Alert archive / Colorado / Tornado Warnings in 1991

Tornado Warning 18, NWS Denver/Boulder, CO

May 31, 1991Logan County, Morgan County, Washington County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 31, 1991, 10:25 PM MDT for Logan County, Morgan County, Washington County, Colorado. It was in force for 35 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 31, 1991, 10:25 PM MDT (04:25 UTC)
Expired: May 31, 1991, 11:00 PM MDT
In force: 35 min
Issued by: NWS Denver/Boulder, CO
Area: Whole counties

Counties Logan County, CO, Morgan County, CO, Washington County, CO

What was reported inside it

Time	Report	Where	Remark
May 31, 10:28 PM MDT	Hail 1.75	Morgan, 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 00:00Z, 4.4 hours before the alert went out and 51 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 169 J/kg
Mixed-layer CIN: -99 J/kg
Mixed-layer LCL: 1122 m above ground
0-6 km bulk shear: 62 kt
0-1 km storm-relative helicity: -14 m²/s²
0-3 km storm-relative helicity: 160 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 010427
TORDEN
COC075-087-121-010500-

BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
1025 PM MDT FRI MAY 31 1991

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A TORNADO
WARNING EFFECTIVE UNTIL 1100 PM MDT FOR PEOPLE IN THE FOLLOWING
COUNTIES

IN NORTHEASTERN COLORADO
     SOUTHERN LOGAN...NORTHEASTERN MORGAN AND NORTHERN
     WASHINGTON

INCLUDING THE FOLLOWING TOWNS/CITIES
     ATWOOD...HILLROSE AND MERINO

AT 1025 PM MDT RADAR INDICATED A POSSIBLE TORNADO 4 MILES NORTH OF
HILLROSE ...OR ABOUT 25 MILES SOUTHWEST OF STERLING.

THE STORM PRODUCING THE TORNADO WAS MOVING EAST NORTHEAST AT ABOUT 10 TO
15 MILES AN HOUR.  THIS IS A DANGEROUS STORM.  IT HAS ALREADY PRODUCED A
TORNADO IN MORGAN COUNTY EARLIER THIS EVENING.   

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 SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR NORTHEASTERN COLORADO
UNTIL 1100 PM MDT.

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

DELGADO

LAT...LON 4030 10292 4031 10361 4052 10360 4070 10294

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 31, 9:19 PM MDT, 1 hour 6 minutes before

COZ011-010500-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
920 PM MDT FRI MAY 31 1991

...THUNDERSTORMS IN DOUGLAS COUNTY...

STRONG THUNDERSTORMS ARE DEVELOPING OVER DOUGLAS COUNTY LATE THIS
EVENING.  THE STRONGEST STORM WAS NORTHEAST OF PALMER LAKE OR ABOUT 40
MILES SOUTH OF DENVER AND WAS MOVING TO THE NORTH AT 25 MPH.

A LINE OF THUNDERSTORMS EXTENDED FROM THIS STRONG STORM NORTH TO NEAR
LITTLETON.  THIS LINE TOO WAS MOVING TO THE NORTH AT ABOUT 25 MPH.

HAIL...LIGHTNING...VERY HEAVY RAIN AND GUSTY WINDS ARE TO BE EXPECTED IN
CENTRAL DOUGLAS COUNTY WITHIN THE NEXT 30 TO 60 MINUTES.  THE SOUTHERN
SECTIONS OF THE DENVER METRO AREA WILL ALSO BE AFFECTED BY THIS LINE OF
STORMS BY 945 PM FRIDAY EVENING.

PERSONS IN THE PATH OF THESE STORMS SHOULD BE ON THE LOOKOUT FOR RAPIDLY
CHANGING WEATHER CONDITIONS AND MOVE TO SAFE SHELTER IF THREATENING
WEATHER APPROACHES.

ET

Local storm report, May 31, 10:05 PM MDT, 20 minutes before

STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
1004 PM MDT FRI MAY 31 1991

PRELIMINARY STORM REPORTS FOR FRIDAY MAY 31 1991

TIME (MDT)  COUNTY/LOCATION                     EVENT

1505    WELD/5 1/2 MI WNW WELLINGTON    PEA SIZE HAIL

1532    DOUGLAS/LINCOLN & I25           GOLF BALL SIZE HAIL

1536    ARAPAHOE/ENGLEWOOD              3/4 INCH DIAMETER HAIL

1544    ARAPAHOE/I25 & COUNTY           HEAVY RAIN REPORTED BY HAM
        LINE ROAD                       "PROBABALY EXCEEDING 2 INCHES
                                        PER HOUR"

1547    ARAPAHOE/I25 & ORCHARD ROAD     1 INCH DIAMETER HAIL

1549    ARAPAHOE/I25 & ORCHARD ROAD     3/4 INCH DIAMETER HAIL

1550    ARAPAHOE/ILIFF & I225           3/4 INCH HAIL

1554    ARAPAHOE/ALAMEDA & BUCKLEY      PEA TO MARBLE SIZE HAIL

1555    ARAPAHOE/CENTRAL AURORA         PEA TO MARBLE SIZE HAIL

1558    ARAPAHOE/MISSISSIPPI &          PEA TO MARBLE SIZE HAIL
        BUCKLEY                         1 INCH DEEP

1604    ARAPAHOE/ILIFF & TELURIDE       1 INCH DIAMETER HAIL

1604    ARAPAHOE/MISSISSIPPI &          1/2 INCH DIAMETER HAIL
        TOWER

1606    ARAPAHOE/CHERRY CREEK LAKE      1/2 INCH DIAMETER HAIL

1624    ARAPAHOE/DRY CREEK &            1 INCH DIAMETER HAIL
        YOSEMITE

1628    ARAPAHOE/BUCKLEY NATIONAL       NATIONAL GUARD REPORTED FUNNEL
        GUARD BASE                      SOUTH WEST OF BUCKLEY

1637    ARAPAHOE/DRY CREEK &            3/4 INCH HAIL .38 INCHES OF RAIN
        YOSEMITE                        IN 20 MINUTES

1640    DOUGLAS/CASTLEROCK              1/2 INCH DIAMETER HAIL

1645    ADAMS/WATKINS                   1 INCH DIAMETER HAIL

1659    DOUGLAS/3 MILES SOUTH EAST      MARBLE TO 1 INCH DIAMETER HAIL
        OF PARKER

1700    DOUGLAS/5 MILES EAST SOUTH      1 INCH DIAMETER HAIL
        EAST OF PARKER

1700    DOUGLAS/3 MILES SOUTH EAST      MARBLE SIZE HAIL
        OF PARKER

1706    DOUGLAS/2 MILES NORTH EAST      MARBLE SIZE HAIL
        OF PARKER

1743    ELBERT/HIGHWY 86                MARBLE SIZE HAIL

1753    ELBERT/PARKER HIGHLAND          1 INCH DIAMETER HAIL
        ESTATES

1801    ELBERT/2 MILES SOUTH OF         GOLF BALL SIZE HAIL
        RAPAHOE COUNTY LINE

1807    JEFFERSON/NORTH WEST CORNER     1/2 TO 3/4 INCH HAIL
        OF ROCKY FLATS

1808    ARAPAHOE/10 MILES SOUTH         MARBLE SIZE HAIL 2 INCHES DEEP
        WEST OF BYERS

1812    BOULDER/28TH & DIAGONAL         HEAVY RAIN GREATER THAN 1 INCH
                                        PER HOUR WITH SOME STREET
                                        FLOODING

1843    ADAMS/3 MILES WEST OF BENNETT   HEAVY RAIN GREATER THAN 1 INCH
                                        PER HOUR

1847    JEFFERSON/58TH & RALSTON ROAD   MARBLE SIZE HAIL

1849    ELBERT/ELIZABETH                1 INCH DIAMETER HAIL 1 1/2
                                        INCHES DEEP

1908    ADAMS/BENNETT                   MARBLE SIZE HAIL

1919    DOUGLAS/2 MILES NORTH EAST      MARBLE SIZE HAIL
        OF PARKER

1921    ELBERT/KIOWA                    MARBLE SIZE HAIL

SIMMONS

Special weather statement, May 31, 10:11 PM MDT, 14 minutes before

COZ011-010600-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
1015 PM MDT FRI MAY 31 1991

...THUNDERSTORMS IN DENVER AREA...

AT 1010 PM MDT FRIDAY EVENING STRONG THUNDERSTORMS CONTINUED TO DEVELOP
OVER THE DENVER METRO AREA.  HAIL...VERY HEAVY RAIN...LIGHTNING AND
GUSTY WINDS WILL ACCOMPANY THESE STORMS AS THEY MOVE THROUGH THE DENVER
AREA OVER THE NEXT HOUR OR TWO.

THE RAIN AND HAIL ASSOCIATED WITH THESE STORMS WILL BE SUFFICIENT TO
FLOOD LOW LYING AREAS...UNDERPASSES...INTERSECTIONS AND SMALL CREEKS AND
STREAMS.

PERSONS IN THE DENVER AREA SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER AND MOVE TO SAFE SHELTER IF BAD WEATHER APPROACHES.  AVOID
DRIVING THROUGH S)TANDING WATER.

ET

The office that day

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

Issued	Product	Office	Counties	Lasted
May 31, 6:09 PM MDT	Severe Thunderstorm Warning	BOU	Boulder, Jefferson	51 min
May 31, 6:12 PM MDT	Severe Thunderstorm Warning	BOU	Douglas	48 min
May 31, 6:46 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe	59 min
May 31, 7:43 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe	62 min
May 31, 8:38 PM MDT	Severe Thunderstorm Warning	BOU	Morgan	67 min
May 31, 9:06 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe	39 min
May 31, 9:37 PM MDT	Tornado Warning	BOU	Morgan	38 min
May 31, 9:44 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Weld	46 min
May 31, 10:02 PM MDT	Tornado Warning	BOU	Adams, Arapahoe, Washington	28 min
May 31, 10:26 PM MDT	Tornado Warning	BOU	Adams, Washington	34 min
May 31, 10:38 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe	52 min
May 31, 10:48 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe	42 min
May 31, 11:00 PM MDT	Tornado Warning	BOU	Morgan, Washington	45 min
May 31, 11:05 PM MDT	Tornado Warning	BOU	Logan, Washington	40 min
May 31, 11:33 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Weld	42 min
May 31, 11:49 PM MDT	Severe Thunderstorm Warning	BOU	Washington	26 min
May 31, 11:51 PM MDT	Tornado Warning	BOU	Logan	24 min
Jun 1, 12:15 AM MDT	Severe Thunderstorm Warning	BOU	Washington	30 min
Jun 1, 12:15 AM MDT	Severe Thunderstorm Warning	BOU	Weld	45 min
Jun 1, 12:26 AM MDT	Tornado Warning	BOU	Washington	34 min
Jun 1, 1:01 AM MDT	Tornado Warning	BOU	Washington	29 min
Jun 1, 4:05 PM MDT	Severe Thunderstorm Warning	BOU	Denver, Jefferson	40 min
Jun 1, 4:05 PM MDT	Severe Thunderstorm Warning	BOU	Douglas	40 min
Jun 1, 4:36 PM MDT	Tornado Warning	BOU	Jefferson	24 min
Jun 1, 4:57 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Boulder, Denver, Jefferson	48 min
Jun 1, 5:20 PM MDT	Flash Flood Warning	BOU	Adams, Jefferson	115 min
Jun 1, 5:33 PM MDT	Tornado Warning	BOU	Boulder, Jefferson	27 min
Jun 1, 5:44 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe, Denver, Jefferson	46 min
Jun 1, 5:44 PM MDT	Severe Thunderstorm Warning	BOU	Boulder, Weld	46 min

Nearby

Tornado Warnings in Colorado, 1991 Every tornado warning in 1991 Tornadoes 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.