Alert archive / Colorado / Flash Flood Warnings in 2023

Flash Flood Warning 71, NWS Denver/Boulder, CO

August 2, 2023Larimer County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Aug 2, 2023, 11:24 PM MDT for Larimer County, Colorado. It was in force for 5 hr. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 2, 2023, 11:24 PM MDT (05:24 UTC)
Expired
Aug 3, 2023, 4:00 AM MDT
In force
5 hr
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Larimer County, CO

The radar

The Cheyenne radar (KCYS), 86 km from the middle of the area, began a volume at 05:26 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.

What was reported inside it

TimeReportWhereRemark
Aug 3, 12:00 AM MDTFLASH FLOOD2 E Glen Haven, COWater crossing County Road 43 at Streamside Drive.
Aug 3, 12:45 AM MDTFLASH FLOOD3 Ssw Buckhorn Mountain, COWater and debris over County Road 44H.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched 2 storm reports to this flash flood warning; the first came 36 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Grand Junction, CO (KGJT), launched 00:00Z, 5.4 hours before the alert went out and 306 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 00:00Z on 2023-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 798 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Grand Junction, CO at 00:00Z on 2023-08-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 25 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
798 J/kg
Mixed-layer CIN
-64 J/kg
Mixed-layer LCL
2314 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
25 m²/s²
0-3 km storm-relative helicity
145 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.9

Open this sounding in Storm Lab

The text

As transmitted.

849 
WGUS55 KBOU 030524
FFWBOU
COC069-030815-
/O.NEW.KBOU.FF.W.0071.230803T0524Z-230803T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
1124 PM MDT Wed Aug 2 2023

The National Weather Service in Denver has issued a

* Flash Flood Warning for...
  Central Larimer County in north central Colorado...

* Until 215 AM MDT.

* At 1124 PM MDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  0.2 and 0.5 inches of rain have fallen. Additional rainfall 
  amounts of 0.5 to 1 inch are possible in the warned area. Flash 
  flooding is ongoing or expected to begin shortly.The heaviest rain 
  is over the Crystal Mountain and Buckhorn Canyon areas.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar and automated gauges.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  mainly rural areas of Central Larimer County

This includes the following additional locations...
Upper Buckhorn along County Road 44H, Moondance Way, Stringtown 
Gulch, Lower Buckhorn on County Road 27 above Masonville, Crystal 
Mountain, The Retreat and Storm Mountain.

This includes the following streams and drainages...
  Eld Creek, Sheep Creek, Buckhorn Creek, Cedar Creek, Miller Fork, 
  Big Thompson River, Redstone Creek, Black Creek, Pennock Creek and 
  North Fork Fish Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Heavy Rainfall will cause flash flooding of small creeks, streams, 
and ditches in the affected part of the Cameron Peak burn area. Rock 
slides or debris flows can also be expected across rural roads.

&&

LAT...LON 4055 10552 4059 10540 4055 10525 4045 10541

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Gimmestad
4 follow-up statements
911 
WGUS75 KBOU 030636
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
1236 AM MDT Thu Aug 3 2023

COC069-030815-
/O.CON.KBOU.FF.W.0071.000000T0000Z-230803T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Larimer CO-
1236 AM MDT Thu Aug 3 2023

...FLASH FLOOD WARNING FOR THE CAMERON PEAK BURN SCAR REMAINS IN 
EFFECT UNTIL 215 AM MDT EARLY THIS MORNING FOR CENTRAL LARIMER 
COUNTY...

At 1236 AM MDT, emergency management reported that flash flooding 
was occurring over portions of the Cameron Peak Burn Scar. Between 
0.5 and 1 inch of rain has fallen. Additional rainfall amounts up to 
0.5 inches are possible in the warned area. Flash flooding is 
occurring along the lower part of County Road 44H in Buckhorn Canyon 
and on County Road 43 at Streamside Road east of Glen Haven.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding in and around the Cameron Peak Burn Scar.

SOURCE...Emergency management reported.

IMPACT...Life threatening flash flooding of areas in and around
         the Cameron Peak Burn Scar.

Some locations that will experience flash flooding include...
  mainly rural areas of Central Larimer County

This includes the following additional locations...
Upper Buckhorn along County Road 44H, Moondance Way, Stringtown 
Gulch, Lower Buckhorn on County Road 27 above Masonville, Crystal 
Mountain, The Retreat and Storm Mountain.

This includes the following streams and drainages...
  Eld Creek, Sheep Creek, Buckhorn Creek, Cedar Creek, Miller Fork,  
  Redstone Creek, Black Creek, Pennock Creek and North Fork Fish 
  Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Heavy Rainfall will cause flash flooding of small creeks, streams, 
and ditches in the affected part of the Cameron Peak burn area. Rock 
slides or debris flows can also be expected across rural roads.

&&

LAT...LON 4055 10552 4059 10540 4055 10525 4045 10541

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Gimmestad
023 
WGUS55 KBOU 030734
FFWBOU
COC069-031000-
/O.EXT.KBOU.FF.W.0071.000000T0000Z-230803T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
134 AM MDT Thu Aug 3 2023

The National Weather Service in Denver has extended the

* Flash Flood Warning for...
  The Cameron Peak burn scar in...
  Central Larimer County in north central Colorado...

* Until 400 AM MDT.

* At 134 AM MDT, emergency management reported that flash flooding 
  was occurring over portions of the Cameron Peak Burn Scar. Between 
  0.5 and 1.5 inches of rain has fallen. Additional rainfall amounts 
  up to 0.3 inches are possible in the warned area. Flash flooding 
  is occurring along the lower part of County Road 44H in Buckhorn 
  Canyon and on County Road 43 at Streamside Road east of Glen 
  Haven. These roads are closed and evacuations are occurring in 
  these areas.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding in and around the Cameron
           Peak Burn Scar.

  SOURCE...Emergency management reported.

  IMPACT...Life threatening flash flooding of areas in and around
           the Cameron Peak Burn Scar.

* Some locations that will experience flash flooding include...
  mainly rural areas of Central Larimer County

This includes the following additional locations...
Upper Buckhorn along County Road 44H, Moondance Way, Stringtown 
Gulch, Lower Buckhorn on County Road 27 above Masonville, Crystal 
Mountain, The Retreat and Storm Mountain.

This includes the following streams and drainages...
  Eld Creek, Sheep Creek, Buckhorn Creek, Cedar Creek, Miller Fork, 
  Big Thompson River, Redstone Creek, Black Creek, Pennock Creek and 
  North Fork Fish Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Heavy Rainfall will cause flash flooding of small creeks, streams, 
and ditches in the affected part of the Cameron Peak burn area. Rock 
slides or debris flows can also be expected across rural roads.

&&

LAT...LON 4055 10552 4059 10540 4055 10525 4045 10541

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Gimmestad
243 
WGUS75 KBOU 030851
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
251 AM MDT Thu Aug 3 2023

COC069-031000-
/O.CON.KBOU.FF.W.0071.000000T0000Z-230803T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Larimer CO-
251 AM MDT Thu Aug 3 2023

...FLASH FLOOD WARNING FOR THE CAMERON PEAK BURN SCAR REMAINS IN 
EFFECT UNTIL 4 AM MDT EARLY THIS MORNING FOR CENTRAL LARIMER 
COUNTY...

At 251 AM MDT, emergency management reported flooding from earlier 
thunderstorms over parts of the Cameron Peak Burn Scar. Between 0.5 
and 1.5 inches of rain have fallen. Flash flooding was continuing on 
Buckhorn Creek in the lower canyon along County Road 44H and on the 
Miller Fork in The Retreat east of Glen Haven. Runoff was peaking or 
beginning to diminish in these areas.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding in and around the Cameron Peak Burn Scar.

SOURCE...Emergency management reported.

IMPACT...Life threatening flash flooding of areas in and around
         the Cameron Peak Burn Scar.

Some locations that will experience flash flooding include...
  mainly rural areas of Central Larimer County

This includes the following additional locations...
Upper Buckhorn along County Road 44H, Moondance Way, Stringtown 
Gulch, Lower Buckhorn on County Road 27 above Masonville, Crystal 
Mountain, The Retreat and Storm Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding. Check with local officials including Larimer 
County OEM for current details about road closures and evacuation 
orders.

&&

LAT...LON 4055 10552 4059 10540 4055 10525 4045 10541

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Gimmestad
709 
WGUS75 KBOU 030956
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
356 AM MDT Thu Aug 3 2023

COC069-031006-
/O.EXP.KBOU.FF.W.0071.000000T0000Z-230803T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Larimer CO-
356 AM MDT Thu Aug 3 2023

...FLASH FLOOD WARNING FOR THE CAMERON PEAK BURN SCAR WILL EXPIRE AT 
4 AM MDT EARLY THIS MORNING FOR CENTRAL LARIMER COUNTY...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat.

The Buckhorn Road, County Road 44H, remains closed west of Stove 
Prairie road due to flood damage. Other less traveled roads in the 
areas of Buckhorn Canyon, Crystal Mountain, and east of Glen Haven 
likely have significant erosion. Please continue to heed remaining 
road closures and use caution if traveling in these areas.

LAT...LON 4055 10552 4059 10540 4055 10525 4045 10541

$$

Gimmestad

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Denver/Boulder, CO wrote its last area forecast discussion before this flash flood warning went out at Aug 2, 9:35 PM MDT, 1 hour 49 minutes earlier.

Area forecast discussion, Aug 2, 9:35 PM MDT, 1 hour 49 minutes before
Area Forecast Discussion
National Weather Service Denver/Boulder CO
935 PM MDT Wed Aug 2 2023

.UPDATE...
Issued at 934 PM MDT Wed Aug 2 2023

An area of strong thunderstorms with heavy rain and pretty high
winds are pushing northeastward across the Greater Denver and
Palmer Ridge areas at this time. Increased the pops in the GFE
grids appropriately. There is some convection upstream over the
southwestern CWA and quite a bit more over the west slope of
Colorado. The high resolution models show another batch of
convection to move across the forecast after 06Z tonight. The
trajectory of the real data suggests this convection will affect
mainly the northwesterly CWA. We'll see. Will adjust sky, wind
and pop grids.
&&

.SHORT TERM...(This evening through Thursday)
Issued at 303 PM MDT Wed Aug 2 2023

Showers and storms have formed this afternoon mainly over the
higher terrain and the far northeast corner of the state by
Sterling and Fort Morgan. The SPC mesoanalysis shows 1,500-2,000
j/kg of mixed layer CAPE over the northeast corner which is plenty
of instability for strong updrafts to form. Deep layer shear is
around 20-25 knots which is too weak for an organized severe
storm threat. However, some storms will have strong pulses that
could reach severe limits with large hail and damaging wind gusts
possible. The threat for severe storms will mainly be north and
east of a line from Fort Morgan to Last Chance. Farther west,
there is less instability and storms have been weaker. They are
producing brief heavy rain and pose a limited threat of flash
flooding in the recent burn areas. Otherwise, temperatures are
slightly below normal today with decent moisture in the air.

There is an area of mid level moisture showing up on water vapor in
southwest Colorado that will move over our forecast area later
tonight. This may create some showers and weak storms that last
after midnight tonight and a mention of showers and storms were kept
in the forecast throughout the night and into the morning hours
tomorrow. Otherwise, temperatures will be near normal tonight
with mostly cloudy skies.

A shortwave trough seen on water vapor imagery currently over
western Utah and northwest Arizona will move over our forecast area
Thursday afternoon. This trough will provide good forcing which will
lead to better coverage of storms especially over the eastern
plains. Better flow aloft along with lee cyclogenesis increasing low
level winds towards the surface will lead to increased deep layer
shear with surface to 6km values near 40 knots across northeast
Colorado. In addition, there will be increased instability as better
surface moisture will be in place with slight cooling of
temperatures aloft. High resolution models suggest mixed layer
CAPE values upwards of 2,500 j/kg over the far northeast corner
which is ample instability. The combination of strong forcing,
high instability values, and moderate shear will lead to numerous
strong to severe storms in the northeast corner. We are in
agreement with the enhanced risk for severe storms put out by SPC
and there may be a need to expand the coverage of the enhanced
risk farther west into our CWA. The primary threats will be large
hail and damaging winds so a Severe Thunderstorm Watch will likely
be needed tomorrow. Model soundings suggest that just before
sunset, an enhanced low level jet may increase the "hump" in the
hodographs (increased low level SRH) which could lead to a brief
supercell tornado threat mainly east of a line from Sterling to
Akron. However, the broader tornado threat is low due to small
values of low level shear. These strong storms will also produce
heavy rainfall and will pose a flash flood threat. Considering the
heavy rain would be falling on wet soil, a Flood Watch for flash
flooding will likely be needed for Washington, Logan, Phillips,
and Sedgwick Counties.

.LONG TERM...(Thursday night through Wednesday)
Issued at 303 PM MDT Wed Aug 2 2023

There is general agreement for a flat ridge to remain over the
region through the extended period with a few shortwave troughs
moving through the flow aloft. Friday, there is weak subsidence
aloft which will result in subtle drying. Daytime heating will allow
instability to build through the day with MLCAPE values in the 600-
1500 J/kg. This will be enough to support isolated to scattered
afternoon showers and thunderstorms. A quick moving disturbance
brushes across the northeast corner in the afternoon which will
provide better chances for the east plains.

Most guidance progs a cold front to move through Colorado on
Saturday with some uncertainty in the timing. This may have some
impact to the convective potential that afternoon. There will be
sufficient upper level support with a westerly upper level jet
moving in and a shortwave dropping across the northeast corner.
MLCAPE values rise into the 400-800 J/kg range for the high country
and 800-1800 J/kg eastward. With a jet aloft, 0-6km bulk shear 45-55
kts will favor the potential for some strong to severe storms.

Sunday and into early next week, ensemble guidance shows an increase
in moisture over mainly the lower elevations. The ridge aloft
weakens slightly as a trough strengthens to the east resulting in
generally cooler temperatures aloft. Some solutions could bring
highs as low as upper 70s for portions of the plains. A few
disturbances move through the flow during this period, resulting in
chances for afternoon showers/storms.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 935 PM MDT Wed Aug 2 2023

Will keep the TEMPO group for TSRA and VRB20G40KT and BKN050 going
through 05Z at DIA with the convection going through the area
now. Will leave a VCSH in overnight based of current radar and
model data. There shouldn't be any ceiling issues after 06Z.

&&

.HYDROLOGY...
Issued at 303 PM MDT Wed Aug 2 2023

Showers and storms currently over the recent burn areas are
producing brief heavy rain. It is possible a couple flood advisories
will be issued for either the Cameron Peak or east Troublesome burn
areas. It is unlikely a Flash Flood Warning will be issued today but
it is possible given a strong storm in the wrong location.

Scattered storms will be possible again tomorrow over the burn
areas. There will be near to slightly above normal precipitable
water so storms will produce heavy rainfall. With a shortwave aloft
and strong flow aloft, storms will be moving faster tomorrow
compared to the last few days. Therefore, a limited threat of burn
area flash flooding will exist.

There is a low threat for flash flooding over the burn areas Friday
and through the weekend. Moisture and instability will be sufficient
to support afternoon scattered showers and thunderstorms. The threat
will be limited because storm motions will be trending quicker.
Still can't rule out the threat for impacts on the burn areas if
storms track over those areas.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

UPDATE.......RJK
SHORT TERM...Danielson
LONG TERM....Mensch
AVIATION.....RJK
HYDROLOGY....Danielson/Mensch
Hazardous weather outlook, Aug 2, 6:10 PM MDT, 5 hours 14 minutes before
Outdoor Activities Forecast
National Weather Service Denver/Boulder CO
610 PM MDT Wed Aug 2 2023

IT WILL REMAIN UNSETTLED THROUGH MUCH OF THE PERIOD WITH A CHANCE OF
MAINLY AFTERNOON AND EVENING THUNDERSTORMS THROUGH THE PERIOD. AS A
RESULT, TEMPERATURES ARE EXPECTED TO RUN ON THE COOLER SIDE,
GENERALLY BELOW SEASONAL NORMALS.

...The forecast for the central Colorado mountains east of Vail Pass...

.TONIGHT...Mostly cloudy. Chance of thunderstorms in the evening,
then a chance of showers and slight chance of thunderstorms after
midnight. Lows in the mid 40s. Chance of rain 50 percent.
.THURSDAY...Partly cloudy with a slight chance of thunderstorms
in the morning, then mostly cloudy with a chance of thunderstorms
in the afternoon. Highs in the upper 60s. West winds 10 to 20 mph
with gusts up to 30 mph. Chance of precipitation 50 percent.
.THURSDAY NIGHT...Mostly cloudy with a slight chance of
thunderstorms in the evening, then partly cloudy after midnight.
Lows in the mid 40s. West winds 10 to 15 mph with gusts up to
25 mph in the evening, becoming light. Chance of precipitation
20 percent.
.FRIDAY...Partly cloudy with a 40 percent chance of
thunderstorms. Highs in the mid 60s. West winds 10 to 20 mph with
gusts up to 30 mph.
.FRIDAY NIGHT...Mostly clear with a 10 percent chance of
thunderstorms. Lows in the mid 40s.

...Looking further ahead for the mountain areas...

.SATURDAY...Partly cloudy with a 40 percent chance of
thunderstorms. Highs in the upper 60s.
.SATURDAY NIGHT...Partly cloudy with a 20 percent chance of
thunderstorms. Lows in the lower 40s.
.SUNDAY THROUGH MONDAY...Partly cloudy with a 40 percent chance
of thunderstorms. Highs in the mid 60s. Lows in the lower 40s.
.MONDAY NIGHT...Partly cloudy with a chance of rain showers and
slight chance of thunderstorms. Lows in the lower 40s. Chance of
rain 40 percent.
.TUESDAY...Partly cloudy with a 40 percent chance of
thunderstorms. Highs in the mid 60s.
.TUESDAY NIGHT...Mostly clear with a 10 percent chance of
thunderstorms. Lows in the lower 40s.
.WEDNESDAY...Partly cloudy with a 20 percent chance of
thunderstorms. Highs in the upper 60s.

The ultraviolet index for Denver on Thursday is a 11
which is in the extreme category.

The forecast weather and high temperature for Thursday
at a few cities around the country...

Seattle...Sunny and 84.
San Francisco...Mostly Cloudy and 63.
Los Angeles...Sunny and 75.
Salt Lake City...Thunderstorms and 86.
Las Vegas...Sunny and 103.
Chicago...Partly Cloudy and 87.
Dallas...Very hot and 106.
Boston...Sunny and 80.
New York City...Partly Cloudy and 80.
Washington DC...Partly Cloudy and 87.
Atlanta...Thunderstorms and 87.
Miami...Thunderstorms and 91.

In the hours before

Special weather statement, Aug 2, 9:32 PM MDT, 1 hour 52 minutes before
Special Weather Statement
National Weather Service Denver CO
932 PM MDT Wed Aug 2 2023

COZ046-047-030415-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County CO-
Southeast Elbert County Below 6000 Feet/South Lincoln County CO-
932 PM MDT Wed Aug 2 2023

...Strong thunderstorms will impact portions of southeastern Elbert
and southeastern Lincoln Counties through 1015 PM MDT...

At 930 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 8 miles southeast of Matheson to 5 miles south
of Punkin Center to 10 miles south of Forder, or along a line
extending from 16 miles southwest of Limon to 73 miles west of
Cheyenne Wells to 37 miles north of North La Junta. Movement was east
at 25 mph.

HAZARD...Wind gusts of 50 to 55 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Hugo, Genoa, Boyero, Karval, Punkin Center, Kutch, Wild Horse Point
and Forder.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare for sudden gusty winds. Secure loose objects and move to a
safe shelter inside a building or vehicle. The strong winds will
arrive well ahead of the storms.

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3852 10379 3875 10379 3903 10393 3905 10390
      3906 10393 3907 10391 3908 10393 3908 10391
      3909 10392 3910 10389 3913 10389 3913 10397
      3915 10389 3916 10388 3930 10341 3885 10319
      3853 10321
TIME...MOT...LOC 0330Z 257DEG 22KT 3908 10387 3877 10372 3853 10373

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...55 MPH

BARJENBRUCH
Local storm report, Aug 2, 9:57 PM MDT, 1 hour 27 minutes before
Preliminary Local Storm Report
National Weather Service Denver CO
957 PM MDT Wed Aug 2 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0953 PM     Hail             2 ESE Erie              40.02N 105.02W
08/02/2023  M0.88 inch       Weld               CO   Public

            Report via social media.

&&
Special weather statement, Aug 2, 10:13 PM MDT, 1 hour 11 minutes before
Special Weather Statement
National Weather Service Denver CO
1013 PM MDT Wed Aug 2 2023

COZ046-047-030500-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County CO-
Southeast Elbert County Below 6000 Feet/South Lincoln County CO-
1013 PM MDT Wed Aug 2 2023

...Strong thunderstorms will impact portions of east central Elbert
and northeastern Lincoln Counties through 1100 PM MDT...

At 1012 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Limon to near Hugo to 9 miles west of
Boyero. Movement was northeast at 25 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Limon, Hugo, Arriba and Genoa.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare for sudden gusty winds. Secure loose objects and move to a
safe shelter inside a building or vehicle. The strong, gusty winds
will arrive ahead of the actual storms.

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3893 10355 3928 10381 3957 10348 3957 10333
      3942 10315 3898 10316
TIME...MOT...LOC 0412Z 232DEG 21KT 3930 10368 3916 10351 3896 10344

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

BARJENBRUCH
Special weather statement, Aug 2, 10:14 PM MDT, 1 hour 10 minutes before
Special Weather Statement
National Weather Service Denver CO
1014 PM MDT Wed Aug 2 2023

COZ039-043-030500-
Central and South Weld County CO-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield County
CO-
1014 PM MDT Wed Aug 2 2023

...A strong thunderstorm will impact portions of western Weld and
northeastern Boulder Counties through 1100 PM MDT...

At 1014 PM MDT, Doppler radar was tracking a strong thunderstorm near
Frederick, or 25 miles southwest of Greeley, moving north at 15 mph.

HAZARD...Winds in excess of 40 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Longmont, Firestone, Frederick, Berthoud, Dacono and Mead.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4007 10494 4009 10511 4026 10515 4026 10506
      4030 10506 4031 10489
TIME...MOT...LOC 0414Z 168DEG 15KT 4013 10503

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

ENTREKIN
Local storm report, Aug 2, 10:50 PM MDT, 34 minutes before
Preliminary Local Storm Report...Summary
National Weather Service Denver CO
1050 PM MDT Wed Aug 2 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1035 PM     Tstm Wnd Gst     1 SSE Agate             39.46N 103.94W
08/02/2023  M52 MPH          Elbert             CO   Mesonet

            Mesonet station UP693 Agate.

1030 PM     Tstm Wnd Gst     7 SSW Hugo              39.04N 103.52W
08/02/2023  M52 MPH          Lincoln            CO   Mesonet

            Mesonet station EW9214 Hugo.

1025 PM     Tstm Wnd Gst     Hugo                    39.14N 103.47W
08/02/2023  M51 MPH          Lincoln            CO   Mesonet

            Mesonet station EW0539 Hugo.

0953 PM     Hail             2 ESE Erie              40.02N 105.02W
08/02/2023  M0.88 inch       Weld               CO   Public

            Report via social media.

0925 PM     Tstm Wnd Gst     2 SE Denver Intl Airpor 39.85N 104.65W
08/02/2023  M46 MPH          Denver             CO   ASOS

            ASOS station KDEN Denver Intl Airport.

0902 PM     Tstm Wnd Gst     1 N Buckley AFB         39.72N 104.75W
08/02/2023  M46 MPH          Arapahoe           CO   AWOS

            AWOS station KBKF Buckley SFB.

0842 PM     Tstm Wnd Gst     1 ESE Greenwood Village 39.61N 104.89W
08/02/2023  M48 MPH          Arapahoe           CO   Mesonet

            Mesonet station CO186 Greenwood Village
            I-25/Orchard Rd.

0832 PM     Non-Tstm Wnd Gst 1 NNE Lone Tree         39.56N 104.87W
08/02/2023  M49 MPH          Douglas            CO   Mesonet

            Mesonet station CO001 I-25 and C470.

0820 PM     Tstm Wnd Gst     3 NNW Louviers          39.51N 105.02W
08/02/2023  M47 MPH          Douglas            CO   Mesonet

            Mesonet station AT112 Littleton.

&&
Special weather statement, Aug 2, 10:55 PM MDT, 29 minutes before
Special Weather Statement
National Weather Service Denver CO
1055 PM MDT Wed Aug 2 2023

COZ046-047-049-030545-
Washington County CO-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County CO-
Southeast Elbert County Below 6000 Feet/South Lincoln County CO-
1055 PM MDT Wed Aug 2 2023

...Strong thunderstorms will impact portions of east central Elbert,
southern Washington and northeastern Lincoln Counties through 1145 PM
MDT...

At 1053 PM MDT, Doppler radar was tracking gusty outflow winds from
strong thunderstorms along a line extending from 15 miles north of
Genoa to 5 miles north of Arriba to 9 miles south of Flagler, or
along a line extending from 18 miles northeast of Limon to 14 miles
southwest of Seibert. Movement was northeast at 30 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Limon, Hugo, Arriba, Genoa, Thurman, Arickaree School, Anton, Woodlin
School, Lindon and Last Chance.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare for sudden gusty winds. Secure loose objects and move to a
safe shelter inside a building or vehicle. The strong winds will
occur well ahead of the arrival of the rain.

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3916 10363 3944 10389 3950 10372 3967 10370
      3994 10331 3973 10292 3961 10280 3957 10281
      3957 10316 3892 10317
TIME...MOT...LOC 0453Z 217DEG 26KT 3950 10352 3937 10328 3915 10306

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

BARJENBRUCH

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 2, 6:32 PM MDTSpecial Weather StatementBOUTeller43 min
Aug 2, 7:58 PM MDTSpecial Weather StatementBOUDouglas47 min
Aug 2, 8:18 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver, Douglas, Elbert, Jefferson42 min
Aug 2, 8:34 PM MDTSevere Thunderstorm WarningBOUDouglas, Elbert41 min
Aug 2, 8:56 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver, Elbert, Weld28 min
Aug 2, 9:32 PM MDTSpecial Weather StatementBOULincoln43 min
Aug 2, 9:52 PM MDTSevere Thunderstorm WarningBOUWeld23 min
Aug 2, 10:03 PM MDTSevere Thunderstorm WarningBOUElbert27 min
Aug 2, 10:13 PM MDTSpecial Weather StatementBOULincoln47 min
Aug 2, 10:14 PM MDTSpecial Weather StatementBOUBroomfield46 min
Aug 2, 10:32 PM MDTSevere Thunderstorm WarningBOUArapahoe, Elbert43 min
Aug 2, 10:55 PM MDTSpecial Weather StatementBOULincoln50 min
Aug 2, 11:03 PM MDTAreal Flood AdvisoryBOULarimer21 min
Aug 2, 11:57 PM MDTSpecial Weather StatementBOUWashington48 min
Aug 3, 3:01 PM MDTSpecial Weather StatementBOULarimer44 min
Aug 3, 3:20 PM MDTSpecial Weather StatementBOUDenver40 min
Aug 3, 3:23 PM MDTSpecial Weather StatementBOUDouglas52 min
Aug 3, 3:34 PM MDTSevere Thunderstorm WarningBOUAdams, Denver41 min
Aug 3, 3:36 PM MDTSevere Thunderstorm WarningBOUAdams39 min
Aug 3, 3:59 PM MDTSevere Thunderstorm WarningBOULarimer46 min
Aug 3, 4:02 PM MDTSevere Thunderstorm WarningBOUElbert43 min
Aug 3, 4:24 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe51 min
Aug 3, 4:29 PM MDTSevere Thunderstorm WarningBOUWeld46 min
Aug 3, 4:45 PM MDTSpecial Weather StatementBOUElbert45 min
Aug 3, 4:46 PM MDTSpecial Weather StatementBOUWeld44 min
Aug 3, 4:54 PM MDTAreal Flood AdvisoryBOULarimer3 hr
Aug 3, 4:54 PM MDTSevere Thunderstorm WarningBOUElbert51 min
Aug 3, 4:57 PM MDTSevere Thunderstorm WarningBOUAdams48 min
Aug 3, 5:00 PM MDTSpecial Weather StatementBOUWeld45 min
Aug 3, 5:11 PM MDTSevere Thunderstorm WarningBOULarimer34 min
Aug 3, 5:17 PM MDTFlash Flood WarningBOULarimer104 min
Aug 3, 5:26 PM MDTSpecial Weather StatementBOUDenver49 min
Aug 3, 5:40 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln50 min
Aug 3, 5:43 PM MDTSevere Thunderstorm WarningBOULarimer, Weld47 min
Aug 3, 5:48 PM MDTSevere Thunderstorm WarningBOULincoln42 min

Nearby

Flash Flood Warnings in Colorado, 2023Every flash flood warning in 2023

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.