Alert archive / Missouri / Flash Flood Watches in 2017

Flash Flood Watch 6, NWS Kansas City, MO

August 20, 201723 counties in Missouri; 7 counties in Kansas

NWS Kansas City, MO issued this flash flood watch at Aug 20, 2017, 2:36 PM CDT for 23 counties in Missouri; 7 counties in Kansas. It took effect at Aug 21, 2017, 10:00 PM CDT. It was in force for 12 hr.

The area

The counties it named.

The facts

Issued
Aug 20, 2017, 2:36 PM CDT (19:36 UTC)
In effect from
Aug 21, 2017, 10:00 PM CDT
Expired
Aug 22, 2017, 10:00 AM CDT
In force
12 hr
Issued by
NWS Kansas City, MO
Flood severity
None
All 30 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, Bates County, MO, Buchanan County, MO, Caldwell County, MO, Carroll County, MO, Cass County, MO, Chariton County, MO, Clay County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Grundy County, MO, Henry County, MO, Jackson County, MO, Johnson County, MO, Lafayette County, MO, Linn County, MO, Livingston County, MO, Pettis County, MO, Platte County, MO, Ray County, MO, Saline County, MO, Sullivan County, MO

The radar

The Pleasant Hill radar (KEAX), 55 km from the middle of the area, began a volume at 19:37 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 (KFOE), launched 12:00Z, 7.6 hours before the alert went out and 131 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 2017-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 415 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Topeka, KS at 12:00Z on 2017-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 square meters per square second.193958Sfc1 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
415 J/kg
Mixed-layer CIN
-346 J/kg
Mixed-layer LCL
1090 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
-54 m²/s²
Significant tornado parameter
0.0
Supercell composite
-1.2

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Kansas City, MO wrote its last area forecast discussion before this flash flood watch went out at Aug 20, 1:03 PM CDT, 1 hour 33 minutes earlier.

Area forecast discussion, Aug 20, 1:03 PM CDT, 1 hour 33 minutes before
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Hazardous weather outlook, Aug 20, 5:39 AM CDT, 8 hours 57 minutes before
Hazardous Weather Outlook
National Weather Service Kansas City/Pleasant Hill MO
539 AM CDT Sun Aug 20 2017

KSZ025-057-060-102>105-MOZ001>008-011>017-020>025-028>033-037>040-
043>046-053-054-211045-
Atchison KS-Miami-Linn KS-Doniphan-Leavenworth-Wyandotte-Johnson KS-
Atchison MO-Nodaway-Worth-Gentry-Harrison-Mercer-Putnam-Schuyler-
Holt-Andrew-De Kalb-Daviess-Grundy-Sullivan-Adair-Buchanan-Clinton-
Caldwell-Livingston-Linn MO-Macon-Platte-Clay-Ray-Carroll-Chariton-
Randolph-Jackson-Lafayette-Saline-Howard-Cass-Johnson MO-Pettis-
Cooper-Bates-Henry-
539 AM CDT Sun Aug 20 2017

This hazardous weather outlook is for northwest...north central and
west central Missouri...as well as extreme eastern Kansas.

.DAY ONE...Today and Tonight

 Storms this morning will produce 40-50 mph winds across the Kansas
 City metro and points southeastward.

 Heat indices are expected to reach the 100 to 105 degree mark this
 afternoon area-wide.

 More detailed information can be accessed at...
 https://www.weather.gov/eax/hwo

.DAYS TWO THROUGH SEVEN...Monday through Saturday

 Additional storms are possible early Monday morning, and are likely
 Monday night through Tuesday morning. A few storms could become
 strong to severe, particularly Monday night. In addition, heavy rain
 could lead to localized flooding.

 More detailed information can be accessed at...
 https://www.weather.gov/eax/hwo

In the hours before

Special weather statement, Aug 20, 10:13 AM CDT, 4 hours 23 minutes before
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Local storm report, Aug 20, 10:17 AM CDT, 4 hours 19 minutes before
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Local storm report, Aug 20, 11:20 AM CDT, 3 hours 16 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 2:55 AM CDTSpecial Weather StatementEAXAndrew, Holt, Nodaway, Worth50 min
Aug 20, 3:39 AM CDTSpecial Weather StatementEAXAndrew, Buchanan, DeKalb, Gentry, Worth51 min
Aug 20, 8:23 AM CDTSpecial Weather StatementEAXClinton52 min
Aug 20, 5:52 PM CDTSpecial Weather StatementEAXHenry23 min

Nearby

Flash Flood Watches in Missouri, 2017Flash Flood Watches in Kansas, 2017Every flash flood watch in 2017

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.