Alert archive / Colorado / Tornado Warnings in 1999

Tornado Warning 21, NWS Denver/Boulder, CO

June 10, 1999Adams County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Jun 10, 1999, 4:59 PM MDT for Adams County, Colorado. It was in force for 31 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: Jun 10, 1999, 4:59 PM MDT (22:59 UTC)
Expired: Jun 10, 1999, 5:30 PM MDT
In force: 31 min
Issued by: NWS Denver/Boulder, CO
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Adams County, CO

The radar

The Denver radar (KFTG), 29 km from the middle of the area, began a volume at 22:58 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jun 10, 2:30 PM MDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 11.0 hours before the alert went out and 84 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: 125 J/kg
Mixed-layer CIN: -64 J/kg
Mixed-layer LCL: 690 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 7 m²/s²
0-3 km storm-relative helicity: 69 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.

997 
WFUS1 KDEN 102302 RRA
TORDEN
COC001-102330-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
459 PM MDT THU JUN 10 1999

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* TORNADO WARNING FOR...
  EASTERN ADAMS COUNTY IN NORTHEAST COLORADO

* UNTIL 530 PM MDT

* AT 453 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  A THUNDERSTORM WITH A POSSIBLE TORNADO OVER CENTRAL ADAMS COUNTY   
  ABOUT 8 MILES NORTH OF STRASBURG...OR ABOUT 38 MILES EAST OF       
  DENVER...MOVING EAST AT 20 MPH.

HAIL UP TO GOLF BALL SIZE AND WIND GUSTS UP TO 75 MPH ARE ALSO 
POSSIBLE WITH THIS STORM.  WIND DAMAGE WAS REPORTED WITH THIS STORM 
8 MILES NORTH OF BENNETT AROUND 430 PM.

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.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE
NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

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.

LAT...LON 3988 10433 3977 10428 3980 10408 3996 10406

GIMMESTAD
&

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 10, 1:54 PM MDT	Severe Thunderstorm Warning	BOU	Jefferson	36 min
Jun 10, 2:27 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Denver, Jefferson	33 min
Jun 10, 3:00 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Denver	45 min
Jun 10, 3:42 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Denver	33 min
Jun 10, 4:06 PM MDT	Tornado Warning	BOU	Adams	24 min
Jun 10, 4:10 PM MDT	Severe Thunderstorm Warning	BOU	Douglas	50 min
Jun 10, 4:27 PM MDT	Tornado Warning	BOU	Adams	33 min
Jun 10, 5:27 PM MDT	Tornado Warning	BOU	Adams, Arapahoe	33 min

Nearby

Tornado Warnings in Colorado, 1999 Every tornado warning in 1999 Tornadoes in 1999

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.