Alert archive / Colorado / Tornado Warnings in 2004

Tornado Warning 8, NWS Denver/Boulder, CO

May 20, 2004Washington County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 20, 2004, 8:56 PM MDT for Washington County, Colorado. It was in force for 49 min. 7 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: May 20, 2004, 8:56 PM MDT (02:56 UTC)
Expired: May 20, 2004, 9:45 PM MDT
In force: 49 min
Issued by: NWS Denver/Boulder, CO
Area: Counties, with a storm outline in the text

County Washington County, CO

The radar

The Denver radar (KFTG), 128 km from the middle of the area, began a volume at 03:00 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 20, 9:16 PM MDT	HAIL 1.75	5 S Merino, CO
May 20, 9:16 PM MDT	HAIL 1.75	5 S Merino, CO
May 20, 9:16 PM MDT	HAIL 1.75	5 S Merino, CO
May 20, 9:16 PM MDT	HAIL 1.75	5 S Merino, CO
May 20, 9:30 PM MDT	HAIL 2	1 E Prewitt Reservoir, CO	HAIL COVERING I-76 AT MILE MARKER 108.
May 20, 9:30 PM MDT	HAIL 2	1 E Prewitt Reservoir, CO	HAIL COVERING I-76 AT MILE MARKER 108.
May 20, 9:30 PM MDT	HAIL 2	1 E Prewitt Reservoir, CO	HAIL COVERING I-76 AT MILE MARKER 108.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

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 20, 6:15 PM MDT	Tornado Watch	SPC	5 hr

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 2.9 hours before the alert went out and 47 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: 1364 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 2205 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: 128 m²/s²
0-3 km storm-relative helicity: 230 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

420 
WFUS55 KBOU 210256
TORBOU
COC121-210345-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
856 PM MDT THU MAY 20 2004

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

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

* UNTIL 945 PM MDT

* AT 856 PM MDT...THE PUBLIC REPORTED A TORNADO 6 MILES NORTHWEST OF
  MIDWAY...OR ABOUT 17 MILES NORTHWEST OF AKRON...MOVING EAST AT
  25 MPH.

LOCATIONS IN THE WARNING INCLUDE...BUT ARE NOT LIMITED TO...AKRON...
BURDETT...LONE STAR...MIDWAY...OTIS...PLATNER AND PREWITT RESERVOIR.

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.

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 4043 10346 4008 10346 4009 10281 4044 10281

$$

RPK

The office that day

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

Issued	Product	Office	Counties	Lasted
May 20, 6:22 PM MDT	Severe Thunderstorm Warning	BOU	Weld	53 min
May 20, 7:15 PM MDT	Severe Thunderstorm Warning	BOU	Weld	60 min
May 20, 7:34 PM MDT	Tornado Warning	BOU	Morgan, Weld	56 min
May 20, 8:17 PM MDT	Tornado Warning	BOU	Morgan, Weld	58 min

Nearby

Tornado Warnings in Colorado, 2004 Every tornado warning in 2004 Tornadoes in 2004

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.