Alert archive / Colorado / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 193, NWS Denver/Boulder, CO

August 10, 2013Adams County, Arapahoe County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 10, 2013, 7:20 PM MDT for Adams County, Arapahoe County, Colorado. It was in force for 25 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 10, 2013, 7:20 PM MDT (01:20 UTC)
Expired
Aug 10, 2013, 7:45 PM MDT
In force
25 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

Counties Adams County, CO, Arapahoe County, CO

The radar

The Denver radar (KFTG), 18 km from the middle of the area, began a volume at 01:23 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 00:00Z, 1.3 hours before the alert went out and 95 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-pSkew-T log-p diagram, Denver, CO at 00:00Z on 2013-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 00:00Z on 2013-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -33 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
1 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3477 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
-33 m²/s²
0-3 km storm-relative helicity
51 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 10, 3:43 PM MDT, 3 hours 37 minutes earlier.

Area forecast discussion, Aug 10, 3:43 PM MDT, 3 hours 37 minutes before
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Hazardous weather outlook, Aug 10, 10:56 AM MDT, 8 hours 24 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1056 AM MDT SAT AUG 10 2013

COZ030>051-111700-
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-
1056 AM MDT SAT AUG 10 2013

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS WILL AGAIN FORM OVER THE MOUNTAINS AND
HIGHER FOOTHILLS EARLY THIS AFTERNOON. A FEW OF THESE STORMS WILL
MOVE EAST OVER THE NEARBY PLAINS BY AROUND MID-AFTERNOON AS THE
ATMOSPHERE BECOMES WARMER AND MORE UNSTABLE. FARTHER OUT ON THE
PLAINS...THERE IS A GREATER CHANCE FOR THUNDERSTORMS FORMING ALONG
A WIND CONVERGENCE BOUNDARY STRETCHING FROM NEAR KIOWA IN ELBERT
COUNTY TO NEAR STERLING IN LOGAN COUNTY. SOME OF THESE STORMS
COULD BRIEFLY TURN SEVERE LATE THIS AFTERNOON OR EARLY THIS
EVENING. HAILSTONES UP TO 1 INCH IN DIAMETER AND WIND GUSTS TO 60
MPH WILL BE THE MAIN THREATS. ALL OTHER STORMS THIS AFTERNOON AND
EARLY EVENING WILL BE CAPABLE OF WIND GUSTS TO AROUND 45 MPH...
DANGEROUS LIGHTNING AND LIGHT TO MODERATE RAINFALL. THIS STORM
ACTIVITY SHOULD END BEFORE MIDNIGHT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THERE WILL BE A CHANCE OF AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS IN THE MOUNTAINS AND FOOTHILLS SUNDAY THROUGH
WEDNESDAY. CHANCES WILL DECREASE LATE IN THE WEEK WITH A DRIER
WARMER AIRMASS MOVING IN. THERE WILL BE A SLIGHT CHANCE OF
SHOWERS AND STORMS OVER THE PLAINS SUNDAY...THEN BETTER CHANCES
MONDAY AND TUESDAY. IT WILL GO BACK TO A SLIGHT CHANCE OF LATE DAY
SHOWERS AND THUNDERSTORMS WEDNESDAY AND THURSDAY. FRIDAY LOOKS
DRY. THE STORMS ON MONDAY AND TUESDAY MAY PRODUCE HEAVY RAINFALL
AMOUNTS ACROSS MUCH OF THE FORECAST AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY OR TONIGHT.

In the hours before

Special weather statement, Aug 10, 5:56 PM MDT, 1 hour 24 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
556 PM MDT SAT AUG 10 2013

COZ035-036-039-040-110015-
NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE
COUNTIES/EAST BROOMFIELD COUNTY-JEFFERSON AND WEST DOUGLAS COUNTIES
ABOVE  6000 FEET/GILPIN/CLEAR CREEK/NORTHEAST PARK COUNTIES BELOW
9000 FEET-LARIMER AND BOULDER COUNTIES BETWEEN 6000 AND 9000
FEET-BOULDER AND JEFFERSON COUNTIES BELOW 6000 FEET/WEST BROOMFIELD
COUNTY-
556 PM MDT SAT AUG 10 2013

THE NATIONAL WEATHER SERVICE HAS ISSUED A SIGNIFICANT WEATHER
ADVISORY FOR NORTHEASTERN JEFFERSON...EXTREME NORTHWESTERN ADAMS...
BROOMFIELD AND SOUTHEASTERN BOULDER COUNTIES UNTIL 615 PM MDT.

AT 555 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM OVER SOUTHWESTERN BROOMFIELD...OR 16 MILES
NORTHWEST OF DENVER...MOVING SOUTHEAST AT 20 MPH.

WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE BUT ARE NOT LIMITED TO...
SOUTHWESTERN THORNTON...ARVADA...WESTMINSTER...BROOMFIELD...
NORTHGLENN...LAFAYETTE...LOUISVILLE...SUPERIOR...FEDERAL HEIGHTS AND
ROCKY FLATS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 3992 10526 3999 10503 3985 10492 3978 10520
TIME...MOT...LOC 2355Z 324DEG 15KT 3992 10514

RPK
Special weather statement, Aug 10, 6:46 PM MDT, 34 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
646 PM MDT SAT AUG 10 2013

COZ040-110100-
NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE
COUNTIES/EAST BROOMFIELD COUNTY-
646 PM MDT SAT AUG 10 2013

THE NATIONAL WEATHER SERVICE HAS ISSUED A SIGNIFICANT WEATHER
ADVISORY FOR NORTHWESTERN ARAPAHOE...SOUTHWESTERN ADAMS AND SOUTHERN
DENVER COUNTIES UNTIL 700 PM MDT.

AT 645 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM OVER SOUTHWESTERN COMMERCE CITY...OR 5 MILES
NORTH OF DENVER...MOVING SOUTHEAST AT 20 MPH.

WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE BUT ARE NOT LIMITED TO...
DENVER...WESTERN AURORA...SOUTHWESTERN THORNTON AND SOUTHWESTERN
COMMERCE CITY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 3965 10496 3984 10503 3989 10482 3971 10474
TIME...MOT...LOC 0045Z 327DEG 20KT 3981 10495

RPK
Special weather statement, Aug 10, 6:48 PM MDT, 32 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
648 PM MDT SAT AUG 10 2013

COZ040-041-110115-
ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES ABOVE 6000 FEET-NORTH
DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE
COUNTIES/EAST BROOMFIELD COUNTY-
648 PM MDT SAT AUG 10 2013

THE NATIONAL WEATHER SERVICE HAS ISSUED A SIGNIFICANT WEATHER
ADVISORY FOR WESTERN ARAPAHOE AND EXTREME NORTHEASTERN DOUGLAS
COUNTIES UNTIL 715 PM MDT.

AT 648 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM OVER SOUTHWESTERN AURORA...OR 12 MILES SOUTHEAST
OF DENVER...MOVING SOUTHEAST AT 10 MPH.

HAIL UP TO THE SIZE OF NICKELS AND WIND GUSTS UP TO 50 MPH WILL BE
POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE BUT ARE NOT LIMITED TO...
AURORA...EASTERN CENTENNIAL...NORTHWESTERN PARKER AND ARAPAHOE PARK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 3965 10486 3972 10467 3960 10458 3952 10480
TIME...MOT...LOC 0048Z 335DEG 8KT 3963 10476

RPK

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 10, 6:46 PM MDTSpecial Weather StatementBOUDenver14 min
Aug 10, 6:48 PM MDTSpecial Weather StatementBOUDenver27 min
Aug 10, 7:37 PM MDTSevere Thunderstorm WarningBOUAdams38 min
Aug 10, 7:58 PM MDTSpecial Weather StatementBOUAdams32 min
Aug 10, 9:10 PM MDTSevere Thunderstorm WarningBOUMorgan50 min
Aug 10, 10:11 PM MDTSpecial Weather StatementBOULogan49 min
Aug 10, 11:09 PM MDTSpecial Weather StatementBOULincoln51 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2013Every 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.