Severe Thunderstorm Warning 330, NWS Topeka, KS

Area Forecast Discussion
National Weather Service Topeka KS
616 PM CDT Sat Jun 20 2026

.KEY MESSAGES...

- Thunderstorm chances increase this evening, then become likely
overnight into Sunday morning (60-90%). Heavy rainfall with flooding
and severe storms with damaging winds are the primary concerns,
although hail to quarter size and a brief tornado cannot be ruled
out.

- Storms may linger in east central KS Sunday late morning and
afternoon (20-50% chance).

- Temperatures stay a bit cooler than average through next week
alongside periodic storm chances.

&&

.DISCUSSION...
Issued at 248 PM CDT Sat Jun 20 2026

Surface low pressure has been deepening in eastern CO in response to
an upper trough traversing out of the Great Basin and Intermountain
West region. The surface warm front has started to slowly lift north
through the CWA this morning, likely placed along or just south of
the I-70 corridor based on 19z observations and visible satellite.
Meanwhile, a subtle perturbation rounding the low-amplitude ridge
overhead has helped to trigger elevated supercells in central
Nebraska, which have been following the MUCAPE gradient this morning
into the early afternoon. This trajectory would favor these storms
staying just north of the KS/NE border through the afternoon, which
is what more recent HRRR runs have shown as well.

Our main focus remains on this evening and overnight, and we should
stay quiet until then assuming the above scenario pans out.
Shortwave energy from the aforementioned upper trough looks to eject
across the High Plains this evening and eventually across the MO
River Valley by Sunday morning. This feature will lead to the
development of storms in western KS this evening that will
eventually evolve into an MCS. There is still a bit of uncertainty
in whether any discrete storms can develop along the warm front
earlier this evening (around 02-03z) ahead of the MCS, which looks
to move into our area closer to midnight. If these discrete cells
can develop, this would present more of a threat for hail or
tornadoes than anything later on, as sfc winds are more backed at
this time. They become more veered with the approach of the MCS. All
the while, the strengthening LLJ this evening will continue to pump
in more moisture and provide the lift needed to maintain a severe
weather risk as storms enter north central KS. Damaging winds are
the main severe hazard with a lower risk for hail or a brief spin-up
tornado. Flooding is the other primary concern with storms
overnight. In addition to the MCS coming from western KS, CAMs have
shown more rounds of rainfall with clusters and lines of storms
coming southeastward out of Nebraska. This setup could lead to some
locations getting hit by repeated rounds of heavy rainfall if they
go over the same places again and again. While it is uncertain
exactly where this might happen and where the highest amounts could
be as a result, several CAM solutions show pockets of 3-6" through
Sunday morning. The HREF has a subtle signal for intense rainfall
rates, and more specifically, the HRRR has been indicating 2-3"/hr
rainfall rates may be possible in localized areas. Overall, most
locations can expect to see 1-3", but some will probably see those
locally higher amounts mentioned, which presents a concern for flash
flooding and river flooding. Have made no changes to the going Flood
Watch.

Some of the storms and heavy rain may linger into mid/late morning
in east central KS before it eventually moves out and subsidence
takes over behind the upper wave. From there, the chance of any
redeveloping storms in the afternoon and evening will be highly
dependent on the location of any outflow boundary the morning
convection lays out. That or the synoptic cold front could be the
focus for afternoon storms by that point. Current CAMs have this
activity mainly along and south of I-35 before it pushes south later
in the evening. If storms develop before the boundary moves south,
they could have large hail or damaging winds with them.

Getting into the next work week, our area finds itself in a
northwest flow pattern aloft with ridging parked over the
southwestern US. Embedded perturbations rounding the ridge bring
more chances for storms at times through the next week, but
predictability of the timing and placement of these waves tends to
be lower at this range, so PoPs are generally below 50% at any
particular time period. Temperatures look to hold slightly cooler
than average through the week with highs in the upper 70s to low 80s
and lows in the upper 50s to low 60s.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 616 PM CDT Sat Jun 20 2026

Main changes to the forecast were adjustments in timing of TSRA
expected to develop northwest of terminals, tracking southeast
and entering KMHK as early as 05Z and KTOP/KFOE near 06Z. Tempo
groups were kept where intensity of storms are highest and several
rounds of TSRA where conditions may briefly improve. Low end MVFR cigs
follow behind the main area of storms aft 14Z with gradual improvement
to VFR as the fropa and drier air occurs in the 18-20Z timeframe.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Sunday afternoon for KSZ008-KSZ009-KSZ010-
KSZ011-KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026-KSZ034-
KSZ035-KSZ036-KSZ037-KSZ038-KSZ039-KSZ040.
Flood Watch through Sunday evening for KSZ054-KSZ055-KSZ056-KSZ058-
KSZ059.

&&

DISCUSSION...Picha
AVIATION...Prieto

Hazardous Weather Outlook
National Weather Service Topeka KS
252 PM CDT Sat Jun 20 2026

KSZ008>012-020>024-026-034>040-054>056-058-059-212000-
Republic-Washington-Marshall-Nemaha-Brown-Cloud-Clay-Riley-
Pottawatomie-Jackson-Jefferson-Ottawa-Dickinson-Geary-Morris-
Wabaunsee-Shawnee-Douglas-Lyon-Osage-Franklin-Coffey-Anderson-
252 PM CDT Sat Jun 20 2026

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

.DAY ONE...This Afternoon and Tonight

Thunderstorms are likely late tonight, especially through the
overnight hours. Primary hazards are damaging winds and heavy
rainfall leading to flooding, although large hail and a brief
tornado cannot be ruled out.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Severe storms may continue into Sunday morning across east central
KS, along with the potential for heavy rainfall. A few additional
storms may redevelop Sunday afternoon and evening along and south
of Interstate 35.

.SPOTTER INFORMATION STATEMENT...

Spotters may be needed tonight.

Special Weather Statement
National Weather Service Topeka KS
614 PM CDT Sat Jun 20 2026

KSZ010-202345-
Marshall-
614 PM CDT Sat Jun 20 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTH CENTRAL MARSHALL COUNTY
THROUGH 645 PM CDT...

At 613 PM CDT, Doppler radar was tracking a strong thunderstorm near
Wymore, moving southeast at 40 mph.

HAZARD...Strong wind gusts of 50 to 55 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Hail damage to outdoor objects and
         vegetation is possible.

Locations impacted include...
Summerfield and Oketo.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4000 9629 3987 9645 4000 9675
TIME...MOT...LOC 2313Z 294DEG 33KT 4007 9665

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...55 MPH

Prieto