textproduct: Topeka

KEY MESSAGES

-A slight chance for rain returns tonight. Severe storms are then possible Saturday afternoon and evening.

-Periodic chances for thunderstorms remain in the short-term forecast as a surface boundary meanders north and south in the region.

-Long-range models keep POPs going into at least the middle of next week, but confidence in coverage and timing decreases with time.

DISCUSSION

Issued at 217 PM CDT Fri Sep 11 2026

An expansive surface ridge sits east of the area today and low pressure associated with a mid-level shortwave trough is over South Dakota. Strengthening southerly flow and sunshine will take temperatures into the upper 80s this afternoon. Following a dry forecast today, a slight chance for storms returns late tonight and early Saturday as a cold front associated with the low over SD moves into northern KS. Confidence remains low on coverage of rain with a continued lack of concensus from models. The higher resolution short- term models do not show much in the way of development, while the coarser long-range deterministic models are still showing higher coverage of early morning rain. If storms develop, severe weather is not expected tonight and early Saturday. However, a better chance for severe storms will occur Saturday afternoon and evening near the boundary. Trends from models have been to take the boundary further south throughout the day, so by 00Z Sunday it could be near or just south of I-35. HREF has up to 3000 J/kg of SBCAPE near and south of the front, but depending on which model is analyzed, MLCAPE could approach 4000 J/kg without any lingering rain/cloud cover from the A.M. Deep layer shear of 40 to 50 kts and high DCAPE will support a large hail (up to 2" inches in diameter) and damaging wind (60 to 70 mph) risk with any convection that organizes late in the day. A nocturnal LLJ and some isentropic ascent over the boundary could allow for additional development Saturday night. The chance for severe storms, however, will wane overnight as instability diminishes and shear weakens.

The surface boundary will slowly start to move back northward on Sunday while a mid-level ridge expands over the area from the south. Storms could again focus near the boundary, with the better chances in far northeast KS by the afternoon. Lingering A.M. cloud cover could help limit instability, but if a few storms get going in northeast KS during the afternoon, a few organized updrafts could occur. The warm front will then quickly surge northward on Monday as southerly flow increases through the southern and central Plains. A cap and lack of forcing should keep conditions dry.

The surface front returns yet again on Tuesday as low pressure moves into southwest KS, and eventually toward the OK/TX panhandles. The exact position of the boundary through the area is a bit uncertain still, but it could act as another focus for convection. The NBM keeps POPs high in the 40 to 80 percent range Tuesday and Wednesday morning. This may be a bit overdone, at least in timescale, since various long range models have different ideas of frontal position and associated areas of rain. Without good confidence on where the front will be, determining severe risk is challenging at this range.

Monday looks to be the warmest day of this forecast package with highs approaching the mid 90s. Heat index values could be in the 100 to 103 degree range. Otherwise, highs will generally range from the upper 70s north of the front to the upper 80s south of the front each day.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 556 PM CDT Fri Sep 11 2026

VFR at terminals as southerly winds become light this evening. A weak boundary passes through terminals from 11-13Z with wide variances in models developing sct TSRA. Given the drier air in place and models trending drier, decided to omit precip other than increasing cloud cover. Winds veer to the north near 10 kts aft 17Z with the low probability for widely scattered TSRA developing near the boundary in the late afternoon. Currently model trends set the front south of sites so will keep the dry forecast at this time.

TOP WATCHES/WARNINGS/ADVISORIES

None.