textproduct: Topeka

KEY MESSAGES

- Storms are expected to develop across northeast into central KS this afternoon and early evening, some of which could be severe. Large hail, damaging wind, tornadoes, and locally heavy rainfall are all possible.

- A few storms may develop Thursday afternoon southeast of I-35, although that probability is decreasing (20-40%).

- Dry Friday, then turning wet again on Saturday. Temperatures look cooler late this week into early next week.

DISCUSSION

Issued at 248 PM CDT Wed Jun 10 2026

Broad cyclonic flow encompasses the Northern/Central Rockies and Plains early this afternoon. One area of sfc low pressure is noted in southeast CO extending into southwest KS, while another is centered in western MN with a cold front extending into eastern NE. On the mesoscale, there are two main areas to monitor for convective initiation this afternoon. An outflow boundary from morning convection in northern MO may help to focus the first storms in northwest MO and far northeast KS. Additionally, convergence along the sfc trough boundary may help to develop a few storms towards central KS. Our area is right in between these two features. The 18z RAOB had a little bit of MLCIN remaining with not much more surface heating required to erode the cap. SPC mesoanalysis suggests 3000- 3500 J/kg of MLCAPE currently, with models suggesting 4000-4500 J/kg with another hour or two of surface heating. Deep-layer shear is sufficient for supercells as well. One challenge that remains is how long any storms may remain discrete before cell interactions come into play. There is a component of shear vectors that's parallel to the boundaries, but not entirely. More recent HRRR runs have shown better directional shear in the low levels with a more southerly sfc wind compared to earlier, resulting in better low-level shear this afternoon as well. As such, tornadoes will remain a potential threat with any storms as long as they remain discrete. Large hail and damaging wind continue to be the main severe hazards with either supercells or multicell clusters after storms interact with each other. Pwat remains high, so these storms should be efficient rainfall producers with heavy downpours. 12z CAMs and HRRR runs thereafter have been fairly consistent in only isolated areas seeing amounts greater than an inch, and the 90th percentile of the HREF supports this idea as well. With this in mind, would not rule out some localized flooding if a storm stays over the same area for a long time, but think this threat looks too isolated to support a flood watch across a large area.

Storms should diminish towards/after sunset as inhibition increases and the sfc low to our southwest deepens, which pushes the sfc boundaries to our north. A second round of storms is favored to remain north of our area in Nebraska, which is where the better forcing is with the nose of the LLJ and approaching cold front. Heading into Thursday, the frontal boundary moves across the area and has been trending faster. Much of the guidance now has this almost entirely through our area by 21z Thursday. This presents a low probability for storms to develop southeast of I-35 in the afternoon, though some guidance suggests we may miss this round entirely.

Friday brings a drier and cooler air mass, leading to a quieter day with highs in the 80s and sfc high pressure overhead. This is short- lived, however, as southerly low-level flow returns moisture into the area with zonal flow aloft as we sit between ridging to our south and troughing to our north. A mid-level perturbation should trigger another round of showers and storms during the afternoon and evening. The exact area of greatest risk will depend on where the sfc frontal boundary sets up, but will need to monitor once again for flooding concerns with high Pwat and potential for severe weather. The boundary looks to sag south for Sunday, lowering rain chances but still keeping the baroclinic zone close enough to justify some chance PoPs for the area.

Northwest flow aloft takes shape early next week. While rain chances are less certain, this should usher in a much cooler and drier air mass than we've seen recently, bringing highs down into the 70s and dew points in the 50s!

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1220 PM CDT Wed Jun 10 2026

Main concern this TAF period is coverage and timing of TS early this evening. Think there's enough of a signal in the morning CAM guidance to go with prevailing TS at all terminals, but shortened the window a bit from previous issuance. From there, expect southerly winds to pick up again overnight with the increasing low- level wind field. A cold front approaches terminals late in the period, though the wind shift to the NW looks like it might occur just after the current forecast period at Topeka sites.

TOP WATCHES/WARNINGS/ADVISORIES

None.