Alert archive / Utah / Flash Flood Warnings in 2021

Flash Flood Warning 44, NWS Grand Junction, CO

July 27, 2021Grand County, Utah

NWS Grand Junction, CO issued this flash flood warning at Jul 27, 2021, 1:51 PM MDT for Grand County, Utah. It was in force for 88 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 27, 2021, 1:51 PM MDT (19:51 UTC)
Expired
Jul 27, 2021, 3:19 PM MDT
In force
88 min
Issued by
NWS Grand Junction, CO
Area
Storm-based polygon
Flood severity
None

County Grand County, UT

The radar

The Grand Junction radar (KGJX), 145 km from the middle of the area, began a volume at 19:51 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

Grand Junction, CO (KGJT), launched 12:00Z, 7.9 hours before the alert went out and 126 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, Grand Junction, CO at 12:00Z on 2021-07-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 28 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, Grand Junction, CO at 12:00Z on 2021-07-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -20 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
28 J/kg
Mixed-layer CIN
-304 J/kg
Mixed-layer LCL
1735 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
-20 m²/s²
0-3 km storm-relative helicity
-8 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

305 
WGUS55 KGJT 271951
FFWGJT
UTC019-272245-
/O.NEW.KGJT.FF.W.0044.210727T1951Z-210727T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Grand Junction CO
151 PM MDT Tue Jul 27 2021

The National Weather Service in Grand Junction has issued a

* Flash Flood Warning for...
  South Central Grand County in east central Utah...

* Until 445 PM MDT.

* At 151 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. The expected rainfall rate is 1 
  to 2 inches in 1 hour. 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...
  Highway 313 on route to Canyonlands National Park and Dead Horse 
  Point State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3866 10976 3856 10971 3852 10982 3862 10988

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

$$

KJS
1 follow-up statement
258 
WGUS75 KGJT 272119
FFSGJT

Flash Flood Statement
National Weather Service Grand Junction CO
319 PM MDT Tue Jul 27 2021

UTC019-272129-
/O.CAN.KGJT.FF.W.0044.000000T0000Z-210727T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grand UT-
319 PM MDT Tue Jul 27 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTH CENTRAL GRAND COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat.

LAT...LON 3866 10976 3856 10971 3852 10982 3862 10988

$$

KJS

The office that day

Everything else NWS Grand Junction, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 26, 6:10 PM MDTFlash Flood WarningGJTSan Juan3 hr
Jul 26, 6:11 PM MDTFlash Flood WarningGJTSan Juan3 hr
Jul 26, 6:21 PM MDTFlash Flood WarningGJTSan Juan3 hr
Jul 26, 7:07 PM MDTAreal Flood AdvisoryGJTGrand3 hr
Jul 26, 7:44 PM MDTFlash Flood WarningGJTGrand3 hr
Jul 26, 7:55 PM MDTSpecial Weather StatementGJTSan Juan50 min
Jul 26, 9:32 PM MDTAreal Flood AdvisoryGJTSan Juan118 min
Jul 27, 12:47 PM MDTAreal Flood AdvisoryGJTSan Juan3 hr
Jul 27, 1:27 PM MDTAreal Flood AdvisoryGJTGrand24 min
Jul 27, 2:29 PM MDTAreal Flood AdvisoryGJTSan Juan2 hr

Nearby

Flash Flood Warnings in Utah, 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.