Alert archive / Wyoming / Flash Flood Warnings in 2018

Flash Flood Warning 3, NWS Cheyenne, WY

May 18, 2018Goshen County, Wyoming

NWS Cheyenne, WY issued this flash flood warning at May 18, 2018, 11:58 PM MDT for Goshen County, Wyoming. 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: May 18, 2018, 11:58 PM MDT (05:58 UTC)
Expired: May 19, 2018, 6:00 AM MDT
In force: 6 hr
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Flood severity: None

County Goshen County, WY

The radar

The Cheyenne radar (KCYS), 149 km from the middle of the area, began a volume at 06:00 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.

The nearest sounding before it

Rapid City, SD (KRAP), launched 00:00Z, 6.0 hours before the alert went out and 216 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: 229 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 1207 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: -22 m²/s²
0-3 km storm-relative helicity: -19 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.6

Open this sounding in Storm Lab

The text

As transmitted.

037 
WGUS55 KCYS 190558
FFWCYS
WYC015-191200-
/O.NEW.KCYS.FF.W.0003.180519T0558Z-180519T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Cheyenne WY
1158 PM MDT FRI MAY 18 2018

The National Weather Service in Cheyenne has issued a

* Flash Flood Warning for...
  North central Goshen County in southeastern Wyoming...

* Until 600 AM MDT Saturday

* At 1153 PM MDT, local law enforcement officials reported flash 
  flooding occurring in the warned area. Up to 4 or 5 inches of rain 
  have already fallen in the headwaters of Rawhide Creek across 
  northern Goshen County. Flash flooding is already occurring.

* Some locations that will experience flooding include...
  Jay Em and Hwy 85 At Rawhide Creek. 

Flood waters are moving down Rawhide Creek from northern Goshen 
county towards the south. These flood waters have washed out a 
bridge along Harris Ranch Road, one-half mile west of Highway 85 
near Jay Em. Residents along Rawhide Creek downstream of Jay Em 
should beware of rising waters and seek higher ground if necessary.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 4261 10427 4239 10431 4229 10424 4226 10433
      4236 10440 4246 10453 4260 10449

$$

Hahn

The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 18, 6:01 PM MDT	Areal Flood Advisory	CYS	Goshen, Niobrara	6 hr
May 18, 6:18 PM MDT	Special Weather Statement	CYS	Goshen	57 min
May 18, 7:20 PM MDT	Special Weather Statement	CYS	Platte	55 min
May 19, 8:01 AM MDT	Flash Flood Warning	CYS	Laramie	3 hr
May 19, 10:01 AM MDT	Areal Flood Warning	CYS	Goshen, Laramie, Niobrara, Platte	6 hr
May 19, 3:18 PM MDT	Areal Flood Warning	CYS	Goshen, Laramie	6 hr

Nearby

Flash Flood Warnings in Wyoming, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.