Alert archive / Colorado / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 106, NWS Denver/Boulder, CO

July 21, 1997Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 21, 1997, 6:12 PM MDT for Weld County, Colorado. It was in force for 48 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
Jul 21, 1997, 6:12 PM MDT (00:12 UTC)
Expired
Jul 21, 1997, 7:00 PM MDT
In force
48 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Weld County, CO

The radar

The Cheyenne radar (KCYS), 102 km from the middle of the area, began a volume at 00:11 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

Denver, CO (KDNR), launched 00:00Z, 0.2 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 00:00Z on 1997-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 67 joules per kilogram.LCLEL10008507005003002001001 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 1997-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -11 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
67 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
3399 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
-11 m²/s²
0-3 km storm-relative helicity
-4 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 220013 RRA
SVRDEN
COC123-220100-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
612 PM MDT MON JUL 21 1997

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SEVERE
THUNDERSTORM WARNING EFFECTIVE UNTIL 700 PM MDT FOR PEOPLE IN THE
FOLLOWING COUNTIES...

IN NORTHEAST COLORADO
     EAST CENTRAL WELD

INCLUDING THE FOLLOWING LOCATIONS
     NEW RAYMER AND STONEHAM

AT 612 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM 11 MILES NORTH OF NEW RAYMER...OR ABOUT 33 MILES
WEST OF STERLING.

THE STORM WAS MOVING SOUTH/SOUTHEAST AT 15 MILES PER HOUR AND WILL 
BE MOVING INTO THE STONEHAM AND NEW RAYMER AREAS BY 650 PM.  

LARGE HAIL AND DAMAGING WIND GUSTS UP TO 60 MPH ARE 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.  STAY AWAY 
FROM WINDOWS.  REMEMBER...SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES 
WITH LITTLE OR NO ADVANCED WARNING.  

BARJENBRUCH

LAT...LON 4080 10360 4053 10359 4054 10386 4080 10389
          4088 10381

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, Jul 21, 1:25 PM MDT, 4 hours 47 minutes before
COZ049-212000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
125 PM MDT MON JUL 21 1997

...THUNDERSTORM WITH HEAVY RAIN IN CENTRAL WASHINGTON COUNTY...

AT 123 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
THUNDERSTORM JUST WEST OF ELBA...OR ABOUT 16 MILES SOUTH OF AKRON.
THIS STORM WAS PRODUCING TORRENTIAL RAIN...SMALL HAIL...AND GUSTY
WINDS UP TO 50 MPH.

THE STORM WAS NEARLY STATIONARY...AND WILL PRODUCE 1 TO 2 INCHES OF
RAIN IN 30 MINUTES OR LESS.

HEAVY RAINS MAY FLOOD LOW LYING AREAS.  DO NOT DRIVE ACROSS FLOODED
ROADS.  WATER LEVELS OF SMALL STREAMS AND RIVERS MAY ALSO
RISE...THEREFORE SEEK HIGHER GROUND IF THREATENED BY FLOOD WATERS.

BARJENBRUCH
Special weather statement, Jul 21, 1:26 PM MDT, 4 hours 46 minutes before
COZ049-212000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
125 PM MDT MON JUL 21 1997

...THUNDERSTORM WITH HEAVY RAIN IN CENTRAL WASHINGTON COUNTY...

AT 123 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
THUNDERSTORM JUST WEST OF ELBA...OR ABOUT 16 MILES SOUTH OF AKRON.
THIS STORM WAS PRODUCING TORRENTIAL RAIN...SMALL HAIL...AND GUSTY
WINDS UP TO 50 MPH.

THE STORM WAS NEARLY STATIONARY...AND WILL PRODUCE 1 TO 2 INCHES OF
RAIN IN 30 MINUTES OR LESS.

HEAVY RAINS MAY FLOOD LOW LYING AREAS.  DO NOT DRIVE ACROSS FLOODED
ROADS.  WATER LEVELS OF SMALL STREAMS AND RIVERS MAY ALSO
RISE...THEREFORE SEEK HIGHER GROUND IF THREATENED BY FLOOD WATERS.

BARJENBRUCH

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.