Alert archive / Kansas / Flash Flood Warnings in 2026

Flash Flood Warning 8, NWS Topeka, KS

May 18, 2026Geary County, Pottawatomie County, Riley County, Kansas

NWS Topeka, KS issued this flash flood warning at May 18, 2026, 7:17 PM CDT for Geary County, Pottawatomie County, Riley County, Kansas. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: May 18, 2026, 7:17 PM CDT (00:17 UTC)
Expired: May 18, 2026, 10:24 PM CDT
In force: 3 hr
Issued by: NWS Topeka, KS
Area: Storm-based polygon
Flood severity: None

Counties Geary County, KS, Pottawatomie County, KS, Riley County, KS

The radar

The Topeka radar (KTWX), 52 km from the middle of the area, began a volume at 00:19 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where	Remark
May 18, 7:25 PM CDT	FLASH FLOOD	Manhattan, KS	Social media video of water 8 inches deep over road.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched one storm report to this flash flood warning; the first came 8 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Topeka, KS (KTOP), launched 00:00Z, 0.3 hours before the alert went out and 102 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 3248 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 1108 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 209 m²/s²
0-3 km storm-relative helicity: 370 m²/s²
Significant tornado parameter: 4.1
Supercell composite: 22.8

Open this sounding in Storm Lab

The text

As transmitted.

039 
WGUS53 KTOP 190017
FFWTOP
KSC061-149-161-190415-
/O.NEW.KTOP.FF.W.0008.260519T0017Z-260519T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Topeka KS
717 PM CDT Mon May 18 2026

The National Weather Service in Topeka has issued a

* Flash Flood Warning for...
  Northwestern Geary County in east central Kansas...
  Southwestern Pottawatomie County in northeastern Kansas...
  Southern Riley County in northeastern Kansas...

* Until 1115 PM CDT.

* At 716 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. The expected rainfall rate is 1 to 3 inches in 1 
  hour. Additional rainfall amounts of 1 to 2 inches are possible in 
  the warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Manhattan, Junction City, Ogden, Grandview Plaza, Keats and Tuttle 
  Creek Lake.

This includes Interstate 70 between mile markers 290 and 308.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3901 9696 3905 9696 3909 9696 3920 9685
      3938 9668 3922 9647 3907 9664 3897 9676
      3899 9696

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-3 INCHES IN 1 HOUR

$$

CP

2 follow-up statements

437 
WGUS73 KTOP 190128
FFSTOP

Flash Flood Statement
National Weather Service Topeka KS
828 PM CDT Mon May 18 2026

KSC061-149-161-190415-
/O.CON.KTOP.FF.W.0008.000000T0000Z-260519T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Geary KS-Pottawatomie KS-Riley KS-
828 PM CDT Mon May 18 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM CDT THIS 
EVENING FOR NORTHWESTERN GEARY, SOUTHWESTERN POTTAWATOMIE AND 
SOUTHERN RILEY COUNTIES...

At 826 PM CDT, the public reported thunderstorms producing heavy 
rain in Manhattan with water 8 inches deep over the road. Between 
1.5 and 3 inches of rain have fallen. Additional rainfall amounts up 
to 0.5 inches are possible in the warned area. Flash flooding is 
already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Public reported.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Manhattan, Junction City, Ogden, Grandview Plaza, Keats and Tuttle 
  Creek Lake.

This includes Interstate 70 between mile markers 290 and 308.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3901 9696 3905 9696 3909 9696 3920 9685
      3938 9668 3922 9647 3907 9664 3897 9676
      3899 9696

FLASH FLOOD...OBSERVED
EXPECTED RAINFALL RATE...2-4 INCHES IN 1 HOUR

$$

CP

452 
WGUS73 KTOP 190324 RRA
FFSTOP

Flash Flood Statement
National Weather Service Topeka KS
1024 PM CDT Mon May 18 2026

KSC061-149-161-190334-
/O.CAN.KTOP.FF.W.0008.000000T0000Z-260519T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Geary KS-Pottawatomie KS-Riley KS-
1024 PM CDT Mon May 18 2026

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN GEARY, 
SOUTHWESTERN POTTAWATOMIE AND SOUTHERN RILEY COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

&&

LAT...LON 3901 9696 3905 9696 3909 9696 3920 9685
      3938 9668 3922 9647 3907 9664 3897 9676
      3899 9696

$$

CP

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Topeka, KS wrote its last area forecast discussion before this flash flood warning went out at May 18, 6:22 PM CDT, 55 minutes earlier. Its key messages:

Severe thunderstorms becoming numerous early to mid afternoon today and spreading east to southeast this evening. Very large hail, damaging winds, and tornadoes all quite possible.
Flash flooding remains a concern through tonight especially where heavy rain fall Sunday night.
Gusty south winds on track for the next several hours in southwestern areas.

Area forecast discussion, May 18, 6:22 PM CDT, 55 minutes before

Area Forecast Discussion
National Weather Service Topeka KS
622 PM CDT Mon May 18 2026

.KEY MESSAGES...

- Severe thunderstorms becoming numerous early to mid afternoon today
  and spreading east to southeast this evening. Very large hail,
  damaging winds, and tornadoes all quite possible.

- Flash flooding remains a concern through tonight especially where
  heavy rain fall Sunday night.

- Gusty south winds on track for the next several hours in
  southwestern areas.

&&

.DISCUSSION...
Issued at 200 PM CDT Mon May 18 2026

Warm, humid airmass was surging north into central Kansas ahead of a
cold front toward a nearly-stationary front just northeast of
northeast Kansas with a modest upper wave just upstream. Instability
of 3000 J/kg already commonplace in central Kansas at 17Z with 40-50
knots of deep-layer shear. Vectors for this layer remain close to
parallel to the front so there is some uncertainty in how long
storms can remain discrete, but some backing of low-level flow and
otherwise good setup brings all severe hazards in play. Main area of
concern over the next few hours is north-central Kansas with storms
spreading east and southeast and becoming more widespread with time.
Threats should turn more to wind versus strong tornado in eastern
areas as mode shifts to more linear. Overall a more progressive
system should keep storm residence somewhat limited, but areas that
saw heavy rain Sunday night will not take much more rain to
experience flash flooding and intense updrafts with PW values around
1.5 inches will bring quick rainfall. Storms push southeast before
dawn with flash flooding threat falling off, though rivers and
creeks may be high for a few more days. Surface winds

Next few days continue to look benign with modified Canadian high
pressure in place with cooler temperatures. Moisture return in the
mid-levels supports at least moderate precipitation chances Thursday
into Thursday night but instability remains modest. A more unstable
airmass should return around the holiday weekend though forcing for
ascent is not readily apparent.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 611 PM CDT Mon May 18 2026

Line of strong/severe thunderstorms pushing through KMHX currently
with continued eastward movement of main convective line. TEMPO
group through 01-05z for KTOP and KFOE for TSRA with viz 1SM and
MVFR/IFR conditions. Conditions improve from west to east later in
forecast period, around 05z for western TAF sites; 10z for eastern
TAF sites.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Tuesday morning for KSZ008-KSZ009-KSZ010-KSZ011-
KSZ012-KSZ020-KSZ021-KSZ022-KSZ023-KSZ024-KSZ026-KSZ034-KSZ035-
KSZ036-KSZ037-KSZ038-KSZ039-KSZ040-KSZ054-KSZ055-KSZ056-KSZ058-
KSZ059.
Wind Advisory until 9 PM CDT this evening for KSZ035-KSZ036-KSZ037-
KSZ038-KSZ054.

&&

DISCUSSION...Poage
AVIATION...JTW

Hazardous weather outlook, May 18, 1:38 PM CDT, 5 hours 39 minutes before

Hazardous Weather Outlook
National Weather Service Topeka KS
138 PM CDT Mon May 18 2026

KSZ008>012-020>024-026-034>040-054>056-058-059-191845-
Republic-Washington-Marshall-Nemaha-Brown-Cloud-Clay-Riley-
Pottawatomie-Jackson-Jefferson-Ottawa-Dickinson-Geary-Morris-
Wabaunsee-Shawnee-Douglas-Lyon-Osage-Franklin-Coffey-Anderson-
138 PM CDT Mon May 18 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

South winds sustained around 25 MPH with gusts around 45 MPH are
forecast for locations southwest of a line from Abilene to Alma to
Emporia in to the evening.

Severe thunderstorms are expected through the middle of the
afternoon in north central Kansas. These storms may form into a
line as they move east and southeast late this afternoon and this
evening. Very large hail, damaging wind gusts, and a few strong
tornadoes are the main hazards.

Localized flooding is also a concern, especially if storms
persist over areas that received heavy rain Sunday night. A Flood
Watch remains in effect through 7 AM Tuesday morning.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotters will likely be needed this afternoon or tonight.

&&

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

In the hours before

Local storm report, May 18, 6:31 PM CDT, 46 minutes before

Preliminary Local Storm Report
National Weather Service Topeka KS
631 PM CDT Mon May 18 2026

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

0538 PM     Tornado          5 NW Frankfort          39.77N 96.45W
05/18/2026                   Marshall           KS   Emergency Mngr

            Damage reported by EM of grain bins and
            trees.

&&

SMB

Local storm report, May 18, 6:34 PM CDT, 43 minutes before

Preliminary Local Storm Report
National Weather Service Topeka KS
634 PM CDT Mon May 18 2026

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

0622 PM     Tstm Wnd Gst     Ogden                   39.11N 96.71W
05/18/2026  E65 MPH          Riley              KS   Public

&&

ST

Local storm report, May 18, 6:40 PM CDT, 37 minutes before

Preliminary Local Storm Report
National Weather Service Topeka KS
640 PM CDT Mon May 18 2026

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

0628 PM     Tstm Wnd Gst     3 N Manhattan           39.23N 96.57W
05/18/2026  M67 MPH          Riley              KS   Public

&&

ST

Local storm report, May 18, 6:41 PM CDT, 36 minutes before

Preliminary Local Storm Report
National Weather Service Topeka KS
641 PM CDT Mon May 18 2026

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

0641 PM     Tstm Wnd Gst     7 NNE Manhattan         39.27N 96.52W
05/18/2026  M59 MPH          Pottawatomie       KS   Public

            Personal weather station.

&&

ST

Local storm report, May 18, 6:50 PM CDT, 27 minutes before

Preliminary Local Storm Report
National Weather Service Topeka KS
650 PM CDT Mon May 18 2026

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

0649 PM     Tstm Wnd Gst     2 SW Louisville         39.23N 96.34W
05/18/2026  M78 MPH          Pottawatomie       KS   Public

            Measured on a personal weather station.

&&

ST

Local storm report, May 18, 6:53 PM CDT, 24 minutes before

Preliminary Local Storm Report
National Weather Service Topeka KS
653 PM CDT Mon May 18 2026

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

0622 PM     Tstm Wnd Gst     Ogden                   39.11N 96.71W
05/18/2026  E65 MPH          Riley              KS   Public

0628 PM     Tstm Wnd Gst     3 N Manhattan           39.23N 96.57W
05/18/2026  M67 MPH          Riley              KS   Public

&&

The office that day

Everything else NWS Topeka, KS issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 18, 7:07 PM CDT	Areal Flood Advisory	TOP	Marshall, Nemaha	2 hr
May 18, 7:20 PM CDT	Severe Thunderstorm Warning Considerable damage threat	TOP	Brown, Nemaha	40 min
May 18, 7:22 PM CDT	Tornado Warning	TOP	Jackson	23 min
May 18, 7:27 PM CDT	Severe Thunderstorm Warning Considerable damage threat	TOP	Brown, Jackson, Jefferson, Nemaha, Shawnee	33 min
May 18, 7:28 PM CDT	Severe Thunderstorm Warning	TOP	Geary, Jackson, Pottawatomie, Riley, Shawnee, Wabaunsee	36 min
May 18, 7:31 PM CDT	Severe Thunderstorm Warning	TOP	Geary, Lyon, Morris, Wabaunsee	44 min
May 18, 7:41 PM CDT	Flash Flood Warning	TOP	Geary, Riley, Wabaunsee	3 hr
May 18, 7:47 PM CDT	Tornado Warning	TOP	Lyon, Morris, Wabaunsee	28 min
May 18, 7:49 PM CDT	Areal Flood Advisory	TOP	Pottawatomie, Wabaunsee	3 hr
May 18, 7:53 PM CDT	Severe Thunderstorm Warning	TOP	Coffey, Jefferson, Lyon, Osage, Shawnee, Wabaunsee	52 min
May 18, 7:56 PM CDT	Tornado Warning	TOP	Lyon, Wabaunsee	19 min
May 18, 8:00 PM CDT	Severe Thunderstorm Warning Considerable damage threat	TOP	Coffey, Franklin, Lyon, Osage, Wabaunsee	45 min
May 18, 8:08 PM CDT	Tornado Warning	TOP	Osage, Shawnee, Wabaunsee	22 min
May 18, 8:28 PM CDT	Severe Thunderstorm Warning Considerable damage threat	TOP	Douglas, Franklin, Jefferson, Osage, Shawnee	47 min
May 18, 8:36 PM CDT	Severe Thunderstorm Warning	TOP	Lyon	39 min
May 18, 9:11 PM CDT	Areal Flood Advisory	TOP	Lyon	114 min
May 18, 9:11 PM CDT	Severe Thunderstorm Warning	TOP	Franklin	22 min
May 18, 9:13 PM CDT	Severe Thunderstorm Warning	TOP	Coffey, Lyon	47 min
May 18, 9:45 PM CDT	River Flood Warning	TOP	Marshall	41 hr
May 18, 9:56 PM CDT	Special Weather Statement	TOP	Coffey	34 min
May 18, 10:18 PM CDT	Severe Thunderstorm Warning	TOP	Coffey, Lyon	42 min
May 18, 10:57 PM CDT	Severe Thunderstorm Warning	TOP	Anderson, Coffey	33 min
May 18, 11:07 PM CDT	Severe Thunderstorm Warning	TOP	Anderson, Coffey	23 min
May 18, 11:25 PM CDT	Severe Thunderstorm Warning	TOP	Anderson, Franklin	20 min
May 18, 11:37 PM CDT	Areal Flood Advisory	TOP	Anderson, Coffey	3 hr

Nearby

Flash Flood Warnings in Kansas, 2026 Every flash flood warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.