Alert archive / Colorado / Severe Thunderstorm Warnings in 1991
Severe Thunderstorm Warning 45, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at May 31, 1991, 4:20 PM MDT for Adams County, Arapahoe County, Denver County, Colorado. It was in force for 40 min. 2 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
- May 31, 1991, 4:20 PM MDT (22:20 UTC)
- Expired
- May 31, 1991, 5:00 PM MDT
- In force
- 40 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties
Counties Adams County, CO, Arapahoe County, CO, Denver County, CO
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 31, 4:37 PM MDT | Hail 0.75 | Arapahoe, CO | |
| May 31, 4:45 PM MDT | Hail 1 | Arapahoe, 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
Denver, CO (KDEN), launched 12:00Z, 10.3 hours before the alert went out and 111 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1512 m above ground
- 0-6 km bulk shear
- 51 kt
- 0-1 km storm-relative helicity
- -33 m²/s²
- 0-3 km storm-relative helicity
- 72 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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, May 31, 3:06 PM MDT, 1 hour 14 minutes before
COZ011-312200-
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
305 PM MDT THU MAY 30 1991
...THUNDERSTORMS DEVELOPING IN SOUTHERN METRO DENVER AREA...
THUNDERSTORMS WERE DEVELOPING IN NORTHERN DOUGLASS AND WESTERN ARAPAHOE
COUNTIES THIS AFTERNOON. AT 300 PM MDT...NATIONAL WEATHER SERVICE
DOPPLER RADAR INDICATED A COUPLE OF THUNDERSTORMS NEAR SOUTHERN AURORA
AND ALSO JUST SOUTH OF LITTLETON. THE STORMS WERE MOVING NORTH
NORTHEAST AT ABOUT 20 MILES AN HOUR.
THESE STORMS COULD PRODUCE HAIL...GUSTY WIND AND BRIEF HEAVY RAIN.
MINOR STREET FLOODING IS ALSO POSSIBLE. RESIDENTS OF THE METRO DENVER
AREA SHOULD MONITOR WEATHER CONDITIONS AND BE PREPARED TO TAKE THE
NECESSARY SAFETY PRECAUTIONS SHOULD THREATENING WEATHER APPROACH.
STAY TUNED TO NOAA WEATHER RADIO...COMMERCIAL RADIO OR TELEVISION FOR
LATER STATEMENTS AND POSSIBLE WARNINGS.
DELGADO...WSFO DENVERThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 31, 3:29 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe, Denver | 31 min |
| May 31, 3:29 PM MDT | Severe Thunderstorm Warning | BOU | Douglas | 31 min |
| May 31, 3:56 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe, Denver | 34 min |
| May 31, 4:20 PM MDT | Severe Thunderstorm Warning | BOU | Douglas | 40 min |
| May 31, 4:30 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe | 45 min |
| May 31, 4:56 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe, Douglas | 49 min |
| May 31, 5:14 PM MDT | Severe Thunderstorm Warning | BOU | Adams | 46 min |
| May 31, 5:45 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe | 60 min |
Nearby
Severe Thunderstorm Warnings in Colorado, 1991Every severe thunderstorm warning in 1991
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.