Alert archive / Colorado / Tornado Warnings in 1991

Tornado Warning 4, NWS Denver/Boulder, CO

May 22, 1991Douglas County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 22, 1991, 6:45 PM MDT for Douglas County, Colorado. It was in force for 45 min.

The area

The counties it named.

The facts

Issued
May 22, 1991, 6:45 PM MDT (00:45 UTC)
Expired
May 22, 1991, 7:30 PM MDT
In force
45 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties

County Douglas County, CO

The nearest sounding before it

Denver, CO (KDEN), launched 00:00Z, 0.8 hours before the alert went out and 158 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 00:00Z on 1991-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 194 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 00:00Z on 1991-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 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
194 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
2233 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
117 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDEN 230049
TORDEN
COC005-031-035-230130-

BULLETIN...EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
645 PM MDT WED MAY 22 1991

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A TORNADO
WARNING EFFECTIVE UNTIL 730 PM MDT FOR PEOPLE IN THE FOLLOWING
COUNTIES

IN NORTHEASTERN COLORADO
     WESTERN ARAPAHOE...SOUTH CENTRAL DENVER AND EXTREME
     NORTHERN DOUGLAS

INCLUDING THE FOLLOWING TOWNS/CITIES
     AURORA AND DENVER

AT 645 PM MDT SPOTTERS REPORTED A FUNNEL CLOUD DEVELOPING ABOUT 9 MILES
SOUTH OF DENVER IN THE C-470 AND QUEBEC AVENUE AREA.  RADAR ALSO
INDICATES THE POSSIBLE DEVELOPMENT OF A TORNADO OCCURRING.
THIS THUNDERSTORM IS MOVING TO THE NORTHEAST ABOUT 15 MPH.

1/2 INCH DIAMETER HAIL HAS BEEN REPORTED IN THE AREA OF C-470 AND
QUEBEC AVENUES.  HEAVY RAIN HAS ALSO CAUSED SOME LOCAL STREET
FLOODING IN THE DENVER METRO AREA.

IN HOMES GO TO THE BASEMENT OR INTO A CLOSET OR BATHROOM.  IN
SCHOOLS...HIGH RISES AND HOSPITALS GO TO AN INTERIOR HALLWAY ON
THE LOWEST FLOOR. IF IN MOBILE HOMES OR VEHICLES...EVACUATE
THEM AND GO TO A SUBSTANTIAL SHELTER.  IF NO SHELTER IS
AVAILABLE...LIE FLAT IN THE NEAREST DITCH OR OTHER LOW SPOT.
IN ALL CASES...STAY AWAY FROM WINDOWS...DOORS AND OUTSIDE WALLS.

INTENSE LIGHTNING IS REPORTED WITH THIS STORM.  IF OUTDOORS...
STAY AWAY FROM HIGH OBJECTS.  MOVE INDOORS IF POSSIBLE.  WHEN
INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID USING
TELEPHONES AND ELECTRICAAL EQUIPMENT.

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

GCF...WSFO DENVER

LAT...LON 3957 10468 3957 10495 3970 10495 3980 10476

What forecasters said that day

The local office's own words before this tornado 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 22, 2:41 PM MDT, 4 hours 4 minutes before
COZ011-222130-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
240 PM MDT WED MAY 22 1991

...STRONG THUNDERSTORMS DEVELOPING IN LARIMER COUNTY...

AT 230PM A STRONG THUNDERSTORM DEVELOPED 6 MILES NORTHEAST OF ESTES
PARK...ABOUT 25 MILES WEST-SOUTHWEST OF FORT COLLINS.  THE BUREAU OF
RECLAMATION OFFICE AT ESTES PARK REPORTED PEA SIZE HAIL WITH THIS STORM.
THE STORM IS MOVING NORTHEAST AT ABOUT 15 MPH.

BRIEF HEAVY RAIN...FREQUENT HLIGHTNING...AND GUSTY WINDS COULD ACCOMPANY
THIS STORM.  IF THREATENING WEATHER APPROACHES MOVE INDOORS OR TO A SAFE
AREA.  STAY TUNED TO NOAA WEATHER RADIO OR OTHER NEWS MEDIA FOR THE
LATEST INFORMATION ON THIS STORM.

DANKERS
Special weather statement, May 22, 3:27 PM MDT, 3 hours 18 minutes before
COZ011-222215-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
325 PM MDT WED MAY 22 1991

...BRIEF HEAVY RAIN AND SMALL HAIL ALONG THE BIG THOMPSON...

AT 315 PM THE THUNDERSTORMS IN LARIMER COUNTY APPEARED TO BE DECREASING
IN STRENGTH.  THE STORM WAS LOCATED 17 MILES SOUTHWEST OF FORT COLLINS.
THE THUNDERSTORMS PRODUCED HALF INCH HAIL AT GLEN HAVEN AND PEA SIZE
HAIL AT VIRGINIA DALE.  THE STORM CONTINUES MOVING NORTHEAST AT ABOUT
10 MPH.

SMALL CREEKS AND STREAMS IN THE POUDRE BASIN AREA COULD HAVE RAPID WATER
LEVEL RISES TO NEAR BANKFULL CONDITIONS DUE TO THE HEAVY PRECIPITATION.
THE POUDRE RIVER HAS RISEN ABOUT ONE FOOT NEAR FORT COLLINS BUT IS STILL
WELL BELOW BANKFULL STAGE.

RESIDENTS IN THE VICINITY OF THIS STORM CAN STILL EXPECT BRIEF HEAVY
RAIN...FREQUENT LIGHTNING...AND GUSTY WINDS.  IF THREATENING WEATHER
APPROACHES MOVE INDOORS OR TO A SAFE AREA.  IF YOU ARE NEAR A SMALL
STREAM OR CREEK IN THE POUDRE BASIN AND BIG THOMPSON AREAS...WATCH WATER
LEVELS AND BE PREPARED TO MOVE TO HIGHER GROUND IF NECESSARY.  STAY
TUNED TO NOAA WEATHER RADIO OR OTHER NEWS MEDIA FOR THE LATEST
INFORMATION ON THIS STORM.

DANKERS
Special weather statement, May 22, 3:43 PM MDT, 3 hours 2 minutes before
COZ011-222230-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
340 PM MDT WED MAY 22 1991

...STRONG THUNDERSTORM IN WESTERN BOULDER COUNTY...

AT 330PM MDT A VERY STRONG THUNDERSTORM HAS OVER WESTERN BOULDER COUNTY.
THE CENTER OF THIS THUNDERSTORM WAS LOCATED 3 MILES NORTHWEST OF
NEDERLAND OR ABOUT 13 MILES WEST OF BOULDER COLORADO.  THE THUNDERSTORM
WAS MOVING TO THE NORTH ABOUT 15 MPH.  HEAVY RAIN AND PEA SIZE HAIL WAS
OBSERVED IN ROLLINSVILLE.  HEAVY RAIN WAS ALSO REPORTED AT NEDERLAND.

GUSTY WINDS...BRIEF HEAVY RAIN...HAIL AND LIGHTNING WILL ACCOMPANY
THIS THUNDERSTORM.  PERSONS IN WESTERN BOULDER COUNTY ALONG THE PEAK
TO PEAK HIGHWAY FROM NEDERLAND NORTH SHOULD MOVE INDOORS TO A PLACE
OF SAFETY IF THREATENING WEATHER APPROACHES.  STAY TUNED TO NEWS MEDIA
OR NOAA WEATHER RADIO FOR ADDITIONAL WEATHER FORECASTS AND BULLETINS.

END...GCF...WSFO DENVER
Special weather statement, May 22, 4:49 PM MDT, 1 hour 56 minutes before
COZ011-222330-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
450 PM MDT WED MAY 22 1991

...THUNDERSTORMS CONTINUE ALONG THE FRONT RANGE...

AT 450PM MDT THUNDERSTORMS CONTINUE TO RUMBLE OVER THE FRONT RANGE
FOOTHILLS FROM SOUTHERN LARIMER COUNTY NEAR THE TOWN OF ALLENSPARK
SOUTH THROUGH WESTERN BOULDER AND GILPIN AND CLEAR CREEK COUNTIES.
A THUNDERSTORM WAS ALSO DETECTED IN NORTHERN JEFFERSON COUNTY 4 MILES
NORTH OF GOLDEN.  MOST OF THESE THUNDERSTORMS ARE OF MODERATE INTENSITY
BUT THEY HAVE THE CAPABILITY OF PRODUCING BRIEF HEAVY RAIN...GUSTY WINDS
...HAIL AND FREQUENT LIGHTNING.  THE THUNDERSTORMS ARE MOVING TO THE
NORTH ABOUT 15 MPH.

THE STRONGEST THUNDERSTORM CELL WAS NORTH OF ALLENSPARK AND WAS
APPROACHING THE TOWN OF ESTES PARK.  THIS STORM PRODUCED SOME HEAVY
RAIN AND PEA SIZE HAIL IN ALLENSPARK.

PEOPLE ALONG THE FRONT RANGE FOOTHILLS FROM ESTES PARK SOUTH TO NEAR
IDAHO SPRINGS SHOULD BE ALERT AND MOVE INDOORS TO A PLACE OF SAFETY IF
THREATENING WEATHER APPROACHES.  KEEP AN EYE ON SMALL CREEKS AND STREAMS
ALONG THE FOOTHILLS AS THEY COULD EXHIBIT RAPID RISES IN WATER LEVELS
TO NEAR BANKFULL CONDITIONS.  BE PREPARED TO MOVE TO HIGHER GROUND IF
NECESS=ARY.  1/2 TO 1 INCH OF RAIN COULD FALL IN SOME LOCATIONS IN LESS
THAN AN HOUR.

END...GCF...WSFO DENVER
Special weather statement, May 22, 5:01 PM MDT, 1 hour 44 minutes before
COZ011-012-230000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
500 PM MDT WED MAY 22 1991

...THUNDERSTORMS DEVELOPING IN WELD COUNTY...

AT 450PM MDT THUNDERSTORMS HAD DEVELOPED IN SOUTHERN WELD COUNTY JUST
NORTH OF BRIGHTON...ABOUT 25 MILES NORTH OF DENVER.  THESE STORMS...LIKE
THE THUNDERSTORMS IN THE FOOTHILLS...ARE CAPABLE OF PRODUCING BRIEF
PERIODS OF HEAVY RAIN...SMALL HAIL...FREQUENT LIGHTNING AND GUSTY WINDS.
BRIGHTON HAVD SOME LIGHT RAIN AS THE THUNDERSTORM FORMED AND MOVED
NORTHWARD.  THESE STORMS ARE MOVING NORTH-NORTHEAST ABOUT 15 MPH.

IF THREATENING WEATHER APPROACHES...TAKE NECESSARY SAFETY PRECAUTIONS.

END...DRB...WSFO DENVER
Special weather statement, May 22, 5:36 PM MDT, 1 hour 9 minutes before
COZ011-012-230045-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
535 PM MDT WED MAY 22 1991

...HEAVY RAIN WITH THUNDERSTORMS IN WELD COUNTY...

AT 530PM MDT WELD COUNTY SHERIFFS DEPUTY REPORTED VERY HEAVY RAINS WITH
ZERO VISIBILITY BETWEEN PLATTEVILLE AND FORT LUPTON.  THESE STORMS ARE
CONTINUING TO BUILD AND MOVE NORTHEAST ACROSS WELD COUNTY AT ABOUT 15
MPH.  MOTORISTS SHOULD BE AWARE THAT PONDING OF WATER CAN OCCUR IN LOW
LYING AREAS...SUCH AS UNDERPASSES.

IF THREATENING WEATHER APPROACHES...TAKE NECESSARY SAFETY PRECAUTIONS.

END...DRB...WSFO DENVER

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, 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, 4:17 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Washington43 min
May 23, 4:25 PM MDTSevere Thunderstorm WarningBOUArapahoe65 min
May 23, 5:00 PM MDTSevere Thunderstorm WarningBOUArapahoe, Washington60 min

Nearby

Tornado Warnings in Colorado, 1991Every tornado warning in 1991Tornadoes 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; the sounding from the Mesonet's radiosonde archive.