Alert archive / Colorado / Tornado Warnings in 1991

Tornado Warning 31, NWS Denver/Boulder, CO

June 6, 1991Adams County, Weld County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Jun 6, 1991, 3:35 PM MDT for Adams County, Weld County, Colorado. It was in force for 25 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
Jun 6, 1991, 3:35 PM MDT (21:35 UTC)
Expired
Jun 6, 1991, 4:00 PM MDT
In force
25 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties

Counties Adams County, CO, Weld County, CO

What was reported inside it

TimeReportWhereRemark
Jun 6, 4:09 PM MDTHail 1Adams, 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, 9.6 hours before the alert went out and 104 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 1991-06-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 1991-06-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -71 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
NaN m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
-71 m²/s²
0-3 km storm-relative helicity
7 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 062138
TORDEN
COC001-123-062200-

BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
335 PM MDT THU JUN 06 1991

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A TORNADO
WARNING EFFECTIVE UNTIL 400 PM MDT FOR PEOPLE IN THE FOLLOWING
COUNTIES

IN NORTHEASTERN COLORADO
     WESTERN ADAMS AND EXTREME SOUTHWESTERN WELD

INCLUDING THE FOLLOWING TOWNS/CITIES
     BRIGHTON

AT 335 PM MDT THE PUBLIC REPORTED A TORNADO 1 MILE NORTH OF TOWER ROAD
AND 88TH AVENUE...ABOUT 10 MILES NORTHEAST OF DENVER. 

THE STORM PRODUCING THE TORNADO WAS MOVING NORTH AT ABOUT 20 MPH.

THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT.  GET
UNDER A WORKBENCH OR OTHER PIECE OF STURDY FURNITURE.  IF NO
BASEMENT IS AVAILABLE...SEEK SHELTER ON THE LOWEST FLOOR OF THE
BUILDING IN AN INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET.  USE
BLANKETS OR PILLOWS TO COVER YOUR BODY AND ALWAYS STAY FROM
WINDOWS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER.  IF NO SHELTER IS AVAILABLE...LIE FLAT IN
THE NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH
YOUR HANDS.

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 WEATHER SERVICE
FORECAST OFFICE IN DENVER.

DRB

LAT...LON 3984 10457 3983 10483 4004 10483 4005 10457

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, Jun 6, 12:53 PM MDT, 2 hours 42 minutes before
COZ011-012-013-014-062100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
1245PM MDT THU JUNE 6 1991

...THUNDERSTORMS BEGINNING TO BUILD IN FLASH FLOOD WATCH AREA...

THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR THE FRONT RANGE/PIKES PEAK
AND NORTHEASTERN PLAINS AREA OF COLORADO UNTIL 9PM THIS EVENING. EARLY
THIS AFTERNOON STORMS WERE BEGINNING TO BUILD IN THE SOUTHERN PORTION
OF THE WATCH AREA AND INCREASED ACTIVITY IS EXPECTED LATER THIS
AFTERNOON AS AN UPPER AIR DISTURBANCE MOVES INTO THE AREA.

SINCE THIS MORNING THE STEERING WINDS HAVE BECOME MORE SOUTHWESTERLY
SO THAT STORMS WHICH FORM IN THE WATCH AREA SHOULD MOVE TOWARD THE
NORTHEAST. THIS MAY HELP TO DECREASE THE RAINFALL IN ANY GIVEN AREA.

HOWEVER...A LOT OF MOISTURE AND SIGNIFICANT INSTABILITY REMAIN OVER
THE WATCH AREA AND SOME AREAS ARE EXPECTED TO RECEIVE AN INCH OR
MORE OF RAIN THIS AFTERNOON AND EARLY EVENING. THESE RAINS WILL BE
ACCOMPANIED BY CONSIYDERABLE PONDING OF WATER IN STREETS AND LOW LYING
AREAS. THIS REMAINS A POTENTIALLY DANGEROUS SITUATION.

FURTHER STATEMENTS OR WARNINGS WILL BE ISSUED AS CONDITIONS REQUIRE.

TUNNELL
Special weather statement, Jun 6, 2:12 PM MDT, 1 hour 23 minutes before
COZ011-062100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
210 PM MDT THU JUNE 6 1991

...STRONG THUNDERSTORMS BUILDING OVER SOUTHEAST METRO DENVER...

AT 205 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWED STRONG
THUNDERSTORMS BUILDING OVER SOUTHEAST METRO DENVER NEAR CENTENNIAL
AIRPORT.  THESE STORMS WERE MOVING TO THE NORTH AT 15 MPH.

ALL PEOPLE IN THE GREATER DENVER METRO AREA INCLUDING AURORA AND
EAST DENVER SHOULD BE ALERT FOR FREQUENT DANGEROUS LIGHTNING...
HAIL AND STRONG GUSTY WINDS FROM THESE STORMS UNTIL 300 PM MDT THIS
AFTERNOON.  HEAVY RAIN MAY PRODUCE FLOODING OF STREETS...HIGHWAYS...
SMALL STREAMS AND GULLIES AND LOW LYING OR FLOOD PRONE AREAS.

ADDITIONAL STATEMENTS OR POSSIBLE WARNINGS WILL BE ISSUED AS CONDITIONS
WARRANT.

GARD...WSFO DENVER
Special weather statement, Jun 6, 3:07 PM MDT, 28 minutes before
COZ011-062200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
310 PM MDT THU JUNE 6 1991

...STRONG THUNDERSTORMS DEVELOPING OVER NORTHEAST PARK COUNTY...

AT 300 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED STRONG
THUNDERSTORMS DEVELOPING OVER NORTHEAST PARK COUNTY AND HEADING TOWARDS
SOUTHERN JEFFERSON COUNTY.  THESE STORMS WERE MOVING TO THE NORTHEAST AT
20 MPH.

MOTORISTS ON ROADS IN THIS AREA SHOULD BE ALERT FOR BRIEF HEAVY
SHOWERS WITH SMALL HAIL AND POSSIBLE FLOODING OF ROADWAYS.  ROCKSLIDES
RELEASED BY HEAVY SHOWERS ARE ALSO POSSIBLE ALONG CANYON HIGHWAYS.
RESIDENTS IN SOUTHERN JEFFERSON COUNTY SHOULD ALSO BE ALERT FOR RAPID
WATER LEVEL RISES ON STREAMS GAND IN GULLIES.

ADDITIONAL STATEMENTS OR POSSIBLE WARNINGS WILL BE ISSUED AS CONDITIONS
WARRANT.

DRB...WSFO DENVER

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 6, 3:59 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver46 min
Jun 6, 3:59 PM MDTSevere Thunderstorm WarningBOUWeld46 min
Jun 6, 4:41 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver64 min
Jun 6, 4:41 PM MDTSevere Thunderstorm WarningBOUWeld64 min
Jun 6, 4:53 PM MDTSevere Thunderstorm WarningBOUWeld52 min
Jun 6, 5:15 PM MDTFlash Flood WarningBOUArapahoe80 min
Jun 6, 5:23 PM MDTTornado WarningBOUAdams, Arapahoe37 min
Jun 6, 5:40 PM MDTSevere Thunderstorm WarningBOUAdams, Weld65 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.