textproduct: Topeka

KEY MESSAGES

- Hot and humid conditions will continue to provide a chance for thunderstorms tonight through Monday night.

- There is a risk for severe weather each day through Monday night. The greatest risk for severe storms including tornadoes looks to be Monday afternoon and Monday night.

- Much cooler weather and a break from showers and storms is forecast to move in Tuesday.

DISCUSSION

Issued at 228 PM CDT Sat May 16 2026

19Z water vapor imagery showed an upper trough over the Northern Rockies and Pacific Northwest with southwest upper flow over the central plains. Surface obs had an area of low pressure still over the OK/TX panhandles with an inverted trough through central KS and into southeast NEB. A moist and hot airmass had developed south of this boundary with dewpoints in the middle and upper 60s.

This afternoon and tonight: There still isn't much of a shortwave to force convection and the 18Z Topeka RAOB showed stout inhibition was still in place. But continued heating of the moist boundary layer into the lower 90s is expected to reduce inhibition for deep moist convection to near zero between 5 and 7 pm. As a result convergence along the weak boundary across far northern KS should act as a focus for convective development. MUCAPE values are expected to be between 2500 and 4000 J/kg but 0-6km bulk shear looks to be light at 30KT or less across much of the forecast area. This may make it difficult for updrafts to sustain themselves pointing towards a wind threat. Better shear to the north may support some risk for hail. CAMs have shown some consistency with isolated storms developing north of I-70 between 6 and 8pm and lifting into NEB through the early evening. Overnight models show an MCS forming off the high plains and propagating east. This makes sense with a 40-50KT low level jet feeding high theta-e air into the boundary. The question is how far south will the MCS go. The models tend to pool the higher boundary layer moisture along and north of the KS/NEB state line and the CAMs seem to want to keep the bowing segment north in the deeper moisture. But I am hesitant to buy completely into that idea with the nose of the low level jet providing lift over north central and northeast KS. With the 12Z ARW showing convection moving along the 36 highway corridor, have kept some likely POPs going into the early morning hours. By the time this moves through, straight line winds will likely be the greatest concern.

Sunday: There is a fair bit more uncertainty in how things evolve on Sunday with models showing various ideas. The NAM and RAP strengthen the mid level cap while the GFS brings some cooler mid level temps in at 700MB. An then is there any remnant outflow from tonight's storms. With the moderately unstable airmass still in place across the forecast area am not sure I agree with the RAP and NAM in no convection developing off the dry line. Then again there isn't a lot of support from the CAMs for the GFS idea. So have some 30-40 percent chance POPs for the western counties by the late afternoon. Instability east of the dryline should be more than enough for convective initiation, but again deep layer shear is progged to be relatively weak. So the main concerns would be large hail and damaging winds.

There is pretty good agreement from the models for a strengthening pressure gradient on Sunday. The gradient looks strong enough for sustained winds around 30 mph and gusts up to 45 mph so have gone ahead and issued a wind advisory for much of the area.

Monday: There is good consensus in the synoptic pattern among the models with a shortwave lifting over the triple point across central KS by the late afternoon. With moderate to strong instability and improving wind profiles developing, supercell storms are forecast to form along the dryline and warm front. Discrete storms will be capable of tornadoes but I am wondering if the forcing is strong enough that convection fills in along the boundaries. We'll be looking at storm modes more closely as the event starts to get into the time frame of the CAMs. Am comfortable with the categorical POPs from the NBM as models have been consistent for several days now with storms along the front as it pushes east and southeast Monday night.

Tuesday and beyond: Have not made any chances to the mid-range forecast as the NBM seems to have a reasonable handle on the overall pattern. Surface ridging is forecast to move over the plains Tuesday and Wednesday. This should shift POPs south of the forecast area with noticeably cooler temperatures forecast. The 00Z guidance was a little slower in developing return flow on the back side of the surface ridge. The 12Z ECMWF has southerly low level flow by Friday which should help temps warm back into the 70s and 80s for the end of the forecast. The NBM has some slight chance POPs in the forecast for Thursday through Saturday. It's hard to find a strong reason for or against the slight chance POPs and there maybe some shortwave energy impacting the central plains by the end of the forecast period.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 545 PM CDT Sat May 16 2026

VFR conditions expected. Chances for storms near terminals is too low to include in TAF. KMHK has a slightly higher chance for nearby storms, but chances remain around 20%. Gusts are expected to subside after sunset this evening which could lead to a period of LLWS overnight, but conditions appear too marginal. Winds increase from the south after sunrise Sunday, gusting at 25-35kts through the day. There remains a signal for some high- end MVFR cigs early Sunday at KTOP/KFOE, but think the probability is low enough to keep out of TAF.

CLIMATE

Issued at 228 PM CDT Sat May 16 2026

Record High Temperature

Sunday May 17 Record (Year) Forecast Topeka 92 (1907) 89 Concordia 96 (1996) 96

Monday May 18 Record (Year) Forecast Topeka 94 (1975) 91 Concordia 94 (1967, 1988) 91

Record Warm Low Temperature

Sunday May 17 Record (Year) Forecast Topeka 73 (1996) 69 Concordia 68 (1902, 1906) 67

Monday May 18 Record (Year) Forecast Topeka 71 (1911) 70 Concordia 72 (1911) 66

TOP WATCHES/WARNINGS/ADVISORIES

Wind Advisory from 9 AM to 9 PM CDT Sunday for KSZ008-KSZ009- KSZ010-KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ034- KSZ035-KSZ036-KSZ037-KSZ038-KSZ039-KSZ054-KSZ055-KSZ058.