Alert archive / Colorado / Flash Flood Warnings in 2021

Flash Flood Warning 65, NWS Denver/Boulder, CO

August 3, 2021Elbert County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Aug 3, 2021, 2:58 PM MDT for Elbert County, Colorado. 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
Aug 3, 2021, 2:58 PM MDT (20:58 UTC)
Expired
Aug 3, 2021, 5:00 PM MDT
In force
2 hr
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

County Elbert County, CO

The radar

The Denver radar (KFTG), 56 km from the middle of the area, began a volume at 21:01 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

Denver, CO (KDNR), launched 12:00Z, 9.0 hours before the alert went out and 99 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-pSkew-T log-p diagram, Denver, CO at 12:00Z on 2021-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 12 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2021-08-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -16 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
12 J/kg
Mixed-layer CIN
-226 J/kg
Mixed-layer LCL
2110 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-16 m²/s²
0-3 km storm-relative helicity
-6 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

033 
WGUS55 KBOU 032058
FFWBOU
COC039-032300-
/O.NEW.KBOU.FF.W.0065.210803T2058Z-210803T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
258 PM MDT Tue Aug 3 2021

The National Weather Service in Denver has issued a

* Flash Flood Warning for...
  North Central Elbert County in east central Colorado...

* Until 500 PM MDT.

* At 258 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, gulches,
           roads, and poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  mainly rural areas of North Central Elbert County

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3931 10416 3930 10422 3940 10426 3942 10422
      3942 10416 3939 10413

FLASH FLOOD...RADAR INDICATED

$$

Meier
1 follow-up statement
956 
WGUS75 KBOU 032252
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
452 PM MDT Tue Aug 3 2021

COC039-032302-
/O.EXP.KBOU.FF.W.0065.000000T0000Z-210803T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Elbert CO-
452 PM MDT Tue Aug 3 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 5 PM MDT THIS AFTERNOON FOR 
NORTH CENTRAL ELBERT COUNTY...

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

LAT...LON 3931 10416 3930 10422 3940 10426 3942 10422
      3942 10416 3939 10413

$$

Meier

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 2, 6:26 PM MDTFlash Flood WarningBOULarimer116 min
Aug 3, 3:41 AM MDTFlash Flood WatchBOUBoulder, Clear Creek, Gilpin, Grand, Jackson, Jefferson and 3 more18 hr
Aug 3, 8:10 AM MDTAreal Flood AdvisoryBOUGrand3 hr
Aug 3, 2:22 PM MDTAreal Flood AdvisoryBOUDouglas, Jefferson113 min
Aug 3, 3:48 PM MDTAreal Flood AdvisoryBOUAdams, Arapahoe, Elbert87 min
Aug 3, 4:05 PM MDTFlash Flood WarningBOUAdams, Arapahoe115 min

Nearby

Flash Flood Warnings in Colorado, 2021Every 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.