textproduct: Topeka

KEY MESSAGES

- Numerous severe storms are expected late this afternoon over north central Kansas, spreading across northeast Kansas this evening and overnight. Threats include very large hail (2-4+ inches in diameter), Damaging wind gusts to 80 mph, flash flooding, and tornadoes (a few strong).

- A Flood Watch is in effect for all of northeast and north central Kansas where antecedent heavy rainfall has enhanced the threat for flash flooding this evening.

- After cooler and dry conditions Tue. and Wed., storm chances return with the highest being on Thursday. Widespread severe probabilities are low at this time.

DISCUSSION

Issued at 232 AM CDT Mon May 18 2026

Active early Monday morning as a decaying line of slow moving thunderstorms impacts portions of northeast and east central Kansas. Overall threat has shifted to heavy rainfall as hourly rainfall rates of 1 to 2 inches have been observed. Totals have currently ranged from 1 to 5 inches with the highest amounts focused over north central Kansas. As the low level jet wanes, activity is anticipated to dissipate by mid morning, leaving the stratus in place and potentially an outflow boundary in far eastern Kansas to MO. How quickly the atmosphere recovers in eastern Kansas is uncertain, potentially generating scattered severe storms by mid afternoon. Confidence in this scenario is somewhat bolstered by the last few runs of the HRRR/RAP, forming convection south of I-70 and east of I-35. Forecast soundings in vicinity of this outflow boundary exhibit strong low and mid level wind shear and elevated CAPE up to around 3000 J/KG. If this occurs, damaging wind gusts, large hail, and a few tornadoes cannot be ruled out earlier in the afternoon. Overall confidence for the above scenario is low-medium, owning to timing and location inconsistencies of current convection and where the boundary settles by midday.

In terms of the main severe weather setup, no major changes were noted in forecast trends as the moderate severe risk from SPC remains centered from the Flint Hills region to the Kansas/Nebraska border. Negatively tilted upper trough axis across the Four Corners Region is anticipated to eject into the western high plains between 21Z-00Z. At this time, dryline/cold front is oriented southwest to northeast over north central Kansas as rich low level moisture raises dewpoints into the low 70s pooling just ahead of the stalled boundary. In addition clouds are anticipated to scatter out by late afternoon, resulting in SFC CAPE exceeding 5000 J/KG amid minimal inhibition. Strong convergence along the front is sufficient for discreet convection to form in the 3-5 PM timeframe over north central Kansas. Initial severe storms will be most intense in terms of very large hail (2-4+ inches diameter) and strong tornadoes, especially as the low level jet strengthens in the early evening. The strong tornado threat persists into the early evening with any discrete supercells.

Bulk shear vectors parallel to the front suggest discrete cells transition to a line of storms around 7 PM. Main hazards with the squall line are damaging wind gusts to 80 mph , brief tornadoes along the leading edge, and large hail as they quickly translate east southeast through eastern Kansas. Forward propagating corfidi vectors are weak (20 kts) while PWAT values increase above 1.5 inches and low/mid level moisture saturates the column. Given the several inches of rainfall that occurred the last evening, decided to expand the Flood Watch to cover the entire forecast area through Tuesday morning. Estimated rainfall totals tonight range from 2 to 5 inches, increasing the likelihood for localized flash flooding. Activity exits into Missouri between 3 and 6 AM Tuesday.

Much cooler airmass settles in behind the front Tuesday and Wednesday afternoons as highs only peak in the middle to upper 60s. Showers and isolated storm chances return by Thursday as broad upper troughing amplifies to the north and west. However, given the influence from sfc ridge to the northeast and lack of good return moisture, the overall severe threat is low. Better dynamics return by Friday evening, signaling the possibility for strong storms in the Kansas region.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 558 AM CDT Mon May 18 2026

Low end VFR stratus to start period at terminals as scattered TSRA continues to impact KTOP/KFOE through 15Z. There is a low probability that isolated TSRA may redevelop just south of KFOE in the 15-19Z timeframe. Observed MVFR stratus builds eastward between 13-15Z and will quickly lift back to VFR as south winds increase from 10 to 20 kts sustained in the afternoon. A line of TSRA and fropa is trending faster, progged to be around 23Z at KMHK and 01Z at KTOP/KFOE as winds veer to the northwest above 10 kts behind the storms.

CLIMATE

Issued at 234 AM CDT Mon May 18 2026

Record High Temperature

Monday May 18 Record (Year) Forecast Topeka 94 (1975) 87 Concordia 94 (1967, 1988) 84

Record Warm Low Temperature

Monday May 18 Record (Year) Forecast Topeka 71 (1911) 68 Concordia 72 (1911) 61

TOP WATCHES/WARNINGS/ADVISORIES

Flood Watch through Tuesday morning for KSZ008-KSZ009-KSZ010- KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026-KSZ034- KSZ035-KSZ036-KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056- KSZ058-KSZ059. Wind Advisory from 9 AM this morning to 9 PM CDT this evening for KSZ035-KSZ036-KSZ037-KSZ038-KSZ054.