Alert archive / Colorado / Severe Thunderstorm Warnings in 2014

Severe Thunderstorm Warning 100, NWS Denver/Boulder, CO

June 21, 2014Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 21, 2014, 3:43 PM MDT for Weld County, Colorado. It was in force for 27 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: Jun 21, 2014, 3:43 PM MDT (21:43 UTC)
Expired: Jun 21, 2014, 4:10 PM MDT
In force: 27 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

County Weld County, CO

The radar

The Cheyenne radar (KCYS), 75 km from the middle of the area, began a volume at 21:47 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

Denver, CO (KDEN), launched 12:00Z, 9.7 hours before the alert went out and 125 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: 37 J/kg
Mixed-layer CIN: -319 J/kg
Mixed-layer LCL: 2293 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: -29 m²/s²
0-3 km storm-relative helicity: 20 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 Jun 21, 3:31 PM MDT, 12 minutes earlier.

Area forecast discussion, Jun 21, 3:31 PM MDT, 12 minutes before

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Hazardous weather outlook, Jun 21, 10:59 AM MDT, 4 hours 44 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1059 AM MDT SAT JUN 21 2014

COZ030>051-221700-
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-
1059 AM MDT SAT JUN 21 2014

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS WILL DEVELOP THIS AFTERNOON ON THE
PLAINS...WITH ONLY ISOLATED SHOWERS AND THUNDERSTORMS OVER THE
MOUNTAINS. WITH A LITTLE MORE MOISTURE OVER THE PLAINS TODAY THE
STORMS WILL BE A BIT MORE NUMEROUS AND STRONGER. ONE OR TWO STORMS
COULD BECOME SEVERE WITH HAIL AROUND AN INCH IN DIAMETER AND WIND
GUSTS TO 60 MPH. SOME OF THE STORMS MAY ALSO PRODUCE HEAVY
RAINFALL...BUT THE RISK OF FLOODING IS LOW.

THE THREAT OF SEVERE WEATHER IS MAINLY EAST OF FORT MORGAN AND
LIMON. STORMS WILL CONTINUE ON THE PLAINS IN THE EVENING...AND A
FEW COULD LINGER PAST MIDNIGHT NEAR THE EASTERN BORDER.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

SCATTERED THUNDERSTORMS WILL BE POSSIBLE EACH DAY...MAINLY DURING
THE AFTERNOON AND EVENING HOURS. SOME OF THE STORMS WILL PROBABLY
LINGER INTO THE WEE HOURS OF THE MORNING OUT ON THE EASTERN
PLAINS. IN ADDITION...A FEW OF THE STORMS MAY BE STRONG OR SEVERE
WITH LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS.

TEMPERATURES WILL BE BELOW NORMAL DURING THE FIRST PART OF THE
WEEK WITH SOME WARMING EXPECTED TOWARD THE END OF THE WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED OVER THE NORTHEAST PLAINS AFTER 2
PM THIS AFTERNOON.

In the hours before

Local storm report, Jun 21, 3:25 PM MDT, 18 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
Jun 20, 11:33 PM MDT	Special Weather Statement	BOU	Washington	57 min
Jun 21, 12:31 AM MDT	Special Weather Statement	BOU	Washington	59 min
Jun 21, 2:41 PM MDT	Tornado Warning	BOU	Adams, Weld	16 min
Jun 21, 2:47 PM MDT	Tornado Warning	BOU	Adams	28 min
Jun 21, 3:14 PM MDT	Tornado Warning	BOU	Adams, Arapahoe	18 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2014 Every severe thunderstorm warning in 2014

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.