Alert archive / Kansas / Flash Flood Watches in 2021

Flash Flood Watch 1, NWS Kansas City, MO

May 20, 20217 counties in Kansas; 5 counties in Missouri

NWS Kansas City, MO issued this flash flood watch at May 20, 2021, 2:40 PM CDT for 7 counties in Kansas; 5 counties in Missouri. It took effect at May 20, 2021, 4:00 PM CDT. It was in force for 5 hr.

The area

The counties it named.

The facts

Issued
May 20, 2021, 2:40 PM CDT (19:40 UTC)
In effect from
May 20, 2021, 4:00 PM CDT
Expired
May 20, 2021, 8:43 PM CDT
In force
5 hr
Issued by
NWS Kansas City, MO
Flood severity
None

Counties Atchison County, KS, Doniphan County, KS, Johnson County, KS, Leavenworth County, KS, Linn County, KS, Miami County, KS, Wyandotte County, KS, Andrew County, MO, Buchanan County, MO, Holt County, MO, Nodaway County, MO, Platte County, MO

The radar

The Pleasant Hill radar (KEAX), 87 km from the middle of the area, began a volume at 19:42 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.

The nearest sounding before it

Topeka, KS (KTOP), launched 12:00Z, 7.7 hours before the alert went out and 75 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-pSkew-T log-p diagram, Topeka, KS at 12:00Z on 2021-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Topeka, KS at 12:00Z on 2021-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 76 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
584 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
76 m²/s²
0-3 km storm-relative helicity
59 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

625 
WGUS63 KEAX 201940
FFAEAX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Kansas City/Pleasant Hill MO
240 PM CDT Thu May 20 2021

KSZ025-057-060-102>105-MOZ002-011-012-020-028-211100-
/O.NEW.KEAX.FF.A.0001.210520T2100Z-210521T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Atchison KS-Miami-Linn KS-Doniphan-Leavenworth-Wyandotte-
Johnson KS-Nodaway-Holt-Andrew-Buchanan-Platte-
Including the cities of Atchison, Paola, Osawatomie, Louisburg, 
Pleasanton, La Cygne, Mound City, Wathena, Elwood, Troy, 
Highland, Fort Leavenworth, Leavenworth, Lansing, 
Kansas City Kansas, Overland Park, Stanley, Olathe, Shawnee, 
Lenexa, Maryville, Oregon, Maitland, Forest City, Craig, 
Savannah, Country Club Villa, St. Joseph Airport, St. Joseph, 
Parkville, Platte City, Riverside, Weatherby Lake, and Weston
240 PM CDT Thu May 20 2021

...FLASH FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT...

The National Weather Service in Kansas City/Pleasant Hill has
issued a

* Flash Flood Watch for portions of Kansas and Missouri, 
  including the following areas, in Kansas, Atchison KS, 
  Doniphan, Johnson KS, Leavenworth, Linn KS, Miami, and 
  Wyandotte. In Missouri, Andrew, Buchanan, Holt, Nodaway, and 
  Platte. 

* Through late tonight

* Showers and thunderstorms with localized heavy rainfall are
  expected this afternoon and this evening across parts of eastern
  Kansas and northwestern Missouri. This may lead to localized
  areas of 1.5 to 3 inches of rain, on top of already saturated
  grounds.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that conditions may develop that lead
to flash flooding. Flash flooding is a VERY DANGEROUS SITUATION.

You should monitor later forecasts and be prepared to take action
should Flash Flood Warnings be issued.

&&

$$
1 follow-up statement
461 
WGUS63 KEAX 210143
FFAEAX

Flood Watch
National Weather Service Kansas City/Pleasant Hill MO
843 PM CDT Thu May 20 2021


KSZ025-057-060-102>105-MOZ002-011-012-020-028-210245-
/O.CAN.KEAX.FF.A.0001.000000T0000Z-210521T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Atchison KS-Miami-Linn KS-Doniphan-Leavenworth-Wyandotte-
Johnson KS-Nodaway-Holt-Andrew-Buchanan-Platte-
Including the cities of Atchison, Paola, Osawatomie, Louisburg, 
Pleasanton, La Cygne, Mound City, Wathena, Elwood, Troy, 
Highland, Fort Leavenworth, Leavenworth, Lansing, 
Kansas City Kansas, Overland Park, Stanley, Olathe, Shawnee, 
Lenexa, Maryville, Oregon, Maitland, Forest City, Craig, 
Savannah, Country Club Villa, St. Joseph Airport, St. Joseph, 
Parkville, Platte City, Riverside, Weatherby Lake, and Weston
843 PM CDT Thu May 20 2021

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of Kansas and Missouri has
been cancelled. Significant rainfall amounts are no longer
expected.

$$

The office that day

Everything else NWS Kansas City, MO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 20, 3:48 AM CDTRiver Flood WarningEAXAtchison, Leavenworth42 hr
May 20, 3:18 PM CDTRiver Flood WarningEAXLeavenworth15 hr

Nearby

Flash Flood Watches in Kansas, 2021Flash Flood Watches in Missouri, 2021Every flash flood watch in 2021

Sources

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