Alert archive / Colorado / Severe Thunderstorm Watches in 2018
Severe Thunderstorm Watch 334
The Storm Prediction Center issued this severe thunderstorm watch at Aug 6, 2018, 2:37 PM MDT for 11 counties in Colorado; 5 counties in Nebraska; Goshen County, Laramie County, Platte County, Wyoming. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 6, 2018, 2:37 PM MDT (20:37 UTC)
- Expired
- Aug 6, 2018, 10:00 PM MDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
Counties Adams County, CO, Arapahoe County, CO, Boulder County, CO, Broomfield County, CO, Denver County, CO, Jefferson County, CO, Larimer County, CO, Logan County, CO, Morgan County, CO, Washington County, CO, Weld County, CO, Banner County, NE, Cheyenne County, NE, Kimball County, NE, Morrill County, NE, Scotts Bluff County, NE, Goshen County, WY, Laramie County, WY, Platte County, WY
The radar
The Cheyenne radar (KCYS), 67 km from the middle of the area, began a volume at 20:37 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
23 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 6, 2:43 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 47 min |
| Aug 6, 3:23 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 52 min |
| Aug 6, 3:26 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 49 min |
| Aug 6, 3:55 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 35 min |
| Aug 6, 3:56 PM MDT | Severe Thunderstorm Warning | CYS | Box Butte, Morrill | 49 min |
| Aug 6, 4:04 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 26 min |
| Aug 6, 4:27 PM MDT | Severe Thunderstorm Warning | BOU | Morgan, Weld | 48 min |
| Aug 6, 4:30 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 45 min |
| Aug 6, 4:33 PM MDT | Severe Thunderstorm Warning | CYS | Morrill | 42 min |
| Aug 6, 4:42 PM MDT | Severe Thunderstorm Warning | CYS | Converse, Niobrara, Platte | 33 min |
| Aug 6, 5:08 PM MDT | Severe Thunderstorm Warning | CYS | Morrill | 26 min |
| Aug 6, 5:11 PM MDT | Severe Thunderstorm Warning | CYS | Goshen, Platte | 16 min |
| Aug 6, 5:12 PM MDT | Severe Thunderstorm Warning | BOU | Morgan, Weld | 48 min |
| Aug 6, 5:55 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 35 min |
| Aug 6, 5:56 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Morgan | 22 min |
| Aug 6, 6:48 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Weld | 42 min |
| Aug 6, 7:14 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe | 31 min |
| Aug 6, 7:41 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe, Elbert | 49 min |
| Aug 6, 7:48 PM MDT | Tornado Warning | BOU | Arapahoe, Elbert | 27 min |
| Aug 6, 8:00 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe, Elbert | 45 min |
| Aug 6, 8:25 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe | 35 min |
| Aug 6, 8:28 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe, Douglas | 17 min |
| Aug 6, 9:00 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe | 11 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Denver, CO (KDEN), launched 12:00Z, 8.6 hours before the alert went out and 137 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
- 573 J/kg
- Mixed-layer CIN
- -216 J/kg
- Mixed-layer LCL
- 855 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- -26 m²/s²
- 0-3 km storm-relative helicity
- 20 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 5, 6:05 PM MDT | Mesoscale Discussion | SPC | Larimer | 115 min |
| Aug 6, 12:21 PM MDT | Mesoscale Discussion | SPC | Baca, Bent, Costilla, Crowley, Custer, El Paso and 7 more | 114 min |
| Aug 6, 12:59 PM MDT | Severe Thunderstorm Watch | SPC | Baca, Bent, Crowley, Custer, Douglas, Elbert and 10 more | 9 hr |
| Aug 6, 2:02 PM MDT | Mesoscale Discussion | SPC | Boulder, Larimer, Morgan, Weld | 88 min |
| Aug 6, 5:24 PM MDT | Mesoscale Discussion | SPC | Adams, Arapahoe, Bent, Boulder, Broomfield, Cheyenne and 24 more | 66 min |
| Aug 5, 7:16 PM MDT | Mesoscale Discussion | SPC | Harlan | 119 min |
| Aug 5, 8:32 PM MDT | Mesoscale Discussion | SPC | Adams, Burt, Butler, Cass, Clay, Colfax and 17 more | 2 hr |
| Aug 6, 1:31 PM MDT | Mesoscale Discussion | SPC | Boone, Buffalo, Burt, Butler, Cass, Colfax and 26 more | 89 min |
| Aug 6, 2:49 PM MDT | Mesoscale Discussion | SPC | Box Butte, Cherry, Dawes, Sheridan, Sioux | 86 min |
| Aug 6, 5:38 PM MDT | Mesoscale Discussion | SPC | Johnson, Nemaha, Otoe, Pawnee, Richardson | 2 hr |
Nearby
Severe Thunderstorm Watches in Colorado, 2018Severe Thunderstorm Watches in Nebraska, 2018Severe Thunderstorm Watches in Wyoming, 2018Every severe thunderstorm watch in 2018
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.