Alert archive / Colorado / Tornado Warnings in 2018

Tornado Warning 50, NWS Denver/Boulder, CO

August 8, 2018Weld County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Aug 8, 2018, 6:27 AM MDT for Weld County, Colorado. It was in force for 33 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
Aug 8, 2018, 6:27 AM MDT (12:27 UTC)
Expired
Aug 8, 2018, 7:00 AM MDT
In force
33 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Tornado
Radar indicated
Hail
1.25 in

County Weld County, CO

The radar

The Cheyenne radar (KCYS), 82 km from the middle of the area, began a volume at 12:31 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
Aug 8, 6:33 AM MDTHAIL 1.253 Ne Pawnee Buttes, CO
Aug 8, 6:37 AM MDTTORNADO1 Nw Keota, COBRIEF TOUCHDOWN IN OPEN FIELD. NO DAMAGE REPORTED. NO INJURIES.
Aug 8, 6:37 AM MDTTORNADO5 Nnw Keota, COCORRECTS PREVIOUS TORNADO REPORT FROM 1 NW KEOTA. BRIEF TOUCHDOWN IN OPEN FIELD. NO DAMAGE REPORTED. NO INJURIES.

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

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 0.5 hours before the alert went out and 118 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 2018-08-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 965 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 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 2018-08-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 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
965 J/kg
Mixed-layer CIN
-187 J/kg
Mixed-layer LCL
1263 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
43 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

641 
WFUS55 KBOU 081227
TORBOU
COC123-081300-
/O.NEW.KBOU.TO.W.0050.180808T1227Z-180808T1300Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Denver CO
627 AM MDT WED AUG 8 2018

The National Weather Service in Denver Colorado has issued a

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

* Until 700 AM MDT.
    
* At 627 AM MDT, a severe thunderstorm capable of producing a tornado
  was located near Pawnee Buttes, or 31 miles southwest of Kimball,
  moving south at 25 mph.

  HAZARD...Tornado and half dollar 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.

* Locations impacted include...
  Pawnee Buttes and Keota. 

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.

&&

LAT...LON 4087 10404 4088 10376 4061 10381 4065 10417
TIME...MOT...LOC 1227Z 013DEG 23KT 4082 10394 

TORNADO...RADAR INDICATED
HAIL...1.25IN

$$

SCHLATTER
1 follow-up statement
468 
WWUS55 KBOU 081239
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
639 AM MDT WED AUG 8 2018

COC123-081300-
/O.CON.KBOU.TO.W.0050.000000T0000Z-180808T1300Z/
Weld CO-
639 AM MDT WED AUG 8 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 700 AM MDT FOR
NORTHEASTERN WELD COUNTY...
    
At 639 AM MDT, a severe thunderstorm capable of producing a tornado
was located near Pawnee Buttes, or 34 miles southwest of Kimball,
moving south at 15 mph.

HAZARD...Tornado and golf 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.

Locations impacted include...
Pawnee Buttes and Keota. 

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.

&&

LAT...LON 4083 10402 4081 10382 4061 10381 4065 10417
TIME...MOT...LOC 1239Z 011DEG 12KT 4078 10395 

TORNADO...RADAR INDICATED
HAIL...1.75IN

$$

SCHLATTER

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 7, 6:07 PM MDTSevere Thunderstorm WarningBOUWashington38 min
Aug 7, 6:14 PM MDTSevere Thunderstorm WarningBOUAdams, Denver27 min
Aug 7, 7:24 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe19 min
Aug 8, 12:13 AM MDTSpecial Weather StatementBOULincoln47 min
Aug 8, 4:46 AM MDTSpecial Weather StatementBOULogan44 min
Aug 8, 5:52 AM MDTSpecial Weather StatementBOULogan38 min
Aug 8, 5:56 AM MDTSpecial Weather StatementBOUWashington34 min
Aug 8, 6:17 AM MDTSevere Thunderstorm WarningBOUWeld43 min
Aug 8, 6:57 AM MDTTornado WarningBOUWeld33 min
Aug 8, 7:28 AM MDTSevere Thunderstorm WarningBOUMorgan, Weld47 min
Aug 8, 8:17 AM MDTSpecial Weather StatementBOUMorgan28 min
Aug 8, 8:30 AM MDTSpecial Weather StatementBOUElbert45 min
Aug 8, 8:58 AM MDTSevere Thunderstorm WarningBOUElbert47 min
Aug 8, 9:39 AM MDTSevere Thunderstorm WarningBOUElbert, Lincoln33 min

Nearby

Tornado Warnings in Colorado, 2018Every tornado warning in 2018Tornadoes in 2018

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.