Alert archive / Colorado / Tornado Warnings in 2013

Tornado Warning 9, NWS Denver/Boulder, CO

April 8, 2013Washington County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Apr 8, 2013, 9:17 PM MDT for Washington County, Colorado. It was in force for 28 min. 1 report 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 8, 2013, 9:17 PM MDT (03:17 UTC)
Expired: Apr 8, 2013, 9:45 PM MDT
In force: 28 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon

County Washington County, CO

The radar

The Denver radar (KFTG), 129 km from the middle of the area, began a volume at 03:18 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	Remark
Apr 8, 9:38 PM MDT	HAIL 1.25	11 Ne Akron, 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 8, 2:16 PM MDT	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 3.3 hours before the alert went out and 42 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: 105 J/kg
Mixed-layer CIN: -87 J/kg
Mixed-layer LCL: 2884 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 81 m²/s²
0-3 km storm-relative helicity: 258 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.

302 
WFUS55 KBOU 090317
TORBOU
COC121-090345-
/O.NEW.KBOU.TO.W.0009.130409T0317Z-130409T0345Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
917 PM MDT MON APR 8 2013

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* TORNADO WARNING FOR...
  NORTH CENTRAL WASHINGTON COUNTY IN NORTHEAST COLORADO

* UNTIL 945 PM MDT

* AT 917 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO NEAR AKRON.   
  THIS STORM WAS MOVING NORTHEAST AT 30 MPH.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

IN ADDITION TO THE TORNADO...THIS STORM IS CAPABLE OF PRODUCING LARGE
DAMAGING HAIL AND DESTRUCTIVE STRAIGHT LINE WINDS.

&&

LAT...LON 4009 10323 4024 10333 4044 10316 4035 10297
      4022 10295
TIME...MOT...LOC 0317Z 225DEG 27KT 4018 10321

$$

1 follow-up statement

644 
WWUS55 KBOU 090335
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
935 PM MDT MON APR 8 2013

COC121-090345-
/O.CON.KBOU.TO.W.0009.000000T0000Z-130409T0345Z/
WASHINGTON CO-
935 PM MDT MON APR 8 2013

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 945 PM MDT FOR NORTH
CENTRAL WASHINGTON COUNTY...

AT 935 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO.  THIS STORM WAS
LOCATED OVER NORTH CENTRAL WASHINGTON COUNTY...OR 9 MILES NORTHEAST
OF AKRON. THIS STORM WAS MOVING NORTHEAST AT 30 MPH.

THE SEVERE THUNDERSTORM WILL REMAIN OVER MAINLY RURAL AREAS OF THE 
WARNED COUNTY NORTH OF PLATNER AND OTIS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 4018 10303 4040 10319 4044 10316 4035 10297
      4022 10295
TIME...MOT...LOC 0335Z 231DEG 27KT 4026 10307

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 8, 6:31 PM MDT	Special Weather Statement	BOU	Washington	44 min
Apr 8, 7:03 PM MDT	Severe Thunderstorm Warning	BOU	Morgan, Washington	27 min
Apr 8, 7:17 PM MDT	Tornado Warning	BOU	Phillips	28 min
Apr 8, 7:24 PM MDT	Tornado Warning	BOU	Washington	36 min
Apr 8, 7:34 PM MDT	Tornado Warning	BOU	Morgan, Washington	26 min
Apr 8, 7:46 PM MDT	Severe Thunderstorm Warning	BOU	Phillips	29 min
Apr 8, 7:59 PM MDT	Tornado Warning	BOU	Morgan, Washington	46 min
Apr 8, 8:06 PM MDT	Tornado Warning	BOU	Washington	24 min
Apr 8, 8:20 PM MDT	Severe Thunderstorm Warning	BOU	Phillips, Sedgwick	40 min
Apr 8, 8:33 PM MDT	Tornado Warning	BOU	Washington	27 min
Apr 8, 8:52 PM MDT	Tornado Warning	BOU	Washington	23 min
Apr 8, 9:00 PM MDT	Tornado Warning	BOU	Logan, Phillips	30 min
Apr 8, 9:31 PM MDT	Tornado Warning	BOU	Phillips	29 min
Apr 8, 9:45 PM MDT	Tornado Warning	BOU	Washington	30 min
Apr 8, 10:01 PM MDT	Severe Thunderstorm Warning	BOU	Sedgwick	29 min

Nearby

Tornado Warnings in Colorado, 2013 Every tornado warning in 2013 Tornadoes 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.