textproduct: Topeka

KEY MESSAGES

- Thunderstorms are likely (60-90%) to develop by this evening. Storms could be severe with large hail, damaging winds and torrential rainfall.

- A flood watch is posted for tonight into Wednesday morning across east central KS. This watch may need to be extended into Thursday for additional rainfall.

- Cooler weather is forecast to move in by Friday. Be on the lookout for some frost Saturday morning.

DISCUSSION

Issued at 240 AM CDT Tue Oct 13 2026

A closed upper low was noted over NV per the 07Z water vapor imagery. Over the plains, southwest flow persisted between a broad upper ridge along the TX/LA gulf coasts. Surface obs placed a low over east central CO with a cold front extending east through the state. Better moisture return through the southern plains was also seen as middle 70s dewpoints were almost to the Red River.

Continued moisture advection into the surface front across the forecast area should allow the boundary layer to become moderately unstable with MUCAPE values between 2000 and 3000 J/kg. On top of that stronger southwesterly upper flow over the boundary should increase bulk shear values to around 50KT. So there looks to be the potential for severe storms developing along the boundary late this afternoon. Most guidance shows low level flow veered to the southwest for much of the day. But towards 00Z the 850 winds are progged to back more to the south. This increased convergence along the boundary should be what helps convection to initiate and last into the early morning hours. The bulk shear will be supportive of supercell structure with the storms. So large hail and damaging winds will be a concern. The tornado risk still looks conditional on the local wind fields along of the boundary.

Abnormally high moisture content is forecast ahead of the boundary with PWs around 2 inches. This would be a record value for 00Z/14 and a couple standard deviations above the mean. So thunderstorms are expected to be efficient rainfall producers with rates around 2 inches per hour realistic. Overall for the entire event through Thursday, blends and ensembles are showing increasing probabilities for exceeding 2 and 3 inches of rain across east central KS. With how unusually moist the airmass is, felt it prudent to go with a flood watch for east central KS. After collaboration the higher confidence in heavy rain was for tonight. So the watch has been posted into Wednesday morning. But if models continue to show another slug of moisture lifting into eastern KS with the upper wave Wednesday night and Thursday, the watch may need to be extended into the day Thursday. Other changes to the NBM was to lower high temps for today and Wednesday. For some reason the blend doesn't resolve the surface front very well and has temps in the lower and middle 90s through the NEB state line. Based on the shorter term models keeping the boundary across the forecast area through the day, blended in some CONSRaw and CONSShort for highs today to show a stronger gradient in temps north to south. For Wednesday there is a good signal for stratus to setup over the area as north and northeast wind provide some weak cool air advection. But the limited insolation alone should be enough to hold temps in the 60s for Wednesday.

The better synoptic scale forcing is forecast to impact the area late Wednesday night and Thursday as the upper low begins to phase in with the northern stream. Because of it phasing with the northern stream, we shouldn't see a negatively tilted wave lift over the forecast area. But there does look to be enough PVA for a surface wave to lift through eastern KS Thursday. A warm conveyor belt is progged to bring good moisture advection back into eastern KS. So have continued with the categorical POPs from the NBM. Eventually the wave should push east of the area Thursday evening. Strong northwest flow aloft is expected to help bring a Canadian surface high into the plains with some of the coolest temps so far this fall. A classic radiational setup for Saturday morning, with light winds and clear skies, could help temps drop into the middle 30s and allow for some frost to develop. The GFS and ECMWF show a low amplitude wave lifting across the forecast area Sunday night. So can't argue with the NBM's slight chance POPs inserted into the forecast. Although confidence in the smaller scale details typically isn't that high for day 6 and 7.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 550 AM CDT Tue Oct 13 2026

It appears based on latest satellite the models have overdone the MVFR CIGS for this morning. So will keep a VFR forecast into the afternoon. Latest CAMs support the timing for TS currently in the forecast so will only make some minor tweaks. As the front surges south overnight, MVFR and possibly IFR CIGS become more likely and there is reasonable agreement from the models with the low clouds.

CLIMATE

Issued at 230 PM CDT Mon Oct 12 2026

Record High Temperature Information:

October 13 Current Record Forecast -------------------------------------------------- Topeka 91, set in 1975 89 Concordia 90, set in 1975 71

Record Warmest Minimum Temperature Information: Note, the lowest temperatures for each date will likely occur around midnight CST.

October 13 Current Record Forecast -------------------------------------------------- Topeka 69, set in 1962, 68, 75 67 Concordia 70, set in 1920 59

TOP WATCHES/WARNINGS/ADVISORIES

Flood Watch from 5 PM CDT this afternoon through Wednesday morning for KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056-KSZ058-KSZ059.