Alert archive / Colorado / Tornado Warnings in 2018

Tornado Warning 19, NWS Denver/Boulder, CO

June 17, 2018Washington County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Jun 17, 2018, 5:05 PM MDT for Washington County, Colorado. It was in force for 25 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
Jun 17, 2018, 5:05 PM MDT (23:05 UTC)
Expired
Jun 17, 2018, 5:30 PM MDT
In force
25 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Tornado
Radar indicated
Hail
2.5 in

County Washington County, CO

The radar

The Goodland radar (KGLD), 124 km from the middle of the area, began a volume at 23:06 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 17, 5:13 PM MDTHAIL 15 Ese Elba, 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.

IssuedProductOfficeLasted
Jun 17, 1:35 PM MDTTornado WatchSPC7 hr

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 11.1 hours before the alert went out and 25 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 2018-06-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2018-06-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -69 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1003 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
-69 m²/s²
0-3 km storm-relative helicity
36 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

259 
WFUS55 KBOU 172305
TORBOU
COC121-172330-
/O.NEW.KBOU.TO.W.0019.180617T2305Z-180617T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Denver CO
505 PM MDT SUN JUN 17 2018

The National Weather Service in Denver Colorado has issued a

* Tornado Warning for...
  East central Washington County in northeastern Colorado...

* Until 530 PM MDT.
    
* At 505 PM MDT, a severe thunderstorm capable of producing a tornado
  was located near Elba, or 18 miles south of Akron, moving east at
  35 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.

* Locations impacted include...
  Elba.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3995 10280 3982 10281 3977 10323 4004 10323
      4007 10280
TIME...MOT...LOC 2305Z 257DEG 29KT 3989 10316 

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

$$

RPK
1 follow-up statement
747 
WWUS55 KBOU 172315
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
515 PM MDT SUN JUN 17 2018

COC121-172330-
/O.CON.KBOU.TO.W.0019.000000T0000Z-180617T2330Z/
Washington CO-
515 PM MDT SUN JUN 17 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 530 PM MDT FOR EAST
CENTRAL WASHINGTON COUNTY...
    
At 515 PM MDT, a severe thunderstorm capable of producing a tornado
was located 6 miles east of Elba, or 19 miles southeast of Akron,
moving east at 35 mph.

HAZARD...Tornado and ping pong 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...
Elba.

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 3995 10280 3982 10281 3977 10323 4004 10323
      4007 10280
TIME...MOT...LOC 2315Z 257DEG 29KT 3991 10305 

TORNADO...RADAR INDICATED
HAIL...1.50IN

$$

RPK

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 17, 1:40 PM MDTSpecial Weather StatementBOUSedgwick35 min
Jun 17, 1:44 PM MDTSevere Thunderstorm WarningBOUSedgwick31 min
Jun 17, 1:51 PM MDTTornado WarningBOUSedgwick24 min
Jun 17, 2:13 PM MDTTornado WarningBOUSedgwick17 min
Jun 17, 2:36 PM MDTAreal Flood AdvisoryBOUDouglas114 min
Jun 17, 3:52 PM MDTSevere Thunderstorm WarningBOUArapahoe38 min
Jun 17, 4:20 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe25 min
Jun 17, 4:32 PM MDTSevere Thunderstorm WarningBOUWashington43 min
Jun 17, 4:58 PM MDTSevere Thunderstorm WarningBOUWashington47 min
Jun 17, 5:29 PM MDTTornado WarningBOUWashington20 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.