Alert archive / Wyoming / Flash Flood Warnings in 2021

Flash Flood Warning 7, NWS Cheyenne, WY

July 29, 2021Albany County, Carbon County, Wyoming

NWS Cheyenne, WY issued this flash flood warning at Jul 29, 2021, 2:23 PM MDT for Albany County, Carbon County, Wyoming. It was in force for 101 min. 1 report 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: Jul 29, 2021, 2:23 PM MDT (20:23 UTC)
Expired: Jul 29, 2021, 4:04 PM MDT
In force: 101 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), 129 km from the middle of the area, began a volume at 20:26 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
Jul 29, 3:08 PM MDT	FLASH FLOOD	8 W Centennial, WY	1 INCH RAINFALL WITHIN 30MIN, PEA SIZE HAIL AT 10,200 FT.

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

The nearest sounding before it

Riverton, WY (KRIW), launched 12:00Z, 8.4 hours before the alert went out and 250 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.

285 
WGUS55 KCYS 292023
FFWCYS
WYC001-007-300015-
/O.NEW.KCYS.FF.W.0007.210729T2023Z-210730T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Cheyenne WY
223 PM MDT Thu Jul 29 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 615 PM MDT.

* At 223 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...
  Deep Creek Campground, Bow River Campground, Brooklyn Lake 
  Campground, Brooklyn Lake, Sugar Loaf Campground, Nash Fork 
  Campground and Arlington.

This includes the following highways...
	Interstate 80 in Wyoming between mile markers 265 and 279.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4126 10636 4128 10646 4138 10648 4152 10646
      4164 10635 4168 10623 4166 10608 4151 10610
      4137 10617 4128 10624

FLASH FLOOD...RADAR INDICATED

$$

Claycomb

1 follow-up statement

153 
WGUS75 KCYS 292204
FFSCYS

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

WYC001-007-292214-
/O.CAN.KCYS.FF.W.0007.000000T0000Z-210730T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Albany WY-Carbon WY-
404 PM MDT Thu Jul 29 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN 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 4126 10636 4128 10646 4138 10648 4152 10646
      4164 10635 4168 10623 4166 10608 4151 10610
      4137 10617 4128 10624

$$

Cox

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, 2:27 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, 3:19 PM MDT	Flash Flood Warning	CYS	Albany, Carbon	104 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.