Alert archive / Colorado / Severe Thunderstorm Warnings in 1987
Severe Thunderstorm Warning 22, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 23, 1987, 3:17 PM MDT for Arapahoe County, Douglas County, Jefferson County, Colorado. It was in force for 58 min. 3 reports came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- Jun 23, 1987, 3:17 PM MDT (21:17 UTC)
- Expired
- Jun 23, 1987, 4:15 PM MDT
- In force
- 58 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties
Counties Arapahoe County, CO, Douglas County, CO, Jefferson County, CO
The radar
The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jun 23, 3:30 PM MDT | Hail 0.75 | Jefferson, CO | |
| Jun 23, 3:39 PM MDT | Hail 0.75 | Arapahoe, CO | |
| Jun 23, 3:54 PM MDT | Hail 1.5 | Jefferson, CO |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.
The nearest sounding before it
Fort Carson/Butt, CO (KFCS), launched 12:00Z, 9.3 hours before the alert went out and 94 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
- 115 J/kg
- Mixed-layer CIN
- -166 J/kg
- Mixed-layer LCL
- 1262 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 114 m²/s²
- 0-3 km storm-relative helicity
- 242 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.6
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
What 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.
In the hours before
Special weather statement, Jun 23, 2:06 PM MDT, 1 hour 11 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 205 PM MDT TUE JUN 23 1987 ...RAPID THUNDERSTORM DEVELOPMENT EXPECTED NORTH AND WEST DENVER METRO AREA... ...TORNADO WATCH IN EFFECT FOR MUCH OFEASTERN COLORADO... A TORNADO WATCH IS NOW IN EFFECT FOR A LARGE PART OF COLORADO EAST OF MOUNTAINS AND NORTH OF ABOUT THE ARKANSAS RIVER. THUNDERSTORMS THAT HAVE BEGUN TO DEVELOP NEAR DENVER WILL INTENSIFY BEFORE 3 PM. STRONGEST STORMS ARE LIKELY FROM NEAR BRIGHTON THRU THE NORTHERN DENVER METRO AREA INTO EXTREME EASTERN JEFFERSON COUNTY. THE STORMS WILL INTENSIFY RAPIDLY BETWEEN NOW AND 300 PM AND MAY BECOME SEVERE. BRIEF HEAVY RAINS ARE LIKELY WITH THE STORMS.. KAPLAN
The office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 23, 2:20 PM MDT | Tornado Warning | BOU | Arapahoe, Douglas, Jefferson | 30 min |
| Jun 23, 2:20 PM MDT | Tornado Warning | BOU | Denver | 30 min |
| Jun 23, 2:34 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 56 min |
| Jun 23, 2:54 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe, Douglas | 61 min |
| Jun 23, 2:54 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Denver | 61 min |
| Jun 23, 3:17 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Denver, Weld | 58 min |
| Jun 23, 4:11 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Morgan, Weld | 59 min |
| Jun 23, 4:11 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe, Denver | 59 min |
| Jun 23, 5:53 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe | 42 min |
| Jun 23, 5:59 PM MDT | Tornado Warning | BOU | Weld | 41 min |
Nearby
Severe Thunderstorm Warnings in Colorado, 1987Every severe thunderstorm warning in 1987
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.