Alert archive / Colorado / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 81, NWS Denver/Boulder, CO

June 8, 1998Douglas County, Jefferson County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 8, 1998, 5:32 PM MDT for Douglas County, Jefferson County, Colorado. It was in force for 28 min. 2 reports 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
Jun 8, 1998, 5:32 PM MDT (23:32 UTC)
Expired
Jun 8, 1998, 6:00 PM MDT
In force
28 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), 56 km from the middle of the area, began a volume at 23:35 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.

What was reported inside it

TimeReportWhereRemark
Jun 8, 5:57 PM MDTHail 1.75Columbine, CO
Jun 8, 5:58 PM MDTHail 1Columbine, 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

Denver, CO (KDNR), launched 12:00Z, 11.5 hours before the alert went out and 168 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 1998-06-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 56 joules per kilogram.LCLLFCEL10008507005003002001001 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 1998-06-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -97 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
56 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
546 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
-97 m²/s²
0-3 km storm-relative helicity
-66 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDEN 082332 RRA
SVRDEN
COC035-059-090000-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
532 PM MDT MON JUN 8 1998

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
     NORTHWESTERN DOUGLAS COUNTY IN NORTHEAST COLORADO
     EAST CENTRAL JEFFERSON COUNTY IN NORTHEAST COLORADO

* UNTIL 600 PM MDT

* AT 530 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER INDIAN HILLS...OR ABOUT 17 MILES SOUTHWEST
  OF DENVER...MOVING EAST AT 20 MILES PER HOUR.

* LOCATIONS IN THE WARNING INCLUDE...SOUTHWESTERN DENVER...
  SOUTHWESTERN LAKEWOOD...LITTLETON...CHATFIELD RESERVOIR...
  IDLEDALE...INDIAN HILLS...MORRISON...RED ROCKS PARK AND TINY TOWN

VERY 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.

LAT...LON 3969 10524 3953 10528 3949 10502 3965 10502

COOPER

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, Jun 8, 1:45 PM MDT, 3 hours 47 minutes before
COZ035-038-043-082030-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO...CORRECTED
145 PM MDT MON JUN 8 1998

.CORRECTED HEADER...

...STRONG THUNDERSTORMS IN EASTERN LARIMER COUNTY...

AT 140 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED AN AREA OF
THUNDERSTORMS EXTENDING FROM FORT COLLINS TO VIRGINIA DALE.

AT 135 PM MDT A WEATHER SPOTTER REPORTED PEA SIZE HAIL OCCURRING AT FORT
COLLINS WITH ONE OF THE STORMS.

THE STORMS WERE MOVING EAST AT 10 TO 15 MILES PER HOUR.

PERSONS IN OR NEAR FORT COLLINS...GREELEY...AULT...EATON...GALETON...
HARMONY...LUCERNE...NUNN...PIERCE...PURCELL...SEVERANCE...TIMNATH...
WELLINGTON AND WINDSOR

SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND MOVE TO A PLACE
OF SAFETY WHEN THE STORMS APPROACH.  DANGEROUS LIGHTNING...PEA TO MARBLE
SIZE HAIL...BRIEF HEAVY RAIN...AND GUSTY WINDS TO 40 MPH ARE POSSIBLE
WITH THESE STORMS.

COOPER
Special weather statement, Jun 8, 1:45 PM MDT, 3 hours 47 minutes before
COZ035-038-043-082030-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO...CORRECTED
145 PM MDT MON JUN 8 1998

.CORRECTED HEADER...

...STRONG THUNDERSTORMS IN EASTERN LARIMER COUNTY...

AT 140 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED AN AREA OF
THUNDERSTORMS EXTENDING FROM FORT COLLINS TO VIRGINIA DALE.

AT 135 PM MDT A WEATHER SPOTTER REPORTED PEA SIZE HAIL OCCURRING AT FORT
COLLINS WITH ONE OF THE STORMS.

THE STORMS WERE MOVING EAST AT 10 TO 15 MILES PER HOUR.

PERSONS IN OR NEAR FORT COLLINS...GREELEY...AULT...EATON...GALETON...
HARMONY...LUCERNE...NUNN...PIERCE...PURCELL...SEVERANCE...TIMNATH...
WELLINGTON AND WINDSOR

SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND MOVE TO A PLACE
OF SAFETY WHEN THE STORMS APPROACH.  DANGEROUS LIGHTNING...PEA TO MARBLE
SIZE HAIL...BRIEF HEAVY RAIN...AND GUSTY WINDS TO 40 MPH ARE POSSIBLE
WITH THESE STORMS.

COOPER
Special weather statement, Jun 8, 1:45 PM MDT, 3 hours 47 minutes before
COZ035-038-043-08230-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
145 PM MDT MON JUN 8 1998

...STRONG THUNDERSTORMS IN EASTERN LARIMER COUNTY...

AT 140 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED AN AREA OF
THUNDERSTORMS EXTENDING FROM FORT COLLINS TO VIRGINIA DALE.

AT 135 PM MDT A WEATHER SPOTTER REPORTED PEA SIZE HAIL OCCURRING AT FORT
COLLINS WITH ONE OF THE STORMS.

THE STORMS WERE MOVING EAST AT 10 TO 15 MILES PER HOUR.

PERSONS IN OR NEAR FORT COLLINS...GREELEY...AULT...EATON...GALETON...
HARMONY...LUCERNE...NUNN...PIERCE...PURCELL...SEVERANCE...TIMNATH...
WELLINGTON AND WINDSOR

SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND MOVE TO A PLACE
OF SAFETY WHEN THE STORMS APPROACH.  DANGEROUS LIGHTNING...PEA TO MARBLE
SIZE HAIL...BRIEF HEAVY RAIN...AND GUSTY WINDS TO 40 MPH ARE POSSIBLE
WITH THESE STORMS.

COOPER

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 7, 6:39 PM MDTSevere Thunderstorm WarningBOULogan51 min
Jun 8, 2:25 AM MDTSevere Thunderstorm WarningBOUWeld35 min
Jun 8, 3:00 AM MDTSevere Thunderstorm WarningBOULogan, Weld40 min
Jun 8, 3:02 AM MDTSevere Thunderstorm WarningBOULogan, Weld38 min
Jun 8, 4:11 PM MDTSevere Thunderstorm WarningBOUBoulder, Jefferson49 min
Jun 8, 4:59 PM MDTSevere Thunderstorm WarningBOUAdams, Denver, Jefferson46 min
Jun 8, 5:59 PM MDTSevere Thunderstorm WarningBOUArapahoe, Denver, Douglas, Jefferson31 min

Nearby

Severe Thunderstorm Warnings in Colorado, 1998Every severe thunderstorm warning in 1998

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.