Severe thunderstorms produced several short-lived landspouts, large hail, damaging winds. Five landspouts, all rated EF-0, touched down briefly in portions of eastern Adams and Morgan Counties.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS BOU wrote it up.
Severe thunderstorms produced several short-lived landspouts, large hail, damaging winds. Five landspouts, all rated EF-0, touched down briefly in portions of eastern Adams and Morgan Counties. Large hail, up to half dollar size, was observed in eastern Adams, Logan, and Washington counties. Intense thunderstorm winds, ranging from 60 to 80 mph, were reported in northern Lincoln, western Logan, and southeastern Washington counties. The winds downed a power line along Logan County Road 34, north of Sterling. Minor tree damage was observed in northeast Lincoln County.
The local office's own words before the first event, 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 the first event at Jun 19, 8:31 AM MST, 4 hours 34 minutes earlier.
Area Forecast Discussion National Weather Service Denver/Boulder CO 931 AM MDT Sat Jun 19 2021 .UPDATE... Issued at 909 AM MDT Sat Jun 19 2021 No significant changes to the ongoing forecast. There is a batch of high cloudiness moving over the corridor and adjacent plains this morning, with a break behind it. Disturbance over northwestern CO this morning, will move across north central and northeast CO this afternoon/evening. Plenty of low level moisture with dewpoints in the low 60s east of a Longmont to Limon line, some of this will mix out along the urban corridor by the afternoon. Healthy CAPES as mentioned in this mornings discussion, with DCAPE values around 1300 j/kg as well this afternoon. Storm motions this afternoon northwest around 25 mph, which should help minimize the threat of flooding. Best chance of severe thunderstorms should be east of line from around Greeley to Limon. Strong winds gusts in excess of 60 mph, and hail up to half dollar size not out of the question. && .SHORT TERM...(Today and tonight) Issued at 346 AM MDT Sat Jun 19 2021 The upper ridge of high pressure has been suppressed southward into southern Arizona and New Mexico today as a stronger west and northwest flow develops further north into Colorado. A weak upper level trof will move across Northern Colorado this afternoon and evening with some weak large scale ascent this afternoon. Moisture levels are significantly higher from 24 hours ago as integrated PW trends showing values around .80" of an inch over the Front range and upwards of a 1.25" further east on the healthy CAPES as mentioned in this mornings discussion, but good DCAPE values around 1300 j/kg as well this afternoon. Storm motions this afternoon northwest around 25 mph,which should help minimize the threat of any potential flooding issues. plains. Dewpoints are currently in the 50s and a few lower 60s on the far plains. There is a threat of severe storms on the plains this afternoon/early evening with ML CAPE values of 1500-3000j/kg available. Shear profile has improved today for the potential for severe storms as mid level flow increasing to 30-4kt. SPC has put much of the northeast plains in a slight chance for severe with the main threat of damaging winds up to 60 mph and large hail. Further west over the Front Range, forecast soundings are more inverted-v soundings with still dry low levels and expect mainly gusty winds with the storms. Once the storms get into the richer, moist air further east, storms expected to intensify. As a wild card, there is a fair amount of cloudiness across western Colorado and even some showers now, so there could be some limits on how much surface heating we may get this morning and possibly could impact the instability for the afternoon. Something to at least watch for. Temperatures will be a few degrees warmer today as 700mb temperatures warm back up to around +17C. Once the trof shifts east by later this evening, expect stronger northwest winds will develop in a subsident airmass. Cross sections showing cross barrier flow around 25kt, so could see some gusts in the 20 to 35 mph over the mountains and east slopes. .LONG TERM...(Sunday through Friday) Issued at 346 AM MDT Sat Jun 19 2021 Sunday and Monday, a shortwave trough moving over the northern Rockies and Great Plains will bring cooling and an increase in precipitation to northeast Colorado. Model agreement on the timing and impacts of the system is improving, though the ECM is still a bit slower with it than the GFS. WPC ensemble cluster analysis suggests high confidence in the synoptic situation through at least Monday night, especially for the central Rockies. As the trough advances, weak synoptic subsidence will be slowly replaced by ascent to a maximum of around 10 to 15 mb/hr from the surface to the mid levels briefly on Sunday evening. A cold front will move over the plains Sunday, beginning with a northerly surge in the morning then more northeasterly winds in the late afternoon and evening. This front will bring colder air, upslope flow into the Front Range, and an increase in stability across the plains. The stronger cold air advection will probably occur after the afternoon high so only slightly cooler temperatures are expected through the afternoon Sunday. Temperatures Sunday should be closer to normal on the plains, with highs in the mid 80s followed by overnight lows in the 50s. Much more significant will be the increase in low to mid level stability, with low to mid level lapse rates falling to about 5 C/km by Sunday evening. On the plains, precipitation will become more stratiform by the evening with increasing stability behind the front. Isolated showers and storms Sunday afternoon will become scattered to widespread showers with isolated storms embedded. The high country will see more isolated coverage overall as the stratiform event stays east of the Continental Divide. A roughly 100 knot jet max in the shortwave will pass close to northeast Colorado Sunday evening through Monday, and the increased flow aloft should mean better shear and faster storm motion. Scattered to widespread showers are expected to persist into Monday morning, then coverage will quickly decrease through the day. Temperatures will be cooler Monday, with highs possibly down into the 70s across the area. There is some uncertainty here as model forecast temperatures for Monday through Tuesday have started trending warmer quickly. However, variance in ensemble and MOS guidance is also increasing quickly so I've decided to limit the warming trend in the forecast until confidence improves as decent cooling should be expected with the front, widespread precipitation, and cloud coverage. Some more isolated storms are possible Monday afternoon, initiating over the high terrain with still limited severe potential. Upper ridging sets back in behind the exiting trough late Monday and early Tuesday, with a return to weak synoptic subsidence. Tuesday and Wednesday will see warming and drying again, with highs now forecast to be back into the mid 90s on the plains and 80s in the high country by Wednesday afternoon. More isolated storms can be expected, mainly over the high terrain, in the afternoons but overall the forecast is quite dry. Another shortwave trough which was deepening off the west coast earlier in the period may start moving on shore late Tuesday or Wednesday and bring some cooling, moisture and increased precipitation for Thursday into the weekend. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) Issued at 925 AM MDT Sat Jun 19 2021 Expect a round of showers and thunderstorms this afternoon, mainly between 21z-00z with strong and gusty winds up to 40kt as the main impact for the terminals. Drier air will work in this evening with a diminishing thunderstorm threat and clearing skies. Northwest winds this morning will transition to northeast after 17z with speeds less than 10 kts, then gusty northwest winds to 25 kts develop with showers and thunderstorms moving across the terminals by 21z. && .HYDROLOGY... Issued at 346 AM MDT Sat Jun 19 2021 With higher moisture levels today, there is a low threat for flash flooding in the burn scars. Overall threat is still low as storms will be moving at a decent clip. Sunday and Monday, there will be a better chance of showers and thunderstorms and more moisture will be available as well. Storms are expected to be moving but there could be enough rain with the stronger storms to cause minor flooding in the new burn areas. This low risk of flooding will continue through Monday and is mainly for the burn areas east of the Continental Divide, especially in the foothills. Starting Tuesday, drier conditions will reduce the risk through at least mid week. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && UPDATE...Cooper SHORT TERM...Entrekin LONG TERM...EJD AVIATION...Cooper/Entrekin HYDROLOGY...Entrekin
Hazardous Weather Outlook National Weather Service Denver/Boulder CO 1040 AM MDT Sat Jun 19 2021 COZ030>051-201645- 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- 1040 AM MDT Sat Jun 19 2021 This hazardous weather outlook is for northeast and north central Colorado. .DAY ONE...Today and Tonight Another round of scattered showers and thunderstorms will develop towards the noon hour in the mountains and then move across the plains through the afternoon and early evening. Some storms may become severe with hail up to 1.25 inches in diameter and wind gusts to 65 mph. The greatest threat of severe thunderstorms will be along east of line from New Raymer to Fort Morgan to Limon. The storms will diminish from west to east early this evening. .DAYS TWO THROUGH SEVEN...Sunday through Friday A cold front will bring cooler temperatures and a better chance of rain late Sunday and early Monday. Then we'll warm right back up again with highs back into the 90s on the plains by the middle of next week. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed across the northeast plains of Colorado after 3 pm.
Special Weather Statement
National Weather Service Denver CO
125 PM MDT Sat Jun 19 2021
COZ045-046-192000-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County CO-Central and East Adams and Arapahoe Counties CO-
125 PM MDT Sat Jun 19 2021
...Brief Landspout Tornadoes Possible...
At 122 PM MDT, conditions are becoming favorable for the development
of landspout tornadoes over eastern portions of Adams and Arapahoe
counties and northeast Elbert county. However, at this time it is
unknown which if any storm would produce a landspout. Any landspouts
which develop are expected to pose a limited threat.
Locations impacted include...
Deer Trail, Agate, Cottonwood Valley, Shamrock, Leader and Byers.
Landspout tornadoes can form with a developing thunderstorm before
rain, hail, and even thunder is observed. Landspout tornadoes are not
usually associated with a wall cloud and are often difficult to
detect with weather radar.
&&
LAT...LON 3940 10424 3939 10422 3943 10417 3945 10417
3946 10419 3949 10421 3944 10423 3944 10424
4000 10420 4000 10373 3939 10375 3938 10413
3941 10414 3938 10416 3940 10420 3938 10422
3938 10424
RPKSpecial Weather Statement National Weather Service Denver CO 157 PM MDT Sat Jun 19 2021 COZ040-192030- North Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield County CO- 157 PM MDT Sat Jun 19 2021 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN ARAPAHOE...CENTRAL DENVER AND SOUTHWESTERN ADAMS COUNTIES UNTIL 230 PM MDT... At 156 PM MDT, Doppler radar was tracking a strong thunderstorm over western Aurora, or 4 miles east of Denver, moving east at 25 mph. Wind gusts up to 50 mph will be possible with this storm. Locations impacted include... Denver, Aurora, southern Thornton, northern Centennial, southern Commerce City, Greenwood Village, southwestern Denver International Airport and Buckley AFB. PRECAUTIONARY/PREPAREDNESS ACTIONS... Prepare for sudden gusty winds. Secure loose objects and move to a safe shelter inside a building or vehicle. If on or near a lake, get out of the water and move indoors or inside a vehicle. Remember, lightning can strike out to 10 miles from the parent thunderstorm. If you can hear thunder, you are close enough to be struck by lightning. Move to safe shelter now! Do not be caught on the water in a thunderstorm. && A Severe Thunderstorm Watch remains in effect until 900 PM MDT for northeastern Colorado. LAT...LON 3960 10495 3984 10496 3986 10470 3964 10468 TIME...MOT...LOC 1956Z 247DEG 22KT 3971 10486 RPK
The Denver radar (KFTG), 45 km away, was scanning. The volume nearest the first event began at 20:03 UTC.
5 tornado, 5 hail, 5 thunderstorm wind. Local standard time, as filed.
A landspout touched down briefly in an open field. No damage was observed.
A landspout touched down briefly in an open field. No damage was observed.
A landspout touched down briefly in an open field. No damage was observed.
A landspout touched down briefly in an open field. No damage was observed.
A landspout touched down briefly in an open field. No damage was observed.
Intense thunderstorm winds downed a powerline north of Sterling.
Strong winds snapped small tree limbs across Akron.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2021Every state in 2021This day in weather historyThe tornado archive for Colorado, 2021Warnings in Colorado, June 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 964600, 964601, 964602, 964603, 964604, 964594, 964595, 964599, 964616, 964596, 964615, 964598, 964597, 964610, 964609.