Alert archive / Colorado / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 115, NWS Denver/Boulder, CO

August 11, 1997Douglas County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 11, 1997, 4:32 PM MDT for Douglas County, Colorado. It was in force for 43 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued
Aug 11, 1997, 4:32 PM MDT (22:32 UTC)
Expired
Aug 11, 1997, 5:15 PM MDT
In force
43 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Douglas County, CO

The radar

The Denver radar (KFTG), 61 km from the middle of the area, began a volume at 22:35 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Grand Junction, CO (KGJT), launched 12:00Z, 10.5 hours before the alert went out and 302 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, Grand Junction, CO at 12:00Z on 1997-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Grand Junction, CO at 12:00Z on 1997-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 145 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
3 J/kg
Mixed-layer CIN
-197 J/kg
Mixed-layer LCL
1483 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
145 m²/s²
0-3 km storm-relative helicity
159 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 112235 RRA
SVRDEN
COC035-112315-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
432 PM MDT MON AUG 11 1997

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SEVERE
THUNDERSTORM WARNING EFFECTIVE UNTIL 515 PM MDT FOR PEOPLE IN THE
FOLLOWING COUNTIES...

IN NORTHEAST COLORADO
     CENTRAL DOUGLAS

INCLUDING THE FOLLOWING LOCATIONS
     ROXBOROUGH PARK AND SPRUCEWOOD

AT 432 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM 3 MILES NORTH OF SPRUCEWOOD...OR ABOUT 26 MILES
SOUTH OF DENVER.

THE STORM WAS MOVING EAST AT 15 MILES PER HOUR.

HAIL UP TO AN INCH IN DIAMETER ALONG WITH AN INCH OF RAIN IN 30 
MINUTES IS POSSIBLE WITH THIS SEVERE THUNDERSTORM. IF YOU ARE IN THE 
PATH OF THE STORM...PUT YOUR CAR IN A GARAGE AND MOVE TO A 
SUBSTANTIAL SHELTER.

HEAVY RAINS MAY FLOOD LOW LYING AREAS.  STAY OUT OF FLOODED AREAS 
AND DO NOT CROSS FLOODED ROADS AS THEY MAY BE WASHED OUT. WATER 
LEVELS OF SMALL STREAMS AND RIVERS MAY ALSO RISE...THEREFORE SEEK 
HIGHER GROUND IF THREATENED BY FLOOD WATERS.

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

LAT...LON 3940 10491 3927 10498 3936 10515 3944 10510

GIMMESTAD

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, Aug 11, 10:51 AM MDT, 5 hours 41 minutes before
COZ030-032>050-120600-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1115 AM MDT DAY MMM DD 1997

THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES

ADAMS     ARAPAHOE     BOULDER   CLEAR CREEK   DENVER       DOUGLAS
ELBERT    GILPIN       GRAND     JACKSON       JEFFERSON    LARIMER
LINCOLN   LOGAN        MORGAN    PARK          PHILLIPS     SEDGWICK
SUMMIT    WASHINGTON   WELD

SYNOPSIS: A WEAK UPPER LEVEL DISTURBANCE WILL MOVE THROUGH THE AREA
THIS AFTERNOON AND EVENING WHICH WILL BE THE IGNITER FOR SCATTERED
SHOWERS AND THUNDERSTORMS.  THE BEST TIME FOR THE SHOWERS AND
THUNDERSTORMS WILL BE BETWEEN 4 PM AND 9 PM ALONG THE URBAN CORIDOR
AND BETWEEN 6 PM AND MIDNIGHT IN THE PLAINS.

DONT EXPECT ENOUGH DAYTIME HEATING TO CAUSE REAL UNSTABLE
CONDITIONS SO THE STORMS ARE NOT EXPECTED TO BE SEVERE.  SPOTTER
ACTIVATION IS NOT ANTICIPATED.

TA
Special weather statement, Aug 11, 10:51 AM MDT, 5 hours 41 minutes before
COZ030-032>050-120600-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1115 AM MDT MON AUG 11 1997

THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES

ADAMS     ARAPAHOE     BOULDER   CLEAR CREEK   DENVER       DOUGLAS
ELBERT    GILPIN       GRAND     JACKSON       JEFFERSON    LARIMER
LINCOLN   LOGAN        MORGAN    PARK          PHILLIPS     SEDGWICK
SUMMIT    WASHINGTON   WELD

SYNOPSIS: A WEAK UPPER LEVEL DISTURBANCE WILL MOVE THROUGH THE AREA
THIS AFTERNOON AND EVENING WHICH WILL BE THE IGNITER FOR SCATTERED
SHOWERS AND THUNDERSTORMS.  THE BEST TIME FOR THE SHOWERS AND
THUNDERSTORMS WILL BE BETWEEN 4 PM AND 9 PM ALONG THE URBAN CORIDOR
AND BETWEEN 6 PM AND MIDNIGHT IN THE PLAINS.

DON'T EXPECT ENOUGH DAYTIME HEATING TO CAUSE REAL UNSTABLE
CONDITIONS SO THE STORMS ARE NOT EXPECTED TO BE SEVERE.  SPOTTER
ACTIVATION IS NOT ANTICIPATED.

TA
Special weather statement, Aug 11, 11:15 AM MDT, 5 hours 17 minutes before
COZ030-032>050-120600-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1115 AM MDT MON AUG 11 1997

THIS OUTLOOK PERTAINS TO THE FOLLOWING COLORADO COUNTIES

ADAMS     ARAPAHOE     BOULDER   CLEAR CREEK   DENVER       DOUGLAS
ELBERT    GILPIN       GRAND     JACKSON       JEFFERSON    LARIMER
LINCOLN   LOGAN        MORGAN    PARK          PHILLIPS     SEDGWICK
SUMMIT    WASHINGTON   WELD

SYNOPSIS: A WEAK UPPER LEVEL DISTURBANCE WILL MOVE THROUGH THE AREA
THIS AFTERNOON AND EVENING WHICH WILL BE THE IGNITER FOR SCATTERED
SHOWERS AND THUNDERSTORMS.  THE BEST TIME FOR THE SHOWERS AND
THUNDERSTORMS WILL BE BETWEEN 4 PM AND 9 PM ALONG THE URBAN CORIDOR
AND BETWEEN 6 PM AND MIDNIGHT IN THE PLAINS.

DONT EXPECT ENOUGH DAYTIME HEATING TO CAUSE REAL UNSTABLE
CONDITIONS SO THE STORMS ARE NOT EXPECTED TO BE SEVERE.  SPOTTER
ACTIVATION IS NOT ANTICIPATED.

TA

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 3:12 PM MDTSevere Thunderstorm WarningBOUDenver, Jefferson48 min
Aug 11, 3:40 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver35 min
Aug 11, 4:49 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe41 min
Aug 11, 5:42 PM MDTSevere Thunderstorm WarningBOUElbert33 min

Nearby

Severe Thunderstorm Warnings in Colorado, 1997Every severe thunderstorm warning in 1997

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; radar from the NEXRAD Level II archive.