Flash Flood Warning 10, NWS Denver/Boulder, CO

403 
WGUS75 KBOU 230448
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
1048 PM MDT Wed Jul 22 2026

COC073-230545-
/O.CON.KBOU.FF.W.0010.000000T0000Z-260723T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lincoln CO-
1048 PM MDT Wed Jul 22 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1145 PM MDT THIS
EVENING FOR NORTHEASTERN LINCOLN COUNTY...

At 1048 PM MDT, Doppler radar and automated rain gauges indicated
thunderstorms producing heavy rain across the warned area. Between
1.5 and 4 inches of rain have fallen. 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...
  Hugo, Arriba and Genoa.

This includes the following streams and drainages...
  Hell Creek, Long Creek, Dugout Creek, Big Sandy Creek, Sevenmile
  Creek and South Fork Republican River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

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

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 3934 10361 3926 10364 3919 10365 3908 10367
      3903 10363 3908 10345 3919 10334 3924 10316
      3939 10316 3937 10351

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

09

Area Forecast Discussion
National Weather Service Denver/Boulder CO
552 PM MDT Wed Jul 22 2026

.KEY MESSAGES...

- Storm coverage and intensity increases today and Thursday as
  monsoonal moisture moves into the region. Storms will be
  capable of producing locally heavy rainfall along with a
  localized threat of flash flooding.

- Storm coverage expected to decrease again by Friday into this
  upcoming weekend, although mountain areas should see at least
  scattered storm coverage each afternoon and evening.

- Temperatures will rise back into the upper 90's to lower 100's
  over northeast Colorado for the weekend into early next week.

&&

.DISCUSSION /Through Wednesday/...
Issued at 209 PM MDT Wed Jul 22 2026

Today and tomorrow will bring beneficial rainfall to a majority
of the area with an isolated risk of flash flooding. High
temperatures will reach the low to mid 90s once again today across
the plains. There are already several storms ongoing across the
high country and the Palmer Divide. Storms today will migrate into
the plains by mid-afternoon and push east into the early evening.
Scattered showers and thunderstorms will likely continue across
our area through at least midnight tonight.

Low-level flow is currently southeast which is continuing to
provide ample moisture to our area. Additionally, we already have
MLCAPE of 500-1000 J/kg and 20-30 knots of bulk shear as of early
this afternoon. Storms will be outflow dominant, so any storm
could produce gusty winds up to 50-60 mph with the highest risk
across the plains.

PWATs are at 150-200% of normal today and will approach
climatological record high values on Thursday. We have a low
flooding risk today given slow storm motions and the warm cloud
layer depth approaching 5000 feet. The highest risk of flooding
will be across the high country, mainly for burn areas and also
where storms train or for areas that received significant rainfall
yesterday (and thus have lower flash flood guidance).

A shortwave moves through tomorrow during the day which should
provide a slight increase in rainfall coverage tomorrow afternoon
as well as high temperatures in the upper 80s for the plains.
Storms will once again form in the high country by late morning to
early afternoon and then move into the plains during the
afternoon and evening. Storm motion will be faster than today
(around 20 kts) given increased flow aloft, but tomorrow still
carries a low risk for flash flooding. Additionally, the warm
cloud layer should be deeper than today allowing for more
efficient warm rain processes. Tomorrow will likely be the 3rd day
in a row of rainfall for some areas. Rainfall rates could once
again approach 2-3 inches per hour, so the WPC is now highlighting
most of our area in a slight (2 out of 4) risk for flooding.

In summary, there are several ingredients in place that lead us
to be concerned about the potential for isolated instances of
flash flooding in our area, but also some ingredients that will
lessen the extent of the threat. Given the nature of these storms,
there will be varying rainfall totals across short distances.
Overall, additional rainfall totals across the area will generally
be around 0.25 to 0.75 inches with some isolated totals of 2-3+
inches by Thursday evening.

The high pressure will build back into the area starting Friday
and strengthen through the weekend. The last several model runs
have been keying in on the heat peaking on Sunday. This is when
temperatures across the plains could reach 100 degrees F once
again, given the thermal ridge aloft will be near 20 C and
centered over our area. Record highs could be in play and a Heat
Advisory could be needed as we get closer to the weekend. A chance
for scattered showers is expected to continue through the weekend
for the high country.

By Monday and Tuesday, models show the ridge weakening and
shifting slightly off to the southeast. At the same time, moisture
from the remnants of Bertha could be pulled into the Southwest
United States and into western Colorado. This will be something to
watch as this could bring an increase in rain chances, mainly for
the high country. Otherwise, highs should still be in the mid to
upper 90s for the plains through much of next week.

&&

.AVIATION /00Z TAFS through 00Z Friday/...
Issued at 539 PM MDT Wed Jul 22 2026

Weak convection persists across the Denver metro this evening,
with several outflow boundaries noted on TDEN TDWR at this time.
Forecast guidance does not have a great handle on how this will
evolve over the next few hours, though recent radar trends would
support at least a chance of TSRA for a couple more hours before
diminishing late this evening.

Given the rather uncertain near term forecast, this makes the
post-convective forecast also lower confidence than normal.
Eventually we should see drainage flow attempt to develop at
DEN/APA, but there are hints of a weak cyclone somewhere over the
north metro overnight tonight. There's also a low end chance of
some stratus development after 06z tonight... but not enough to do
much other than keep the FEW/SCT010.

By tomorrow morning, winds should weaken fairly quickly and
eventually turn to the north/northeast. Most guidance develops a
broken line of convection that moves through the terminals from
roughly 21-02z during the afternoon... with fairly high confidence
of at least some brief impacts from both TSRA and gusty outflow
winds.

&&

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

&&

DISCUSSION...MV
AVIATION...Hiris

Preliminary Local Storm Report
National Weather Service Denver CO
422 PM MDT Wed Jul 22 2026

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

0415 PM     Non-Tstm Wnd Gst 2 SE Denver Intl Airpor 39.85N 104.65W
07/22/2026  M62 MPH          Denver             CO   ASOS

            ASOS station KDEN Denver Intl Airport.

&&

Preliminary Local Storm Report
National Weather Service Denver CO
431 PM MDT Wed Jul 22 2026

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

0415 PM     Tstm Wnd Gst     2 SE Denver Intl Airpor 39.85N 104.65W
07/22/2026  M62 MPH          Denver             CO   ASOS

            Corrects previous non-tstm wnd gst report
            from 2 SE Denver Intl Airport. ASOS station
            KDEN Denver Intl Airport.

&&

Preliminary Local Storm Report
National Weather Service Denver CO
837 PM MDT Wed Jul 22 2026

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

0815 PM     Tstm Wnd Gst     3 NW Sterling           40.66N 103.25W
07/22/2026  M61 MPH          Logan              CO   Public

            Personal weather station.

0815 PM     Tstm Wnd Gst     3 WSW Sterling          40.62N 103.27W
07/22/2026  M82 MPH          Logan              CO   AWOS

            AWOS station KSTK Sterling.

0809 PM     Tstm Wnd Gst     2 NW Sterling           40.65N 103.25W
07/22/2026  M62 MPH          Logan              CO   Public

            Personal weather station.

0803 PM     Tstm Wnd Gst     2 NE Merino             40.50N 103.33W
07/22/2026  M53 MPH          Logan              CO   Public

            Personal weather station.

0655 PM     Tstm Wnd Gst     3 SE Brush              40.23N 103.59W
07/22/2026  M72 MPH          Morgan             CO   Public

            WeatherLink station.

0649 PM     Tstm Wnd Gst     1 SSW Hillrose          40.31N 103.53W
07/22/2026  M53 MPH          Morgan             CO   Public

            Personal weather station. Recorded at 53 mph
            gust before the station stopped reporting.

0648 PM     Tstm Wnd Gst     4 S Hillrose            40.27N 103.53W
07/22/2026  M51 MPH          Morgan             CO   Public

            Personal weather station. Recorded a 51 mph
            gust before the station stopped reporting.

0604 PM     Tstm Wnd Gst     1 E Arriba              39.29N 103.25W
07/22/2026  M62 MPH          Lincoln            CO   Public

            WeatherLink station.

&&