Flash Flood Warning 28, NWS Denver/Boulder, CO

392 
WGUS75 KBOU 150317
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
917 PM MDT Fri Aug 14 2026

COC121-150327-
/O.CAN.KBOU.FF.W.0028.000000T0000Z-260815T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Washington CO-
917 PM MDT Fri Aug 14 2026

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN WASHINGTON
COUNTY...

The heavy rain has moved out of the warned area, but light rain will
continue for the next hour. Please continue to heed any remaining
closures.

A Flood Watch remains in effect until 1000 PM MDT for portions of
central, east central, and northeast Colorado.

&&

LAT...LON 3962 10331 3957 10289 3984 10286 4001 10291
      4003 10313 3981 10329

$$

09

Area Forecast Discussion
National Weather Service Denver/Boulder CO
540 PM MDT Fri Aug 14 2026

.KEY MESSAGES...

- Flash flooding and a few severe storms will be the main threats
  through this evening, as another round of storms moves east-
  northeast across the forecast area.

- Monsoon moisture lasts through the weekend, bringing scattered
  showers and thunderstorms each day with locally heavy rain and a
  severe weather threat.

- Warming and drying trend still set to begin Monday.

- Another active day possible middle of next week.

&&

.DISCUSSION /Through Friday/...
Issued at 111 PM MDT Fri Aug 14 2026

Our main concern late this afternoon and evening will be another
round of strong thunderstorms, capable of producing flash flooding
and severe weather. Nearly full sunshine over the plains has
allowed the airmass to destabilize through early this afternoon.
Low level moisture was rather impressive with dewpoints holding in
the lower to mid 60s east of the I-25 Corridor. That's pushing
MLCAPE values into the 1000-2000 J/kg range per latest SPC
analysis. While bulk shear is marginal (only around 25 kts) for
organized severe storms, we have sufficient instability to drive
large hail and damaging wet microbursts from stronger storms.
While there was some drying noted in the 700-600 mb layer on the
most recent ACARS soundings, we still expect efficient rain
producers given low level moisture and updraft intensity, and
enough to warrant a Flood Watch for flash flooding in areas that
saw recent heavy rains - see HYDROLOGY section below for more
details.

Like most convective episodes, there will probably be some weaker
convection that lingers behind the initial stronger storms that
push east across the plains. Otherwise look for gradual clearing
overnight, but patchy fog/stratus development once again with a
very moist boundary layer.

On Saturday, deep layer shear increases as flow aloft strengthens
from the west-southwest. At the same time, we'll still have a fair
amount of low/mid level moisture present, which means growing
instability and another round of afternoon and evening storms.
Some of these may be severe again due to increased shear but
a little decrease in instability as some slight drying is still
forecast.

Sunday is shaping up to be another active weather day, and
potentially even higher than Saturday as persistent low level
easterly flow and moisture advection occurs over the plains. A
failure mode would be too much moisture/low level cloudiness over
the plains, but at the same time that could mean even greater
instability and more favorable shear profiles if we get enough
heating to break the cap.

We're still on course for drier weather Monday and Tuesday as the
ridge axis retrogrades slightly. That allows for a drier west-
northwest flow aloft and warm advection. High temperatures will
likely (>70% chance) return to 90F+ by Tuesday.

Wednesday should feature higher chances of storms again (30-50%
chance), as another front is scheduled to bring slight cooling
but moistening late Tuesday into Wednesday. We don't see much
change in the overall pattern through the end of next week, which
at this point favors fairly normal Colorado weather with near
normal temperatures and isolated to scattered afternoon and
evening storms each day.

&&

.AVIATION /00Z TAFS through 00Z Sunday/...
Issued at 530 PM MDT Fri Aug 14 2026

Showers and thunderstorms are ongoing at all terminals and will
likely continue for the next few hours before gradually shifting
east this evening. Due to higher confidence of convection
lingering, have upgraded the PROB30 to a TEMPO though 03Z, with a
PROB30 from 03Z to 05Z. Lightning and VRB outflow winds up to 30
kts are likely with any storm. Some uncertainty with winds behind
the storms this evening, but guidance does favor light and
variable winds before a light drainage flow replaces it. Low
stratus down to 500 feet is possible with the light and variable
winds, so have introduced it to the TAF. Will continue to monitor
to see if it develops overnight.

Similar set-up is expected for tomorrow, with convection beginning
20Z-21Z. Heavy rain reducing visibilities, lightning and gusty
outflow winds will be the main concerns. However, guidance is in
more agreement of showers/storms ending by 01/02Z rather than
lingering into the evening like today.

&&

.HYDROLOGY...
Issued at 111 PM MDT Fri Aug 14 2026

While there was some mid level drying noted in the 700-600 mb
layer, instability is growing and precipitable water (PW) content
remains near 150% of normal. Warm cloud depths are expected to
average around 4,000-5,000 feet, just a tad less than yesterday.
Mean storm motion is expected to be a little higher as well,
closer to 15-20 kts as mean cloud layer flow has strengthen
slightly. Storms will still be efficient rainers today given the
above mentioned favorable parameters, but likely just a notch down
from yesterday. That still means we could see storms producing a
quick 1-2" in 30-45 minutes, and local totals pushing 3" where
storm mergers occur (per Local Probability Matched Means). Flash
flood guidance has dropped rather considerably in areas that saw
heavy rain yesterday, and enough to warrant another Flood Watch
for flash flooding in those locations.

For Saturday and Sunday, strong storms are expected again although
PW values are expected to nudge slightly lower (~125% of normal).
Locally heavy rains can still expected due to intensity of storms,
along with local flooding impacts mainly from training storms
since storm motions will be faster (20-25 kts).

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 10 PM MDT this evening for COZ036-041-042-
044>049.

&&

DISCUSSION...20
AVIATION...MAI
HYDROLOGY...20

Special Weather Statement
National Weather Service Denver CO
540 PM MDT Fri Aug 14 2026

COZ042-150015-
Northeast Weld County CO-
540 PM MDT Fri Aug 14 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN WELD COUNTY UNTIL
615 PM MDT...

At 540 PM MDT, Doppler radar was tracking a strong thunderstorm near
Grover, or 43 miles northeast of Greeley, moving east at 5 mph.

HAZARD...Landspouts, wind gusts of 50 to 55 mph, and penny size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
  Grover.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is also occurring with this storm and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4100 10428 4100 10409 4083 10418 4086 10428
TIME...MOT...LOC 2340Z 287DEG 4KT 4092 10425

LANDSPOUT...POSSIBLE
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 TO 55 MPH

63

Special Weather Statement
National Weather Service Denver CO
557 PM MDT Fri Aug 14 2026

COZ046-150045-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County CO-
557 PM MDT Fri Aug 14 2026

...A LINE OF STRONG THUNDERSTORMS WILL IMPACT EASTERN ELBERT AND
NORTHEASTERN LINCOLN COUNTIES UNTIL 645 PM MDT...

At 557 PM MDT, Doppler radar was tracking a line of strong
thunderstorms extending from over Limon to 10 miles southwest of
Thurman, or extending from over Limon to 25 miles northeast of Limon,
moving north at 10 mph.

HAZARD...Landspouts, wind gusts of 50 to 55 mph, and half inch size
         hail.

SOURCE...Radar indicated.

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

Locations impacted include...
  Limon and Genoa.

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 3937 10324 3923 10349 3920 10372 3950 10371
      3954 10344 3957 10333 3957 10331
TIME...MOT...LOC 2356Z 185DEG 10KT 3928 10369 3933 10347 3948 10332

LANDSPOUT...POSSIBLE
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 TO 55 MPH

63

Special Weather Statement
National Weather Service Denver CO
614 PM MDT Fri Aug 14 2026

COZ049-150100-
Washington County CO-
614 PM MDT Fri Aug 14 2026

...A LINE OF STRONG THUNDERSTORMS WILL IMPACT SOUTHEASTERN WASHINGTON
COUNTY UNTIL 7 PM MDT...

At 614 PM MDT, Doppler radar was tracking a line of strong
thunderstorms extending from 5 miles east of Gary to 11 miles south
of Lindon, or extending from 16 miles west of Akron to 27 miles
northeast of Limon, moving east at 15 mph.

HAZARD...Wind gusts of 50 to 55 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...
  Akron, Otis, Elba, Arickaree School, Anton, Platner and Thurman.

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 3957 10341 3984 10327 4003 10347 4013 10347
      4020 10298 3986 10280 3978 10280 3957 10292
TIME...MOT...LOC 0014Z 265DEG 14KT 4009 10350 3981 10318 3957 10339

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 TO 55 MPH

63

Preliminary Local Storm Report
National Weather Service Denver CO
700 PM MDT Fri Aug 14 2026

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

0403 PM     Flash Flood      2 S Englewood           39.62N 104.99W
08/14/2026                   Arapahoe           CO   Public

            Report via social media of minor street
            flooding at Belleview and Broadway through
            Hampden. Time estimated.

0355 PM     Flash Flood      1 NW Englewood          39.65N 105.00W
08/14/2026                   Arapahoe           CO   Broadcast Media

            Relayed report of several inches of standing
            water near the intersection of Hampden and
            Sante Fe after the rain had ended. Time
            estimated.

&&

Special Weather Statement
National Weather Service Denver CO
700 PM MDT Fri Aug 14 2026

COZ049-150145-
Washington County CO-
700 PM MDT Fri Aug 14 2026

...A LINE OF STRONG THUNDERSTORMS WILL IMPACT SOUTHEASTERN WASHINGTON
COUNTY UNTIL 745 PM MDT...

At 700 PM MDT, Doppler radar was tracking a line of strong
thunderstorms extending from 12 miles south of Otis to over Thurman,
or extending from 16 miles southeast of Akron to 33 miles northeast
of Limon, moving east at 10 mph.

HAZARD...Wind gusts up to 50 mph and half inch 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...
  Arickaree School, Cope, Anton and Thurman.

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 3957 10332 3984 10318 4002 10313 4000 10280
      3957 10280
TIME...MOT...LOC 0100Z 266DEG 10KT 3999 10302 3979 10308 3958 10321

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

63

Special Weather Statement
National Weather Service Denver CO
703 PM MDT Fri Aug 14 2026

COZ041-046-150145-
Elbert/Central and East Douglas Counties Above 6000 Feet CO-North
and Northeast Elbert County Below 6000 Feet/North Lincoln County
CO-
703 PM MDT Fri Aug 14 2026

...A LINE OF STRONG THUNDERSTORMS WILL IMPACT CENTRAL ELBERT AND
NORTHEASTERN LINCOLN COUNTIES UNTIL 745 PM MDT...

At 703 PM MDT, Doppler radar was tracking a line of strong
thunderstorms extending from 5 miles east of Elbert to near Thurman,
or extending from 41 miles west of Limon to 34 miles northeast of
Limon, moving north at 15 mph.

HAZARD...Wind gusts up to 50 mph and half inch 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, Elbert, Kiowa, Simla, Genoa, Matheson, Cedar Point 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 3942 10425 3944 10380 3956 10347 3957 10324
      3957 10315 3952 10315 3917 10362 3913 10425
      3913 10454 3941 10455
TIME...MOT...LOC 0103Z 180DEG 13KT 3920 10445 3927 10361 3955 10317

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

63