Alert archive / Colorado / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 155, NWS Denver/Boulder, CO

September 4, 1997Washington County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Sep 4, 1997, 6:12 PM MDT for Washington County, Colorado. It was in force for 33 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
Sep 4, 1997, 6:12 PM MDT (00:12 UTC)
Expired
Sep 4, 1997, 6:45 PM MDT
In force
33 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Washington County, CO

The radar

The Denver radar (KFTG), 131 km from the middle of the area, began a volume at 00:15 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 50 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 1997-09-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 246 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, Denver, CO at 00:00Z on 1997-09-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
246 J/kg
Mixed-layer CIN
-78 J/kg
Mixed-layer LCL
1872 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
89 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDEN 050014 RRA
SVRDEN
COC121-050045-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
612 PM MDT THU SEP 4 1997

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SEVERE
THUNDERSTORM WARNING EFFECTIVE UNTIL 645 PM MDT FOR PEOPLE IN THE
FOLLOWING COUNTIES...

IN NORTHEAST COLORADO
     NORTHEASTERN WASHINGTON

INCLUDING THE FOLLOWING LOCATIONS
     AKRON AND BURDETT

AT 612 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM 9 MILES NORTHWEST OF AKRON.

THE STORM WAS MOVING NORTH AND NORTHWEST AT 15 MILES PER HOUR.

LARGE HAIL 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.

SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55 MPH...
DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN. FOR YOUR
PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME
OR BUSINESS. HEAVY RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO
AREAS WHERE WATER COVERS THE ROAD.

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

ENTREKIN

LAT...LON 4040 10286 4013 10314 4019 10336 4035 10349
          4044 10331

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, Sep 4, 4:03 PM MDT, 2 hours 9 minutes before
COZ041-042300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
403 PM MDT THU SEP 4 1997

...STRONG THUNDERSTORM IN SOUTHEASTERN DOUGLAS AND WEST CENTRAL
ELBERT COUNTIES OF COLORADO...

AT 359 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM OVER LARKSPUR...OR ABOUT 36 MILES SOUTH OF
DENVER.

THE STORM WAS MOVING EAST AT 15 TO 20 MILES PER HOUR.

PERSONS IN OR NEAR ELBERT...ELIZABETH...GREENLAND...KIOWA...LARKSPUR
AND PONDEROSA PARK

SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND MOVE TO A PLACE
OF SAFETY IF BAD WEATHER APPROACHES.

DANGEROUS LIGHTNING...SMALL HAIL...BRIEF HEAVY RAIN...AND GUSTY WINDS
WILL OCCUR WITH THIS STORM.

HEAVY RAINS MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES. AVOID THESE 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.

INTENSE LIGHTNING IS REPORTED WITH THIS STORM. IF OUTDOORS...STAY
AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF
POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID
USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY
ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.

GARD...WSFO DENVER
Special weather statement, Sep 4, 4:04 PM MDT, 2 hours 8 minutes before
COZ041-042300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
403 PM MDT THU SEP 4 1997

...STRONG THUNDERSTORM IN SOUTHEASTERN DOUGLAS AND WEST CENTRAL
ELBERT COUNTIES OF COLORADO...

AT 359 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM OVER LARKSPUR...OR ABOUT 36 MILES SOUTH OF
DENVER.

THE STORM WAS MOVING EAST AT 15 TO 20 MILES PER HOUR.

PERSONS IN OR NEAR ELBERT...ELIZABETH...GREENLAND...KIOWA...LARKSPUR
AND PONDEROSA PARK

SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND MOVE TO A PLACE
OF SAFETY IF BAD WEATHER APPROACHES.

DANGEROUS LIGHTNING...SMALL HAIL...BRIEF HEAVY RAIN...AND GUSTY WINDS
WILL OCCUR WITH THIS STORM.

HEAVY RAINS MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES. AVOID THESE 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.

INTENSE LIGHTNING IS REPORTED WITH THIS STORM. IF OUTDOORS...STAY
AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF
POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID
USING TELEPHONES UNLESS IT IS AN LEMERGENCY. TRY TO UNPLUG UNNECESSARY
ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.

GARD...WSFO DENVER

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 4, 6:37 PM MDTSevere Thunderstorm WarningBOULogan, Washington38 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.