Alert archive / Kansas / Flash Flood Warnings in 2020

Flash Flood Warning 21, NWS Kansas City, MO

July 30, 2020Johnson County, Leavenworth County, Wyandotte County, Kansas

NWS Kansas City, MO issued this flash flood warning at Jul 30, 2020, 2:39 PM CDT for Johnson County, Leavenworth County, Wyandotte County, Kansas. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 30, 2020, 2:39 PM CDT (19:39 UTC)
Expired: Jul 30, 2020, 8:30 PM CDT
In force: 6 hr
Issued by: NWS Kansas City, MO
Area: Storm-based polygon
Flood severity: None

Counties Johnson County, KS, Leavenworth County, KS, Wyandotte County, KS

The radar

The Pleasant Hill radar (KEAX), 69 km from the middle of the area, began a volume at 19:38 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 63 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: 770 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 511 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: -9 m²/s²
0-3 km storm-relative helicity: 1 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

288 
WGUS53 KEAX 301939
FFWEAX
KSC091-103-209-310130-
/O.NEW.KEAX.FF.W.0021.200730T1939Z-200731T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Kansas City/Pleasant Hill MO
239 PM CDT Thu Jul 30 2020

The National Weather Service in Pleasant Hill has issued a

* Flash Flood Warning for...
  Wyandotte County in northeastern Kansas...
  Leavenworth County in northeastern Kansas...
  Johnson County in east central Kansas...

* Until 830 PM CDT.

* At 233 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain were moving into the warned area. Flash flooding is 
  is expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flooding of small creeks and streams, urban areas, 
           highways, streets and underpasses as well as other 
           drainage and low lying areas.

* Some locations that will experience flooding include...
  Overland Park, Olathe, Shawnee, Lenexa, Leavenworth, Leawood,
  Prairie Village, Gardner, Lansing, Merriam, Mission, Bonner
  Springs, De Soto, Parkville, Spring Hill, Tonganoxie, Basehor,
  Edwardsville, Fairway and Mission Hills.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

&&

LAT...LON 3942 9518 3942 9497 3938 9493 3939 9489
      3931 9491 3926 9483 3921 9483 3921 9478
      3917 9475 3919 9468 3915 9466 3915 9461
      3874 9461 3874 9506 3898 9506 3899 9508
      3896 9509 3898 9516 3896 9519 3897 9519

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

Pietrycha

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 29, 7:16 PM CDT	Special Weather Statement	EAX	Miami	44 min
Jul 29, 8:17 PM CDT	Areal Flood Advisory	EAX	Johnson, Miami, Wyandotte	3 hr
Jul 29, 11:25 PM CDT	River Flood Warning	EAX	Atchison	37 hr
Jul 30, 12:54 PM CDT	Flash Flood Warning	EAX	Linn, Miami	6 hr
Jul 30, 2:44 PM CDT	River Flood Warning	EAX	Doniphan	35 hr
Jul 30, 3:53 PM CDT	Flash Flood Warning	EAX	Atchison, Doniphan	6 hr

Nearby

Flash Flood Warnings in Kansas, 2020 Every flash flood warning in 2020

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.