textproduct: Topeka

KEY MESSAGES

- A hot and humid airmass is expected to stick around this weekend and could break some records for highs and warm lows.

- The heat and humidity will bring a potential for severe storms each afternoon. Although thunderstorm development is not guaranteed. If you have outdoor plans, be sure to check the latest forecast.

- Monday is setting up to have the greatest risk for severe storms that could be capable of tornadoes. Be weather aware on Monday!

DISCUSSION

Issued at 230 PM CDT Fri May 15 2026

19Z water vapor imagery showed the mean westerlies across the northern tier of the country with an upper low north of MN and another north of WA. This pattern favored a more zonal flow over the central plains with little evidence of shortwave energy immediately upstream. Surface obs placed an area of low pressure of the OK/TX panhandles with an inverted trough extending north through north central KS and into eastern NEB. The 18Z RAOB from Topeka showed there was still a substantial CAP to any surface parcels.

Severe potential for this evening looks to be tied to convection developing over southeast NEB along the inverted trough axis. There is a moderately unstable airmass over the forecast area with latest SPC analysis showing around 3000 J/kg of MUCAPE. The strong inhibition noted on the 18Z sounding is forecast to weaken as the airmass continues to heat up through 6pm but not completely go away. So with the lack of shortwave energy noted in water vapor, it may be the convergence along the boundary that sets off convection. Bulk shear is pretty modest at around 30KT. This suggests that if storms form near the state line they may be quick to merge with nearby storms with mainly a wind and hail risk. Latest CAMs have trended towards keeping much of the convective activity north of the state line though, and after about 9pm the inhibition is forecast to increase as the boundary layer begins to stabilize. So there may be a small window from 7 to 11pm when storms may pose a threat. Overnight there is an increasing signal for an MCS to move out of eastern NEB and IA. With the low level jet veering to the west southwest, the track of any MCS is more likely to be into MO. So there is a risk for severe storms this evening, but latest analysis points to the risk being relatively small.

Saturday and Sunday are expected to be similar setups to today with a hot and humid airmass providing plentiful instability for storms, but with the better dynamics remaining mainly west of the forecast area and some modest inhibition through peak heating. This would create a conditional risk for severe weather tied to whether storms can develop. One thing to keep an eye on is the GFS wanting to surge the dryline into north central KS Sunday afternoon. This could provide a focus for storm formation during the late afternoon and evening.

Monday is shaping up to the the most dangerous day of the next several with models in reasonable agreement bringing a shortwave out of the southern Rockies with a slight negative tilt to it. This is progged to force a cold front into a very unstable environment with a very good wind profile for supercell storms. If storms can remain discrete there will be a real risk for tornadoes. 12Z NAM/GFS want to erode any inhibition away early in the afternoon with storms blowing up along the boundary by mid afternoon. Will have to wait to get a better idea of storm mode for Monday, but the combination of instability, lift and forcing are enough that everyone will need to be alert to the weather Monday.

The 12Z model guidance is in pretty good agreement with the synoptic pattern through Tuesday and show the frontal boundary exiting the forecast area Tuesday morning. This should shift any severe risk to the southeast of the area for Tuesday afternoon. The NBM shows small spreads in temps through Monday and the 12Z operational progs of 925 and 850MB temps support the initialization from the NBM, so have not changed the temp forecast much. There is good confidence in a hot and humid airmass sticking around through the weekend. Tuesday and Wednesday should see a break from the heat and storms chances as surface ridging moves through the plains. There are some slight chance POPs in the forecast for Thursday and Friday as southerly return flow redevelops. This is a low confidence forecast since models don't really show strong shortwave activity or a strong surge of low level moisture to destabilize the atmosphere.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1243 AM CDT Sat May 16 2026

VFR through the period. FEW to SCT low clouds form into the afternoon with daytime mixing. Southerly winds increase through the period with gusts to around 25 kt by late afternoon. Shower and thunderstorm potential exists but remains too low for inclusion at this time.

CLIMATE

Issued at 1245 AM CDT Sat May 16 2026

Record High Temperature for May 16

Record (Year) Forecast Topeka 95 (1931) 91 Concordia 93 (2019) 93

Record High Temperature for May 17

Record (Year) Forecast Topeka 92 (1907) 90 Concordia 96 (1996) 98

Record Highest Low Temperature for May 17

Record (Year) Forecast Topeka 73 (1996) 67 Concordia 68 (1902, 1906) 66

Record High Temperature for May 18

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

Record Highest Low Temperature for May 18

Record (Year) Forecast Topeka 71 (1911) 70 Concordia 72 (1911) 67

TOP WATCHES/WARNINGS/ADVISORIES

None.