Severe Thunderstorm Warning 9, NWS Denver/Boulder, CO

920 
WWUS55 KBOU 242102
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
302 PM MDT Thu Apr 24 2025

COC001-242112-
/O.CAN.KBOU.SV.W.0009.000000T0000Z-250424T2130Z/
Adams CO-
302 PM MDT Thu Apr 24 2025

...SEVERE THUNDERSTORM WARNING IS CANCELLED FOR NORTHWESTERN ADAMS 
COUNTY...

The storm which prompted the warning has moved out of the area. 
Therefore, the warning has been cancelled.

&&

LAT...LON 4000 10476 4014 10476 4015 10446 4000 10448
TIME...MOT...LOC 2051Z 188DEG 9KT 4001 10466

$$


COC123-242130-
/O.CON.KBOU.SV.W.0009.000000T0000Z-250424T2130Z/
Weld CO-
302 PM MDT Thu Apr 24 2025

...SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM MDT 
FOR SOUTH CENTRAL WELD COUNTY...

At 302 PM MDT, a severe thunderstorm was located over Hudson, or 27 
miles south of Greeley, moving north at 10 mph.

HAZARD...Half dollar size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

Locations impacted include...
  Brighton, Fort Lupton, Lochbuie, Hudson and Keenesburg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Seek shelter inside a well-built structure and stay away from 
windows. This storm is capable of producing large hail.

Tornadoes can develop quickly from severe thunderstorms. Seek 
shelter immediately in an interior room on the lowest floor of a 
well-built structure.

&&

LAT...LON 4000 10476 4014 10476 4015 10446 4000 10448
TIME...MOT...LOC 2051Z 188DEG 9KT 4001 10466

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.25 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH

$$

RPK

471 
WWUS55 KBOU 242125
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
325 PM MDT Thu Apr 24 2025

COC123-242135-
/O.EXP.KBOU.SV.W.0009.000000T0000Z-250424T2130Z/
Weld CO-
325 PM MDT Thu Apr 24 2025

...SEVERE THUNDERSTORM WARNING WILL EXPIRE AT 330 PM MDT FOR SOUTH 
CENTRAL WELD COUNTY...

The storm which prompted the warning has weakened below severe 
limits, and has exited the warned area. Therefore, the warning will 
be allowed to expire.

&&

LAT...LON 4000 10476 4014 10476 4015 10446 4000 10448
TIME...MOT...LOC 2102Z 188DEG 9KT 4004 10465

$$

RPK

Area Forecast Discussion
National Weather Service Denver/Boulder CO
147 PM MDT Thu Apr 24 2025

.KEY MESSAGES...

- Another round of showers and thunderstorms this afternoon and
  evening, some of which could be severe along and east of the
  urban corridor.

- Cooler Friday with light rain showers.

- Critical fire weather conditions Monday afternoon for the
  eastern plains.

- Mild and dry next week.

&&

.SHORT TERM /Through Friday/...
Issued at 147 PM MDT Thu Apr 24 2025

Southwest flow aloft will prevail while an east-southeast low
level flow advects moisture into eastern Colorado. This has
resulted in mostly cloudy skies and cool temperatures over most of
the eastern plains with a stable airmass in place. The increase
in moisture made it to the urban corridor with dew points in the
40s. Skies were mostly sunny this morning allowing temperatures to
reach the mid 60s to lower 70s. RAP model continues to show
MLCAPE of 1000-1500 (J/kg) across the urban corridor and nearby
plains. A cyclone has formed over the south part of the Denver
area. Along this convergent boundary we are seeing towering
cumulus and should see storms form along it by mid afternoon.
Additional storm development is expected over the northern urban
corridor mid to late afternoon. Large hail, up to golfball size
will be the main threat. Isolated wind gusts to 60 mph and a brief
tornado will also be possible. Storms will weaken as they head
into a less unstable airmass over the eastern plains.

The threat for severe storms will end early to mid evening as the
airmass stabilizes. However the chance for showers and
thunderstorms will continue through the evening, mainly over
northern Colorado behind a cold front pushing south into the area.
Showers and storms end by midnight as the colder air behind the
front stabilizes the airmass. Moisture and colder air moving into
northeast Colorado will saturate the airmass leading to low
clouds, fog, and drizzle after midnight and into Friday morning.

Easterly low level flow will keep low clouds with areas of fog
and drizzle going for much of Friday morning, and perhaps into the
afternoon in and near the foothills due to upslope flow. Highs
will be chilly with upper 40s to lower 50s across northeast
Colorado. This will stabilize the airmass over the foothills and
eastward. The mountains become slightly unstable with MLCAPE
climbing to 500 (J/kg). This is expected to lead to widely
scattered showers and thunderstorms over the mountains. As the
convective tracks eastward and encounters the cool and stable
airmass, the showers and storms are expected to dissipate.

&&

.LONG TERM /Friday night through Thursday/...
Issued at 147 PM MDT Thu Apr 24 2025

Broad but relatively weak southwesterly flow aloft will
overspread the region on Saturday ahead of a closed upper low
moving into California, entraining enough mid-level moisture in
the afternoon to support isolated to scattered afternoon
showers/thunderstorms, generally favoring the higher terrain. At
the surface, healthy southerly winds will promote ample warm
advection, returning temperatures to above normal values region-
wide.

As the low lifts northeast through the Great Basin, southwest
flow along its leading edge will increase into Sunday, helping to
push highs potentially into the 80's for the lower elevations,
with limited change for the high country. Precipitation chances
will be buffered substantially under much drier low-levels.
There's growing confidence in critical fire weather conditions
across a broad portion of the forecast area for Sunday afternoon,
particularly the southern half where humidity will be lowest.

By Monday, the primary low is slated to transition into more of
an open wave, with a secondary low shearing off the southern tip
of the trough. It's a messy pattern which inherently carries
greater uncertainty as far as how things play out through the
week, but for Monday we'll at least be looking at considerably
cooler temperatures following a frontal passage and greater
afternoon precipitation potential, most pronounced in the
mountains. Our southern plains could hold onto some fire weather
concerns too depending on the frontal timing.

Details are fuzzier Tuesday onwards, with general west to
northwest flow prevailing aloft and potentially punctuated by a
few shortwaves and opportunities for spring-like convection most
afternoons, albeit there are no strong signals.

&&

.AVIATION...(18Z TAFS through 18Z Friday)
Issued at 1151 AM MDT Thu Apr 24 2025

Scattered thunderstorms are expected to form after 19Z and then
track eastward. Best chance for a thunderstorm at DEN will be 20Z
to 23Z. Hail (possibly large 1.75 (in) diameter) will be the main
threat with the stronger storms. Outflow winds to 30 knots will be
possible as well, with a slight chance at wind gusts over 40
knots.

Cold front pushes south through the Denver area 02-04Z, bringing
northeast winds and increasing low level moisture. Scattered
showers and isolated thunderstorms will be possible behind the
front for a brief period of time. Low clouds form behind the front
with ceilings falling below 1000 feet after 06Z. Visibility will
likely be reduced to 1sm to 3sm due to the low clouds and drizzle.
Dense fog will also be possible towards 12Z with visibility at or
below 1/4sm. The low clouds and reduced visibility will linger
most/all of Friday morning with ceilings slowly rising after 18Z.

&&

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

&&

SHORT TERM...Meier
LONG TERM...Rodriguez
AVIATION...Meier

Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1024 AM MDT Thu Apr 24 2025

COZ030>051-251630-
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-
1024 AM MDT Thu Apr 24 2025

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

.DAY ONE...Today and Tonight

Scattered thunderstorms are expected to develop this afternoon
and continue into the evening hours. A few strong to severe storms
are expected over the Front Range and nearby plains, mainly west
of a line form Fort Morgan to Limon to the base of the foothills.
Large hail up to golfball size will be the main threat, but
isolated damaging winds and a brief tornado will be possible as
well.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Cooler Friday with potential for fog across the lower elevations.
Critical fire weather conditions are likely come Sunday under
warm, dry and breezy conditions.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may needed mid afternoon to early evening. Any
reports of severe weather will be appreciated.

Special Weather Statement
National Weather Service Denver CO
127 PM MDT Thu Apr 24 2025

COZ040-041-043-242030-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County CO-Elbert/Central and
East Douglas Counties Above 6000 Feet CO-Central and South Weld
County CO-
127 PM MDT Thu Apr 24 2025

...A LINE OF STRONG THUNDERSTORMS WILL IMPACT EASTERN DENVER...
WESTERN ARAPAHOE...SOUTHWESTERN WELD...WESTERN ADAMS AND
NORTHEASTERN DOUGLAS COUNTIES UNTIL 230 PM MDT...

At 127 PM MDT, Doppler radar was tracking a line of strong
thunderstorms extending from near Hudson to over Lone Tree, or
extending from 26 miles northeast of Denver to 14 miles south of
Denver, moving southeast at 5 mph.

HAZARD...Landspouts and wind gusts up to 40 mph.

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...
  Eastern Denver, Aurora, Centennial, eastern Highlands Ranch,
  northeastern Commerce City, Parker, Brighton, Greenwood Village,
  Lone Tree, Denver International Airport, D.I.A Terminal and
  Concourses, Lochbuie, Hudson, Buckley SFB, Arapahoe Park, Barr
  Lake, The Pinery, northern Castle Pines, Cherry Hills Village and
  Foxfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If a tornado is spotted seek shelter inside a sturdy building.

&&

LAT...LON 3948 10497 3990 10485 4010 10473 4010 10450
      3985 10461 3946 10473
TIME...MOT...LOC 1926Z 299DEG 4KT 4003 10466 3985 10479 3977 10482
3952 10492

LANDSPOUT...POSSIBLE
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

RPK

Special Weather Statement
National Weather Service Denver CO
211 PM MDT Thu Apr 24 2025

COZ036-040-041-242045-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County CO-Elbert/Central and
East Douglas Counties Above 6000 Feet CO-Jefferson and West
Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast
Park Counties Below 9000 Feet CO-
211 PM MDT Thu Apr 24 2025

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN ARAPAHOE AND
NORTHEASTERN DOUGLAS COUNTIES UNTIL 245 PM MDT...

At 211 PM MDT, Doppler radar was tracking a strong thunderstorm over
Sedalia, or 21 miles south of Denver, moving east at 10 mph.

HAZARD...Landspouts, wind gusts up to 40 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...
  Southeastern Highlands Ranch, Castle Rock, southwestern Parker,
  Lone Tree, Castle Pines, Sedalia, Louviers, The Pinery, Franktown
  and Shamballa.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If a tornado is spotted seek shelter inside a sturdy building.

&&

LAT...LON 3947 10504 3951 10505 3957 10481 3936 10474
      3933 10501
TIME...MOT...LOC 2011Z 260DEG 10KT 3943 10497

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

RPK

Special Weather Statement
National Weather Service Denver CO
215 PM MDT Thu Apr 24 2025

COZ040-242045-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County CO-
215 PM MDT Thu Apr 24 2025

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN ARAPAHOE AND
SOUTHWESTERN ADAMS COUNTIES UNTIL 245 PM MDT...

At 215 PM MDT, Doppler radar was tracking a strong thunderstorm over
Aurora, or 14 miles east of Denver, moving northeast at 10 mph.

HAZARD...Landspouts, wind gusts up to 40 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...
  Aurora, northeastern Centennial, Arapahoe Park and Buckley SFB.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If a tornado is spotted seek shelter inside a sturdy building.

&&

LAT...LON 3961 10474 3970 10481 3978 10464 3967 10457
TIME...MOT...LOC 2015Z 241DEG 7KT 3970 10469

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

RPK

Special Weather Statement
National Weather Service Denver CO
235 PM MDT Thu Apr 24 2025

COZ040-041-242115-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County CO-Elbert/Central and
East Douglas Counties Above 6000 Feet CO-
235 PM MDT Thu Apr 24 2025

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN ELBERT...SOUTH
CENTRAL ARAPAHOE AND NORTHEASTERN DOUGLAS COUNTIES UNTIL 315 PM
MDT...

At 235 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles southeast of Arapahoe Park, or 21 miles southeast of Denver,
moving east at 10 mph.

HAZARD...Landspouts, wind gusts up to 40 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...
  Southern Aurora.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

If a tornado is spotted seek shelter inside a sturdy building.

&&

LAT...LON 3963 10469 3967 10451 3965 10451 3966 10450
      3964 10449 3961 10449 3960 10450 3960 10449
      3959 10450 3959 10449 3957 10449 3957 10448
      3949 10448 3949 10468
TIME...MOT...LOC 2035Z 259DEG 10KT 3955 10463

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

RPK