Alert archive / Colorado / Tornado Warnings in 1998

Tornado Warning 1, NWS Denver/Boulder, CO

May 21, 1998Weld County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 21, 1998, 4:22 PM MDT for Weld 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
May 21, 1998, 4:22 PM MDT (22:22 UTC)
Expired
May 21, 1998, 4:50 PM MDT
In force
28 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), 86 km from the middle of the area, began a volume at 22:23 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, 10.4 hours before the alert went out and 127 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.

302 
WFUS1 KDEN 212224 RRA
TORDEN
COC123-212250-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
422 PM MDT THU MAY 21 1998

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* TORNADO WARNING FOR...
     NORTHEAST WELD COUNTY IN NORTHEAST COLORADO

* UNTIL 450 PM MDT

* AT 415 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  THUNDERSTORM WITH A POSSIBLE TORNADO OVER NORTHEASTERN WELD
  COUNTY...OR ABOUT 38 MILES NORTHWEST OF STERLING...MOVING EAST AT
  20 MILES PER HOUR.

THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT. GET UNDER A
WORKBENCH OR OTHER PIECE OF STURDY FURNITURE. IF NO BASEMENT IS
AVAILABLE...SEEK SHELTER ON THE LOWEST FLOOR OF THE BUILDING IN AN
INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET. USE BLANKETS OR PILLOWS TO
COVER YOUR BODY AND ALWAYS STAY AWAY FROM WINDOWS.

THIS TORNADO WARNING REPLACES THE SEVERE THUNDERSTORM WARNING ISSUED AT
357 PM MDT.

LAT...LON 4093 10394 4083 10386 4089 10369 4097 10376

LESZCYNSKI

What forecasters said that day

The local office's own words before this tornado 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 21, 11:53 AM MDT, 4 hours 29 minutes before
COZ030-032>050-220600-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
1153 AM MDT THU MAY 21 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:  AN UPPER SYSTEM PUSHED EAST OF THE AREA EARLIER THIS
MORNING...BRINGING MORE STABLE AND DRY CONDITIONS...AS WELL AS
DOWNSLOPE WINDS...TO PLAINS ADJACENT TO THE FOOTHILLS.  HOWEVER...AT
THE SURFACE AN AREA OF LOW PRESSURE WAS OVER SOUTHWEST WASHINGTON
COUNTY AT THIS TIME...AND IS EXPECTED TO MOVE LITTLE THROUGH THE
AFTERNOON.  THE ASSOCIATED WIND FIELD WILL KEEP AREAS EAST AND NORTH
OF THE LOW IN MORE MOIST UPSLOPE FLOW...AREAS TO THE SOUTH AND WEST
WILL BE MUCH DRIER.  SO THE SHOWERS AND THUNDERSTORMS THAT DEVELOP
OVER THE ALPINE AREAS BY EARLY AFTERNOON WILL DISSIPATED WHEN THEY
PUSH OFF THE FOOTHILLS INTO THESE DRY AREAS.  EXPECT ONLY ISOLATED
THUNDERSTORMS AFTER 4 PM IN JEFFERSON...DENVER...DOUGLAS...ELBERT...
LINCOLN...ARAPAHOE COUNTIES.

THE UPPER SYSTEM THAT PUSHED THROUGH EARLIER HAS LEFT A FAIRLY
STABLE AREA AT THE MID LEVELS OF THE ATMOSPHERE.  THIS WILL MAKE
THUNDERSTORMS DEVELOPMENT MORE DIFFICULT...EVEN IN THE MORE MOIST
COUNTIES.  EXPECTED WIDELY SCATTERED SHOWERS AND THUNDERSTORMS AFTER
2:30 PM IN BOULDER...LARIMER...WELD...MORGAN...ADAMS...WASHINGTON
...LOGAN...PHILLIPS...AND SEDGWICK COUNTIES.

SPOTTER ACTIVATION MAY BE NEEDED AFTER 3 PM OVER THE FAR NORTHEAST
BORDER COUNTIES OF COLORADO.    RJK
Special weather statement, May 21, 12:25 PM MDT, 3 hours 57 minutes before
COZ030-032>050-220600-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
1153 AM MDT THU MAY 21 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:  AN UPPER SYSTEM PUSHED EAST OF THE AREA EARLIER THIS
MORNING...BRINGING MORE STABLE AND DRY CONDITIONS...AS WELL AS
DOWNSLOPE WINDS...TO PLAINS ADJACENT TO THE FOOTHILLS.  HOWEVER...AT
THE SURFACE AN AREA OF LOW PRESSURE WAS OVER SOUTHWEST WASHINGTON
COUNTY AT THIS TIME...AND IS EXPECTED TO MOVE LITTLE THROUGH THE
AFTERNOON.  THE ASSOCIATED WIND FIELD WILL KEEP AREAS EAST AND NORTH
OF THE LOW IN MORE MOIST UPSLOPE FLOW...AREAS TO THE SOUTH AND WEST
WILL BE MUCH DRIER.  SO THE SHOWERS AND THUNDERSTORMS THAT DEVELOP
OVER THE ALPINE AREAS BY EARLY AFTERNOON WILL DISSIPATED WHEN THEY
PUSH OFF THE FOOTHILLS INTO THESE DRY AREAS.  EXPECT ONLY ISOLATED
THUNDERSTORMS AFTER 4 PM IN JEFFERSON...DENVER...DOUGLAS...ELBERT...
LINCOLN...ARAPAHOE COUNTIES.

THE UPPER SYSTEM THAT PUSHED THROUGH EARLIER HAS LEFT A FAIRLY
STABLE AREA AT THE MID LEVELS OF THE ATMOSPHERE.  THIS WILL MAKE
THUNDERSTORMS DEVELOPMENT MORE DIFFICULT...EVEN IN THE MORE MOIST
COUNTIES.  EXPECTED WIDELY SCATTERED SHOWERS AND THUNDERSTORMS AFTER
2:30 PM IN BOULDER...LARIMER...WELD...MORGAN...ADAMS...WASHINGTON
...LOGAN...PHILLIPS...AND SEDGWICK COUNTIES.

SPOTTER ACTIVATION MAY BE NEEDED AFTER 3 PM OVER THE FAR NORTHEAST
BORDER C"OUNTIES OF COLORADO.    RJK
Special weather statement, May 21, 4:16 PM MDT, 6 minutes before
COZ043-044-212245-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
416 PM MDT THU MAY 21 1998

...THUNDERSTORM IN
   FAR EAST CENTRAL WELD AND WEST CENTRAL MORGAN COUNTIES OF COLORADO

AT 409 PM MDT THE PUBLIC REPORTED A POSSIBLE TORNADO BETWEEN FORT
MORGAN AND WIGGINS. WEATHER SERVICE DOPPLER RADAR INDICATED A
THUNDERSTORM ABOUT 3 MILES SOUTH OF ORCHARD...OR ABOUT 16 MILES WEST
OF FORT MORGAN...MOVING NORTHEAST AT 30 MILES PER HOUR.

THIS STORM LIES ALONG A BOUNDARY WHICH MAY PRODUCE A BRIEF FUNNEL
CLOUD OR LANDSPOUT.

PERSONS IN OR NEAR GOODRICH...JACKSON RESERVOIR...ORCHARD...WELDONA
AND WIGGINS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND
MOVE TO A PLACE OF SAFETY IF BAD WEATHER APPROACHES.

ENTREKIN
Special weather statement, May 21, 4:16 PM MDT, 6 minutes before
COZ043-044-212245-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
416 PM MDT THU MAY 21 1998

...THUNDERSTORM IN
   FAR EAST CENTRAL WELD AND WEST CENTRAL MORGAN COUNTIES OF COLORADO

AT 409 PM MDT THE PUBLIC REPORTED A POSSIBLE TORNADO BETWEEN FORT
MORGAN AND WIGGINS. WEATHER SERVICE DOPPLER RADAR INDICATED A
THUNDERSTORM ABOUT 3 MILES SOUTH OF ORCHARD...OR ABOUT 16 MILES WEST
OF FORT MORGAN...MOVING NORTHEAST AT 30 MILES PER HOUR.

THIS STORM LIES ALONG A BOUNDARY WHICH MAY PRODUCE A BRIEF FUNNEL
CLOUD OR LANDSPOUT.

PERSONS IN OR NEAR GOODRICH...JACKSON RESERVOIR...ORCHARD...WELDONA
AND WIGGINS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER AND
MOVE TO A PLACE OF SAFETY IF BAD WEATHER APPROACHES.

ENTREKIN

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, 1:50 PM MDTSevere Thunderstorm WarningBOULogan55 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, 4:51 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

Tornado Warnings in Colorado, 1998Every tornado warning in 1998Tornadoes 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.