Severe Thunderstorm Warning 166, NWS Topeka, KS

Area Forecast Discussion
National Weather Service Topeka KS
545 PM CDT Sat May 16 2026

.KEY MESSAGES...

- Hot and humid conditions will continue to provide a chance for
  thunderstorms tonight through Monday night.

- There is a risk for severe weather each day through Monday night.
  The greatest risk for severe storms including tornadoes looks to be
  Monday afternoon and Monday night.

- Much cooler weather and a break from showers and storms is forecast
  to move in Tuesday.

&&

.DISCUSSION...
Issued at 228 PM CDT Sat May 16 2026

19Z water vapor imagery showed an upper trough over the Northern
Rockies and Pacific Northwest with southwest upper flow over the
central plains. Surface obs had an area of low pressure still over
the OK/TX panhandles with an inverted trough through central KS and
into southeast NEB. A moist and hot airmass had developed south of
this boundary with dewpoints in the middle and upper 60s.

This afternoon and tonight: There still isn't much of a shortwave to
force convection and the 18Z Topeka RAOB showed stout inhibition was
still in place. But continued heating of the moist boundary layer
into the lower 90s is expected to reduce inhibition for deep moist
convection to near zero between 5 and 7 pm. As a result convergence
along the weak boundary across far northern KS should act as a focus
for convective development. MUCAPE values are expected to be between
2500 and 4000 J/kg but 0-6km bulk shear looks to be light at 30KT or
less across much of the forecast area. This may make it difficult
for updrafts to sustain themselves pointing towards a wind threat.
Better shear to the north may support some risk for hail. CAMs have
shown some consistency with isolated storms developing north of I-70
between 6 and 8pm and lifting into NEB through the early evening.
Overnight models show an MCS forming off the high plains and
propagating east. This makes sense with a 40-50KT low level jet
feeding high theta-e air into the boundary. The question is how far
south will the MCS go. The models tend to pool the higher boundary
layer moisture along and north of the KS/NEB state line and the CAMs
seem to want to keep the bowing segment north in the deeper moisture.
But I am hesitant to buy completely into that idea with the nose of
the low level jet providing lift over north central and northeast KS.
With the 12Z ARW showing convection moving along the 36 highway
corridor, have kept some likely POPs going into the early morning
hours. By the time this moves through, straight line winds will
likely be the greatest concern.

Sunday: There is a fair bit more uncertainty in how things evolve on
Sunday with models showing various ideas. The NAM and RAP strengthen
the mid level cap while the GFS brings some cooler mid level temps
in at 700MB. An then is there any remnant outflow from tonight's
storms. With the moderately unstable airmass still in place across
the forecast area am not sure I agree with the RAP and NAM in no
convection developing off the dry line. Then again there isn't a lot
of support from the CAMs for the GFS idea. So have some 30-40
percent chance POPs for the western counties by the late afternoon.
Instability east of the dryline should be more than enough for
convective initiation, but again deep layer shear is progged to be
relatively weak. So the main concerns would be large hail and
damaging winds.

There is pretty good agreement from the models for a strengthening
pressure gradient on Sunday. The gradient looks strong enough for
sustained winds around 30 mph and gusts up to 45 mph so have gone
ahead and issued a wind advisory for much of the area.

Monday: There is good consensus in the synoptic pattern among the
models with a shortwave lifting over the triple point across central
KS by the late afternoon. With moderate to strong instability and
improving wind profiles developing, supercell storms are forecast to
form along the dryline and warm front. Discrete storms will be
capable of tornadoes but I am wondering if the forcing is strong
enough that convection fills in along the boundaries. We'll be
looking at storm modes more closely as the event starts to get into
the time frame of the CAMs. Am comfortable with the categorical POPs
from the NBM as models have been consistent for several days now with
storms along the front as it pushes east and southeast Monday night.

Tuesday and beyond: Have not made any chances to the mid-range
forecast as the NBM seems to have a reasonable handle on the overall
pattern. Surface ridging is forecast to move over the plains Tuesday
and Wednesday. This should shift POPs south of the forecast area
with noticeably cooler temperatures forecast. The 00Z guidance was a
little slower in developing return flow on the back side of the
surface ridge. The 12Z ECMWF has southerly low level flow by Friday
which should help temps warm back into the 70s and 80s for the end
of the forecast. The NBM has some slight chance POPs in the forecast
for Thursday through Saturday. It's hard to find a strong reason for
or against the slight chance POPs and there maybe some shortwave
energy impacting the central plains by the end of the forecast
period.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 545 PM CDT Sat May 16 2026

VFR conditions expected. Chances for storms near terminals is
too low to include in TAF. KMHK has a slightly higher chance for
nearby storms, but chances remain around 20%. Gusts are expected
to subside after sunset this evening which could lead to a period
of LLWS overnight, but conditions appear too marginal. Winds
increase from the south after sunrise Sunday, gusting at 25-35kts
through the day. There remains a signal for some high- end MVFR
cigs early Sunday at KTOP/KFOE, but think the probability is low
enough to keep out of TAF.

&&

.CLIMATE...
Issued at 228 PM CDT Sat May 16 2026

Record High Temperature

Sunday May 17
                 Record (Year)           Forecast
Topeka           92 (1907)               89
Concordia        96 (1996)               96

Monday May 18
                 Record (Year)           Forecast
Topeka           94 (1975)               91
Concordia        94 (1967, 1988)         91

Record Warm Low Temperature

Sunday May 17
                 Record (Year)           Forecast
Topeka           73 (1996)               69
Concordia        68 (1902, 1906)         67

Monday May 18
                 Record (Year)           Forecast
Topeka           71 (1911)               70
Concordia        72 (1911)               66

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 9 AM to 9 PM CDT Sunday for KSZ008-KSZ009-
KSZ010-KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ034-
KSZ035-KSZ036-KSZ037-KSZ038-KSZ039-KSZ054-KSZ055-KSZ058.

&&

DISCUSSION...Wolters
AVIATION...Flanagan
CLIMATE...Drake/Wolters

Hazardous Weather Outlook
National Weather Service Topeka KS
241 PM CDT Sat May 16 2026

KSZ008>012-020>024-026-034>040-054>056-058-059-171945-
Republic-Washington-Marshall-Nemaha-Brown-Cloud-Clay-Riley-
Pottawatomie-Jackson-Jefferson-Ottawa-Dickinson-Geary-Morris-
Wabaunsee-Shawnee-Douglas-Lyon-Osage-Franklin-Coffey-Anderson-
241 PM CDT Sat May 16 2026

This Hazardous Weather Outlook is for portions of east central,
north central, and northeast Kansas.

.DAY ONE...This Afternoon and Tonight

Thunderstorms are expected to develop over parts of north central
and northeast Kansas late this afternoon and move north into
Nebraska this evening. The storms will be capable of producing
damaging winds and large hail. Overnight a second round of
thunderstorms may impact areas along US highway 36. These storms
may be capable of damaging straight line winds during the early
morning hours of Sunday.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Thunderstorms are possible again Sunday afternoon and Sunday
evening. If storms are able to develop they could become severe
with large hail and damaging winds the main concern. The better
chance for storms is expected to be west of a line from Council
Grove to Seneca.

The greatest chance for severe weather is still shaping up to be
Monday afternoon and Monday night. There is good confidence in
storms developing over north central KS by the early evening and
moving across all of northeast and east central Kansas through the
night. Storms will be capable of producing tornadoes, very large
hail, damaging winds and flash flooding. People should be prepared
for thunderstorms impacting the area.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report severe weather to the National
Weather Service in Topeka.

&&

More detailed information can be found at:
www.weather.gov/media/top/DssPacket.pdf

Wolters

Preliminary Local Storm Report
National Weather Service Topeka KS
810 PM CDT Sat May 16 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0753 PM     Hail             1 N Agenda              39.72N 97.43W
05/16/2026  M2.75 Inch       Republic           KS   Trained Spotter

            Trained spotter just north of Agenda
            reported 2.5 to 3.0 inch hail.

&&

ST

Preliminary Local Storm Report
National Weather Service Topeka KS
844 PM CDT Sat May 16 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0840 PM     Hail             1 N Narka               39.97N 97.43W
05/16/2026  M1.75 Inch       Republic           KS   Public

&&

ST

Preliminary Local Storm Report
National Weather Service Topeka KS
857 PM CDT Sat May 16 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0830 PM     Hail             Morrowville             39.84N 97.17W
05/16/2026  E1.00 Inch       Washington         KS   Trained Spotter

&&

ST

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