Alert archive / Colorado / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 21, NWS Denver/Boulder, CO

May 23, 1991Adams County, Arapahoe County, Washington County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at May 23, 1991, 4:17 PM MDT for Adams County, Arapahoe County, Washington County, Colorado. It was in force for 43 min. 1 report 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 23, 1991, 4:17 PM MDT (22:17 UTC)
Expired
May 23, 1991, 5:00 PM MDT
In force
43 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties

Counties Adams County, CO, Arapahoe County, CO, Washington County, CO

What was reported inside it

TimeReportWhereRemark
May 23, 5:07 PM MDTHail 1.75Washington, 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 62 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.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 12:00Z on 1991-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 63 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 1991-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 23 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
63 J/kg
Mixed-layer CIN
-100 J/kg
Mixed-layer LCL
915 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
23 m²/s²
0-3 km storm-relative helicity
12 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KDEN 232222
SVRDEN
COC001-005-121-232300-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
417 PM MDT THU MAY 23 1991

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SEVERE
THUNDERSTORM WARNING EFFECTIVE UNTIL 500 PM MDT FOR PEOPLE IN
THE FOLLOWING COUNTIES

IN NORTHEASTERN COLORADO
     EASTERN ADAMS...EASTERN ARAPAHOE AND EXTREME SOUTHWESTERN
     WASHINGTON

INCLUDING THE FOLLOWING TOWNS/CITIES
     DEER TRAIL

AT 417 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE
THUNDERSTORM 9 MILES EAST OF DEER TRAIL...OR ABOUT 29 MILES NORTH OF
LIMON.  

THE STORM WAS MOVING EAST AT ABOUT 10 TO 20 MPH.  

THIS WARNING REPLACES THE TORNADO WARNING PREVIOUSLY IN EFFECT FOR
PORTIONS OF SOUTHEAST ADAMS AND EASTERN ARAPAHOE COUNTIES.  

IF SEVERE WEATHER APPROACHES YOUR AREA...GO INSIDE A STURDY
SHELTER AWAY FROM CREEK BEDS AND OTHER FLOOD PRONE AREAS.
REMEMBER...A SEVERE THUNDERSTORM CAN PRODUCE LARGE DAMAGING
HAIL...DAMAGING WINDS OF OVER 60 MPH...DEADLY LIGHTNING...AND
HEAVY RAINS THAT CAN QUICKLY FLOOD A LOW LYING AREA.

THESE STORMS CAN PRODUCE A TORNADO WITH LITTLE OR NO ADVANCE
WARNING...SO BE ON THE LOOKOUT AND BE PREPARED TO MOVE TO A
PLACE OF SAFETY IF ONE IS SPOTTED.

A TORNADO WATCH REMAINS IN EFFECT FOR MUCH OF EASTERN COLORADO UNTIL
8 PM MDT. 

TO REPORT SEVERE WEATHER HAVE THE NEAREST LAW ENFORCEMENT
AGENCY RELAY YOUR REPORT TO THE NATIONAL WEATHERs SERVICE
FORECAST OFFICE IN DENVER.

DANKERS...WSFO DENVER

LAT...LON 3960 10361 3958 10410 3977 10408 3999 10362

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 22, 6:12 PM MDTTornado WarningBOUDouglas33 min
May 22, 6:37 PM MDTSevere Thunderstorm WarningBOUWeld68 min
May 22, 6:45 PM MDTTornado WarningBOUArapahoe, Denver45 min
May 22, 6:45 PM MDTTornado WarningBOUDouglas45 min
May 22, 7:23 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld67 min
May 22, 7:29 PM MDTTornado WarningBOUMorgan46 min
May 23, 1:25 PM MDTSevere Thunderstorm WarningBOUArapahoe35 min
May 23, 1:26 PM MDTSevere Thunderstorm WarningBOUJefferson64 min
May 23, 1:58 PM MDTSevere Thunderstorm WarningBOUAdams, Denver, Jefferson62 min
May 23, 2:01 PM MDTSevere Thunderstorm WarningBOUArapahoe29 min
May 23, 2:30 PM MDTSevere Thunderstorm WarningBOUArapahoe45 min
May 23, 3:06 PM MDTTornado WarningBOUAdams, Arapahoe39 min
May 23, 3:33 PM MDTSevere Thunderstorm WarningBOUArapahoe, Denver, Douglas57 min
May 23, 3:45 PM MDTTornado WarningBOUAdams, Arapahoe30 min
May 23, 3:51 PM MDTTornado WarningBOUAdams, Arapahoe, Denver, Douglas39 min
May 23, 4:25 PM MDTSevere Thunderstorm WarningBOUArapahoe65 min
May 23, 5:00 PM MDTSevere Thunderstorm WarningBOUArapahoe, Washington60 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.