419 FXUS63 KTOP 191143 AFDTOPArea Forecast Discussion National Weather Service Topeka KS 643 AM CDT Fri Sep 19 2025
.KEY MESSAGES...
- Patchy dense fog this morning across eastern Kansas.
- Another round of storms late this afternoon or evening, a few may become strong, producing small hail and gusty winds. Not expecting widespread severe storms.
- An active weather pattern continues into next week with cooler temperatures and near daily precipitation chances.
&&
.DISCUSSION... Issued at 114 AM CDT Fri Sep 19 2025
In the wake of a departing upper-level trough, surface wind has diminished and dewpoint depressions are near zero. This is leading to areas of fog across northeast Kansas. Fog could be dense at times, mainly across river valleys and low-lying areas. Fog may develop further south and east through the early morning, before clearing out shortly after sunrise.
Most of the day Friday should be clear and quiet. Another upper- level wave will dive out of the northern Plains this afternoon. Lift associated with this wave and an increasing low- level jet should lead to scattered thunderstorms late this afternoon and into the evening. Timing of the wave will be key in determining how strong storms will become today. If thunderstorms don`t develop until the evening our chances for severe storms is a bit lower due to an expected decoupling of the boundary layer and lower amounts of instability. If the wave arrives this afternoon and storms develop, we could see a parameter space favorable for some low-end supercells with effective shear around 45 knots and CAPE around 1,000 J/Kg. Central Kansas, namely Republic, Cloud, Ottawa, and Dickinson Counties, stand the best chance (10% or less) of seeing severe storms this afternoon or early evening. Otherwise, just general thunderstorms are expected to overspread central and eastern Kansas late in the evening and overnight. Storms could have rain rates around one inch an hour with PWATs above 1.5 inches and at least a few hundred joules of elevated instability.
Most of the day Sunday should be dry in the wake of a departing wave. This break will likely be brief though as wave after wave may move through the central Plains next week with westerly to northwesterly flow aloft and southerly flow at the surface bringing reinforcing shots of moisture. Temperatures are favored to around normal for this time of the year with highs in the 70s to low 80s and lows in the 60s.
&&
.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 640 AM CDT Fri Sep 19 2025
Fog at airports will begin to lift and scatter within a few hours following sunrise. Have VFR visibilities returning by 15Z. Winds will remain very light today with high pressure overhead. Rain and thunderstorm chances begin to increase at sites late this evening and overnight, toward the end of the 12Z period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES... None.
&&
$$
DISCUSSION...Jones AVIATION...Teefey
NWS TOP Office Area Forecast Discussion