Alert archive / Colorado / Flash Flood Warnings in 2011

Flash Flood Warning 5, NWS Denver/Boulder, CO

July 5, 2011Grand County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 5, 2011, 5:34 PM MDT for Grand County, Colorado. It was in force for 86 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 5, 2011, 5:34 PM MDT (23:34 UTC)
Expired
Jul 5, 2011, 7:00 PM MDT
In force
86 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

County Grand County, CO

The radar

The Denver radar (KFTG), 111 km from the middle of the area, began a volume at 23:38 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, 11.6 hours before the alert went out and 222 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 2011-07-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 45 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 2011-07-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 5 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
45 J/kg
Mixed-layer CIN
-407 J/kg
Mixed-layer LCL
1874 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
5 m²/s²
0-3 km storm-relative helicity
-34 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.

113 
WGUS55 KBOU 052334
FFWBOU
COC049-060100-
/O.NEW.KBOU.FF.W.0005.110705T2334Z-110706T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
534 PM MDT TUE JUL 5 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN GRAND COUNTY IN NORTH CENTRAL COLORADO

* UNTIL 700 PM MDT

* AT 531 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  HEAVY RAIN FROM A THUNDERSTORM 3 MILES SOUTHWEST OF FRASER...  OR  
  48 MILES WEST OF DENVER.  THIS STORM WAS MOVING EAST AT 10 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO FRASER AND 
  ALONG SAINT LOUIS CREEK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING 
ESPECIALLY ALONG SAINT LOUIS CREEK...ROADS AND ROADSIDE 
CULVERTS. THE HEAVY RAINS COULD ALSO TRIGGER ROCK SLIDES OR DEBRIS 
FLOWS IN STEEP TERRAIN.

&&

LAT...LON 3997 10578 3988 10577 3987 10590 3996 10592

$$
2 follow-up statements
770 
WGUS75 KBOU 052357
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
557 PM MDT TUE JUL 5 2011

COC049-060100-
/O.CON.KBOU.FF.W.0005.000000T0000Z-110706T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GRAND CO-
557 PM MDT TUE JUL 5 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 700 PM MDT FOR
SOUTHEASTERN GRAND COUNTY...

AT 555 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THE 
HEAVY RAIN HAD ENDED ALONG SAINT LOUIS CREEK NEAR FRASER.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
FRASER AND SAIT LOUIS CREEK.

DOPPLER RADAR ESTIMATES THAT AROUND ONE HALF INCH OF RAIN MAY HAVE 
FALLEN ALONG SAINT LOUIS CREEK IN LESS THAN 45 MINUTES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAIN WILL CAUSE FLASH FLOODING ALONG 
SAINT LOUIS CREEK...ROADS AND ROADSIDE CULVERTS. THE HEAVY 
RAINS COULD ALSO TRIGGER ROCK SLIDES OR DEBRIS FLOWS IN STEEP 
TERRAIN.

&&

LAT...LON 3997 10578 3988 10577 3987 10590 3996 10592

$$
145 
WGUS75 KBOU 060057
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
657 PM MDT TUE JUL 5 2011

COC049-060107-
/O.EXP.KBOU.FF.W.0005.000000T0000Z-110706T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GRAND CO-
657 PM MDT TUE JUL 5 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 700 PM MDT FOR SOUTHEASTERN
GRAND COUNTY...

THE STORM THAT PROMPTED THE WARNING HAS EXITED THE AREA.

LAT...LON 3997 10578 3988 10577 3987 10590 3996 10592

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 5, 3:15 AM MDTFlash Flood WatchBOUAdams, Arapahoe, Boulder, Broomfield, Clear Creek, Denver and 12 more23 hr
Jul 5, 5:41 PM MDTSpecial Weather StatementBOUAdams34 min

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.