textproduct: Topeka

KEY MESSAGES

- Scattered thunderstorms expected to develop tonight after sunset. A few severe storms possible (30%), with large hail and damaging winds the main hazards.

- Much cooler tomorrow and Wednesday behind cold front, with occasional periods of rain.

- Gradually warming up again towards the weekend.

DISCUSSION

Issued at 1245 PM CDT Mon May 4 2026

Broad confluent flow evident on water vapor imagery this afternoon, with one deep upper low dropping southeast over the Northern Plains while another spins just offshore California. The northern stream low is beginning to push a cold front southward through the area. As that occurs this evening, isentropic ascent will increase along and north of the boundary, allowing scattered thunderstorms to develop within the unstable airmass. Forecast soundings indicate storms will likely be a bit high-based and elevated, but in an environment of moderate CAPE (1500-2000 J/kg), moderate effective shear (~35 kts), and very steep mid-level lapse rates (8-8.5 C/km). So large hail potentially up to golf ball size looks to be the main hazard with any initially developing storm, followed by some damaging wind potential as updrafts become more numerous just along/behind the front.

Much cooler air will filter in behind the front overnight. With the southern stream upper low still well to our southwest, we'll see a longer period of continued isentropic ascent atop the chilly airmass. So off and on rain chances look to continue throughout the day Tuesday and into Wednesday. Particularly if low clouds can linger throughout the day, this will keep temperatures down, with highs in the upper 50s to low 60s.

The main trough axis looks to pass off to our east by Thursday, bringing in drier and sunnier conditions. This should help us begin another warming trend into the weekend ahead of our next upper trough. Details with this system are fuzzy 5-6 days out, but in generally expect another increase in rain chances as it approaches.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1222 PM CDT Mon May 4 2026

Light winds and VFR conditions will continue this afternoon and into the evening. Around 02-04 UTC a cold front will begin to push south through the main TAF sites, shifting winds to the northeast. A few scattered thunderstorms are also likely to develop along the front, most likely in the 03-08 UTC timeframe. Ceilings stay generally VFR, though can't rule out some lower ceilings late in the period as rain chances begin to increase again.

TOP WATCHES/WARNINGS/ADVISORIES

None.