Alert archive / Wyoming / Flash Flood Warnings in 2021

Flash Flood Warning 1, NWS Cheyenne, WY

May 17, 2021Albany County, Carbon County, Wyoming

NWS Cheyenne, WY issued this flash flood warning at May 17, 2021, 2:05 PM MDT for Albany County, Carbon County, Wyoming. It was in force for 2 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 17, 2021, 2:05 PM MDT (20:05 UTC)
Expired: May 17, 2021, 4:28 PM MDT
In force: 2 hr
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Flood severity: None

Counties Albany County, WY, Carbon County, WY

The radar

The Cheyenne radar (KCYS), 132 km from the middle of the area, began a volume at 20:04 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

Riverton, WY (KRIW), launched 12:00Z, 8.1 hours before the alert went out and 272 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1437 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 3 m²/s²
0-3 km storm-relative helicity: 99 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

093 
WGUS55 KCYS 172005
FFWCYS
WYC001-007-172300-
/O.NEW.KCYS.FF.W.0001.210517T2005Z-210517T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Cheyenne WY
205 PM MDT Mon May 17 2021

The National Weather Service in Cheyenne has issued a

* Flash Flood Warning for...
  Southeastern Carbon County in south central Wyoming...
  Southwestern Albany County in southeastern Wyoming...

* Until 500 PM MDT.

* At 202 PM MDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to one inch of rain has 
  already fallen over the northwest portion of the Muilen Fire burn 
  scar. Flash flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by nearly stationary thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flooding of small creeks and streams, and other drainage 
           and low lying areas.

Excessive rainfall over the northwest portion of the Mullen Fire 
burn scar will result in debris flow. The debris flow can consist of 
rock, mud, vegetation and other loose materials.

This includes the following streams and drainages...
North Mullen Creek, Savage Run Creek, Cottonwood Creek, Devils Gate
Creek, West Fork Devils Gate Creek, Bear Creek, South Mullen Creek,
Horse Creek, Boat Creek, Hans Creek, North Platte River, Douglas
Creek, Spring Creek, Sheep Creek, Mullen Creek, Big Creek and East
Fork Devils Gate Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move away from recently burned areas. Life-threatening flooding of
creeks, roads and normally dry arroyos is likely. The heavy rains
will likely trigger rockslides, mudslides and debris flows in steep
terrain, especially in and around these areas.

Flooding is occurring or is imminent. It is important to know where
you are relative to streams, rivers, or creeks which can become
killers in heavy rains. Campers and hikers should avoid streams or
creeks.

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 4104 10640 4117 10650 4124 10635 4116 10627

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

$$

Jamski

1 follow-up statement

007 
WGUS75 KCYS 172228
FFSCYS

Flash Flood Statement
National Weather Service Cheyenne WY
428 PM MDT Mon May 17 2021

WYC001-007-172238-
/O.CAN.KCYS.FF.W.0001.000000T0000Z-210517T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Carbon WY-Albany WY-
428 PM MDT Mon May 17 2021

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN CARBON AND SOUTHWESTERN
ALBANY COUNTIES IS CANCELLED...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 4104 10640 4117 10650 4124 10635 4116 10627

$$

Hammer

The office that day

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

Issued	Product	Office	Counties	Lasted
May 17, 5:36 AM MDT	Dense Fog Advisory	CYS	Albany, Laramie	5 hr
May 17, 1:34 PM MDT	Special Weather Statement	CYS	Laramie	26 min
May 17, 1:48 PM MDT	Areal Flood Advisory	CYS	Albany, Carbon	3 hr
May 17, 4:47 PM MDT	Special Weather Statement	CYS	Laramie	28 min
May 17, 5:22 PM MDT	Special Weather Statement	CYS		38 min

Nearby

Flash Flood Warnings in Wyoming, 2021 Every flash flood warning 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.