Alert archive / Colorado / Flash Flood Watches in 2021

Flash Flood Watch 7, NWS Denver/Boulder, CO

July 29, 202116 counties in Colorado

NWS Denver/Boulder, CO issued this flash flood watch at Jul 29, 2021, 2:03 PM MDT for 16 counties in Colorado. It took effect at Jul 30, 2021, 11:00 AM MDT. It was in force for 34 hr.

The area

The counties it named.

The facts

Issued
Jul 29, 2021, 2:03 PM MDT (20:03 UTC)
In effect from
Jul 30, 2021, 11:00 AM MDT
Expired
Jul 31, 2021, 9:00 PM MDT
In force
34 hr
Issued by
NWS Denver/Boulder, CO
Flood severity
None

Counties Adams County, CO, Arapahoe County, CO, Boulder County, CO, Broomfield County, CO, Clear Creek County, CO, Denver County, CO, Douglas County, CO, Elbert County, CO, Gilpin County, CO, Grand County, CO, Jackson County, CO, Jefferson County, CO, Larimer County, CO, Park County, CO, Summit County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 59 km from the middle of the area, began a volume at 20:03 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, 8.1 hours before the alert went out and 170 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 2021-07-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 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 2021-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 1 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
2 J/kg
Mixed-layer CIN
-369 J/kg
Mixed-layer LCL
2462 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
1 m²/s²
0-3 km storm-relative helicity
23 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

890 
WGUS65 KBOU 292003
FFABOU

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Denver CO
203 PM MDT Thu Jul 29 2021

COZ032>035-300415-
/O.NEW.KBOU.FF.A.0007.210730T1700Z-210731T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grand and Summit Counties Below 9000 Feet-South and East
Jackson/Larimer/North and Northeast Grand/Northwest Boulder
Counties Above 9000 Feet-South and Southeast Grand/West Central
and Southwest Boulder/Gilpin/Clear Creek/Summit/North and West
Park Counties Above 9000 Feet-Larimer and Boulder Counties
Between 6000 and 9000 Feet-
Including the cities of Winter Park, Rocky Mountain National
Park, Laramie and Medicine Bow Mountains, Red Feather Lakes,
Breckenridge, Williams Fork Mountains, Glendevey, Indian Peaks,
Nederland, Eisenhower Tunnel, Kremmling, East Slopes Southern
Gore Range, Mount Evans, Grand Lake, Cameron Pass, East Slopes
Mosquito Range, Berthoud Pass, Granby, Kenosha Mountains, Estes
Park, Willow Creek Pass, Hot Sulphur Springs, Dillon, Fraser, and
Rabbit Ears Range
203 PM MDT Thu Jul 29 2021

...FLASH FLOOD WATCH IN EFFECT FROM FRIDAY MORNING THROUGH FRIDAY 
EVENING...

The National Weather Service in Denver has issued a

* Flash Flood Watch for Portions of central and north central 
  Colorado, including the following areas, in central Colorado, 
  Grand and Summit Counties Below 9000 Feet and South and Southeast 
  Grand/West Central and Southwest Boulder/Gilpin/Clear 
  Creek/Summit/North and West Park Counties Above 9000 Feet. In 
  north central Colorado, Larimer and Boulder Counties Between 6000 
  and 9000 Feet and South and East Jackson/Larimer/North and 
  Northeast Grand/Northwest Boulder Counties Above 9000 Feet.

* From Friday morning through Friday evening.

* Thunderstorms will become more numerous across the mountains and 
  foothills by Friday afternoon, and will have potential to produce 
  flash flooding in the burn areas.  The highest threat areas would 
  be the Cameron Peak, East Troublesome, and Williams Fork burn 
  areas, with a little lower threat for the Calwood burn area.  
  Rainfall amounts up to 1 inch will be possible in less than an 
  hour.

* Burn scars will be susceptible to heavy rainfall, leading to quick 
  runoff and possible debris and mud flows.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Barjenbruch
7 follow-up statements
235 
WGUS65 KBOU 300249
FFABOU

Flood Watch
National Weather Service Denver CO
849 PM MDT Thu Jul 29 2021

COZ032>035-310600-
/O.CON.KBOU.FF.A.0007.210730T1700Z-210731T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grand and Summit Counties Below 9000 Feet-South and East
Jackson/Larimer/North and Northeast Grand/Northwest Boulder
Counties Above 9000 Feet-South and Southeast Grand/West Central
and Southwest Boulder/Gilpin/Clear Creek/Summit/North and West
Park Counties Above 9000 Feet-Larimer and Boulder Counties
Between 6000 and 9000 Feet-
Including the cities of Winter Park, Rocky Mountain National
Park, Laramie and Medicine Bow Mountains, Red Feather Lakes,
Breckenridge, Williams Fork Mountains, Glendevey, Indian Peaks,
Nederland, Eisenhower Tunnel, Kremmling, East Slopes Southern
Gore Range, Mount Evans, Grand Lake, Cameron Pass, East Slopes
Mosquito Range, Berthoud Pass, Granby, Kenosha Mountains, Estes
Park, Willow Creek Pass, Hot Sulphur Springs, Dillon, Fraser, and
Rabbit Ears Range
849 PM MDT Thu Jul 29 2021

...FLASH FLOOD WATCH IN EFFECT FROM 11 AM FRIDAY MORNING UNTIL 
MIDNIGHT FRIDAY NIGHT...

The Flash Flood Watch continues for

* Portions of central and north central Colorado, including the 
  following areas, in central Colorado, Grand and Summit Counties 
  Below 9000 Feet and South and Southeast Grand/West Central and 
  Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park 
  Counties Above 9000 Feet. In north central Colorado, Larimer and 
  Boulder Counties Between 6000 and 9000 Feet and South and East 
  Jackson/Larimer/North and Northeast Grand/Northwest Boulder 
  Counties Above 9000 Feet.

* From Friday morning through Friday evening.

* Thunderstorms will become more numerous across the mountains and 
  foothills by Friday afternoon, and will have potential to produce 
  flash flooding in the burn areas.  The highest threat areas would 
  be the Cameron Peak, East Troublesome, and Williams Fork burn 
  areas, with a little lower threat for the Calwood burn area.  
  Rainfall amounts up to 1 inch will be possible in less than an 
  hour.

* Burn scars will be susceptible to heavy rainfall, leading to quick 
  runoff and possible debris and mud flows.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Bowen
965 
WGUS65 KBOU 301049
FFABOU

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Denver CO
449 AM MDT Fri Jul 30 2021

COZ030-031-302300-
/O.EXA.KBOU.FF.A.0007.210730T1700Z-210731T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jackson County Below 9000 Feet-West Jackson and West Grand
Counties Above 9000 Feet-
Including the cities of Rand, North Park, Mt Zirkel, Walden,
Gould, and Spicer
449 AM MDT Fri Jul 30 2021

...FLASH FLOOD WATCH IN EFFECT FROM 11 AM MDT THIS MORNING THROUGH 
THIS EVENING...

The National Weather Service in Denver has expanded the

* Flash Flood Watch to include A portion of north central Colorado, 
  including the following areas, Jackson County Below 9000 Feet and 
  West Jackson and West Grand Counties Above 9000 Feet.

* From 11 AM MDT this morning through this evening.

* Thunderstorms will become more numerous by this afternoon, and 
  will have potential to produce flash flooding in the burn areas. 
  Rainfall amounts up to 1 inch will be possible in less than an 
  hour.

* Burn scars will be particularly susceptible to heavy rainfall, 
  leading to quick runoff and possible debris and mud flows.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

COZ032>035-302300-
/O.CON.KBOU.FF.A.0007.210730T1700Z-210731T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grand and Summit Counties Below 9000 Feet-South and East
Jackson/Larimer/North and Northeast Grand/Northwest Boulder
Counties Above 9000 Feet-South and Southeast Grand/West Central
and Southwest Boulder/Gilpin/Clear Creek/Summit/North and West
Park Counties Above 9000 Feet-Larimer and Boulder Counties
Between 6000 and 9000 Feet-
Including the cities of Winter Park, Rocky Mountain National
Park, Laramie and Medicine Bow Mountains, Red Feather Lakes,
Breckenridge, Williams Fork Mountains, Glendevey, Indian Peaks,
Nederland, Eisenhower Tunnel, Kremmling, East Slopes Southern
Gore Range, Mount Evans, Grand Lake, Cameron Pass, East Slopes
Mosquito Range, Berthoud Pass, Granby, Kenosha Mountains, Estes
Park, Willow Creek Pass, Hot Sulphur Springs, Dillon, Fraser, and
Rabbit Ears Range
449 AM MDT Fri Jul 30 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT FROM 11 AM MDT THIS MORNING 
THROUGH THIS EVENING...

The Flash Flood Watch continues for

* Portions of central and north central Colorado, including the 
  following areas, in central Colorado, Grand and Summit Counties 
  Below 9000 Feet and South and Southeast Grand/West Central and 
  Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park 
  Counties Above 9000 Feet. In north central Colorado, Larimer and 
  Boulder Counties Between 6000 and 9000 Feet and South and East 
  Jackson/Larimer/North and Northeast Grand/Northwest Boulder 
  Counties Above 9000 Feet.

* From 11 AM MDT this morning through this evening.

* Thunderstorms will become more numerous across the mountains and 
  foothills by this afternoon, and will have potential to produce 
  flash flooding in the burn areas.  The highest threat areas would 
  be the Cameron Peak, East Troublesome, and Williams Fork burn 
  areas, with a little lower threat for the Calwood burn area.  
  Rainfall amounts up to 1 inch will be possible in less than an 
  hour.

* Burn scars will be particularly susceptible to heavy rainfall, 
  leading to quick runoff and possible debris and mud flows.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Direnzo
359 
WGUS65 KBOU 301545
FFABOU

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Denver CO
945 AM MDT Fri Jul 30 2021

COZ036>041-043-302345-
/O.EXB.KBOU.FF.A.0007.210731T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-Central and
Southeast Park County-Larimer County Below 6000 Feet/Northwest
Weld County-Boulder And Jefferson Counties Below 6000 Feet/West
Broomfield County-North Douglas County Below
6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield
County-Elbert/Central and East Douglas Counties Above 6000 Feet-
Central and South Weld County-
Including the cities of Hartsel, Elbert, Westcreek, Roggen,
Arvada, Central City, Larkspur, Bailey, Evergreen, Georgetown,
Lakewood, Aurora, Fairplay, Littleton, Brighton, Boulder,
Highlands Ranch, Fort Lupton, Loveland, Kiowa, Eaton, Longmont,
Fondis, Denver International Airport, Golden, Parker, Castle
Rock, City of Denver, Fort Collins, Greeley, Nunn, Idaho Springs,
Lake George, Hereford, and South Park
945 AM MDT Fri Jul 30 2021

...FLASH FLOOD WATCH IN EFFECT FROM 6 PM MDT THIS EVENING UNTIL 9 PM 
SATURDAY EVENING...

The National Weather Service in Denver has expanded the

* Flash Flood Watch to include Portions of central, north central, 
  and northeast Colorado, including the following areas, in central 
  Colorado, Central and Southeast Park County and Jefferson and West 
  Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast Park 
  Counties Below 9000 Feet. In north central Colorado, Larimer 
  County Below 6000 Feet/Northwest Weld County. In northeast 
  Colorado, Boulder And Jefferson Counties Below 6000 Feet/West 
  Broomfield County, Central and South Weld County, Elbert/Central 
  and East Douglas Counties Above 6000 Feet and North Douglas County 
  Below 6000 Feet/Denver/West Adams and Arapahoe Counties/East 
  Broomfield County.

* From 6 PM MDT this evening through Saturday evening.

* Scattered thunderstorms will develop late this afternoon or 
  evening, and may then continue overnight with locally heavy 
  rainfall and potential for flash flooding.  Rainfall amounts of 1 
  to 2 inches in less than an hour will be possible from the 
  stronger storms.  There is a threat that a few storms with heavy 
  rain will continue overnight into early Saturday morning.  
  Additional rounds of showers and storms can be expected Saturday 
  afternoon and evening.

* Flash flooding will be possible in urban and low lying areas. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued. Never drive through a flooded 
area.

&&

$$

COZ030>035-302345-
/O.EXT.KBOU.FF.A.0007.210730T1700Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jackson County Below 9000 Feet-West Jackson and West Grand
Counties Above 9000 Feet-Grand and Summit Counties Below
9000 Feet-South and East Jackson/Larimer/North and Northeast
Grand/Northwest Boulder Counties Above 9000 Feet-South and
Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear
Creek/Summit/North and West Park Counties Above 9000 Feet-Larimer
and Boulder Counties Between 6000 and 9000 Feet-
Including the cities of North Park, Rocky Mountain National Park,
Mt Zirkel, Laramie and Medicine Bow Mountains, Red Feather Lakes,
Breckenridge, Williams Fork Mountains, Glendevey, Indian Peaks,
Nederland, Eisenhower Tunnel, Kremmling, East Slopes Southern
Gore Range, Mount Evans, Grand Lake, Cameron Pass, East Slopes
Mosquito Range, Berthoud Pass, Winter Park, Granby, Hot Sulphur
Springs, Kenosha Mountains, Gould, Willow Creek Pass, Spicer,
Rand, Estes Park, Dillon, Fraser, Walden, and Rabbit Ears Range
945 AM MDT Fri Jul 30 2021

...FLASH FLOOD WATCH NOW IN EFFECT UNTIL 9 PM SATURDAY EVENING...

The Flash Flood Watch is now in effect for

* Portions of central and north central Colorado, including the 
  following areas, in central Colorado, Grand and Summit Counties 
  Below 9000 Feet and South and Southeast Grand/West Central and 
  Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park 
  Counties Above 9000 Feet. In north central Colorado, Jackson 
  County Below 9000 Feet, Larimer and Boulder Counties Between 6000 
  and 9000 Feet, South and East Jackson/Larimer/North and Northeast 
  Grand/Northwest Boulder Counties Above 9000 Feet and West Jackson 
  and West Grand Counties Above 9000 Feet.

* Through Saturday evening.

* Thunderstorms will become more numerous across the mountains and 
  foothills by this afternoon, and will have potential to produce 
  flash flooding.  The highest threat areas would be the Cameron 
  Peak, East Troublesome, Williams Fork, and Calwood burn areas, but 
  flash flooding will even be possible in non-burn scar areas due to 
  the intensity of the rainfall.  Rainfall amounts around 1.5 inches 
  will be possible in less than an hour.  While storms should 
  gradually diminish overnight, there is still a threat of heavy 
  rain continuing in the foothill areas overnight into early 
  Saturday morning.  Additional rounds of showers and storms can be 
  expected Saturday afternoon and evening.

* Burn scars will be particularly susceptible to heavy rainfall, 
  leading to quick runoff and debris and mud flows. The flood threat 
  may last through the night.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Have multiple ways to receive warnings, including television, 
weather radio, phone, family, and friends. Avoid burn areas in 
particular, and be ready to move to higher ground.

&&

$$

Barjenbruch
599 
WGUS65 KBOU 310116
FFABOU

Flood Watch
National Weather Service Denver CO
716 PM MDT Fri Jul 30 2021

COZ030>035-311215-
/O.CON.KBOU.FF.A.0007.000000T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jackson County Below 9000 Feet-West Jackson and West Grand
Counties Above 9000 Feet-Grand and Summit Counties Below
9000 Feet-South and East Jackson/Larimer/North and Northeast
Grand/Northwest Boulder Counties Above 9000 Feet-South and
Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear
Creek/Summit/North and West Park Counties Above 9000 Feet-Larimer
and Boulder Counties Between 6000 and 9000 Feet-
Including the cities of North Park, Rocky Mountain National Park,
Mt Zirkel, Laramie and Medicine Bow Mountains, Red Feather Lakes,
Breckenridge, Williams Fork Mountains, Glendevey, Indian Peaks,
Nederland, Eisenhower Tunnel, Kremmling, East Slopes Southern
Gore Range, Mount Evans, Grand Lake, Cameron Pass, East Slopes
Mosquito Range, Berthoud Pass, Winter Park, Granby, Hot Sulphur
Springs, Kenosha Mountains, Gould, Willow Creek Pass, Spicer,
Rand, Estes Park, Dillon, Fraser, Walden, and Rabbit Ears Range
716 PM MDT Fri Jul 30 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH SATURDAY EVENING...

The Flash Flood Watch continues for

* Portions of central and north central Colorado, including the 
  following areas, in central Colorado, Grand and Summit Counties 
  Below 9000 Feet and South and Southeast Grand/West Central and 
  Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park 
  Counties Above 9000 Feet. In north central Colorado, Jackson 
  County Below 9000 Feet, Larimer and Boulder Counties Between 6000 
  and 9000 Feet, South and East Jackson/Larimer/North and Northeast 
  Grand/Northwest Boulder Counties Above 9000 Feet and West Jackson 
  and West Grand Counties Above 9000 Feet.

* Through Saturday evening.

* Showers and thunderstorms will continue off and on through 
  Saturday, and have potential to produce additional flash 
  flooding.  The highest flash flood threat areas would be the 
  Cameron Peak, East Troublesome, Williams Fork, and Calwood burn 
  areas, but flash flooding will even be possible in non-burn scar 
  areas due to the intensity of the rainfall.  Rainfall amounts 
  around 1.5 inches will be possible in less than an hour, with 
  storm total accumulations even higher.  While storms should 
  gradually diminish overnight, there is still a threat of heavy 
  rain continuing in the foothill areas overnight into early 
  Saturday morning.  Additional rounds of showers and storms can be 
  expected Saturday afternoon and evening.

* Burn scars will be particularly susceptible to heavy rainfall, 
  leading to quick runoff and debris and mud flows. The flood threat 
  may last through the night.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Have multiple ways to receive warnings, including television, 
weather radio, phone, family, and friends. Avoid burn areas in 
particular, and be ready to move to higher ground.

&&

$$

COZ036>041-043-311215-
/O.CON.KBOU.FF.A.0007.000000T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-Central and
Southeast Park County-Larimer County Below 6000 Feet/Northwest
Weld County-Boulder And Jefferson Counties Below 6000 Feet/West
Broomfield County-North Douglas County Below
6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield
County-Elbert/Central and East Douglas Counties Above 6000 Feet-
Central and South Weld County-
Including the cities of Hartsel, Elbert, Westcreek, Roggen,
Arvada, Central City, Larkspur, Bailey, Evergreen, Georgetown,
Lakewood, Aurora, Fairplay, Littleton, Brighton, Boulder,
Highlands Ranch, Fort Lupton, Loveland, Kiowa, Eaton, Longmont,
Fondis, Denver International Airport, Golden, Parker, Castle
Rock, City of Denver, Fort Collins, Greeley, Nunn, Idaho Springs,
Lake George, Hereford, and South Park
716 PM MDT Fri Jul 30 2021

...FLASH FLOOD WATCH IN EFFECT FROM 6 PM MDT THIS EVENING UNTIL 9 PM 
SATURDAY EVENING...

The Flash Flood Watch continues for

* Portions of central, north central, and northeast Colorado, 
  including the following areas, in central Colorado, Central and 
  Southeast Park County and Jefferson and West Douglas Counties 
  Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 
  9000 Feet. In north central Colorado, Larimer County Below 6000 
  Feet/Northwest Weld County. In northeast Colorado, Boulder And 
  Jefferson Counties Below 6000 Feet/West Broomfield County, Central 
  and South Weld County, Elbert/Central and East Douglas Counties 
  Above 6000 Feet and North Douglas County Below 6000 
  Feet/Denver/West Adams and Arapahoe Counties/East Broomfield 
  County.

* Through Saturday evening.

* Showers and thunderstorms may continue overnight, with locally 
  heavy rainfall and potential for flash flooding.  Rainfall amounts 
  of 1 to 2 inches in less than an hour will be possible from the 
  stronger storms.  Additional rounds of showers and storms can be 
  expected through Saturday evening.

* Flash flooding will be possible in urban and low lying areas. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued. Never drive through a flooded 
area.

&&

$$

Barjenbruch
312 
WGUS65 KBOU 311112
FFABOU

Flood Watch
National Weather Service Denver CO
512 AM MDT Sat Jul 31 2021

COZ030>035-312100-
/O.CON.KBOU.FF.A.0007.000000T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jackson County Below 9000 Feet-West Jackson and West Grand
Counties Above 9000 Feet-Grand and Summit Counties Below
9000 Feet-South and East Jackson/Larimer/North and Northeast
Grand/Northwest Boulder Counties Above 9000 Feet-South and
Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear
Creek/Summit/North and West Park Counties Above 9000 Feet-Larimer
and Boulder Counties Between 6000 and 9000 Feet-
Including the cities of North Park, Rocky Mountain National Park,
Mt Zirkel, Laramie and Medicine Bow Mountains, Red Feather Lakes,
Breckenridge, Williams Fork Mountains, Glendevey, Indian Peaks,
Nederland, Eisenhower Tunnel, Kremmling, East Slopes Southern
Gore Range, Mount Evans, Grand Lake, Cameron Pass, East Slopes
Mosquito Range, Berthoud Pass, Winter Park, Granby, Hot Sulphur
Springs, Kenosha Mountains, Gould, Willow Creek Pass, Spicer,
Rand, Estes Park, Dillon, Fraser, Walden, and Rabbit Ears Range
512 AM MDT Sat Jul 31 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS EVENING...

The Flash Flood Watch continues for

* Portions of central and north central Colorado, including the 
  following areas, in central Colorado, Grand and Summit Counties 
  Below 9000 Feet and South and Southeast Grand/West Central and 
  Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park 
  Counties Above 9000 Feet. In north central Colorado, Jackson 
  County Below 9000 Feet, Larimer and Boulder Counties Between 6000 
  and 9000 Feet, South and East Jackson/Larimer/North and Northeast 
  Grand/Northwest Boulder Counties Above 9000 Feet and West Jackson 
  and West Grand Counties Above 9000 Feet.

* Through this evening.

* Additional rounds of showers and storms can be expected later this 
  morning and will continue into this evening,  The stronger storms 
  will produce 1-2 inches of rainfall in less than one hour.

* Burn scars will be especially susceptible to heavy rainfall, 
  leading to quick runoff and debris and mud flows.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

COZ036>041-043-312100-
/O.CON.KBOU.FF.A.0007.000000T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-Central and
Southeast Park County-Larimer County Below 6000 Feet/Northwest
Weld County-Boulder And Jefferson Counties Below 6000 Feet/West
Broomfield County-North Douglas County Below
6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield
County-Elbert/Central and East Douglas Counties Above 6000 Feet-
Central and South Weld County-
Including the cities of Hartsel, Elbert, Westcreek, Roggen,
Arvada, Central City, Larkspur, Bailey, Evergreen, Georgetown,
Lakewood, Aurora, Fairplay, Littleton, Brighton, Boulder,
Highlands Ranch, Fort Lupton, Loveland, Kiowa, Eaton, Longmont,
Fondis, Denver International Airport, Golden, Parker, Castle
Rock, City of Denver, Fort Collins, Greeley, Nunn, Idaho Springs,
Lake George, Hereford, and South Park
512 AM MDT Sat Jul 31 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH THIS EVENING...

The Flash Flood Watch continues for

* Portions of central, north central, and northeast Colorado, 
  including the following areas, in central Colorado, Central and 
  Southeast Park County and Jefferson and West Douglas Counties 
  Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 
  9000 Feet. In north central Colorado, Larimer County Below 6000 
  Feet/Northwest Weld County. In northeast Colorado, Boulder And 
  Jefferson Counties Below 6000 Feet/West Broomfield County, Central 
  and South Weld County, Elbert/Central and East Douglas Counties 
  Above 6000 Feet and North Douglas County Below 6000 
  Feet/Denver/West Adams and Arapahoe Counties/East Broomfield 
  County.

* Through this evening.

* Additional rounds of showers and storms can be expected later this 
  morning and will continue into this evening.  The stronger storms 
  will produce 1-2 inches of rainfall in less than one hour.

* Flash flooding will be possible in urban and low lying areas. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

Cooper
279 
WGUS65 KBOU 311830
FFABOU

Flood Watch
National Weather Service Denver CO
1230 PM MDT Sat Jul 31 2021

COZ030>035-010230-
/O.CON.KBOU.FF.A.0007.000000T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jackson County Below 9000 Feet-West Jackson and West Grand
Counties Above 9000 Feet-Grand and Summit Counties Below
9000 Feet-South and East Jackson/Larimer/North and Northeast
Grand/Northwest Boulder Counties Above 9000 Feet-South and
Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear
Creek/Summit/North and West Park Counties Above 9000 Feet-Larimer
and Boulder Counties Between 6000 and 9000 Feet-
Including the cities of North Park, Rocky Mountain National Park,
Mt Zirkel, Laramie and Medicine Bow Mountains, Red Feather Lakes,
Breckenridge, Williams Fork Mountains, Glendevey, Indian Peaks,
Nederland, Eisenhower Tunnel, Kremmling, East Slopes Southern
Gore Range, Mount Evans, Grand Lake, Cameron Pass, East Slopes
Mosquito Range, Berthoud Pass, Winter Park, Granby, Hot Sulphur
Springs, Kenosha Mountains, Gould, Willow Creek Pass, Spicer,
Rand, Estes Park, Dillon, Fraser, Walden, and Rabbit Ears Range
1230 PM MDT Sat Jul 31 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING...

The Flash Flood Watch continues for

* Portions of central and north central Colorado, including the 
  following areas, in central Colorado, Grand and Summit Counties 
  Below 9000 Feet and South and Southeast Grand/West Central and 
  Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park 
  Counties Above 9000 Feet. In north central Colorado, Jackson 
  County Below 9000 Feet, Larimer and Boulder Counties Between 6000 
  and 9000 Feet, South and East Jackson/Larimer/North and Northeast 
  Grand/Northwest Boulder Counties Above 9000 Feet and West Jackson 
  and West Grand Counties Above 9000 Feet.

* Until 9 PM MDT this evening.

* Additional rounds of showers and storms can be expected through 
  this evening.  The stronger storms will produce 1-2 inches of 
  rainfall in less than one hour.

* Burn scars will be especially susceptible to heavy rainfall, 
  leading to quick runoff and debris and mud flows.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Have multiple ways to receive warnings, including television, 
weather radio, phone, family, and friends. Avoid burn areas in 
particular, and be ready to move to higher ground.

&&

$$

COZ036>041-043-010230-
/O.CON.KBOU.FF.A.0007.000000T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-Central and
Southeast Park County-Larimer County Below 6000 Feet/Northwest
Weld County-Boulder And Jefferson Counties Below 6000 Feet/West
Broomfield County-North Douglas County Below
6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield
County-Elbert/Central and East Douglas Counties Above 6000 Feet-
Central and South Weld County-
Including the cities of Hartsel, Elbert, Westcreek, Roggen,
Arvada, Central City, Larkspur, Bailey, Evergreen, Georgetown,
Lakewood, Aurora, Fairplay, Littleton, Brighton, Boulder,
Highlands Ranch, Fort Lupton, Loveland, Kiowa, Eaton, Longmont,
Fondis, Denver International Airport, Golden, Parker, Castle
Rock, City of Denver, Fort Collins, Greeley, Nunn, Idaho Springs,
Lake George, Hereford, and South Park
1230 PM MDT Sat Jul 31 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING...

The Flash Flood Watch continues for

* Portions of central, north central, and northeast Colorado, 
  including the following areas, in central Colorado, Central and 
  Southeast Park County and Jefferson and West Douglas Counties 
  Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 
  9000 Feet. In north central Colorado, Larimer County Below 6000 
  Feet/Northwest Weld County. In northeast Colorado, Boulder And 
  Jefferson Counties Below 6000 Feet/West Broomfield County, Central 
  and South Weld County, Elbert/Central and East Douglas Counties 
  Above 6000 Feet and North Douglas County Below 6000 
  Feet/Denver/West Adams and Arapahoe Counties/East Broomfield 
  County.

* Until 9 PM MDT this evening.

* Additional rounds of showers and storms can be expected this 
  afternoon and evening. The stronger storms will produce 1-2 inches 
  of rainfall in less than one hour.  The main threat of flooding 
  will be along and west of I-25, and across the Palmer Divide area.

* Flash flooding will be possible in urban and low lying areas. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued. Never drive through a flooded 
area.

&&

$$

Barjenbruch
543 
WGUS65 KBOU 312011
FFABOU

Flood Watch
National Weather Service Denver CO
211 PM MDT Sat Jul 31 2021

COZ043-312115-
/O.CAN.KBOU.FF.A.0007.000000T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Central and South Weld County-
Including the cities of Fort Lupton, Greeley, Eaton, and Roggen
211 PM MDT Sat Jul 31 2021

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for Central and Southern Weld County has been 
cancelled.

Heavy rain should stay farther west and closer to the Front Range.  
The threat of flash flooding has diminished.

$$

COZ030>035-010300-
/O.CON.KBOU.FF.A.0007.000000T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jackson County Below 9000 Feet-West Jackson and West Grand
Counties Above 9000 Feet-Grand and Summit Counties Below
9000 Feet-South and East Jackson/Larimer/North and Northeast
Grand/Northwest Boulder Counties Above 9000 Feet-South and
Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear
Creek/Summit/North and West Park Counties Above 9000 Feet-Larimer
and Boulder Counties Between 6000 and 9000 Feet-
Including the cities of North Park, Rocky Mountain National Park,
Mt Zirkel, Laramie and Medicine Bow Mountains, Red Feather Lakes,
Breckenridge, Williams Fork Mountains, Glendevey, Indian Peaks,
Nederland, Eisenhower Tunnel, Kremmling, East Slopes Southern
Gore Range, Mount Evans, Grand Lake, Cameron Pass, East Slopes
Mosquito Range, Berthoud Pass, Winter Park, Granby, Hot Sulphur
Springs, Kenosha Mountains, Gould, Willow Creek Pass, Spicer,
Rand, Estes Park, Dillon, Fraser, Walden, and Rabbit Ears Range
211 PM MDT Sat Jul 31 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING...

The Flash Flood Watch continues for

* Portions of central and north central Colorado, including the 
  following areas, in central Colorado, Grand and Summit Counties 
  Below 9000 Feet and South and Southeast Grand/West Central and 
  Southwest Boulder/Gilpin/Clear Creek/Summit/North and West Park 
  Counties Above 9000 Feet. In north central Colorado, Jackson 
  County Below 9000 Feet, Larimer and Boulder Counties Between 6000 
  and 9000 Feet, South and East Jackson/Larimer/North and Northeast 
  Grand/Northwest Boulder Counties Above 9000 Feet and West Jackson 
  and West Grand Counties Above 9000 Feet.

* Until 9 PM MDT this evening.

* Additional rounds of showers and storms can be expected through 
  this evening.  The stronger storms will produce up to 1 inch of 
  rain in an hour, but the persistent nature of showers and storms 
  will still be capable of producing flash flooding, especially in 
  burn areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

COZ036>041-010300-
/O.CON.KBOU.FF.A.0007.000000T0000Z-210801T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-Central and
Southeast Park County-Larimer County Below 6000 Feet/Northwest
Weld County-Boulder And Jefferson Counties Below 6000 Feet/West
Broomfield County-North Douglas County Below
6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield
County-Elbert/Central and East Douglas Counties Above 6000 Feet-
Including the cities of Hartsel, Elbert, Westcreek, Arvada,
Central City, Larkspur, Bailey, Evergreen, Georgetown, Lakewood,
Aurora, Fairplay, Littleton, Brighton, Boulder, Highlands Ranch,
Loveland, Kiowa, Longmont, Fondis, Denver International Airport,
Golden, Parker, Castle Rock, City of Denver, Fort Collins, Nunn,
Idaho Springs, Lake George, Hereford, and South Park
211 PM MDT Sat Jul 31 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING...

The Flash Flood Watch continues for

* Portions of central, north central, and northeast Colorado, 
  including the following areas, in central Colorado, Central and 
  Southeast Park County and Jefferson and West Douglas Counties 
  Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 
  9000 Feet. In north central Colorado, Larimer County Below 6000 
  Feet/Northwest Weld County. In northeast Colorado, Boulder And 
  Jefferson Counties Below 6000 Feet/West Broomfield County, 
  Elbert/Central and East Douglas Counties Above 6000 Feet and North 
  Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe 
  Counties/East Broomfield County.

* Until 9 PM MDT this evening.

* Additional showers and storms can be expected into early evening. 
  The stronger storms will be capable of producing up to 1 inch of 
  rain in 30 minutes. If showers or storms become more persistent, 
  then there is still a threat of flash flooding.

* Flash flooding will be possible in urban and low lying areas. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued. Never drive through a flooded 
area.

&&

$$

Barjenbruch

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 29, 4:59 PM MDTSpecial Weather StatementBOUJackson31 min
Jul 29, 5:21 PM MDTSevere Thunderstorm WarningBOUJackson24 min
Jul 29, 5:38 PM MDTAreal Flood AdvisoryBOUJackson, Larimer2 hr

Nearby

Flash Flood Watches in Colorado, 2021Every flash flood watch 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.