Severe Thunderstorm Warning 321, NWS Denver/Boulder, CO

Area Forecast Discussion
National Weather Service Denver/Boulder CO
129 PM MDT Sun Aug 10 2025

.KEY MESSAGES...

- Another round of strong to severe thunderstorms possible this
  afternoon across the urban corridor and eastern plains.

- Elevated fire conditions will continue over the higher terrain
  through Wednesday.

- Drier and warmer weather develops Monday and continues through
  Wednesday.

&&

.DISCUSSION /Through Sunday/...
Issued at 129 PM MDT Sun Aug 10 2025

Over the past couple hours, northeast winds have surged westward,
into the northern foothills. It's been a little slow to make it
into the southern foothills. Outflow from convection to the
southwest of Denver will likely keep the best moisture out of the
southern foothills. A Severe Thunderstorm Watch has been issued
for much of eastern Colorado and most of the urban corridor
(except Jefferson County) where dew points are in the 50s (or
better), MLCAPE is 1000- 2000 J/kg and 0-6km Bulk Shear is 35-40
knots. These ingredients are expected to produce strong/severe
storms, including some supercell thunderstorms. Large hail to 2.5
inch in diameter and 70 mph will be the main threats. A tornado or
two is also possible. Isolated flash flooding will be possible
where multiple storms train over the same area. The Severe
Thunderstorm Watch runs until 8PM, afterwards storms should be
weaker. However, some models show a second round of weaker storms
mid to late evening, so will continue with decent (30- 60%) PoPs
for this.

For Monday, the upper level trough axis will be just east of the
area with a dry subsident northwest flow aloft. In addition to the
drier air in place, soundings show a strong mid level inversion,
around 450mb. This is expected to keep showers and storms from
developing on Monday. If this system slows a little, the southern
part of the forecast area could pick up a few showers and storms,
so will have low PoPs in these areas.

The upper level high begins to build over the area Tuesday and
will be centered over the Central Rockies Wednesday and at least
into early Thursday. Warmer air returns to the area under this
pattern with highs expected to reach the 90s Wednesday and
Thursday across northeast Colorado. Dry conditions are expected
for Tuesday and Wednesday with dry air over the area and the
subtropical moisture cut off from the area. On Thursday, the ridge
may drift eastward enough for the subtropical moisture to lift
northward into the area.

For Friday and next weekend, the upper level high will be over
the south central and southeast part of the country. This will
result in a weak south to southwest flow across the Central and
Southern Rockies. Subtropical (monsoon) moisture travels northward
into the area. Expected at least scattered afternoon/evening
thunderstorms in the mountains each day (Friday-Sunday) under this
pattern and possibly onto the plains. Temperatures take a step
back and will be closer to normal, which is upper 80s to lower 90s
over northeast Colorado.

&&

.AVIATION /18Z TAFS through 18Z Monday/...
Issued at 1141 AM MDT Sun Aug 10 2025

Light north/northeast winds will increase as they shift
northeast/east as a boundary moves through soon. With
thunderstorms already forming over the higher terrain west and
southwest of Denver, expect them to affect APA around 19Z. The
initial storms are expected to stay south of DEN, but not by much
with outflow winds possible, so a wind shift to the
south/southeast seems the most likely direction for the first wind
shift this afternoon. Moved up the PROB30 to 19Z with storms near
DEN and will continue with the PROB30 through the afternoon. With
an evening round of storms possible, will have a PROB30 until
04Z.

For Monday, south to southwest drainage winds are expected to
become north to northeast after 16Z and stay northeasterly through
the day. With drier air moving in and a strong mid level
inversion, no thunderstorms are expected in the Denver area
Monday.

&&

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

&&

DISCUSSION...Meier
AVIATION...Meier

Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
933 AM MDT Sun Aug 10 2025

COZ030>051-111500-
Jackson County Below 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
Grand and Summit Counties Below 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-Larimer and Boulder Counties Between 6000 and 9000 Feet-
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-
Central and Southeast Park County-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County-
Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
933 AM MDT Sun Aug 10 2025

This hazardous weather outlook is for northeast and north central
Colorado.

.DAY ONE...Today and Tonight

Scattered showers and thunderstorms will track east across the
area this afternoon and evening. Thunderstorms will be most
numerous over the Palmer Divide and eastward across Elbert and
Lincoln Counties. A few storms could become severe, mainly over
the plains where golfball size hail and 70 mph winds will be
possible.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Drier conditions return to the area Monday and continue into at
least mid week. Temperatures will begin to warm as well with highs
returning to the 90s Wednesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be required today or tonight.

Special Weather Statement
National Weather Service Denver CO
1214 PM MDT Sun Aug 10 2025

COZ034-036-039-101900-
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet CO-South and
Southeast Grand/West Central and Southwest Boulder/Gilpin/Clear
Creek/Summit/North and West Park Counties Above 9000 Feet CO-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County CO-
1214 PM MDT Sun Aug 10 2025

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN PARK...
SOUTHEASTERN CLEAR CREEK...CENTRAL JEFFERSON AND NORTHWESTERN
DOUGLAS COUNTIES UNTIL 1 PM MDT...

At 1214 PM MDT, Doppler radar was tracking a strong thunderstorm
over Conifer, or 25 miles southwest of Denver, moving northeast at
15 mph.

HAZARD...Wind gusts up to 40 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...
  Southwestern Denver, southwestern Lakewood, southwestern
  Littleton, Golden, Evergreen, Morrison, Aspen Park, Indian Hills,
  Tiny Town, Conifer, Kittredge, Idledale, Red Rocks Park, Pine
  Junction, Chatfield Reservoir, Wah Keeney Park, Genesee, Shaffers
  Crossing, Ken Caryl and Columbine.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3976 10522 3964 10510 3963 10511 3962 10511
      3963 10509 3962 10509 3962 10510 3961 10510
      3961 10508 3959 10505 3957 10505 3956 10506
      3952 10508 3943 10539 3956 10551
TIME...MOT...LOC 1814Z 232DEG 11KT 3952 10534

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

Bonner

Special Weather Statement
National Weather Service Denver CO
119 PM MDT Sun Aug 10 2025

COZ037-101945-
Central and Southeast Park County CO-
119 PM MDT Sun Aug 10 2025

...A STRONG THUNDERSTORM WILL IMPACT EASTERN PARK COUNTY UNTIL 145
PM MDT...

At 119 PM MDT, Doppler radar was tracking a strong thunderstorm 6
miles north of Lake George, or 51 miles southwest of Denver, moving
east at 15 mph.

HAZARD...Wind gusts up to 40 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...
  Lake George.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3898 10547 3913 10547 3913 10544 3911 10543
      3911 10542 3910 10541 3910 10540 3911 10540
      3910 10539 3910 10537 3913 10537 3913 10533
      3897 10533
TIME...MOT...LOC 1919Z 270DEG 14KT 3907 10540

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Bonner

Special Weather Statement
National Weather Service Denver CO
241 PM MDT Sun Aug 10 2025

COZ040-045-102115-
Central and East Adams and Arapahoe Counties CO-North Douglas
County Below 6000 Feet/Denver/West Adams and Arapahoe
Counties/East Broomfield County CO-
241 PM MDT Sun Aug 10 2025

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN DENVER...
NORTHWESTERN ARAPAHOE AND WESTERN ADAMS COUNTIES UNTIL 315 PM MDT...

At 241 PM MDT, Doppler radar was tracking a strong thunderstorm 6
miles southeast of Commerce City, or 10 miles northeast of Denver,
moving east at 15 mph.

HAZARD...Wind gusts up to 40 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...
  Northeastern Denver, Aurora, eastern Commerce City, Denver
  International Airport, D.I.A Terminal and Concourses, Watkins,
  Manila Village and Buckley SFB.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3968 10481 3985 10490 4000 10455 4000 10451
      3964 10442 3965 10449 3966 10450 3965 10451
      3965 10452
TIME...MOT...LOC 2041Z 248DEG 14KT 3980 10478

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Bonner