Alert archive / Iowa / Flash Flood Warnings in 2018

Flash Flood Warning 3, NWS Sioux Falls, SD

June 14, 2018Lyon County, O'Brien County, Osceola County, Iowa

NWS Sioux Falls, SD issued this flash flood warning at Jun 14, 2018, 7:01 AM CDT for Lyon County, O'Brien County, Osceola County, Iowa. It was in force for 3 hr. 9 reports 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: Jun 14, 2018, 7:01 AM CDT (12:01 UTC)
Expired: Jun 14, 2018, 10:00 AM CDT
In force: 3 hr
Issued by: NWS Sioux Falls, SD
Area: Storm-based polygon
Flood severity: None

Counties Lyon County, IA, O'Brien County, IA, Osceola County, IA

The radar

The Sioux Falls radar (KFSD), 93 km from the middle of the area, began a volume at 12:00 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
Jun 14, 7:45 AM CDT	FLASH FLOOD	Hartley, IA	Worst Flooding in over two years. Storm sewers backing up all over town.
Jun 14, 7:50 AM CDT	HEAVY RAIN 5.9	Sanborn, IA
Jun 14, 8:00 AM CDT	FLASH FLOOD	3 Ese Sheldon, IA	WATER FLOWING OVER OAK HILL AVE. SOUTH OF 300TH ST
Jun 14, 8:04 AM CDT	HEAVY RAIN 6.5	1 Ene Hartley, IA
Jun 14, 8:22 AM CDT	HEAVY RAIN 6.2	4 W Hartley, IA
Jun 14, 8:30 AM CDT	HEAVY RAIN 5.5	Sanborn, IA	REPORTED VIA SOCIAL MEDIA.
Jun 14, 8:40 AM CDT	HEAVY RAIN 1.4	Melvin, IA
Jun 14, 9:15 AM CDT	HEAVY RAIN 5.15	2 W Hartley, IA
Jun 14, 9:19 AM CDT	HEAVY RAIN 5	Hartley, IA

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

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 0.0 hours before the alert went out and 218 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: 1543 J/kg
Mixed-layer CIN: -305 J/kg
Mixed-layer LCL: 1231 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 219 m²/s²
0-3 km storm-relative helicity: 312 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.2

Open this sounding in Storm Lab

The text

As transmitted.

091 
WGUS53 KFSD 141201
FFWFSD
IAC119-141-143-141500-
/O.NEW.KFSD.FF.W.0003.180614T1201Z-180614T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Sioux Falls SD
701 AM CDT THU JUN 14 2018

The National Weather Service in Sioux Falls has issued a

* Flash Flood Warning for...
  Northeastern Lyon County in northwestern Iowa...
  Western Osceola County in northwestern Iowa...
  Northern O'Brien County in northwestern Iowa...

* Until 1000 AM CDT.

* At 657 AM CDT, the public reported thunderstorms producing heavy 
  rain across the warned area, including water across Hwy 18 east of 
  Hartley, IA. Radar estimates around two inches of rain has already 
  fallen in this area, with rain likely to continue for the next 
  hour or two.

* Some locations that will experience flooding include...
  Sibley, Hartley, Sanborn, Primghar, Little Rock, Ashton, Melvin and
  Archer.

Additional rainfall amounts of an inch or more are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4303 9568 4326 9587 4349 9610 4349 9568
      4316 9539 4303 9548

$$

VandenBoogart

2 follow-up statements

038 
WGUS73 KFSD 141314
FFSFSD

Flash Flood Statement
National Weather Service Sioux Falls SD
814 AM CDT THU JUN 14 2018

IAC119-141-143-141500-
/O.CON.KFSD.FF.W.0003.000000T0000Z-180614T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lyon IA-Osceola IA-O'Brien IA-
814 AM CDT THU JUN 14 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1000 AM CDT FOR
NORTHEASTERN LYON...WESTERN OSCEOLA AND NORTHERN O'BRIEN COUNTIES...

At 812 AM CDT, the broadcast media reported 6.5" of rain from 
thunderstorms in Hartley Iowa.  Flash flooding is expected. Although 
rain has ended in these locations, flooding can be expected to 
continue this morning. 

Some locations that will experience flooding include...
Sibley, Hartley, Sanborn, Primghar, Little Rock, Ashton, Melvin and
Archer.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4303 9568 4326 9587 4349 9610 4349 9568
      4316 9539 4303 9548

$$

BT

779 
WGUS73 KFSD 141458
FFSFSD

Flash Flood Statement
National Weather Service Sioux Falls SD
958 AM CDT THU JUN 14 2018

IAC119-141-143-141507-
/O.EXP.KFSD.FF.W.0003.000000T0000Z-180614T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lyon IA-Osceola IA-O'Brien IA-
958 AM CDT THU JUN 14 2018

...THE FLASH FLOOD WARNING FOR NORTHEASTERN LYON...WESTERN OSCEOLA
AND NORTHERN O'BRIEN COUNTIES WILL EXPIRE AT 1000 AM CDT...

Flood waters have receded. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 4303 9568 4326 9587 4349 9610 4349 9568
      4316 9539 4303 9548

$$

BT

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 14, 3:15 AM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Plymouth, Woodbury	30 min
Jun 14, 3:41 AM CDT	Severe Thunderstorm Warning	FSD	Cherokee, Plymouth	34 min
Jun 14, 4:18 AM CDT	Severe Thunderstorm Warning	FSD	Clay, O'Brien	27 min
Jun 14, 5:32 AM CDT	Severe Thunderstorm Warning	FSD	Clay, O'Brien	28 min
Jun 14, 6:20 AM CDT	Severe Thunderstorm Warning	FSD	Lyon, Osceola	12 min
Jun 14, 7:37 AM CDT	Flash Flood Warning	FSD	Buena Vista, Clay	3 hr
Jun 14, 10:08 AM CDT	River Flood Warning	FSD	Buena Vista, Clay	38 days
Jun 14, 10:41 AM CDT	Areal Flood Warning	FSD	O'Brien, Sioux	24 hr
Jun 14, 2:50 PM CDT	Heat Advisory	FSD	Buena Vista, Cherokee, Clay, Dickinson, Ida, O'Brien and 4 more	3 days

Nearby

Flash Flood Warnings in Iowa, 2018 Every flash flood warning in 2018

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.