337
FXUS63 KTOP 171720
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1220 PM CDT Mon Aug 17 2026

.KEY MESSAGES...

- Patchy fog this morning, then dry weather with near average
temperatures is forecast for today.

- There is a slight risk for severe thunderstorms Tuesday
evening/night, but much uncertainty exists with this setup.

- Another chance of showers and storms (30-50%) comes late Wednesday
night into Thursday morning.

- Temperatures may trend slightly warmer into next weekend, but look
to remain near seasonal norms.

&&

.DISCUSSION...
Issued at 441 AM CDT Mon Aug 17 2026

The forecast area is on the southern edge of the main westerlies
aloft, which cover the northern tier of the CONUS while the ridge
has been pushed just to our south. A convectively induced vort max
near the OK panhandle is on track to keep that batch of storms in
southern KS this morning. Surface high pressure is now in control
over the Central Plains, and the combination of light winds, clear
skies, and cooling below crossover temperatures has allowed for some
patchy fog to form. Soundings show this shallow fog should mix out
an hour or so after sunrise, but in the meantime, be on the lookout
for quick reductions in visibility in low-lying areas.

The rest of today looks dry with partly cloudy skies and highs in
the 80s. One thing to watch towards the evening hours will be a
shortwave ejecting out of the Northern Rockies into the High Plains
that is progged to spark some convection in western Nebraska. Given
the position of the LLJ, it would make sense that any convection
that sustains itself overnight would stay in Nebraska, which is what
most CAMs have shown. The 00z HRRR appears to be an outlier in
bringing more scattered convection into our area overnight, but it`s
worth monitoring to ensure that is indeed the case. Most CAMs track
the storms through the MO River Valley overnight, which may end up
clipping northern KS Tuesday morning mainly around the Hwy 36
corridor.

The aforementioned convection Tuesday morning is the first factor
that complicates the forecast for the rest of Tuesday, which looks
to be based on mesoscale processes difficult to ascertain at this
time range. If enough rain and cloud cover linger far enough south,
that could keep temperatures cooler than forecast and also have an
effect on how much destabilization occurs. That convection could
also leave an outflow boundary that may or may not be the focus for
developing storms later. Interestingly, the 06z short-term guidance
has trended further south with the sfc low pressure in western KS,
which keeps the warm front further south (consensus would have it
around the KS River Valley). This then brings the cold front through
the area faster with storms potentially further south than previous
runs had as well. Regardless of which side of the warm front you
look at, forecast soundings show a lot of CIN with a surface-based
or mixed-layer parcel, so it would seem to be tough to get a storm
going until the cold front comes through and triggers elevated
storms, which is what the CAMs seem to be showing. While deep-layer
shear is sufficient for supercells, am skeptical as to how much of
that will be realized given that issue. Still, if a strong enough
updraft develops, can`t rule out some storms producing damaging
winds or small hail. All this to say, there is decent confidence in
storms forming, but what is uncertain is the timing and intensity of
them. They should move out during the overnight hours.

By Wednesday, cooler temperatures are once again forecast behind the
front with highs back in the 80s. Northwest flow develops aloft with
a large trough encompassing eastern Canada into the Great Lakes
region. Another embedded perturbation aloft looks to trigger another
round of thunderstorms Wednesday evening into early Thursday
morning, but uncertainty in the timing and placement of that wave
keeps PoPs limited to 30-50% for now. The rest of the week into next
weekend sees the upper ridge building to our west, which favors at
least a slight warming trend. Cluster analysis shows good agreement
on that ridge, but it does show differing ideas on how well
amplified the Great Lakes trough will still be by the weekend. That
could have an effect on how much we will actually warm up if we keep
more easterly winds in the low levels. So while highs are forecast
to be a bit warmer next weekend than the middle of this week, they
are generally still close to average, and a small warmup seems
reasonable at this time.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1216 PM CDT Mon Aug 17 2026

VFR conditions and light winds will continue through
tonight. After sunrise tomorrow, winds increase a bit out of the
southeast. Could also see weakening showers and storms approach late
in the period, but the best chance should stay to the north.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION...Picha
AVIATION...Reese