FXUS63 KTOP 050007 AFDTOP Area Forecast Discussion National Weather Service Topeka KS 707 PM CDT Mon May 4 2026 .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 /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 650 PM CDT Mon May 4 2026 A few scattered thunderstorms may develop over or close to the terminals after 3Z. A cold front will pass through and most of the thunderstorms will move southeast of the terminals. light rain showers may continue through after 9Z into the morning hours, north of the front. At this time ceilings should remain above 4000 feet. && .TOP WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Reese AVIATION...Gargan