Alert archive / Colorado / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 110, NWS Denver/Boulder, CO

July 1, 1998Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 1, 1998, 6:29 PM MDT for Weld County, Colorado. It was in force for 46 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
Jul 1, 1998, 6:29 PM MDT (00:29 UTC)
Expired
Jul 1, 1998, 7:15 PM MDT
In force
46 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Weld County, CO

The radar

The Cheyenne radar (KCYS), 53 km from the middle of the area, began a volume at 00:28 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, 0.5 hours before the alert went out and 143 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 1998-07-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1351 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 1998-07-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 square meters per square second.1939Sfc1 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
1351 J/kg
Mixed-layer CIN
-39 J/kg
Mixed-layer LCL
2220 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
91 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.9

Open this sounding in Storm Lab

The text

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

454 
WUUS1 KDEN 020030 RRA
SVRDEN
COC123-020115-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
629 PM MDT WED JUL 1 1998

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
     CENTRAL WELD COUNTY IN NORTHEAST COLORADO

* UNTIL 715 PM MDT

* AT 625 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 9 MILES NORTHEAST OF PURCELL...OR ABOUT 25     
  MILES NORTHEAST OF GREELEY...MOVING EAST SOUTHEAST AT 15 MILES PER 
  HOUR.

LOCATIONS IN THE WARNING INCLUDE...BRIGGSDALE...GROVER AND PURCELL

IF SEVERE WEATHER APPROACHES YOUR AREA...GO INSIDE A STURDY SHELTER
AWAY FROM CREEK BEDS AND OTHER FLOOD-PRONE AREAS. REMEMBER...A SEVERE
THUNDERSTORM CAN PRODUCE LARGE DAMAGING HAIL...DAMAGING WINDS OVER 60
MPH...DEADLY LIGHTNING...AND VERY HEAVY RAIN.

LAT...LON 4089 10465 4056 10468 4057 10415 4088 10414

KLEYLA

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 1, 6:03 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln42 min
Jul 1, 6:27 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln48 min
Jul 1, 6:52 PM MDTSevere Thunderstorm WarningBOUMorgan53 min
Jul 1, 7:15 PM MDTTornado WarningBOUWeld30 min
Jul 1, 7:16 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln44 min
Jul 1, 7:44 PM MDTTornado WarningBOUMorgan, Weld31 min
Jul 1, 9:29 PM MDTSevere Thunderstorm WarningBOUMorgan41 min
Jul 2, 5:31 PM MDTSevere Thunderstorm WarningBOULarimer, Weld29 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.