Flash Flood Warning 8, NWS Denver/Boulder, CO

171 
WGUS75 KBOU 040649
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
1249 AM MDT Sat Jul 4 2026

COC073-121-040915-
/O.CON.KBOU.FF.W.0008.000000T0000Z-260704T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lincoln CO-Washington CO-
1249 AM MDT Sat Jul 4 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 315 AM MDT EARLY THIS
MORNING FOR NORTHEASTERN LINCOLN AND SOUTHEASTERN WASHINGTON
COUNTIES...

At 1249 AM MDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Between 2.5 and 4 inches of rain have
fallen. Additional rainfall amounts up to 1 inch are possible in the
warned area. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar indicated.

IMPACT...Flash flooding of small creeks and streams, gulches, roads,
         and poor drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Thurman.

This includes the following streams and drainages...
  Dugout Creek, Arikaree River, North Fork Arikaree River, Gordon
  Creek and Hell Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to higher ground now. Act quickly to protect your life.

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

&&

LAT...LON 3969 10322 3970 10318 3970 10299 3968 10293
      3968 10289 3967 10289 3967 10288 3959 10289
      3959 10290 3958 10290 3958 10292 3957 10292
      3957 10315 3945 10315 3945 10324 3946 10324
      3947 10327 3951 10328 3951 10329 3956 10329

FLASH FLOOD...RADAR INDICATED

$$

63

263 
WGUS75 KBOU 040725
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
125 AM MDT Sat Jul 4 2026

COC073-121-040915-
/O.CON.KBOU.FF.W.0008.000000T0000Z-260704T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lincoln CO-Washington CO-
125 AM MDT Sat Jul 4 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 315 AM MDT EARLY THIS
MORNING FOR NORTHEASTERN LINCOLN AND SOUTHEASTERN WASHINGTON
COUNTIES...

At 125 AM MDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Between 3 and 5 inches of rain have
fallen. Additional rainfall amounts up to 0.5 inches are possible in
the warned area. Flash flooding is ongoing or expected to begin
shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar indicated.

IMPACT...Flash flooding of small creeks and streams, gulches, roads,
         and poor drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Thurman.

This includes the following streams and drainages...
  Dugout Creek, Arikaree River, North Fork Arikaree River, Gordon
  Creek and Hell Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to higher ground now. Act quickly to protect your life.

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

&&

LAT...LON 3969 10322 3970 10318 3970 10299 3968 10293
      3968 10289 3967 10289 3967 10288 3959 10289
      3959 10290 3958 10290 3958 10292 3957 10292
      3957 10315 3945 10315 3945 10324 3946 10324
      3947 10327 3951 10328 3951 10329 3956 10329

FLASH FLOOD...RADAR INDICATED

$$

63

371 
WGUS55 KBOU 040911
FFWBOU
COC073-121-041015-
/O.EXT.KBOU.FF.W.0008.000000T0000Z-260704T1015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
311 AM MDT Sat Jul 4 2026

The National Weather Service in Denver has extended the

* Flash Flood Warning for...
  Northeastern Lincoln County in east central Colorado...
  Southeastern Washington County in northeastern Colorado...

* Until 415 AM MDT.

* At 311 AM MDT, Doppler radar indicated thunderstorms produced heavy
  rain across the warned area earlier tonight. Local law enforcement
  reported Flash flooding was occurring along Highway 61 between
  County Roads 4 and 8 in Logan county. Between 2.5 and 3.5 inches of
  rain fell earlier. Flooding impacts will continue, as additional
  rainfall amounts of 0.1 to 0.5 inches are possible in the warned
  area for the next 30 mins. Therefore the warning was extended for
  one hour.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flash flooding of small creeks and streams, gulches,
           roads, and poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Thurman.

This includes the following streams and drainages...
  North Fork Arikaree River, Dugout Creek, Hell Creek, Gordon Creek
  and Arikaree River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to higher ground now. Act quickly to protect your life.

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

&&

LAT...LON 3969 10322 3970 10318 3970 10299 3968 10293
      3968 10289 3967 10289 3967 10288 3959 10289
      3959 10290 3958 10290 3958 10292 3957 10292
      3957 10315 3945 10315 3945 10324 3946 10324
      3947 10327 3951 10328 3951 10329 3956 10329

FLASH FLOOD...RADAR INDICATED

$$

09

396 
WGUS75 KBOU 040918
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
318 AM MDT Sat Jul 4 2026

COC073-121-041015-
/O.CON.KBOU.FF.W.0008.000000T0000Z-260704T1015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lincoln CO-Washington CO-
318 AM MDT Sat Jul 4 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 AM MDT EARLY THIS
MORNING FOR NORTHEASTERN LINCOLN AND SOUTHEASTERN WASHINGTON
COUNTIES...

At 318 AM MDT, Doppler radar indicated thunderstorms produced heavy
rain across the warned area earlier tonight. Local law enforcement
reported Flash flooding was occurring along Highway 61 between County
Roads 4 and 8 in Washington county. Between 2.5 and 3.5 inches of
rain fell earlier. Flooding impacts will continue, as additional
rainfall amounts of 0.1 to 0.5 inches are possible in the warned area
for the next 30 mins. Therefore the warning was extended for one
hour.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar indicated.

IMPACT...Flash flooding of small creeks and streams, gulches, roads,
         and poor drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Thurman.

This includes the following streams and drainages...
  North Fork Arikaree River, Dugout Creek, Hell Creek, Gordon Creek
  and Arikaree River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to higher ground now. Act quickly to protect your life.

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

&&

LAT...LON 3969 10322 3970 10318 3970 10299 3968 10293
      3968 10289 3967 10289 3967 10288 3959 10289
      3959 10290 3958 10290 3958 10292 3957 10292
      3957 10315 3945 10315 3945 10324 3946 10324
      3947 10327 3951 10328 3951 10329 3956 10329

FLASH FLOOD...RADAR INDICATED

$$

09

735 
WGUS75 KBOU 041022
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
422 AM MDT Sat Jul 4 2026

COC073-121-041032-
/O.EXP.KBOU.FF.W.0008.000000T0000Z-260704T1015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lincoln CO-Washington CO-
422 AM MDT Sat Jul 4 2026

...FLASH FLOOD WARNING HAS EXPIRED FOR NORTHEASTERN LINCOLN AND
SOUTHEASTERN WASHINGTON COUNTIES...

The heavy rain has ended. Flood waters have receded. Flooding is no
longer expected to pose a threat. Please continue to heed any
remaining closures.

&&

LAT...LON 3969 10322 3970 10318 3970 10299 3968 10293
      3968 10289 3967 10289 3967 10288 3959 10289
      3959 10290 3958 10290 3958 10292 3957 10292
      3957 10315 3945 10315 3945 10324 3946 10324
      3947 10327 3951 10328 3951 10329 3956 10329

$$

09

Area Forecast Discussion
National Weather Service Denver/Boulder CO
627 PM MDT Fri Jul 3 2026

.KEY MESSAGES...

- Last day of critical fire weather conditions as winds gradually
  relax. However, still plenty of hot, dry weather ahead.

- Another round of nocturnal (and potentially severe) convection
  possible tonight.

- Scattered strong to severe storms expected for the afternoon and
  early evening of the 4th.

- A few storms expected each day of the coming week, with the
  highest probabilities shaping up for Tuesday and Wednesday from
  the Front Range eastward.

&&

.DISCUSSION /Through Friday/...
Issued at 233 PM MDT Fri Jul 3 2026

Another day (and night) of uncertainty with regard to convective
development. CAMs have not been doing a great job of assessing
potential and duration of nocturnal convection, and amount of low
level moisture surging westward from MCSs in the Central/High
Plains the last couple of nights.

As of early this afternoon, weak convection has been developing
over the northern mountains and foothills. As that moves east onto
the plains, a couple storms are expected to tap into the higher
MLCAPE near 1500-2000 J/kg and become severe late this afternoon
into early evening. Where more uncertainty enters the forecast is
overnight, and that's when a couple pieces of the puzzle attempt
to come together and produce another round of strong to
potentially severe storms. That potential would extend farther
west toward the I-25 Corridor. That would be fueled by outflow
from the initial round of storms over the northern tier of
Colorado, and potentially another outflow from a more organized
storm complex (MCS) over Nebraska. That second surge would likely
arrive later in the evening, and that could spark storms that
linger well past midnight. At the same time, we'll also have some
upper level support from the left exit region of an upper level
speed max. While weakly capped, the lift from any upslope would
likely be enough to break through and initiate more storms. MLCAPE
by that time would be a little lower (800-1600 J/kg), but still
enough for a couple strong to severe storms that linger well past
midnight.

Saturday, the 4th of July, is still shaping up to serve up some
of nature's fireworks. It will likely be a more active
thunderstorm day with higher MLCAPE across the Front Range and
adjacent plains. Some patchy morning stratus is possible, but not
enough to significantly impact warming and cap erosion by early
to mid afternoon. MLCAPE is forecast to increase to 1500-2000 J/kg
along/east of the I-25 Corridor, but at the same time there is
plenty of uncertainty with exactly how far west the greatest
moisture and instability can hold (highly dependent on strength of
surges tonight). Most likely, deeper instability holds roughly
east of I-25, with lesser certainty west of I-25. We think storm
initiation will be in/very close to the Front Range Mountains and
Foothills by early afternoon, with eastward propagation across
the plains from mid afternoon through early evening. 0-6km bulk
shear is forecast to increase to 30-35 kts, enough for supercell
development. Initial isolated severe storms are expected to have a
large hail threat, and those storms may then attempt to organize
into a linear structure onto the plains with a greater high wind
threat (in addition to the hail). A failure mode would be if the
airmass remains too capped due to weak synoptic subsidence seen
arriving in the afternoon. Anyone planning outdoor celebrations or
activities tomorrow should remain weather aware and be prepared
to take shelter or move off open waters before storms arrive.
Finally, with the above mentioned arrival of subsidence, we do
think the vast majority of storms should clear the forecast area
before dark and any fireworks shows.

By Sunday and Monday, upper level ridging builds across Colorado.
While this will tend to stabilize things a bit, it will still be
hot and residual moisture means a continued chance of storms each
afternoon and evening. Typically this pattern has the most
convection occurring over Park County and the Front Range
Mountains into the Palmer Divide area, with lower probabilities to
the north and east. High temperatures will likely reach the 90-95
degree range over the plains, after just slight cooling (near
normal temps) for Saturday.

For Tuesday and Wednesday, the upper level ridge is forecast to
flatten with weak zonal flow developing across the forecast area.
As low level moisture remains locked in east of the Rockies,
instability builds slightly and shear improves so scattered
thunderstorms are expected both days with potential for a couple
severe storms. Temperatures will remain a few degrees above
normal.

Drying is expected for the latter portion of the weak as there is
growing confidence we remain under zonal flow aloft. Some lee
troughing is also forecast, which means the greatest chance of
storms will likely shift to the eastern plains while drier air and
a return of elevated fire weather conditions (with increasing
breezes) is expected over the high country.

&&

.AVIATION /00Z TAFS through 00Z Sunday/...
Issued at 625 PM MDT Fri Jul 3 2026

Current radar imagery shows showers and thunderstorms developing
east of the Denver metro area, over the northern Colorado plains,
and off the foothills near the I-25 corridor. One of these
thunderstorms just tracked over KDEN, and has exited the vicinity
to the northeast. The chance for a thunderstorm near the terminals
will increase between 02Z and 05Z, as outflow boundaries from the
storm activity to the southeast and another boundary moving in
from the north collide and fire up additional convection.

A similar setup will be in place tomorrow with winds starting out SW
or variable before becoming ENE-E at KDEN and S-SE at KAPA. Winds at
KBJC will likely turn to the NE and remain light, as has occurred
over the last few afternoons with a cyclone near KDEN and KAPA.
Another round of thunderstorms is expected tomorrow afternoon,
with the peak of activity occurring slightly earlier than today,
between 19Z and 01Z. Gusty outflows up to 35-40KT will be possible
with shower or thunderstorm activity tomorrow.

Smoke aloft will continue to cause slant-range visibility concerns,
especially near sunrise and sunset when the sun angle is low.
Shower activity may provide some relief from the hazy skies but
smoke aloft will continue until a major pattern change arrives, or
until fire activity decreases.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 7 PM MDT this evening for COZ214.

&&

DISCUSSION...20
AVIATION...AA

Preliminary Local Storm Report
National Weather Service Denver CO
728 PM MDT Fri Jul 3 2026

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

0620 PM     Hail             3 NW Buckingham         40.64N 104.02W
07/03/2026  M1.25 Inch       Weld               CO   Public

&&

BR

Preliminary Local Storm Report
National Weather Service Denver CO
820 PM MDT Fri Jul 3 2026

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

0805 PM     Hail             7 SSW Reiradon Hill     40.48N 103.08W
07/03/2026  E1.25 Inch       Logan              CO   Trained Spotter

            Time estimated from radar.

&&

AA

Preliminary Local Storm Report
National Weather Service Denver CO
835 PM MDT Fri Jul 3 2026

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

0746 PM     Hail             2 WNW Union             40.36N 103.54W
07/03/2026  E1.00 Inch       Morgan             CO   Public

            Time estimated from radar.

&&

AA

Special Weather Statement
National Weather Service Denver CO
1042 PM MDT Fri Jul 3 2026

COZ041-045-046-040530-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County CO-Central and East Adams and Arapahoe Counties CO-
Elbert/Central and East Douglas Counties Above 6000 Feet CO-
1042 PM MDT Fri Jul 3 2026

...A LINE OF STRONG THUNDERSTORMS WILL IMPACT ARAPAHOE AND
NORTHWESTERN ELBERT COUNTIES UNTIL 1130 PM MDT...

At 1042 PM MDT, Doppler radar was tracking a line of strong
thunderstorms extending from 6 miles southeast of Byers to 5 miles
east of Elbert, or extending from 36 miles northwest of Limon to 41
miles west of Limon, moving east at 15 mph.

HAZARD...Wind gusts up to 50 mph and penny 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...
  Deer Trail and Fondis.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

Heavy rain is occurring with these storms and may lead to flooding.
Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3916 10451 3945 10440 3968 10417 3967 10393
      3939 10414 3914 10425
TIME...MOT...LOC 0441Z 277DEG 12KT 3965 10414 3943 10436 3920 10445

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

63

Preliminary Local Storm Report
National Weather Service Denver CO
1128 PM MDT Fri Jul 3 2026

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

1115 PM     Flash Flood      8 S Reiradon Hill       40.47N 103.01W
07/03/2026                   Logan              CO   Law Enforcement

            Flash flooding occurring along HWY 61
            between County Roads 4 and 8.

&&