Alert archive / Colorado / Tornado Warnings in 1998

Tornado Warning 12, NWS Denver/Boulder, CO

July 1, 1998Weld County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Jul 1, 1998, 7:15 PM MDT for Weld County, Colorado. It was in force for 30 min. 1 report came from 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, with what was reported inside it.

The facts

Issued: Jul 1, 1998, 7:15 PM MDT (01:15 UTC)
Expired: Jul 1, 1998, 7:45 PM MDT
In force: 30 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), 79 km from the middle of the area, began a volume at 01:18 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.

What was reported inside it

Time	Report	Where	Remark
Jul 1, 7:25 PM MDT	Hail 1	Cornish, CO

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 1.3 hours before the alert went out and 118 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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.

686 
WFUS1 KDEN 020116 RRA
TORDEN
COC123-020145-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
715 PM MDT WED JUL 1 1998

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

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

* UNTIL 745 PM MDT

* AT 711 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  THUNDERSTORM WITH A POSSIBLE TORNADO 7 MILES SOUTH OF BRIGGSDALE...
  OR ABOUT 24 MILES EAST OF GREELEY...MOVING EAST SOUTHEAST AT 15    
  MILES PER HOUR.

LOCATIONS IN THE WARNING INCLUDE...BRIGGSDALE

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 4061 10446 4038 10437 4039 10422 4060 10408 4070 10423

KLEYLA

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 1, 6:03 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	42 min
Jul 1, 6:27 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	48 min
Jul 1, 6:29 PM MDT	Severe Thunderstorm Warning	BOU	Weld	46 min
Jul 1, 6:52 PM MDT	Severe Thunderstorm Warning	BOU	Morgan	53 min
Jul 1, 7:16 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	44 min
Jul 1, 7:44 PM MDT	Tornado Warning	BOU	Morgan, Weld	31 min
Jul 1, 9:29 PM MDT	Severe Thunderstorm Warning	BOU	Morgan	41 min
Jul 2, 5:31 PM MDT	Severe Thunderstorm Warning	BOU	Larimer, Weld	29 min

Nearby

Tornado Warnings in Colorado, 1998 Every tornado warning in 1998 Tornadoes 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.