Alert archive / Colorado / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 83, NWS Denver/Boulder, CO

July 6, 2012Adams County, Arapahoe County, Elbert County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 6, 2012, 6:29 PM MDT for Adams County, Arapahoe County, Elbert County, Colorado. It was in force for 43 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: Jul 6, 2012, 6:29 PM MDT (00:29 UTC)
Expired: Jul 6, 2012, 7:12 PM MDT
In force: 43 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Adams County, CO, Arapahoe County, CO, Elbert County, CO

The radar

The Denver radar (KFTG), 36 km from the middle of the area, began a volume at 00:30 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, 0.5 hours before the alert went out and 90 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: 180 J/kg
Mixed-layer CIN: -101 J/kg
Mixed-layer LCL: 1123 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 51 m²/s²
0-3 km storm-relative helicity: 291 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 3.8

Open this sounding in Storm Lab

The text

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

899 
WUUS55 KBOU 070029
SVRBOU
COC001-005-039-070130-
/O.NEW.KBOU.SV.W.0083.120707T0029Z-120707T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
629 PM MDT FRI JUL 6 2012

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTH CENTRAL ELBERT COUNTY IN EAST CENTRAL COLORADO
  CENTRAL ARAPAHOE COUNTY IN NORTHEAST COLORADO
  SOUTH CENTRAL ADAMS COUNTY IN NORTHEAST COLORADO

* UNTIL 730 PM MDT

* AT 628 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING ONE INCH DIAMETER HAIL...
  AND DAMAGING WINDS UP TO ABOUT 60 MPH.  THIS STORM WAS LOCATED 11
  MILES SOUTH OF DEER TRAIL...OR 26 MILES NORTHWEST OF LIMON. THIS
  STORM WAS NEARLY STATIONARY.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  STRASBURG...DEER TRAIL AND BYERS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

HAIL...INTENSE RAIN AND STRONG DAMAGING WINDS ARE LIKELY WITH THIS 
STORM. TAKE COVER IN A SUBSTANTIAL SHELTER UNTIL THE STORM PASSES.  
VERY HEAVY RAIN WILL ALSO PRODUCE FLOODING IN LOW LYING AREAS AND 
POOR DRAINAGES.

&&

LAT...LON 3969 10444 3981 10413 3941 10393 3933 10414
TIME...MOT...LOC 0028Z 289DEG 2KT 3947 10410
WIND...HAIL 60MPH 1.00IN

$$

1 follow-up statement

058 
WWUS55 KBOU 070112
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
712 PM MDT FRI JUL 6 2012

COC001-005-039-070122-
/O.CAN.KBOU.SV.W.0083.000000T0000Z-120707T0130Z/
ELBERT CO-ARAPAHOE CO-ADAMS CO-
712 PM MDT FRI JUL 6 2012

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL ADAMS...CENTRAL
ARAPAHOE AND NORTH CENTRAL ELBERT COUNTIES IS CANCELLED...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS WEAKENED AND IS NO 
LONGER EXPECTED TO PRODUCE SEVERE WEATHER.  ALTHOUGH IT HAS 
WEAKENED...IT MAY STILL PRODUCE LOCALLY HEAVY RAIN AND MINOR 
FLOODING.  SEEK SHELTER IF THE STORMS MOVES INTO YOUR AREA.

LAT...LON 3969 10444 3981 10413 3941 10393 3933 10414
TIME...MOT...LOC 0112Z 289DEG 2KT 3946 10407

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 6, 6:57 PM MDT	Severe Thunderstorm Warning	BOU	Morgan, Washington	50 min
Jul 6, 8:26 PM MDT	Areal Flood Advisory	BOU	Morgan, Washington	94 min
Jul 6, 8:41 PM MDT	Flash Flood Watch	BOU	Arapahoe, Boulder, Broomfield, Clear Creek, Douglas, Elbert and 8 more	32 hr
Jul 6, 8:56 PM MDT	Flash Flood Warning	BOU	Larimer	3 hr
Jul 6, 9:01 PM MDT	Areal Flood Advisory	BOU	Washington	59 min
Jul 6, 9:06 PM MDT	Flash Flood Warning	BOU	Boulder	97 min
Jul 6, 9:46 PM MDT	Severe Thunderstorm Warning	BOU	Logan, Washington	44 min
Jul 6, 11:20 PM MDT	Areal Flood Advisory	BOU	Logan, Washington, Weld	115 min
Jul 7, 3:08 PM MDT	Areal Flood Advisory	BOU	Boulder	97 min
Jul 7, 3:23 PM MDT	Areal Flood Advisory	BOU	Clear Creek	97 min
Jul 7, 3:41 PM MDT	Flash Flood Warning	BOU	Boulder	94 min
Jul 7, 3:45 PM MDT	Flash Flood Warning	BOU	Boulder	90 min
Jul 7, 3:57 PM MDT	Flash Flood Warning	BOU	Clear Creek	93 min
Jul 7, 4:19 PM MDT	Areal Flood Advisory	BOU	Adams, Arapahoe, Denver, Douglas, Jefferson	86 min
Jul 7, 4:30 PM MDT	Areal Flood Advisory	BOU	Boulder	90 min
Jul 7, 4:36 PM MDT	Areal Flood Advisory	BOU	Larimer	84 min
Jul 7, 4:49 PM MDT	Areal Flood Advisory	BOU	Larimer	86 min
Jul 7, 4:53 PM MDT	Flash Flood Warning	BOU	Boulder	106 min
Jul 7, 5:01 PM MDT	Areal Flood Advisory	BOU	Boulder	119 min
Jul 7, 5:35 PM MDT	Areal Flood Advisory	BOU	Boulder	85 min
Jul 7, 5:59 PM MDT	Areal Flood Advisory	BOU	Larimer	91 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2012 Every severe thunderstorm warning in 2012

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.