Alert archive / Colorado / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 252, NWS Denver/Boulder, CO

August 17, 2009Arapahoe County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 17, 2009, 6:46 PM MDT for Arapahoe County, Colorado. It was in force for 29 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 17, 2009, 6:46 PM MDT (00:46 UTC)
Expired
Aug 17, 2009, 7:15 PM MDT
In force
29 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon

County Arapahoe County, CO

The radar

The Denver radar (KFTG), 18 km from the middle of the area, began a volume at 00:48 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 (KDNR), launched 00:00Z, 0.8 hours before the alert went out and 102 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 2009-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 395 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 00:00Z on 2009-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 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
395 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
1610 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
82 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

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

000 
WUUS55 KBOU 180046
SVRBOU
COC005-180115-
/O.NEW.KBOU.SV.W.0252.090818T0046Z-090818T0115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
646 PM MDT MON AUG 17 2009

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

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

* UNTIL 715 PM MDT

* AT 646 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING HALF DOLLAR SIZE HAIL. 
  THIS STORM WAS LOCATED 12 MILES SOUTHWEST OF STRASBURG...OR 26
  MILES EAST OF DENVER...MOVING NORTHEAST AT 15 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO STRASBURG.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF SEVERE WEATHER APPROACHES YOUR AREA...GO INSIDE A STURDY SHELTER
AWAY FROM CREEK BEDS AND OTHER FLOOD-PRONE AREAS. REMEMBER...A SEVERE
THUNDERSTORM CAN PRODUCE LARGE DAMAGING HAIL...DAMAGING WINDS IN
EXCESS OF 58 MPH...DEADLY LIGHTNING...AND VERY HEAVY RAIN.

&&

LAT...LON 3974 10428 3957 10426 3957 10459 3973 10458
TIME...MOT...LOC 0046Z 241DEG 19KT 3963 10448

$$
2 follow-up statements
000 
WWUS55 KBOU 180052
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
652 PM MDT MON AUG 17 2009

COC005-180115-
/O.CON.KBOU.SV.W.0252.000000T0000Z-090818T0115Z/
ARAPAHOE CO-
652 PM MDT MON AUG 17 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM MDT
FOR CENTRAL ARAPAHOE COUNTY...

AT 652 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING HALF DOLLAR SIZE HAIL.  THIS
STORM WAS LOCATED 11 MILES SOUTHWEST OF STRASBURG...OR 27 MILES EAST
OF DENVER...MOVING NORTHEAST AT 15 MPH.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
STRASBURG AND EASTERN AURORA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF SEVERE WEATHER APPROACHES YOUR AREA...GO INSIDE A STURDY SHELTER
AWAY FROM CREEK BEDS AND OTHER FLOOD-PRONE AREAS. REMEMBER...A SEVERE
THUNDERSTORM CAN PRODUCE LARGE DAMAGING HAIL...DAMAGING WINDS IN
EXCESS OF 58 MPH...DEADLY LIGHTNING...AND VERY HEAVY RAIN.

&&

LAT...LON 3974 10428 3957 10426 3957 10459 3973 10458
TIME...MOT...LOC 0052Z 241DEG 19KT 3965 10447

$$
000 
WWUS55 KBOU 180115
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
715 PM MDT MON AUG 17 2009

COC005-180126-
/O.EXP.KBOU.SV.W.0252.000000T0000Z-090818T0115Z/
ARAPAHOE CO-
715 PM MDT MON AUG 17 2009

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL ARAPAHOE COUNTY HAS
EXPIRED...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS EXITED THE AREA.

LAT...LON 3974 10428 3957 10426 3957 10459 3973 10458
TIME...MOT...LOC 0052Z 241DEG 19KT 3965 10447

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 6:03 PM MDTSevere Thunderstorm WarningBOUArapahoe27 min
Aug 17, 6:07 PM MDTSevere Thunderstorm WarningBOUElbert38 min
Aug 17, 6:23 PM MDTTornado WarningBOUElbert37 min
Aug 17, 6:27 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe48 min
Aug 17, 6:32 PM MDTSevere Thunderstorm WarningBOUMorgan, Washington43 min
Aug 17, 6:59 PM MDTTornado WarningBOUElbert, Lincoln31 min
Aug 17, 7:14 PM MDTSevere Thunderstorm WarningBOULogan, Washington46 min
Aug 17, 7:28 PM MDTTornado WarningBOULincoln32 min
Aug 17, 7:45 PM MDTSevere Thunderstorm WarningBOUArapahoe, Elbert45 min
Aug 17, 7:55 PM MDTSevere Thunderstorm WarningBOULogan, Washington27 min
Aug 17, 7:59 PM MDTTornado WarningBOULincoln46 min
Aug 17, 8:15 PM MDTFlash Flood WarningBOULincoln3 hr
Aug 17, 8:44 PM MDTTornado WarningBOULincoln31 min
Aug 17, 9:15 PM MDTSevere Thunderstorm WarningBOULincoln29 min
Aug 17, 9:27 PM MDTSevere Thunderstorm WarningBOUDouglas48 min
Aug 17, 10:00 PM MDTSevere Thunderstorm WarningBOUDouglas30 min
Aug 17, 10:21 PM MDTSevere Thunderstorm WarningBOUElbert29 min
Aug 18, 2:07 AM MDTSevere Thunderstorm WarningBOULincoln53 min
Aug 18, 12:39 PM MDTSevere Thunderstorm WarningBOUDenver, Jefferson36 min
Aug 18, 1:10 PM MDTSevere Thunderstorm WarningBOUArapahoe, Denver, Douglas, Jefferson22 min
Aug 18, 1:16 PM MDTTornado WarningBOUPark24 min
Aug 18, 3:31 PM MDTSpecial Weather StatementBOUElbert44 min
Aug 18, 4:22 PM MDTSpecial Weather StatementBOULincoln53 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2009Every severe thunderstorm warning in 2009

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.