Alert archive / Colorado / Severe Thunderstorm Warnings in 1997
Severe Thunderstorm Warning 114, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 11, 1997, 3:40 PM MDT for Adams County, Arapahoe County, Denver County, Colorado. It was in force for 35 min. 1 report came from 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, with what was reported inside it.
The facts
- Issued
- Aug 11, 1997, 3:40 PM MDT (21:40 UTC)
- Expired
- Aug 11, 1997, 4:15 PM MDT
- In force
- 35 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
Counties Adams County, CO, Arapahoe County, CO, Denver County, CO
The radar
The Denver radar (KFTG), 26 km from the middle of the area, began a volume at 21:40 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 11, 3:40 PM MDT | Hail 1.5 | South Denver, 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.
The nearest sounding before it
Grand Junction, CO (KGJT), launched 12:00Z, 9.7 hours before the alert went out and 321 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.
- 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
The text
As transmitted, in the capitals the NWS used until 2016.
000
TTAA00 KDEN 112143 RRA
SVRDEN
COC001-005-031-112215-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
340 PM MDT MON AUG 11 1997
THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SEVERE
THUNDERSTORM WARNING EFFECTIVE UNTIL 415 PM MDT FOR PEOPLE IN THE
FOLLOWING COUNTIES...
IN NORTHEAST COLORADO
NORTHWESTERN ARAPAHOE...DENVER AND SOUTHWESTERN ADAMS
INCLUDING THE FOLLOWING LOCATIONS
AURORA...SOUTHERN COMMERCE CITY...DENVER AND ENGLEWOOD
AT 340 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM OVER THE WESTERN PART OF DENVER.
THE STORM WAS MOVING EAST AT 25 MILES PER HOUR.
HAIL UP TO ONE INCH IN DIAMETER WAS OCCURRING IN DOWNTOWN DENVER AT
340 PM. WINDS OF UP TO 70 MPH ARE ALSO POSSIBLE. IF YOU ARE IN THE
PATH OF THE STORM...PUT YOUR CAR IN A GARAGE AND MOVE TO A
SUBSTANTIAL SHELTER.
UP TO AN INCH OF RAIN IS ALSO POSSIBLE IN UNDER HALF AN HOUR.
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.
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 3981 10474 3966 10472 3966 10501 3977 10503
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, 4 hours 49 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, 4 hours 49 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, 4 hours 25 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.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 11, 3:12 PM MDT | Severe Thunderstorm Warning | BOU | Denver, Jefferson | 48 min |
| Aug 11, 4:32 PM MDT | Severe Thunderstorm Warning | BOU | Douglas | 43 min |
| Aug 11, 4:49 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe | 41 min |
| Aug 11, 5:42 PM MDT | Severe Thunderstorm Warning | BOU | Elbert | 33 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.