Flash Flood Warning 33, NWS Denver/Boulder, CO

007 
WGUS75 KBOU 162123
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
323 PM MDT Sun Aug 16 2026

COC039-162330-
/O.CON.KBOU.FF.W.0033.000000T0000Z-260816T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Elbert CO-
323 PM MDT Sun Aug 16 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM MDT THIS
AFTERNOON FOR SOUTH CENTRAL ELBERT COUNTY...

At 323 PM MDT, Doppler radar and automated rain gauges indicated that
thunderstorms producing heavy rain had moved out of the warned area.
Between 1 and 2.5 inches of rain have fallen. Additional rainfall
amounts up to 0.3 inches are possible in the warned area. Flash
flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar and automated gauges.

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...
  Mainly rural areas of south central Elbert County.

This includes the following streams and drainages...
  West Bijou Creek, East Bijou Creek, Reed Springs Creek, Big Sandy
  Creek, Spring Branch and Antelope Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be aware of your surroundings and do not drive through flooded roads.
Turn around, don't drown. Most flood deaths occur in vehicles.

Excessive runoff from this storm will cause flash flooding of small
creeks and streams, country roads, farmland along creeks, and other
low lying areas.

&&

LAT...LON 3926 10430 3913 10432 3913 10410 3919 10406
      3930 10418

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

20

753 
WGUS75 KBOU 162147
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
347 PM MDT Sun Aug 16 2026

COC039-162330-
/O.CON.KBOU.FF.W.0033.000000T0000Z-260816T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Elbert CO-
347 PM MDT Sun Aug 16 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM MDT THIS
AFTERNOON FOR SOUTH CENTRAL ELBERT COUNTY...

At 347 PM MDT, trained weather spotters reported flash flooding on
County Road 105 just south of County Road 90. Between 1 and 2.5
inches of rain have fallen. Additional rainfall amounts up to 0.3
inches are possible in the warned area. Flash flooding is already
occurring.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Trained spotters reported.

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...
  Mainly rural areas of south central Elbert County.

This includes the following streams and drainages...
  West Bijou Creek, East Bijou Creek, Reed Springs Creek, Big Sandy
  Creek, Spring Branch and Antelope Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be aware of your surroundings and do not drive through flooded roads.
Turn around, don't drown. Most flood deaths occur in vehicles.

Excessive runoff from this storm will cause flash flooding of small
creeks and streams, country roads, farmland along creeks, and other
low lying areas.

&&

LAT...LON 3926 10430 3913 10432 3913 10410 3919 10406
      3930 10418

FLASH FLOOD...OBSERVED

$$

20

364 
WGUS75 KBOU 162323
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
523 PM MDT Sun Aug 16 2026

COC039-162333-
/O.EXP.KBOU.FF.W.0033.000000T0000Z-260816T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Elbert CO-
523 PM MDT Sun Aug 16 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 530 PM MDT THIS AFTERNOON FOR
SOUTH CENTRAL ELBERT COUNTY...

The heavy rain has ended and flood waters are receding. Please
continue to heed any remaining closures.

&&

LAT...LON 3926 10430 3913 10432 3913 10410 3919 10406
      3930 10418

$$

20

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1238 PM MDT Sun Aug 16 2026

.KEY MESSAGES...

- Scattered thunderstorms expected this afternoon and evening. A
  few of them could become strong to severe, with strong winds,
  large hail, and heavy rainfall.

- Warming and drying trend for Monday and Tuesday, but still
  isolated gusty pm storms/virga.

- More active weather day shaping up for Wednesday with scattered
  severe thunderstorm threat.

- Warmer again through the coming weekend with above normal
  temperatures. Drier Thursday and Friday, but some monsoonal
  moisture likely returns by the weekend.

&&

.DISCUSSION /Through Sunday/...
Issued at 1238 PM MDT Sun Aug 16 2026

Rich, low level air remained in place across the plains this
afternoon. This along with daytime heating is building MLCAPE
into the 1000-1800 J/kg range. Local ACARS soundings still show a
pretty healthy cap in place, but we are warming and should at
least get close to convective temperatures. The most likely area
for convective initiation of course is over the mountains (already
ongoing), but also the higher terrain of the Palmer Divide and
Cheyenne Ridge. Storms will likely move in a southeasterly
direction once they develop, and a weakening cap is expected to
allow propagation across the plains and portions of the I-25
Corridor. Bulk shear will be increasing to 30-35 kts, so enough
shear and instability is present for a few supercells. Thus, large
hail and damaging winds will be a threat with any storms through
mid evening. It should be worth noting that we'll be under the
right entrance region of an upper level speed max, so weak forcing
should help coverage a bit so we did bump pops up ever so
slightly, with the highest odds of storms over the northeast
plains and Palmer Divide. That upper level speed max could also
aid storms to last a bit longer into the evening than normal.

We still expect clearing skies overnight, and enough lingering low
level moisture for some patchy fog over the plains and in the
high mountain valleys.

Monday will feature warmer and drier weather as the ridge axis
retrogrades to the west-northwest. That puts our forecast into a
drier westerly flow aloft, and mid level temperatures will also be
warming. Highs are expected to reach the upper 80s to lower 90s
over the plains and I-25 Corridor. We'll still likely have enough
lingering moisture and strong daytime heating to support isolated
late day convection. The airmass along the I-25 Corridor would be
more supportive of just isolated late afternoon/evening sprinkles
and microbursts as DCAPE grows to ~1500 J/kg. Similar weather
conditions although further warming of a few degrees is expected
for Tuesday. Also, a late afternoon frontal passage will likely
be enough to support growing high based shower/storm coverage into
the Tuesday evening and overnight hours.

Wednesday is still on track to be slightly cooler with increased
chances of storms again as the post frontal airmass will be cooler
and more moist. Average MLCAPE from various models suggest
1000-2000 J/kg, while bulk shear is an impressive 40-50 kts so a
growing severe storm threat will be in the picture.

Thursday and Friday are shaping up to be drier again as the ridge
amplifies, this time across Colorado and eastern Utah. That means
a stronger thermal ridge and high temperatures pushing well above
normal...into the lower to mid 90s across the plains and I-25
Corridor. While the ridge should hold fairly steady across the
Central Rockies through at least next weekend, ensembles have good
agreement for an increase in monsoonal moisture under the ridge.
That would support a return to scattered afternoon and evening
shower/storms as well, with the greatest chances holding over the
mountains at least until early next week.

&&

.AVIATION /18Z TAFS through 18Z Monday/...
Issued at 1136 AM MDT Sun Aug 16 2026

As of 1745z, cumulus clouds are starting to build in the
mountains and the foothills to the west of the three sites with a
scattered deck pushing into KBJC. There is still a cap in place as
seen on ACARS soundings and radar is just starting to show some
returns in Park County. Given the fog that was in place this
morning as well as the cap still in place, we have held off on the
PROB30 from starting until 22z at KDEN and then lasting until
about 3z. Gusty winds, lowering ceilings, and heavy rainfall
(briefly limiting visibility) are possible from any storm that
passes near or directly over the TAF sites. Some CAMs are showing
showers and thunderstorms lingering a bit after 3z, but confidence
is low in this scenario at this time.

There is also some uncertainty on the winds tonight. For now, we
have gone ahead with an E to SE wind this evening before winds
turn to drainage by about 7z. Several CAMs depict outflow
boundaries from storms to the east moving through the metro early
this evening potentially affecting KAPA and KDEN. If this were to
occur, winds could shift more to an east or northeast direction
and briefly gust to around 20 kts.

For tomorrow, winds will start to turn clockwise before settling
on a northeast direction early in the afternoon. Model soundings
show DCAPE values reaching up to 1,500 J/kg and some mid-level
moisture lingering. So, we expect the possibility of virga showers
and dry microbursts starting around 21z and lasting through the
early evening (potentially a bit after the TAF period). These
could bring gusty winds and ceilings lowering to about 12,000 ft
AGL with little to no rainfall expected. Have now included a
PROB30 for this possibility.

&&

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

&&

DISCUSSION...20
AVIATION...MV

Special Weather Statement
National Weather Service Denver CO
130 PM MDT Sun Aug 16 2026

COZ041-162000-
Elbert/Central and East Douglas Counties Above 6000 Feet CO-
130 PM MDT Sun Aug 16 2026

...A STRONG THUNDERSTORM WILL IMPACT WEST CENTRAL ELBERT AND
SOUTHEASTERN DOUGLAS COUNTIES UNTIL 2 PM MDT...

At 130 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles southwest of Elbert, or 41 miles south of Denver, moving east
at 10 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...
  Mainly rural areas of West Central Elbert and Southeastern Douglas
  Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3913 10474 3925 10474 3925 10454 3913 10454
TIME...MOT...LOC 1930Z 266DEG 7KT 3918 10466

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

63

Special Weather Statement
National Weather Service Denver CO
204 PM MDT Sun Aug 16 2026

COZ041-046-162030-
Elbert/Central and East Douglas Counties Above 6000 Feet CO-North
and Northeast Elbert County Below 6000 Feet/North Lincoln County
CO-
204 PM MDT Sun Aug 16 2026

...A LINE OF STRONG THUNDERSTORMS WILL IMPACT SOUTHERN ARAPAHOE...
CENTRAL ELBERT...NORTHWESTERN LINCOLN AND NORTHEASTERN DOUGLAS
COUNTIES UNTIL 230 PM MDT...

At 204 PM MDT, Doppler radar was tracking a line of strong
thunderstorms extending from near Franktown to 9 miles south of
Matheson, or extending from 26 miles southeast of Denver to 20 miles
southwest of Limon, moving northeast 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...
  Elizabeth, Kiowa, Simla, Matheson, Ponderosa Park, Franktown, The
  Pinery, Fondis and Castlewood Canyon.

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 10368 3910 10376 3910 10392 3908 10391
      3908 10393 3907 10391 3906 10393 3905 10391
      3902 10396 3905 10405 3913 10405 3913 10427
      3935 10482 3957 10467
TIME...MOT...LOC 2004Z 207DEG 11KT 3940 10470 3922 10437 3904 10392

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

63

Special Weather Statement
National Weather Service Denver CO
238 PM MDT Sun Aug 16 2026

COZ041-162115-
Elbert/Central and East Douglas Counties Above 6000 Feet CO-
238 PM MDT Sun Aug 16 2026

...A STRONG THUNDERSTORM WILL IMPACT CENTRAL ELBERT COUNTY UNTIL 315
PM MDT...

At 238 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles west of Simla, or 31 miles west of Limon, moving east at 10
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...
  Simla.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3924 10432 3927 10416 3926 10416 3926 10414
      3927 10413 3925 10412 3925 10411 3927 10409
      3926 10409 3925 10408 3925 10406 3924 10406
      3923 10405 3923 10404 3905 10403 3905 10405
      3913 10405 3913 10431
TIME...MOT...LOC 2038Z 266DEG 8KT 3916 10425

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

63