Alert archive / Colorado / Tornado Warnings in 1998

Tornado Warning 14, NWS Denver/Boulder, CO

July 4, 1998Weld County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Jul 4, 1998, 5:18 PM MDT for Weld County, Colorado. It was in force for 27 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 4, 1998, 5:18 PM MDT (23:18 UTC)
Expired
Jul 4, 1998, 5:45 PM MDT
In force
27 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Weld County, CO

The radar

The Denver radar (KFTG), 79 km from the middle of the area, began a volume at 23:18 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, 11.3 hours before the alert went out and 117 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 1998-07-04Temperature 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 km15 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 1998-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 square meters per square second.193958Sfc1 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
2072 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
29 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.

628 
WFUS1 KDEN 042320 RRA
TORDEN
COC123-042345-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
518 PM MDT SAT JUL 4 1998

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

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

* UNTIL 545 PM MDT

* AT 512 PM MDT...THE PUBLIC REPORTED A TORNADO 10 MILES EAST OF
  GILL...OR ABOUT 20 MILES EAST OF GREELEY...MOVING NORTH AT
  15 MILES PER HOUR.

LOCATIONS IN THE WARNING INCLUDE...CORNISH

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A NEARBY REINFORCED
BUILDING. AS A LAST RESORT...SEEK SHELTER IN A CULVERT...DITCH OR LOW
SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

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.

LAT...LON 4056 10447 4035 10448 4037 10416 4058 10415

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, Jul 4, 11:25 AM MDT, 5 hours 53 minutes before
COZ030-032>050-050600-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
1125 AM MDT SAT JUL 4 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:  DECENT EASTERLY UPSLOPE FLOW AND PLENTY OF DEEP MOISTURE
WILL BE AVAILABLE THIS AFTERNOON AND EVENING FOR THUNDERSTORM
DEVELOPMENT ACROSS THE AREA.  THE SUN'S HEATING AND OUTFLOW FROM
OTHER THUNDERSTORMS WILL BE THE MAIN FACTOR IN STARTING THUNDERSTORM
DEVELOPMENT.  CURRENTLY...AREAS SUCH AS THE NORTHEAST CORNER WHERE
THE SURFACE MOISTURE IS THE HIGHEST...ARE UNDER MOSTLY CLOUDY
SKIES.  THIS WILL RETARD DECENT HEATING UNTIL THE CLOUDS DISSIPATE
AROUND NOON TIME.  ALSO...BY LATE THIS AFTERNOON INTO THIS EVENING
...FORECAST MODELS SHOW SOME WEAK LIFT AVAILABLE WITH A SMALL UPPER
LEVEL FEATURE WHICH COULD ALSO AID IN THUNDERSTORM DEVELOPMENT AND
COVERAGE.  WEAK STEERING WINDS ALONG WITH THE AMPLE MOISTURE WILL
PRODUCING HEAVY RAINS IN SOME AREAS FROM THESE STORMS.  A FEW
THUNDERSTORMS MAY REACH SEVERE LIMITS WHERE THE LOW LEVEL MOISTURE
IS THE HIGHEST...OVER THE NORTHEAST CORNER AFTER 4 PM.  BUT OVER ALL
THE MAIN THREAT WILL BE HEAVY RAINS OVER THE FORECAST AREA.  THE
MOUNTAINS AND FOOTHILLS CAN EXPECTED SCATTERED SHOWERS AND STORMS BY
NOON TIME...WITH SCATTERED COVERAGE REACHING...FIRST THE WESTERN
PLAINS BY 2:30 PM...THEN THE EASTERN PLAINS BY 4 PM.

SPOTTER ACTIVATION MAY BE NEEDED BY MID AFTERNOON.

RJK
Special weather statement, Jul 4, 11:25 AM MDT, 5 hours 53 minutes before
COZ030-032>050-050600-

SIGNIFICANT WEATHER OUTLOOK FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
1125 AM MDT SAT JUL 4 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:  DECENT EASTERLY UPSLOPE FLOW AND PLENTY OF DEEP MOISTURE
WILL BE AVAILABLE THIS AFTERNOON AND EVENING FOR THUNDERSTORM
DEVELOPMENT ACROSS THE AREA.  THE SUN'S HEATING AND OUTFLOW FROM
OTHER THUNDERSTORMS WILL BE THE MAIN FACTOR IN STARTING THUNDERSTORM
DEVELOPMENT.  CURRENTLY...AREAS SUCH AS THE NORTHEAST CORNER WHERE
THE SURFACE MOISTURE IS THE HIGHEST...ARE UNDER MOSTLY CLOUDY
SKIES.  THIS WILL RETARD DECENT HEATING UNTIL THE CLOUDS DISSIPATE
AROUND NOON TIME.  ALSO...BY LATE THIS AFTERNOON INTO THIS EVENING
...FORECAST MODELS SHOW SOME WEAK LIFT AVAILABLE WITH A SMALL UPPER
LEVEL FEATURE WHICH COULD ALSO AID IN THUNDERSTORM DEVELOPMENT AND
COVERAGE.  WEAK STEERING WINDS ALONG WITH THE AMPLE MOISTURE WILL
PRODUCING HEAVY RAINS IN SOME AREAS FROM THESE STORMS.  A FEW
THUNDERSTORMS MAY REACH SEVERE LIMITS WHERE THE LOW LEVEL MOISTURE
IS THE HIGHEST...OVER THE NORTHEAST CORNER AFTER 4 PM.  BUT OVER ALL
THE MAIN THREAT WILL BE HEAVY RAINS OVER THE FORECAST AREA.  THE
MOUNTAINS AND FOOTHILLS CAN EXPECTED SCATTERED SHOWERS AND STORMS BY
NOON TIME...WITH SCATTERED COVERAGE REACHING...FIRST THE WESTERN
PLAINS BY 2:30 PM...THEN THE EASTERN PLAINS BY 4 PM.

SPOTTER ACTIVATION MAY BE NEEDED BY MID AFTERNOON.

RJK

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.