal flow aloft as upper ridging has been pushed to the southern tier of the US and troughing covers the northern tier. Surface high pressure has been gradually moving southeast across the region today, leading to tranquil conditions and plenty of sunshine. The change in air mass behind yesterday's front has allowed cooler temperatures and dew points this afternoon, though this won't last long. Southerly return flow develops this evening into tonight, helping to bring a surge of moisture back into the area for Saturday.

In addition to the moisture, isentropic lift increases tonight while embedded shortwaves aloft traverse across the area. While uncertainty remains in coverage, this should allow elevated thunderstorms to form. Confidence is higher towards southwest KS where the LLJ is stronger and should maintain storms, and models have been more consistent in this area as well. For eastern KS into western MO, some of the earlier CAM guidance was more robust in developing scattered convection overnight. The 12Z HRRR and NamNest were particularly aggressive while other CAMs seemed less excited. Even the HRRR has been backing off in more recent runs. As such, confidence is lower in storms developing here, but given the environment in place, this is something we'll need to monitor. Atmospheric profiles suggest 2000-3000 J/kg of MUCAPE along with 35- 40 kts of effective bulk shear, which would support elevated supercells with a risk for large hail or damaging wind. Pwat looks to increase to 1-1.5", which is not quite as high as in recent days, but still pushes the high end of climatology. This would support efficient rainfall with any storms that can develop in this regime. There was enough concern for locally heavy rainfall that in collaboration with neighboring offices, we felt it was a good idea to start the newly issued Flood Watch early enough to cover this time frame, even with the uncertainty in play. (More on the Flood Watch later.)

Heading into Saturday afternoon, the atmosphere is expected to destabilize with further moisture transport, supporting 3000-5000 J/kg of SBCAPE. 12z and 18z HRRR runs have shown mostly veered winds at the surface, but they do appear to back just briefly just before storms develop in far eastern KS, helping to increase deep-layer and low-level shear. As a result, there is a very short window for a tornado risk as storms initially develop along a cold front pushing south, alongside large hail before a wind threat evolves with bowing segments and clusters. These storms should be fairly progressive, but with even higher Pwat (closer to 1.5-2" like we've had recently), this would support heavy rainfall rates conducive to flooding over saturated grounds. If the morning storms indeed occur, this would further exacerbate flooding concerns. 12z model guidance supports a swath of 2-4" rain totals with locally higher amounts possible in parts of east central and northeast KS where the Flood Watch has been issued. The 90th percentile HREF has done a fairly good job recently of capturing the high-end scenarios, which has some of these higher amounts southeast of the KS Turnpike.

Storms should move south of the area late Saturday night, and the front should be south of the area for Sunday. A much cooler and drier air mass is in place, leading to quieter conditions for Sunday and Monday with highs in the 70s and dew points in the 40s and 50s. Northwest flow aloft with weak embedded perturbations may lead to some low-end precipitation chances late in the forecast period, but plenty of time for timing and placement of those to come into focus. Temperatures gradually warm through the first half of next week with highs in the 90s returning by Wednesday.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1213 PM CDT Fri Jun 12 2026

Mostly quiet and VFR conditions are expected with light SSE winds veering a bit to the south late in the period. Main aviation impact to watch will be potential for thunderstorms developing overnight. High-res model solutions vary, so have only gone with a PROB30 mention for Topeka sites for the time being. Confidence further west is even lower, so no mention for MHK yet.

TOP WATCHES / WARNINGS / ADVISORIES

Flood Watch from 1 AM CDT Saturday through Sunday morning for KSZ026-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056-KSZ058-KSZ059.