Alert archive / Colorado / Flash Flood Warnings in 2012

Flash Flood Warning 24, NWS Denver/Boulder, CO

August 1, 2012Larimer County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Aug 1, 2012, 1:38 PM MDT for Larimer County, Colorado. It was in force for 82 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
Aug 1, 2012, 1:38 PM MDT (19:38 UTC)
Expired
Aug 1, 2012, 3:00 PM MDT
In force
82 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

County Larimer County, CO

The radar

The Cheyenne radar (KCYS), 71 km from the middle of the area, began a volume at 19:42 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, 7.6 hours before the alert went out and 206 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 2012-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2012-08-01The 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2829 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
16 m²/s²
0-3 km storm-relative helicity
29 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.

537 
WGUS55 KBOU 011938
FFWBOU
COC069-012100-
/O.NEW.KBOU.FF.W.0024.120801T1938Z-120801T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
138 PM MDT WED AUG 1 2012

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL LARIMER COUNTY IN NORTH CENTRAL COLORADO

* UNTIL 300 PM MDT

* AT 136 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM 4 MILES WEST OF MISHAWAKA...OR
  20 MILES WEST OF FORT COLLINS. THIS STORM WAS MOVING NORTHEAST AT 5
  MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO POUDRE PARK
  AND MISHAWAKA.

DOPPLER RADAR ESTIMATES THAT AROUND ONE INCH OF RAIN HAS FALLEN
FROM THIS STORM IN THE LAST HOUR.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE. TURN AROUND...DO NOT DROWN.

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF CREEKS
AND STREAMS...ROADS...AND ROADSIDE CULVERTS. THE HEAVY RAINS COULD 
ALSO TRIGGER ROCK SLIDES OR DEBRIS FLOWS IN THE HIGH PARK BURN AREA.

&&

LAT...LON 4077 10537 4069 10528 4060 10546 4066 10554

$$
2 follow-up statements
072 
WGUS75 KBOU 012027
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
227 PM MDT WED AUG 1 2012

COC069-012100-
/O.CON.KBOU.FF.W.0024.000000T0000Z-120801T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LARIMER CO-
227 PM MDT WED AUG 1 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 300 PM MDT FOR
CENTRAL LARIMER COUNTY...

AT 221 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED VERY
HEAVY RAIN FROM A THUNDERSTORM 2 MILES WEST OF MISHAWAKA...OR ABOUT
19 MILES NORTHWEST OF FORT COLLINS. THIS STORM WAS NEARLY STATIONARY.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
POUDRE PARK AND MISHAWAKA.

DOPPLER RADAR ESTIMATES THAT AROUND ONE INCH OF RAIN HAS FALLEN FROM 
THIS STORM IN THE LAST HOUR.  LIGHT TO MODERATE RAIN CONTINUES OVER 
THE WARNING AREA.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF CREEKS
AND STREAMS...ROADS...AND ROADSIDE CULVERTS. THE HEAVY RAINS COULD 
ALSO TRIGGER DEBRIS FLOWS OR ROCK SLIDES IN THE HIGH PARK BURN AREA.

MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS
BRIDGES...DIPS...OR OTHER LOW SPOTS IF WATER COVERS THE ROADWAY.
NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL ONE...ON FOOT. TO
ESCAPE RISING WATER CLIMB TO HIGHER GROUND.

&&

LAT...LON 4077 10537 4069 10528 4060 10546 4066 10554

$$
848 
WGUS75 KBOU 012057
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
257 PM MDT WED AUG 1 2012

COC069-012105-
/O.EXP.KBOU.FF.W.0024.000000T0000Z-120801T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LARIMER CO-
257 PM MDT WED AUG 1 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 300 PM MDT FOR CENTRAL
LARIMER COUNTY...

THE STORM THAT PROMPTED THE WARNING HAS EXITED THE AREA.  LIGHT RAIN 
CONTINUES IN THE WARNING AREA...BUT THE THREAT OF FLASH FLOODING HAS 
DIMINISHED. 

BE AWARE THAT THERE ARE OTHER STORMS IN LARIMER COUNTY THAT COULD 
MOVE INTO THE BURN AREA THIS AFTERNOON AND MORE FLOODING RAINFALL 
COULD BE POSSIBLE.   

LAT...LON 4077 10537 4069 10528 4060 10546 4066 10554

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 1, 12:45 PM MDTSpecial Weather StatementBOUJefferson30 min
Aug 1, 1:16 PM MDTAreal Flood AdvisoryBOULarimer89 min
Aug 1, 5:15 PM MDTSpecial Weather StatementBOUWashington30 min

Nearby

Flash Flood Warnings in Colorado, 2012Every flash flood warning in 2012

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.