Alert archive / Colorado / Severe Thunderstorm Warnings in 2026
Severe Thunderstorm Warning 367, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 26, 2026, 6:01 PM MDT for Arapahoe County, Elbert County, Colorado. It was in force for 26 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Aug 26, 2026, 6:01 PM MDT (00:01 UTC)
- Expired
- Aug 26, 2026, 6:27 PM MDT
- In force
- 26 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Hail
- 1.25 in
- Wind
- 60.0 mph
Counties Arapahoe County, CO, Elbert County, CO
The radar
The Denver radar (KFTG), 24 km from the middle of the area, began a volume at 00:03 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
Did it verify
Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.
Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 26, 3:53 PM MDT | Severe Thunderstorm Watch | SPC | 6 hr |
The nearest sounding before it
Grand Junction, CO (KGJT), launched 00:00Z, 0.0 hours before the alert went out and 338 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 598 J/kg
- Mixed-layer CIN
- -7 J/kg
- Mixed-layer LCL
- 3584 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- -5 m²/s²
- 0-3 km storm-relative helicity
- 34 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
759
WUUS55 KBOU 270001
SVRBOU
COC005-039-270045-
/O.NEW.KBOU.SV.W.0367.260827T0001Z-260827T0045Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
601 PM MDT Wed Aug 26 2026
The National Weather Service in Denver has issued a
* Severe Thunderstorm Warning for...
Northwestern Elbert County in east central Colorado...
Western Arapahoe and Central Arapahoe County in northeastern
Colorado...
* Until 645 PM MDT.
* At 601 PM MDT, a severe thunderstorm was located 5 miles southeast
of Arapahoe Park, or 20 miles southeast of Denver, moving east at
15 mph.
HAZARD...60 mph wind gusts and half dollar size hail.
SOURCE...Radar indicated.
IMPACT...Hail damage to vehicles is expected. Expect wind damage to
roofs, siding, and trees.
* Locations impacted include...
Southern Aurora.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Seek shelter inside a well-built structure and stay away from
windows. This storm is capable of producing damaging winds and large
hail.
&&
LAT...LON 3963 10467 3963 10446 3950 10450 3954 10466
3957 10466 3957 10468
PARTITION...408005 508005
TIME...MOT...LOC 0001Z 276DEG 14KT 3958 10462
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.25 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Aponte1 follow-up statement
159
WWUS55 KBOU 270027
SVSBOU
Severe Weather Statement
National Weather Service Denver CO
627 PM MDT Wed Aug 26 2026
COC005-039-270037-
/O.CAN.KBOU.SV.W.0367.000000T0000Z-260827T0045Z/
Arapahoe CO-Elbert CO-
627 PM MDT Wed Aug 26 2026
...SEVERE THUNDERSTORM WARNING IS CANCELLED FOR ELBERT AND WESTERN
ARAPAHOE AND CENTRAL ARAPAHOE COUNTIES...
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled. However, small hail and
gusty winds are still possible with this thunderstorm.
A Severe Thunderstorm Watch remains in effect until 1100 PM MDT
Wednesday for portions of east central and northeast Colorado.
&&
LAT...LON 3963 10467 3963 10446 3950 10450 3954 10466
3957 10466 3957 10468
PARTITION...408005 508005
TIME...MOT...LOC 0001Z 276DEG 14KT 3958 10462
$$
AponteWhat forecasters said that day
The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Denver/Boulder, CO wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 26, 11:40 AM MDT, 6 hours 21 minutes earlier. Its key messages:
- Scattered afternoon/evening thunderstorms expected for the I-25 Corridor and plains. A few storms could become severe, with large hail and strong winds possible.
- Thunderstorm coverage decreases Thursday and Friday with mainly isolated high-based showers/storms with gusty winds.
- Temperatures return to the 90s Friday and Saturday across the plains.
- Thunderstorm coverage increases for late Saturday and Sunday.
Area forecast discussion, Aug 26, 11:40 AM MDT, 6 hours 21 minutes before
Area Forecast Discussion National Weather Service Denver/Boulder CO 1140 AM MDT Wed Aug 26 2026 .KEY MESSAGES... - Scattered afternoon/evening thunderstorms expected for the I-25 Corridor and plains. A few storms could become severe, with large hail and strong winds possible. - Thunderstorm coverage decreases Thursday and Friday with mainly isolated high-based showers/storms with gusty winds. - Temperatures return to the 90s Friday and Saturday across the plains. - Thunderstorm coverage increases for late Saturday and Sunday. && .DISCUSSION /Through Wednesday/... Issued at 1140 AM MDT Wed Aug 26 2026 An upper level high will be centered over Arizona/New Mexico today with ridging extending northward all the way to Alberta. This will lead to a northwest flow aloft over Colorado. Outflow from thunderstorms last night and this morning increased low level moisture but also cooled the airmass. Temperatures are slow to warm this morning, with 11 AM readings only in the mid to upper 70s. DEN ACARS soundings still show a strong inversion centered around 700mb. Forecast model soundings show this as well, but they don't appear strong enough regarding the inversion. This leads to a highly uncertain thunderstorm forecast and severe threat for later today. MLCAPE is still forecasted to climb to 1000-2000 J/kg along and east of the I-25 corridor. The 0-6km bulk shear reaches 30-40 knots. The 30 knots is borderline for severe storms, but where we see east to southeast surface winds around 10 knots, the bulk shear will be closer to 40 knots. This favors areas east of a line from Fort Collins to DIA for severe storms. Because of the slower heating, storm development will likely be delayed with late afternoon and early evening hours being favored. Again, given the strength of the inversion, the severe thunderstorm threat remains highly uncertain. The upper-level high will remain centered to our southeast, but the ridge axis shifts eastward over Colorado on Thursday. This will bring warmer temperatures and some drying. Precipitable water values fall below an inch throughout the area, except for the far eastern plains. Warmer air aloft, less moisture and instability will lead to a notable decrease in thunderstorm activity. There should be enough lingering moisture for isolated high-based showers and thunderstorms. Any rainfall is expected to be light, with gusty outflow winds up to 45 mph possible. However, southeast winds will prevail over far eastern Colorado, helping to preserve low level moisture. MLCAPE will reach 1000-2000 J/kg with 0-6km bulk shear of around 40 knots, which would favor severe thunderstorms. Warmer air aloft may cap convection, though. Convergence along a boundary is likely needed for storms to initially form, and models generally don't show this happening. The high intensifies (slightly) and drifts northeastward for Friday. Temperatures warm further, with highs expected to reach the lower to mid 90s across northeast Colorado. Models hint at a slight increase in moisture, which should fuel a round of afternoon/evening showers and thunderstorms. Given the warm temperatures and limited moisture and instability, the showers/storms are expected to be high-based with gusty outflows being common. For the weekend, an upper level trough (eventually strengthening into a closed low) will track east across the northwest part of the country. This will push the upper level high east of the region, with southwest flow aloft developing over Colorado. We'll see an increase in monsoon moisture leading to a better chance for showers and thunderstorms. The very warm air hangs on for Saturday with lower to mid 90s expected again, but temperatures will cool to the mid 80s to lower 90s for Sunday. The weather pattern for next week starts to look like a late summer/early fall pattern, featuring stronger west to southwest flow aloft with one or two shortwave troughs passing across the region. For now, models show enough moisture each day for a round of showers and thunderstorms. However, wouldn't be surprised if we end up with a dry and breezy day due to subsidence behind an exiting shortwave trough. && .AVIATION /18Z TAFS through 18Z Thursday/... Issued at 1119 AM MDT Wed Aug 26 2026 Not sure about timing of convection due to capping inversion. It's possible tstm development around the area may hold off until after 22z and could linger thru 02z based on latest data. If a stronger storm were to affect one of the airports (10% chance) brief visibility down to 1 to 3 miles with ceilings blo 6000 ft would be possible along with wind gusts to 50 mph along with hail. Tstm threat should diminish after 02z. As far as winds, they should trend to the east by 19z and linger thru the aftn thru 02z. By 02z expect more of a SE direction which will change to southerly by 04z. Overnight expect SSW winds which will trend to light WSW by 14z. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && DISCUSSION...BM AVIATION...RPK
In the hours before
Special weather statement, Aug 26, 2:24 PM MDT, 3 hours 37 minutes before
Special Weather Statement
National Weather Service Denver CO
224 PM MDT Wed Aug 26 2026
COZ037-262100-
Central and Southeast Park County CO-
224 PM MDT Wed Aug 26 2026
...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN PARK COUNTY UNTIL 3
PM MDT...
At 224 PM MDT, Doppler radar was tracking a strong thunderstorm near
Guffey, or 71 miles southwest of Denver, moving east at 10 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...
Guffey.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Monitor the weather situation closely and be alert for threatening
weather conditions.
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3873 10564 3887 10557 3886 10533 3870 10533
3870 10555
TIME...MOT...LOC 2024Z 287DEG 8KT 3879 10552
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH
AponteSpecial weather statement, Aug 26, 3:14 PM MDT, 2 hours 47 minutes before
Special Weather Statement
National Weather Service Denver CO
314 PM MDT Wed Aug 26 2026
COZ041-262145-
Elbert/Central and East Douglas Counties Above 6000 Feet CO-
314 PM MDT Wed Aug 26 2026
...A STRONG THUNDERSTORM WILL IMPACT WEST CENTRAL ELBERT AND
SOUTHEASTERN DOUGLAS COUNTIES UNTIL 345 PM MDT...
At 314 PM MDT, Doppler radar was tracking a strong thunderstorm near
Greenland, or 39 miles south of Denver, moving southeast 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...
Greenland.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Monitor the weather situation closely and be alert for threatening
weather conditions.
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3916 10491 3927 10481 3923 10458 3913 10457
3913 10489 3915 10491
TIME...MOT...LOC 2114Z 298DEG 8KT 3918 10478
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH
AponteLocal storm report, Aug 26, 3:23 PM MDT, 2 hours 38 minutes before
Preliminary Local Storm Report
National Weather Service Denver CO
323 PM MDT Wed Aug 26 2026
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0307 PM Hail 3 ENE Greenland 39.21N 104.79W
08/26/2026 M1.00 Inch Douglas CO Trained Spotter
&&
AGSThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 26, 6:08 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe | 31 min |
| Aug 26, 6:19 PM MDT | Areal Flood Advisory | BOU | Douglas | 3 hr |
| Aug 26, 6:21 PM MDT | Areal Flood Advisory | BOU | Arapahoe, Elbert | 62 min |
| Aug 26, 6:23 PM MDT | Special Weather Statement | BOU | Denver | 37 min |
| Aug 26, 6:25 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe, Elbert, Lincoln, Washington | 50 min |
| Aug 26, 6:37 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe, Denver, Douglas, Jefferson | 38 min |
| Aug 26, 6:40 PM MDT | Areal Flood Advisory | BOU | Adams, Arapahoe, Denver, Jefferson | 2 hr |
| Aug 26, 6:47 PM MDT | Areal Flood Advisory | BOU | Adams, Arapahoe, Elbert | 37 min |
| Aug 26, 7:08 PM MDT | Flash Flood Warning | BOU | Adams, Arapahoe, Elbert | 3 hr |
| Aug 26, 7:08 PM MDT | Severe Thunderstorm Warning | BOU | Lincoln, Washington | 32 min |
| Aug 26, 7:16 PM MDT | Areal Flood Advisory | BOU | Adams, Arapahoe, Denver | 119 min |
| Aug 26, 7:29 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe, Washington | 14 min |
| Aug 26, 7:35 PM MDT | Areal Flood Advisory | BOU | Adams, Arapahoe, Lincoln, Washington | 3 hr |
| Aug 26, 7:47 PM MDT | Special Weather Statement | BOU | Adams, Arapahoe | 43 min |
| Aug 26, 8:29 PM MDT | Special Weather Statement | BOU | Adams | 46 min |
| Aug 27, 2:27 PM MDT | Severe Thunderstorm Warning | BOU | Larimer, Weld | 33 min |
| Aug 27, 2:33 PM MDT | Severe Thunderstorm Warning | BOU | Elbert | 27 min |
| Aug 27, 2:38 PM MDT | Special Weather Statement | BOU | Gilpin | 37 min |
Nearby
Severe Thunderstorm Warnings in Colorado, 2026Every severe thunderstorm warning in 2026
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.