Alert archive / Colorado / Tornado Warnings in 2017

Tornado Warning 13, NWS Denver/Boulder, CO

June 12, 2017Weld County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Jun 12, 2017, 4:35 PM MDT for Weld County, Colorado. It was in force for 25 min. 7 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
Jun 12, 2017, 4:35 PM MDT (22:35 UTC)
Expired
Jun 12, 2017, 5:00 PM MDT
In force
25 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Tornado
Radar indicated
Hail
3.0 in

County Weld County, CO

The radar

The Cheyenne radar (KCYS), 52 km from the middle of the area, began a volume at 22:35 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

TimeReportWhereRemark
Jun 12, 4:35 PM MDTHAIL 32 S Hereford, CO
Jun 12, 4:40 PM MDTHAIL 1.5Hereford, CO
Jun 12, 4:40 PM MDTHAIL 1.754 Wsw Hereford, CO
Jun 12, 4:47 PM MDTHAIL 1.754 E Hereford, CO
Jun 12, 4:48 PM MDTHAIL 2.75Hereford, COFUNNEL CLOUD
Jun 12, 4:50 PM MDTTORNADOS Hereford, COTOUCHED DOWN
Jun 12, 4:50 PM MDTTORNADOS Hereford, COTOUCHED DOWN BRIEFLY

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.

IssuedProductOfficeLasted
Jun 12, 1:11 PM MDTTornado Watch PDSSPC8 hr

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 10.6 hours before the alert went out and 148 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 12:00Z on 2017-06-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 697 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 12:00Z on 2017-06-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 50 square meters per square second.193958Sfc1 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
697 J/kg
Mixed-layer CIN
-160 J/kg
Mixed-layer LCL
1130 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
50 m²/s²
0-3 km storm-relative helicity
153 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

913 
WFUS55 KBOU 122235
TORBOU
COC123-122300-
/O.NEW.KBOU.TO.W.0013.170612T2235Z-170612T2300Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Denver CO
435 PM MDT MON JUN 12 2017

The National Weather Service in Denver Colorado has issued a

* Tornado Warning for...
  North central Weld County in northeastern Colorado...

* Until 500 PM MDT
    
* At 435 PM MDT, a severe thunderstorm capable of producing a tornado
  was located 4 miles southwest of Hereford, or 28 miles southeast of
  Cheyenne, moving northeast at 30 mph.

  HAZARD...Tornado and hail up to three inches in diameter. 

  SOURCE...Radar indicated rotation. 

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely. 

* Locations impacted include...
  Grover and Hereford. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 4096 10406 4081 10431 4097 10449 4100 10444
      4100 10411
TIME...MOT...LOC 2235Z 224DEG 26KT 4092 10434 

TORNADO...RADAR INDICATED
HAIL...3.00IN

$$

Rpk
2 follow-up statements
223 
WWUS55 KBOU 122248
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
448 PM MDT MON JUN 12 2017

COC123-122300-
/O.CON.KBOU.TO.W.0013.000000T0000Z-170612T2300Z/
Weld CO-
448 PM MDT MON JUN 12 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 500 PM MDT FOR NORTH
CENTRAL WELD COUNTY...
    
At 448 PM MDT, a confirmed tornado was located near Hereford, or 30
miles east of Cheyenne, moving northeast at 30 mph.

HAZARD...Damaging tornado and baseball size hail. 

SOURCE...Weather spotters confirmed tornado. 

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely. 

Locations impacted include...
Grover and Hereford. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. TAKE COVER NOW! Move to a
basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 4086 10423 4097 10449 4100 10444 4100 10411
      4096 10406
TIME...MOT...LOC 2248Z 224DEG 26KT 4099 10425 

TORNADO...OBSERVED
HAIL...2.75IN

$$

RPK
840 
WWUS55 KBOU 122302
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
502 PM MDT MON JUN 12 2017

COC123-122311-
/O.EXP.KBOU.TO.W.0013.000000T0000Z-170612T2300Z/
Weld CO-
502 PM MDT MON JUN 12 2017

...THE TORNADO WARNING FOR NORTH CENTRAL WELD COUNTY HAS EXPIRED...
        
The storm which prompted the warning has moved into Wyoming.
Therefore the warning has been allowed to expire.

A tornado watch remains in effect until 800 PM MDT for northeastern
Colorado.

LAT...LON 4086 10423 4097 10449 4100 10444 4100 10411
      4096 10406
TIME...MOT...LOC 2301Z 224DEG 26KT 4106 10417 

$$

RPK

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 11, 9:09 PM MDTSevere Thunderstorm WarningBOUPhillips51 min
Jun 11, 9:13 PM MDTSevere Thunderstorm WarningBOULogan28 min
Jun 12, 11:07 AM MDTAreal Flood AdvisoryBOUGrand24 hr
Jun 12, 2:29 PM MDTSevere Thunderstorm WarningBOULarimer, Weld46 min
Jun 12, 2:36 PM MDTSevere Thunderstorm WarningBOULarimer39 min
Jun 12, 3:08 PM MDTSevere Thunderstorm WarningBOULarimer26 min
Jun 12, 3:15 PM MDTTornado WarningBOUWeld30 min
Jun 12, 3:26 PM MDTSevere Thunderstorm WarningBOUWeld36 min
Jun 12, 3:45 PM MDTTornado WarningBOUWeld30 min
Jun 12, 3:46 PM MDTTornado WarningBOUWeld29 min
Jun 12, 4:13 PM MDTTornado WarningBOUWeld32 min

Nearby

Tornado Warnings in Colorado, 2017Every tornado warning in 2017Tornadoes in 2017

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.