Alert archive / Colorado / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 21, NWS Denver/Boulder, CO

May 21, 1998Logan County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at May 21, 1998, 1:50 PM MDT for Logan County, Colorado. It was in force for 55 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
May 21, 1998, 1:50 PM MDT (19:50 UTC)
Expired
May 21, 1998, 2:45 PM MDT
In force
55 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Logan County, CO

The radar

The Cheyenne radar (KCYS), 135 km from the middle of the area, began a volume at 19:50 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, 7.8 hours before the alert went out and 121 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 1998-05-21Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 1998-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 56 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
2454 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
56 m²/s²
0-3 km storm-relative helicity
158 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.

183 
WUUS1 KDEN 211951 RRA
SVRDEN
COC075-212045-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
150 PM MDT THU MAY 21 1998

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
     NORTH CENTRAL LOGAN COUNTY IN NORTHEAST COLORADO

* UNTIL 245 PM MDT

* AT 147 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 13 MILES WEST OF PEETZ...OR ABOUT 23 MILES
  NORTH OF STERLING...MOVING EAST AT 20 MILES PER HOUR.

* LOCATIONS IN THE WARNING INCLUDE...PEETZ

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 4099 10343 4091 10339 4092 10291 4099 10295

LESZCYNSKI

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 6:22 PM MDTSevere Thunderstorm WarningBOUWashington38 min
May 20, 6:36 PM MDTSevere Thunderstorm WarningBOUWashington24 min
May 20, 7:01 PM MDTSevere Thunderstorm WarningBOUWashington39 min
May 21, 2:19 PM MDTSevere Thunderstorm WarningBOUWeld36 min
May 21, 3:18 PM MDTSevere Thunderstorm WarningBOUWeld42 min
May 21, 3:57 PM MDTSevere Thunderstorm WarningBOUWeld48 min
May 21, 4:22 PM MDTTornado WarningBOUWeld28 min
May 21, 4:51 PM MDTSevere Thunderstorm WarningBOULogan, Weld39 min
May 21, 5:35 PM MDTSevere Thunderstorm WarningBOULogan35 min
May 21, 5:41 PM MDTTornado WarningBOUPhillips, Sedgwick39 min
May 21, 5:47 PM MDTTornado WarningBOUPhillips, Sedgwick33 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.