Alert archive / Colorado / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 119, NWS Denver/Boulder, CO

August 12, 1997Douglas County, Jefferson County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 12, 1997, 4:21 PM MDT for Douglas County, Jefferson County, Colorado. It was in force for 39 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 12, 1997, 4:21 PM MDT (22:21 UTC)
Expired
Aug 12, 1997, 5:00 PM MDT
In force
39 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Douglas County, CO, Jefferson County, CO

The radar

The Denver radar (KFTG), 61 km from the middle of the area, began a volume at 22:24 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 12:00Z, 10.4 hours before the alert went out and 164 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 1997-08-12Temperature 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 1997-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -9 square meters per square second.1939587897Sfc1 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
1399 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
-9 m²/s²
0-3 km storm-relative helicity
0 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 122223 RRA
SVRDEN
COC035-059-122300-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
421 PM MDT TUE AUG 12 1997

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SEVERE
THUNDERSTORM WARNING EFFECTIVE UNTIL 500 PM MDT FOR PEOPLE IN THE
FOLLOWING COUNTIES...

IN NORTHEAST COLORADO
     SOUTHEASTERN JEFFERSON AND WEST CENTRAL DOUGLAS

INCLUDING THE FOLLOWING LOCATIONS
     ROXBOROUGH PARK...SEDALIA...SOUTH PLATTE AND SPRUCEWOOD

AT 421 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM 3 MILES WEST OF SOUTH PLATTE...OR ABOUT 27 MILES
SOUTHWEST OF DENVER.

THE STORM WAS MOVING EAST AT 25 MILES PER HOUR.

HAIL...INTENSE RAIN OF UP TO 2 INCHES IN LESS THAN AN HOUR...AND 
DAMAGING WINDS OF UP TO 70 MPH ARE LIKELY WITH THIS STORM. TAKE 
COVER IN A SUBSTANTIAL SHELTER UNTIL THE STORM PASSES.

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

LAT...LON 3941 10489 3927 10495 3940 10529 3949 10519

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 12, 11:00 AM MDT, 5 hours 21 minutes before
COZ030-032>050-130600-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1100 AM MDT TUE AUG 12 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: AN UPPER LEVEL JETSTREAM AND DAYTIME HEATING WILL COMBINE
WITH ABUNDANT MOISTURE TO FIRE OFF SCATTERED SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND EVENING.  ONE OR TWO STORMS MAY BE
SEVERE BUT MAINLY ONLY RAIN IS EXPECTED.  A FEW STORMS MAY PRODUCE
LOCALLY HEAVY RAIN THOUGH.

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, 6:14 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln46 min
Aug 12, 4:56 PM MDTSevere Thunderstorm WarningBOUDouglas34 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.