Alert archive / Colorado / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 217, NWS Denver/Boulder, CO

August 23, 2013Douglas County, Jefferson County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 23, 2013, 6:22 PM MDT for Douglas County, Jefferson County, Colorado. It was in force for 38 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 23, 2013, 6:22 PM MDT (00:22 UTC)
Expired: Aug 23, 2013, 7:00 PM MDT
In force: 38 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

Counties Douglas County, CO, Jefferson County, CO

The radar

The Denver radar (KFTG), 59 km from the middle of the area, began a volume at 00:24 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 nearest sounding before it

Grand Junction, CO (KGJT), launched 00:00Z, 0.4 hours before the alert went out and 296 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: 7 J/kg
Mixed-layer CIN: -302 J/kg
Mixed-layer LCL: 2624 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: -59 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Denver/Boulder, CO wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 23, 3:10 PM MDT, 3 hours 12 minutes earlier.

Area forecast discussion, Aug 23, 3:10 PM MDT, 3 hours 12 minutes before

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Hazardous weather outlook, Aug 23, 10:46 AM MDT, 7 hours 36 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1046 AM MDT FRI AUG 23 2013

COZ030>051-241700-
JACKSON COUNTY BELOW 9000 FEET-
WEST JACKSON AND WEST GRAND COUNTIES ABOVE 9000 FEET-
GRAND AND SUMMIT COUNTIES BELOW 9000 FEET-
SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/
NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET-
SOUTH AND SOUTHEAST GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/
GILPIN/CLEAR CREEK/SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE
9000 FEET-LARIMER AND BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET-
JEFFERSON AND WEST DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR
CREEK/NORTHEAST PARK COUNTIES BELOW 9000 FEET-
CENTRAL AND SOUTHEAST PARK COUNTY-
LARIMER COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY-
BOULDER AND JEFFERSON COUNTIES BELOW 6000 FEET/WEST BROOMFIELD
COUNTY-
NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND
ARAPAHOE COUNTIES/EAST BROOMFIELD COUNTY-
ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES ABOVE 6000 FEET-
NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD COUNTY-MORGAN COUNTY-
CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES-
NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN
COUNTY-
SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN COUNTY-
LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS COUNTY-
1046 AM MDT FRI AUG 23 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL
COLORADO.

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED TO BEGIN TO FORM OVER THE
HIGHER TERRAIN EARLY THIS AFTERNOON. THE STORMS WILL SPREAD
NORTHEASTWARD INTO THE AFTERNOON AND EARLY EVENING AFFECTING THE
FOOTHILLS AND ADJACENT PLAINS...MAINLY ALONG AND WEST OF I25 AS
WELL AS NORTH OF I76. SOME OF THE STORMS COULD PRODUCE HEAVY
RAIN...AND THERE IS A SMALL CHANCE OF FLASH FLOODING WITH THE
STRONGEST STORMS OVER THE FOOTHILLS BURN AREAS AND ALONG THE FRONT
RANGE. WIND GUSTS TO 45 MPH AND SMALL HAIL ARE ALSO POSSIBLE WITH
THE STORMS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE WILL BE A CHANCE OF LATE DAY SHOWERS AND THUNDERSTORMS OVER
THE MOUNTAINS AND FOOTHILLS THROUGH MUCH OF THE PERIOD. THE PLAINS
CAN EXPECTED NO PRECIPITATION TO A SLIGHT CHANCE OF LATE DAY
STORMS. TEMPERATURES WILL BE SLIGHTLY ABOVE SEASONAL NORMALS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.

In the hours before

Special weather statement, Aug 23, 2:59 PM MDT, 3 hours 23 minutes before

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Special weather statement, Aug 23, 3:19 PM MDT, 3 hours 3 minutes before

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Special weather statement, Aug 23, 3:41 PM MDT, 2 hours 41 minutes before

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Special weather statement, Aug 23, 4:33 PM MDT, 1 hour 49 minutes before

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Special weather statement, Aug 23, 5:05 PM MDT, 1 hour 17 minutes before

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Special weather statement, Aug 23, 5:31 PM MDT, 51 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 23, 6:29 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Weld	31 min
Aug 23, 6:42 PM MDT	Special Weather Statement	BOU	Broomfield	33 min
Aug 23, 6:51 PM MDT	Special Weather Statement	BOU	Adams	39 min
Aug 23, 7:03 PM MDT	Special Weather Statement	BOU	Boulder	42 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2013 Every severe thunderstorm warning in 2013

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.