Alert archive / Colorado / Flash Flood Warnings in 2011

Flash Flood Warning 21, NWS Grand Junction, CO

July 12, 2011Delta County, Mesa County, Colorado

NWS Grand Junction, CO issued this flash flood warning at Jul 12, 2011, 5:20 PM MDT for Delta County, Mesa County, Colorado. It was in force for 4 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
Jul 12, 2011, 5:20 PM MDT (23:20 UTC)
Expired
Jul 12, 2011, 9:45 PM MDT
In force
4 hr
Issued by
NWS Grand Junction, CO
Area
Storm-based polygon
Flood severity
None

Counties Delta County, CO, Mesa County, CO

The radar

The Grand Junction radar (KGJX), 37 km from the middle of the area, began a volume at 23:23 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, 11.3 hours before the alert went out and 43 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 2011-07-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 82 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 2011-07-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 50 square meters per square second.193958Sfc1 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
82 J/kg
Mixed-layer CIN
-90 J/kg
Mixed-layer LCL
1105 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
50 m²/s²
0-3 km storm-relative helicity
57 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

634 
WGUS55 KGJT 122320
FFWGJT
COC029-077-130430-
/O.NEW.KGJT.FF.W.0021.110712T2320Z-110713T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
520 PM MDT TUE JUL 12 2011

THE NATIONAL WEATHER SERVICE IN GRAND JUNCTION HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTH CENTRAL MESA COUNTY IN WEST CENTRAL COLORADO...
  WEST CENTRAL DELTA COUNTY IN WEST CENTRAL COLORADO...

* UNTIL 1030 PM MDT

* AT 519 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  SLOW MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE      
  WARNED AREA. EXPECT RAINFALL RATES OF ONE TO TWO INCHES PER HOUR.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

&&

LAT...LON 3888 10820 3869 10823 3868 10838 3859 10840
      3860 10875 3895 10848

$$

AS
1 follow-up statement
717 
WGUS75 KGJT 130345
FFSGJT

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
945 PM MDT TUE JUL 12 2011

COC029-077-130400-
/O.CAN.KGJT.FF.W.0021.000000T0000Z-110713T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MESA CO-DELTA CO-
945 PM MDT TUE JUL 12 2011

...THE FLASH FLOOD WARNING THAT WAS IN EFFECT FOR WEST CENTRAL DELTA
AND SOUTH CENTRAL MESA COUNTIES IS CANCELLED...

EXCESS RUNOFF FROM HEAVY RAIN HAS ENDED OVER THE WARNED AREA. STREAMS
AND CREEKS IN THE WARNED AREA HAVE RECEDED OR WERE BEGINNING TO
RECEDE...ENDING THE FLOOD THREAT. IF FLOODING HAS BEEN OBSERVED...
PLEASE REPORT IT TO YOUR LOCAL LAW ENFORCEMENT AGENCY.

LAT...LON 3888 10820 3869 10823 3868 10838 3859 10840
      3860 10875 3895 10848

$$

CC

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 11, 9:35 PM MDTAreal Flood AdvisoryGJTMesa77 min
Jul 11, 11:52 PM MDTAreal Flood AdvisoryGJTGarfield, Rio Blanco3 hr
Jul 12, 2:13 PM MDTFlash Flood WarningGJTRio Blanco3 hr
Jul 12, 2:20 PM MDTFlash Flood WarningGJTMontrose, San Miguel3 hr
Jul 12, 2:43 PM MDTFlash Flood WarningGJTMesa3 hr
Jul 12, 3:28 PM MDTAreal Flood AdvisoryGJTDolores, Montezuma4 hr
Jul 12, 4:11 PM MDTAreal Flood AdvisoryGJTGarfield3 hr
Jul 12, 4:28 PM MDTAreal Flood AdvisoryGJTDelta, Mesa3 hr
Jul 12, 4:37 PM MDTFlash Flood WarningGJTDolores, Montezuma3 hr
Jul 12, 4:56 PM MDTFlash Flood WarningGJTDolores, Montrose, San Miguel3 hr
Jul 12, 5:46 PM MDTAreal Flood AdvisoryGJTDelta3 hr

Nearby

Flash Flood Warnings in Colorado, 2011Every flash flood warning in 2011

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.