Alert archive / Colorado / Tornado Warnings in 2017

Tornado Warning 10, NWS Denver/Boulder, CO

June 12, 2017Weld County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Jun 12, 2017, 3:45 PM MDT for Weld County, Colorado. It was in force for 30 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
Jun 12, 2017, 3:45 PM MDT (21:45 UTC)
Expired
Jun 12, 2017, 4:15 PM MDT
In force
30 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Tornado
Radar indicated
Hail
2.5 in

County Weld County, CO

The radar

The Cheyenne radar (KCYS), 33 km from the middle of the area, began a volume at 21:46 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 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, 9.8 hours before the alert went out and 166 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.

378 
WFUS55 KBOU 122145
TORBOU
COC123-122215-
/O.NEW.KBOU.TO.W.0010.170612T2145Z-170612T2215Z/

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

The National Weather Service in Denver Colorado has issued a

* Tornado Warning for...
  Northwestern Weld County in northeastern Colorado...

* Until 415 PM MDT
    
* At 344 PM MDT, a severe thunderstorm capable of producing a tornado
  was located 4 miles southeast of Rockport, or 20 miles south of
  Cheyenne, moving northeast at 40 mph.

  HAZARD...Tornado and tennis ball size hail. 

  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. 

* This tornadic thunderstorm will remain over mainly rural areas of
  northwestern Weld County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This Tornado Warning replaces the Severe Thunderstorm Warning issued
for the same area.

Motorists should not take shelter under highway overpasses. If you
cannot safely drive away from the tornado, as a last resort, either
park your vehicle and stay put, or abandon your vehicle and lie down
in a low lying area and protect yourself from flying debris.

&&

LAT...LON 4076 10473 4081 10486 4100 10472 4100 10439
TIME...MOT...LOC 2144Z 212DEG 33KT 4085 10475 

TORNADO...RADAR INDICATED
HAIL...2.50IN

$$

BAKER
1 follow-up statement
087 
WWUS55 KBOU 122207
SVSBOU

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

COC123-122216-
/O.EXP.KBOU.TO.W.0010.000000T0000Z-170612T2215Z/
Weld CO-
407 PM MDT MON JUN 12 2017

...THE TORNADO WARNING FOR NORTHWESTERN WELD COUNTY WILL EXPIRE AT
415 PM MDT...
    
The tornado threat has diminished and the Tornado Warning has been
cancelled. However, hail up to one inch in diameter remain likely 
and a Severe Thunderstorm Warning remains in effect for the area.  

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

LAT...LON 4076 10473 4081 10486 4100 10472 4100 10439
TIME...MOT...LOC 2206Z 204DEG 22KT 4093 10464 

$$

BAKER

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, 3:46 PM MDTTornado WarningBOUWeld29 min
Jun 12, 4:13 PM MDTTornado WarningBOUWeld32 min
Jun 12, 4:35 PM MDTTornado WarningBOUWeld25 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.