Ottawa, Kansas Weather Forecast Discussion

097
FXUS63 KTOP 201928
AFDTOP
Area 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.
&&
.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.
&&
.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.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Flanagan
AVIATION...Flanagan

NWS TOP Office Area Forecast Discussion