Alert archive / Colorado / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 9, NWS Denver/Boulder, CO

May 10, 1998Larimer County, Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at May 10, 1998, 5:14 PM MDT for Larimer County, Weld County, Colorado. It was in force for 46 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
May 10, 1998, 5:14 PM MDT (23:14 UTC)
Expired
May 10, 1998, 6:00 PM MDT
In force
46 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Larimer County, CO, Weld County, CO

The radar

The Cheyenne radar (KCYS), 64 km from the middle of the area, began a volume at 23:05 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
May 10, 5:15 PM MDTHail 0.75Ft Collins, CO
May 10, 5:25 PM MDTHail 1Ft Collins, 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, 11.2 hours before the alert went out and 176 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 1998-05-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 12 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 1998-05-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 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
12 J/kg
Mixed-layer CIN
-208 J/kg
Mixed-layer LCL
889 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
55 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.

225 
WUUS1 KDEN 102316 RRA
SVRDEN
COC069-123-110000-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
514 PM MDT SUN MAY 10 1998

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
     EAST CENTRAL LARIMER COUNTY IN NORTH CENTRAL COLORADO
     WEST CENTRAL WELD COUNTY IN NORTHEAST COLORADO

* UNTIL 600 PM MDT

* AT 511 PM MDT THE PUBLIC REPORTED A SEVERE THUNDERSTORM 3 MILES
  SOUTHWEST OF FORT COLLINS...MOVING NORTHEAST AT 15 MILES PER HOUR.

* LOCATIONS IN THE WARNING INCLUDE FORT COLLINS...BELLVUE...
  HARMONY...SEVERANCE...TEDS PLACE...TIMNATH AND WELLINGTON

HAIL UP TO 1 INCHE IN DIAMETER HAS BEEN REPORTED WITH THIS STORM. 
IF YOU ARE IN THE PATH OF THE STORM...PUT YOUR CAR IN A GARAGE AND 
MOVE TO A SUBSTANTIAL SHELTER.

COOPER

LAT...LON 4062 10526 4045 10515 4054 10473 4081 10493

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, May 10, 11:15 AM MDT, 5 hours 59 minutes before
COZ030-032>050-110600-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1115 AM MDT SUN MAY 10 1998

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 SURFACE TROUGH IS DEVELOPING ALONG THE FRONT RANGE
FOOTHILLS LATE THIS MORNING...AND IS NOT EXPECTED TO MOVE MUCH UNTIL
THIS EVENING. INITIAL CONVECTION WILL FIRE OVER THE MOUNTAINS AND
FOOTHILLS INITIALLY AFTER 130 PM...THEN BEGIN TO MOVE OUT ONTO THE
URBAN CORRIDOR AROUND 230 PM. OUT FURTHER EAST...THE ATMOSPHERE IS
MORE STABLE...HOWEVER THUNDERSTORMS WILL BEGIN TO DEVELOP AS THE
SURFACE TROUGH PUSHES SLOWLY EASTWARD LATER THIS AFTERNOON AND
EVENING. ANOTHER AREA OF DEVELOPMENT WILL BE ALONG THE COLORADO AND
WYOMING BORDERS ACROSS LARIMER AND WELD COUNTIES...WITH THE
THUNDERSTORMS DEVELOPING THERE AFTER 2 PM.

AN UPPER LEVEL LOW PRESSURE SYSTEM OVER THE GREAT BASIN WILL ALSO
AID IN THUNDERSTORMS AS THE ATMOSPHERE BECOMES MORE UNSTABLE WITH
TIME. THE MAIN THREAT THROUGH THIS EVENING WILL BE SOME ISOLATED
REPORTS OF LARGE HAIL.

SPOTTER ACTIVATION MAY BE NEEDED LATER THIS AFTERNOON AND INTO THE
EVENING...AS THE SURFACE TROUGH MOVES INTO AREAS OF HIGHER
INSTABILITY AND GREATER WIND SHEAR.

ENTREKIN
Special weather statement, May 10, 11:15 AM MDT, 5 hours 59 minutes before
COZ030-032>050-110600-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER CO
1115 AM MDT SUN MAY 10 1998

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 SURFACE TROUGH IS DEVELOPING ALONG THE FRONT RANGE
FOOTHILLS LATE THIS MORNING...AND IS NOT EXPECTED TO MOVE MUCH UNTIL
THIS EVENING. INITIAL CONVECTION WILL FIRE OVER THE MOUNTAINS AND
FOOTHILLS INITIALLY AFTER 130 PM...THEN BEGIN TO MOVE OUT ONTO THE
URBAN CORRIDOR AROUND 230 PM. OUT FURTHER EAST...THE ATMOSPHERE IS
MORE STABLE...HOWEVER THUNDERSTORMS WILL BEGIN TO DEVELOP AS THE
SURFACE TROUGH PUSHES SLOWLY EASTWARD LATER THIS AFTERNOON AND
EVENING. ANOTHER AREA OF DEVELOPMENT WILL BE ALONG THE COLORADO AND
WYOMING BORDERS ACROSS LARIMER AND WELD COUNTIES...WITH THE
THUNDERSTORMS DEVELOPING THERE AFTER 2 PM.

AN UPPER LEVEL LOW PRESSURE SYSTEM OVER THE GREAT BASIN WILL ALSO
AID IN THUNDERSTORMS AS THE ATMOSPHERE BECOMES MORE UNSTABLE WITH
TIME. THE MAIN THREAT THROUGH THIS EVENING WILL BE SOME ISOLATED
REPORTS OF LARGE HAIL.

SPOTTER ACTIVATION MAY BE NEEDED LATER THIS AFTERNOON AND INTO THE
EVENING...AS THE SURFACE TROUGH MOVES INTO AREAS OF HIGHER
INSTABILITY AND GREATER WIND SHEAR.

ENTREKIN

The office that day

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

IssuedProductOfficeCountiesLasted
May 10, 5:26 PM MDTSevere Thunderstorm WarningBOULarimer49 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.