Alert archive / Colorado / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 127, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 14, 2021, 9:28 PM MDT for Logan County, Washington County, Colorado. It was in force for 47 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 14, 2021, 9:28 PM MDT (03:28 UTC)
- Expired
- Aug 14, 2021, 10:15 PM MDT
- In force
- 47 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 50.0 mph
Counties Logan County, CO, Washington County, CO
The radar
The Denver radar (KFTG), 121 km from the middle of the area, began a volume at 03:28 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.
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 14, 3:28 PM MDT | Severe Thunderstorm Watch | SPC | 7 hr |
The nearest sounding before it
Denver, CO (KDNR), launched 00:00Z, 3.5 hours before the alert went out and 55 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
- 666 J/kg
- Mixed-layer CIN
- -45 J/kg
- Mixed-layer LCL
- 3335 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- -22 m²/s²
- 0-3 km storm-relative helicity
- 81 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.4
The text
As transmitted.
107
WUUS55 KBOU 150328
SVRBOU
COC075-121-150415-
/O.NEW.KBOU.SV.W.0127.210815T0328Z-210815T0415Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
928 PM MDT Sat Aug 14 2021
The National Weather Service in Denver Colorado has issued a
* Severe Thunderstorm Warning for...
Northwestern Washington County in northeastern Colorado...
Southwestern Logan County in northeastern Colorado...
* Until 1015 PM MDT.
* At 927 PM MDT, a severe thunderstorm was located over Prewitt
Reservoir, or 15 miles southwest of Sterling, moving south at 20
mph.
HAZARD...Quarter size hail.
SOURCE...Radar indicated.
IMPACT...Damage to vehicles is expected.
* Locations impacted include...
Merino, Prewitt Reservoir and Midway.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4050 10322 4020 10319 4019 10347 4022 10348
4053 10343
TIME...MOT...LOC 0327Z 012DEG 18KT 4045 10336
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH
$$
BARJENBRUCH2 follow-up statements
105
WWUS55 KBOU 150351
SVSBOU
Severe Weather Statement
National Weather Service Denver CO
951 PM MDT Sat Aug 14 2021
COC075-150400-
/O.CAN.KBOU.SV.W.0127.000000T0000Z-210815T0415Z/
Logan CO-
951 PM MDT Sat Aug 14 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN LOGAN COUNTY IS
CANCELLED...
The severe thunderstorm which prompted the warning has moved into
northwest Washington County. Therefore, the warning has been
cancelled.
A Severe Thunderstorm Watch remains in effect until 1100 PM MDT for
northeastern Colorado.
LAT...LON 4020 10319 4019 10347 4022 10344 4044 10340
4044 10324
TIME...MOT...LOC 0350Z 348DEG 18KT 4033 10332
$$
COC121-150415-
/O.CON.KBOU.SV.W.0127.000000T0000Z-210815T0415Z/
Washington CO-
951 PM MDT Sat Aug 14 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1015 PM MDT
FOR NORTHWESTERN WASHINGTON COUNTY...
At 950 PM MDT, a severe thunderstorm was located 7 miles south of
Prewitt Reservoir, or 13 miles northwest of Akron, moving south at 20
mph.
HAZARD...Quarter size hail.
SOURCE...Radar indicated.
IMPACT...Damage to vehicles is expected.
Locations impacted include...
Prewitt Reservoir and Midway.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4020 10319 4019 10347 4022 10344 4044 10340
4044 10324
TIME...MOT...LOC 0350Z 348DEG 18KT 4033 10332
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...<50 MPH
$$
BARJENBRUCH574
WWUS55 KBOU 150412
SVSBOU
Severe Weather Statement
National Weather Service Denver CO
1012 PM MDT Sat Aug 14 2021
COC121-150422-
/O.EXP.KBOU.SV.W.0127.000000T0000Z-210815T0415Z/
Washington CO-
1012 PM MDT Sat Aug 14 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL WASHINGTON
COUNTY WILL EXPIRE AT 1015 PM MDT...
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire. However small hail, gusty winds and brief
heavy rain are still possible with this thunderstorm as it moves
over the area between Akron and Woodrow through 11 PM.
A Severe Thunderstorm Watch remains in effect until 1100 PM MDT for
northeastern Colorado.
LAT...LON 4020 10319 4019 10347 4022 10344 4044 10340
4044 10324
TIME...MOT...LOC 0412Z 012DEG 18KT 4024 10335
$$
GIMMESTADThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 14, 6:48 PM MDT | Flash Flood Warning | BOU | Larimer | 115 min |
| Aug 14, 7:15 PM MDT | Special Weather Statement | BOU | Summit | 30 min |
| Aug 14, 7:38 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 52 min |
| Aug 14, 8:01 PM MDT | Severe Thunderstorm Warning | BOU | Logan | 44 min |
| Aug 14, 8:28 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 47 min |
| Aug 14, 8:29 PM MDT | Severe Thunderstorm Warning | BOU | Sedgwick | 46 min |
| Aug 14, 8:43 PM MDT | Severe Thunderstorm Warning | BOU | Logan, Washington | 47 min |
| Aug 14, 9:15 PM MDT | Severe Thunderstorm Warning | BOU | Phillips, Sedgwick | 14 min |
| Aug 14, 9:31 PM MDT | Special Weather Statement | BOU | Weld | 44 min |
| Aug 15, 2:32 PM MDT | Areal Flood Advisory | BOU | Grand | 88 min |
| Aug 15, 5:19 PM MDT | Special Weather Statement | BOU | Lincoln | 41 min |
| Aug 15, 5:25 PM MDT | Special Weather Statement | BOU | Teller | 65 min |
Nearby
Severe Thunderstorm Warnings in Colorado, 2021Every severe thunderstorm warning in 2021
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.