097 FXUS63 KTOP 201928 AFDTOPArea Forecast Discussion National Weather Service Topeka KS 228 PM CDT Sat Sep 20 2025
.KEY MESSAGES...
- Fog, potentially some dense fog, is expected to develop tonight into Sunday morning.
- Shower and storm chances increase tonight into Sunday. Severe weather is unlikely.
- The active pattern continues with several more waves of showers and storms expected Monday through the middle of next week.
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.DISCUSSION... Issued at 228 PM CDT Sat Sep 20 2025
Quasi-zonal flow is present across the Central Plains this afternoon with several lobes of energy noted over the Rockies, Northern Plains, and Upper Midwest. A lack of focused lift has led to dry conditions today under a mix of clouds and sun. While lift is nebulous, the environment is uncapped with modest instability and a stray shower or storm is possible through this evening.
The next shortwave ejects across the Plains tonight into Sunday, generating showers and storms over central Kansas early Sunday morning that will traverse east through the day. Light winds and high boundary layer moisture favors fog development tonight, most likely across the eastern half of the area where precipitation holds off until later Sunday morning. Dense fog is possible, but coverage and location is uncertain and this potential will need to be monitored this evening and overnight. Fog is expected to lift by mid- morning Sunday.
By Sunday afternoon, any clearing will allow for steepening low- level lapse rates and could provide a window for a stronger storm or two to develop across eastern Kansas Sunday afternoon and early evening before the wave shifts east of the local area. Even with most CAMs showing some degree of destabilization, instability and shear are progged to be modest (1000-1500 J/kg of SBCAPE, 20-25 kts of effective shear) and the overall severe potential is low. Precipitation winds down Sunday evening with dry conditions expected into Monday.
Another strong wave dives southeast across the Rockies and Plains Monday evening, shunting a cold front through the area. A capping inversion should preclude convective development through much of the daytime hours before strong forcing arrives Monday evening and overnight. Convection that develops in central Kansas and southern Nebraska will push southeast during this timeframe and the shear/instability parameter space could support strong to severe storms. Storms may congeal into line or bowing segments with strong cold pools increasing the risk for severe wind gusts. Plenty of uncertainty remains, but this looks to be the main timeframe to monitor for severe potential over the next week.
A closed low slowly advances east Tuesday through Wednesday, keeping chances for showers and storms in the forecast until the system progresses far enough east by late this week. Precipitation amounts aren`t too concerning from a flooding standpoint with ensembles showing a 10-45% chance (highest across east central Kansas) for at least 2 inches of rainfall through Wednesday night. Cloud cover and precipitation keep temperatures cool Tuesday-Thursday with highs in the low to mid 70s.
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.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1220 PM CDT Sat Sep 20 2025
Mainly VFR conditions expected through this evening. Cigs may briefly drop to MVFR this afternoon, particularly at KMHK. Otherwise, calm winds overnight will support fog development, including the potential for dense fog. Highest confidence in VSBY reduction is at KTOP/KFOE, but included a mention at all sites. Fog should lift by 14-15z Sunday with chances for showers or storms near terminals late or just beyond the end of this TAF period.
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.TOP WATCHES/WARNINGS/ADVISORIES... None.
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DISCUSSION...Flanagan AVIATION...Flanagan
NWS TOP Office Area Forecast Discussion