Alert archive / Colorado / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 121, NWS Denver/Boulder, CO

July 15, 1998Adams County, Arapahoe County, Washington County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 15, 1998, 6:47 PM MDT for Adams County, Arapahoe County, Washington County, Colorado. It was in force for 28 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 15, 1998, 6:47 PM MDT (00:47 UTC)
Expired
Jul 15, 1998, 7:15 PM MDT
In force
28 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Adams County, CO, Arapahoe County, CO, Washington County, CO

The radar

The Denver radar (KFTG), 68 km from the middle of the area, began a volume at 00:48 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

N. Platte/Lee Bi, NE (KLBF), launched 00:00Z, 0.8 hours before the alert went out and 303 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, N. Platte/Lee Bi, NE at 00:00Z on 1998-07-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 901 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, N. Platte/Lee Bi, NE at 00:00Z on 1998-07-16The 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
901 J/kg
Mixed-layer CIN
-68 J/kg
Mixed-layer LCL
2298 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
-20 m²/s²
0-3 km storm-relative helicity
-12 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.4

Open this sounding in Storm Lab

The text

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

438 
WUUS1 KDEN 160050 RRA
SVRDEN
COC001-005-121-160115-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
647 PM MDT WED JUL 15 1998

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
     EASTERN ADAMS COUNTY IN NORTHEAST COLORADO
     NORTHEASTERN ARAPAHOE COUNTY IN NORTHEAST COLORADO
     SOUTHWESTERN WASHINGTON COUNTY IN NORTHEAST COLORADO

* UNTIL 715 PM MDT

* AT 643 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER SHAMROCK...OR ABOUT 24 MILES SOUTH OF FORT
  MORGAN...MOVING NORTHEAST AT 15 MILES PER HOUR.


A SECOND STORM WAS LOCATED IN EXTREME SOUTHEAST ADAMS COUNTY.  IT 
WAS ALSO MOVING 15 MILES AN HOUR TO THE EAST.  LOCATIONS IN THE 
WARNING INCLUDE...JOLLY RANCH...LAST CHANCE...SHAMROCK AND WOODROW

STORMS WILL CONTAIN LARGE HAIL AND TORRENTIAL RAIN.  DAMAGING WINDS 
ARE ALSO LIKELY.  TAKE COVER AS THESE STORMS MOVE THROUGH YOUR AREA. 

LAT...LON 3998 10388 3961 10388 3959 10360 3999 10352
RTG

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 15, 6:01 PM MDTTornado WarningBOUWeld29 min
Jul 15, 6:16 PM MDTSevere Thunderstorm WarningBOUAdams, Morgan29 min
Jul 15, 6:55 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld60 min
Jul 15, 7:22 PM MDTTornado WarningBOUMorgan33 min
Jul 15, 8:10 PM MDTSevere Thunderstorm WarningBOULincoln, Washington35 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.