Alert archive / Wyoming / Flash Flood Warnings in 2021

Flash Flood Warning 8, NWS Cheyenne, WY

July 29, 2021Albany County, Carbon County, Wyoming

NWS Cheyenne, WY issued this flash flood warning at Jul 29, 2021, 3:19 PM MDT for Albany County, Carbon County, Wyoming. It was in force for 104 min. 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 29, 2021, 3:19 PM MDT (21:19 UTC)
Expired: Jul 29, 2021, 5:03 PM MDT
In force: 104 min
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), 110 km from the middle of the area, began a volume at 21:20 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, 9.3 hours before the alert went out and 267 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: 1746 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: 9 m²/s²
0-3 km storm-relative helicity: 90 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

456 
WGUS55 KCYS 292119
FFWCYS
WYC001-007-300030-
/O.NEW.KCYS.FF.W.0008.210729T2119Z-210730T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Cheyenne WY
319 PM MDT Thu Jul 29 2021

The National Weather Service in Cheyenne has issued a

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

* Until 630 PM MDT.

* At 319 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Flash flooding is ongoing or 
  expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  North Fork Campground, Centennial and Libby Creek Campground.

This includes the following highways...
	Interstate 80 in Wyoming between mile markers 280 and 292.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4143 10614 4151 10610 4156 10609 4155 10603
      4149 10594 4142 10590 4137 10595 4129 10602
      4124 10608 4126 10619 4128 10624 4137 10617

FLASH FLOOD...RADAR INDICATED

$$

Claycomb

1 follow-up statement

628 
WGUS75 KCYS 292303
FFSCYS

Flash Flood Statement
National Weather Service Cheyenne WY
503 PM MDT Thu Jul 29 2021

WYC001-007-292313-
/O.CAN.KCYS.FF.W.0008.000000T0000Z-210730T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Albany WY-Carbon WY-
503 PM MDT Thu Jul 29 2021

...FLASH FLOOD WARNING IS CANCELLED FOR EAST CENTRAL CARBON AND 
SOUTHWESTERN ALBANY COUNTIES...

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

LAT...LON 4143 10614 4151 10610 4156 10609 4155 10603
      4149 10594 4142 10590 4137 10595 4129 10602
      4124 10608 4126 10619 4128 10624 4137 10617

$$

Claycomb

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 29, 2:01 PM MDT	Flash Flood Watch	CYS	Albany, Carbon, Converse, Goshen, Laramie, Platte	34 hr
Jul 29, 2:23 PM MDT	Flash Flood Warning	CYS	Albany, Carbon	101 min
Jul 29, 2:27 PM MDT	Severe Thunderstorm Warning	CYS	Albany, Carbon	48 min
Jul 29, 3:12 PM MDT	Severe Thunderstorm Warning	CYS	Albany, Carbon	48 min
Jul 29, 3:52 PM MDT	Severe Thunderstorm Warning	CYS	Albany	38 min
Jul 29, 4:41 PM MDT	Areal Flood Advisory	CYS	Albany	3 hr

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.