Alert archive / Colorado / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 4, NWS Denver/Boulder, CO

April 12, 2012Sedgwick County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Apr 12, 2012, 3:07 PM MDT for Sedgwick County, Colorado. It was in force for 53 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Apr 12, 2012, 3:07 PM MDT (21:07 UTC)
Expired: Apr 12, 2012, 4:00 PM MDT
In force: 53 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Sedgwick County, CO

The radar

The Goodland radar (KGLD), 175 km from the middle of the area, began a volume at 21:07 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.

What was reported inside it

Time	Report	Where
Apr 12, 3:21 PM MDT	HAIL 0.75	4 Wsw Sedgwick, CO
Apr 12, 3:24 PM MDT	HAIL 1	2 W Sedgwick, CO
Apr 12, 3:45 PM MDT	HAIL 1.5	1 Ssw Ovid, CO

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Apr 12, 12:47 PM MDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 9.1 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: 34 J/kg
Mixed-layer CIN: -126 J/kg
Mixed-layer LCL: 946 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 201 m²/s²
0-3 km storm-relative helicity: 121 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

223 
WUUS55 KBOU 122107
SVRBOU
COC115-122200-
/O.NEW.KBOU.SV.W.0004.120412T2107Z-120412T2200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
307 PM MDT THU APR 12 2012

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WESTERN SEDGWICK COUNTY IN NORTHEAST COLORADO

* UNTIL 400 PM MDT

* AT 307 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 7
  MILES WEST OF MARKS BUTTE...OR 22 MILES SOUTHWEST OF JULESBURG...
  MOVING NORTHEAST AT 25 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SEDGWICK...
  OVID AND MARKS BUTTE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE
WARNING. PREPARE TO MOVE TO A PLACE OF SAFETY IN A STURDY STRUCTURE
SUCH AS A BASEMENT OR SMALL INTERIOR ROOM IF A TORNADO IS SPOTTED.

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.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM MDT THURSDAY EVENING
FOR NORTHEAST COLORADO.

&&

LAT...LON 4075 10232 4075 10262 4075 10265 4099 10265
      4099 10228
TIME...MOT...LOC 2107Z 227DEG 25KT 4084 10262
WIND...HAIL 60MPH 1.00IN

$$

2 follow-up statements

530 
WWUS55 KBOU 122133
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
333 PM MDT THU APR 12 2012

COC115-122200-
/O.CON.KBOU.SV.W.0004.000000T0000Z-120412T2200Z/
SEDGWICK CO-
333 PM MDT THU APR 12 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM MDT
FOR WESTERN SEDGWICK COUNTY...

AT 332 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 NEAR
SEDGWICK...OR 14 MILES WEST OF JULESBURG...MOVING NORTHEAST AT 25
MPH.

AT 234 PM MDT...A TRAINED SPOTTER REPORTED ONE INCH DIAMETER HAIL
2 MILES WEST OF SEDGWICK.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
SEDGWICK...OVID AND MARKS BUTTE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE
WARNING. PREPARE TO MOVE TO A PLACE OF SAFETY IN A STURDY STRUCTURE
SUCH AS A BASEMENT OR SMALL INTERIOR ROOM IF A TORNADO IS SPOTTED.

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.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM MDT THURSDAY EVENING
FOR NORTHEAST COLORADO.

&&

LAT...LON 4075 10232 4075 10262 4075 10265 4099 10265
      4099 10228
TIME...MOT...LOC 2132Z 216DEG 23KT 4098 10251
WIND...HAIL 60MPH 1.00IN

$$

956 
WWUS55 KBOU 122159
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
359 PM MDT THU APR 12 2012

COC115-122209-
/O.EXP.KBOU.SV.W.0004.000000T0000Z-120412T2200Z/
SEDGWICK CO-
359 PM MDT THU APR 12 2012

...THE SEVERE THUNDERSTORM WARNING FOR WESTERN SEDGWICK COUNTY WILL
EXPIRE AT 400 PM MDT...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS EXITED THE AREA. 

A TORNADO WATCH REMAINS IN EFFECT UNTIL 800 PM MDT THURSDAY EVENING
FOR NORTHEAST COLORADO.

LAT...LON 4075 10232 4075 10262 4075 10265 4099 10265
      4099 10228
TIME...MOT...LOC 2159Z 216DEG 23KT 4112 10237

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 12, 12:49 PM MDT	Special Weather Statement	BOU	Logan	41 min
Apr 12, 2:31 PM MDT	Severe Thunderstorm Warning	BOU	Logan	46 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.