Alert archive / Colorado / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 13, NWS Denver/Boulder, CO

May 20, 2004Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at May 20, 2004, 7:15 PM MDT for Weld County, Colorado. It was in force for 60 min. 8 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, 7:15 PM MDT (01:15 UTC)
Expired: May 20, 2004, 8:15 PM MDT
In force: 60 min
Issued by: NWS Denver/Boulder, CO
Area: Counties, with a storm outline in the text

County Weld County, CO

The radar

The Denver radar (KFTG), 69 km from the middle of the area, began a volume at 01:15 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
May 20, 7:43 PM MDT	HAIL 0.75	7 W Wiggins, CO
May 20, 7:43 PM MDT	HAIL 0.75	7 W Wiggins, CO
May 20, 7:43 PM MDT	HAIL 0.75	7 W Wiggins, CO
May 20, 7:43 PM MDT	HAIL 0.75	7 W Wiggins, CO
May 20, 7:43 PM MDT	HAIL 0.75	7 W Wiggins, CO
May 20, 7:43 PM MDT	HAIL 0.75	7 W Wiggins, CO
May 20, 7:43 PM MDT	HAIL 0.75	7 W Wiggins, CO
May 20, 7:43 PM MDT	HAIL 0.75	7 W Wiggins, CO

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, 1.3 hours before the alert went out and 114 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.

000 
WUUS55 KBOU 210115
SVRBOU
COC123-210215-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
714 PM MDT THU MAY 20 2004

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL WELD COUNTY IN NORTHEAST COLORADO

* UNTIL 815 PM MDT

* AT 714 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 6 MILES EAST OF MILTON RESERVOIR...OR ABOUT 18
  MILES SOUTHEAST OF GREELEY...MOVING NORTHEAST AT 15 MPH.

LOCATIONS IN THE WARNING INCLUDE...BUT ARE NOT LIMITED TO...
BARNESVILLE...KERSEY...MILTON RESERVOIR AND RIVERSIDE RESERVOIR.

SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE
WARNING. PREPARE TO MOVE TO A PLACE OF SAFETY IN A STURDY STRUCTURE
SUCH AS A BASEMENT OR SMALL INTERIOR ROOM IF A TORNADO IS SPOTTED.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1100 PM MDT THURSDAY EVENING
FOR NORTHEASTERN COLORADO.

HAIL UP TO 1.5 INCHES IN DIAMETER HAS BEEN REPORTED WITH THIS STORM 
10 MILES NORTH OF FORT LUPTON AT 6:31 PM MDT. IF YOU ARE IN THE PATH 
OF THE STORM...PUT YOUR CAR IN A GARAGE AND MOVE TO A SUBSTANTIAL 
SHELTER.


LAT...LON 4057 10418 4055 10438 4048 10452 4025 10467
          4016 10453 4019 10417

$$
RJK

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, 7:34 PM MDT	Tornado Warning	BOU	Morgan, Weld	56 min
May 20, 8:17 PM MDT	Tornado Warning	BOU	Morgan, Weld	58 min
May 20, 8:56 PM MDT	Tornado Warning	BOU	Washington	49 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2004 Every severe thunderstorm warning 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.