Alert archive / Colorado / Tornado Warnings in 1999

Tornado Warning 13, NWS Denver/Boulder, CO

May 31, 1999Washington County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 31, 1999, 5:56 PM MDT for Washington County, Colorado. It was in force for 34 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: May 31, 1999, 5:56 PM MDT (23:56 UTC)
Expired: May 31, 1999, 6:30 PM MDT
In force: 34 min
Issued by: NWS Denver/Boulder, CO
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Washington County, CO

The radar

The Denver radar (KFTG), 119 km from the middle of the area, began a volume at 23:57 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
May 31, 5:58 PM MDT	Hail 1	Akron, 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 watch it was issued in

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

Issued	Product	Office	Lasted
May 31, 3:00 PM MDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 11.9 hours before the alert went out and 38 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: 9 J/kg
Mixed-layer CIN: -409 J/kg
Mixed-layer LCL: 738 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: -36 m²/s²
0-3 km storm-relative helicity: 82 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.

999 
WFUS1 KDEN 312358 RRA
TORDEN
COC121-010030-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
556 PM MDT MON MAY 31 1999

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* TORNADO WARNING FOR...
  NORTH CENTRAL WASHINGTON COUNTY IN NORTHEAST COLORADO
  THIS INCLUDES THE CITY OF AKRON

* UNTIL 630 PM MDT

* AT 551 PM MDT...THE PUBLIC AND STORM SPOTTERS REPORTED A TORNADO 5 
WEST OF AKRON...MOVING SOUTHEAST AT 15 MPH.

THIS IS AN EXTREMELY DANGEROUS AND POTENTIALLY LIFE THREATENING 
SITUATION. IF YOU ARE IN THE PATH OF THIS TORNADO...TAKE COVER 
IMMEDIATELY.

THIS REPLACES THE PREVIOUS TORNADO THAT WAS IN EFFECT FOR NORTHERN 
WASHINGTON COUNTY.

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.

LAT...LON 4031 10332 4015 10340 4011 10332 4011 10314
          4027 10310
$$

COOPER

The office that day

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

Issued	Product	Office	Counties	Lasted
May 31, 2:11 PM MDT	Severe Thunderstorm Warning	BOU	Larimer	34 min
May 31, 2:35 PM MDT	Severe Thunderstorm Warning	BOU	Larimer	40 min
May 31, 3:04 PM MDT	Severe Thunderstorm Warning	BOU	Weld	26 min
May 31, 3:24 PM MDT	Severe Thunderstorm Warning	BOU	Weld	36 min
May 31, 3:26 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	34 min
May 31, 3:55 PM MDT	Severe Thunderstorm Warning	BOU	Morgan, Weld	50 min
May 31, 4:07 PM MDT	Severe Thunderstorm Warning	BOU	Morgan	33 min
May 31, 4:23 PM MDT	Severe Thunderstorm Warning	BOU	Morgan	37 min
May 31, 5:12 PM MDT	Tornado Warning	BOU	Morgan, Washington	33 min
May 31, 5:40 PM MDT	Tornado Warning	BOU	Washington	35 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.