Alert archive / Colorado / Tornado Warnings in 2018

Tornado Warning 2, NWS Denver/Boulder, CO

May 27, 2018Adams County, Weld County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 27, 2018, 1:45 PM MDT for Adams County, 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
May 27, 2018, 1:45 PM MDT (19:45 UTC)
Expired
May 27, 2018, 2:15 PM MDT
In force
30 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

Counties Adams County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 34 km from the middle of the area, began a volume at 19:48 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
May 27, 1:13 PM MDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 7.8 hours before the alert went out and 99 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 2018-05-27Temperature 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 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 2018-05-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 square meters per square second.19395878Sfc1 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
4365 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
105 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

119 
WFUS55 KBOU 271945
TORBOU
COC001-123-272015-
/O.NEW.KBOU.TO.W.0002.180527T1945Z-180527T2015Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Denver CO
145 PM MDT SUN MAY 27 2018

The National Weather Service in Denver Colorado has issued a

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

* Until 215 PM MDT.
    
* At 145 PM MDT, a severe thunderstorm capable of producing a tornado
  was located 4 miles south of Prospect Valley, or 33 miles southeast
  of Greeley, moving north at 20 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Expect damage to mobile homes, roofs, and vehicles.

* Locations impacted include...
  Keenesburg, Prospect Valley and Roggen. 

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 3997 10426 3996 10450 4018 10453 4020 10427
TIME...MOT...LOC 1945Z 189DEG 17KT 4002 10441 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

RPK
2 follow-up statements
181 
WWUS55 KBOU 271956
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
156 PM MDT SUN MAY 27 2018

COC001-272006-
/O.CAN.KBOU.TO.W.0002.000000T0000Z-180527T2015Z/
Adams CO-
156 PM MDT SUN MAY 27 2018

...THE TORNADO WARNING FOR NORTH CENTRAL ADAMS COUNTY IS CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 800 PM MDT for
northeastern Colorado.

LAT...LON 4000 10426 4000 10450 4018 10453 4020 10427
TIME...MOT...LOC 1956Z 189DEG 17KT 4007 10440 

$$

COC123-272015-
/O.CON.KBOU.TO.W.0002.000000T0000Z-180527T2015Z/
Weld CO-
156 PM MDT SUN MAY 27 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 215 PM MDT FOR SOUTH
CENTRAL WELD COUNTY...
    
At 156 PM MDT, a severe thunderstorm capable of producing a tornado
was located over Prospect Valley, or 30 miles southeast of Greeley,
moving north at 20 mph.

HAZARD...TORNADO.

SOURCE...Radar indicated rotation.

IMPACT...Expect damage to mobile homes, roofs, and vehicles.

Locations impacted include...
Keenesburg, Prospect Valley and Roggen. 

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 4000 10426 4000 10450 4018 10453 4020 10427
TIME...MOT...LOC 1956Z 189DEG 17KT 4007 10440 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

RPK
124 
WWUS55 KBOU 272015
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
215 PM MDT SUN MAY 27 2018

COC123-272024-
/O.EXP.KBOU.TO.W.0002.000000T0000Z-180527T2015Z/
Weld CO-
215 PM MDT SUN MAY 27 2018

...THE TORNADO WARNING FOR SOUTH CENTRAL WELD COUNTY WILL EXPIRE AT
215 PM MDT...
    
The tornado threat has diminished and the Tornado Warning has been
cancelled. However, large hail and damaging winds remain likely and a
Severe Thunderstorm Warning remains in effect for the area.

A Severe Thunderstorm Watch remains in effect until 800 PM MDT for
northeastern Colorado.

LAT...LON 4000 10426 4000 10450 4018 10453 4020 10427
TIME...MOT...LOC 2014Z 189DEG 17KT 4015 10438 

$$

RPK

The office that day

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

IssuedProductOfficeCountiesLasted
May 27, 12:27 PM MDTSpecial Weather StatementBOULarimer33 min
May 27, 2:14 PM MDTSevere Thunderstorm WarningBOUWeld31 min
May 27, 2:23 PM MDTSevere Thunderstorm WarningBOUPhillips50 min
May 27, 2:44 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld31 min
May 27, 2:47 PM MDTSevere Thunderstorm WarningBOULincoln31 min
May 27, 3:06 PM MDTTornado WarningBOUMorgan, Weld24 min
May 27, 3:36 PM MDTSpecial Weather StatementBOULincoln24 min
May 27, 4:20 PM MDTSevere Thunderstorm WarningBOUWashington40 min
May 27, 4:28 PM MDTTornado WarningBOUMorgan17 min
May 27, 4:37 PM MDTTornado WarningBOUMorgan23 min
May 27, 4:58 PM MDTTornado WarningBOUMorgan, Weld18 min
May 27, 5:21 PM MDTSpecial Weather StatementBOULogan39 min
May 27, 5:38 PM MDTSevere Thunderstorm WarningBOULogan52 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.