Alert archive / Colorado / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 80, NWS Denver/Boulder, CO

June 19, 2021Logan County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 19, 2021, 4:04 PM MDT for Logan County, Colorado. It was in force for 41 min. 2 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 19, 2021, 4:04 PM MDT (22:04 UTC)
Expired
Jun 19, 2021, 4:45 PM MDT
In force
41 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Tornado
Possible
Hail
1.0 in
Wind
60.0 mph

County Logan County, CO

The radar

The Denver radar (KFTG), 153 km from the middle of the area, began a volume at 22:07 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 19, 4:05 PM MDTHAIL 1.25Merino, CODELAYED REPORT. PHOTO SHARED OF LARGER THAN QUARTER SIZE HAIL ON SOCIAL MEDIA. TIME ESTIMATED BY RADAR.
Jun 19, 4:18 PM MDTTSTM WND DMG3 Nnw Sterling, COPOWERLINE DOWN NORTH OF STERLING ALONG COUNTY ROAD 34. TIME ESTIMATED BY RADAR.

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 19, 1:44 PM MDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 10.1 hours before the alert went out and 83 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 2021-06-19Temperature 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 2021-06-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -23 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2627 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
-23 m²/s²
0-3 km storm-relative helicity
44 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

281 
WUUS55 KBOU 192204
SVRBOU
COC075-192245-
/O.NEW.KBOU.SV.W.0080.210619T2204Z-210619T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
404 PM MDT Sat Jun 19 2021

The National Weather Service in Denver Colorado has issued a

* Severe Thunderstorm Warning for...
  Logan County in northeastern Colorado...

* Until 445 PM MDT.

* At 404 PM MDT, severe thunderstorms were located along a line
  extending from 5 miles northwest of Twin Buttes to Prewitt
  Reservoir, or along a line extending from 13 miles southeast of
  Sidney to 16 miles southwest of Sterling, moving east at 30 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees. Hail damage to 
           vehicles is expected.

* Locations impacted include...
  Sterling, Fleming, Merino, Iliff, Peetz, Crook, St Petersburg,
  Proctor, Padroni, Atwood, North Sterling Reservoir, Twin Buttes and
  Logan Corners.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4044 10269 4043 10346 4044 10347 4049 10347
      4100 10326 4100 10265
TIME...MOT...LOC 2204Z 260DEG 27KT 4096 10286 4042 10335 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...60MPH
 
$$

RPK

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 18, 8:57 PM MDTSevere Thunderstorm WarningBOUWeld33 min
Jun 19, 11:54 AM MDTFire Weather WatchBOUGrand, Jackson, Summit15 hr
Jun 19, 1:25 PM MDTSpecial Weather StatementBOUArapahoe35 min
Jun 19, 1:57 PM MDTSpecial Weather StatementBOUDenver33 min
Jun 19, 2:09 PM MDTTornado Warning Tornado observedBOUAdams36 min
Jun 19, 2:40 PM MDTTornado WarningBOUMorgan35 min
Jun 19, 2:52 PM MDTTornado WarningBOUAdams23 min
Jun 19, 2:54 PM MDTTornado WarningBOUElbert21 min
Jun 19, 3:14 PM MDTSevere Thunderstorm WarningBOUWeld31 min
Jun 19, 3:26 PM MDTSevere Thunderstorm WarningBOUAdams, Washington34 min
Jun 19, 3:33 PM MDTSevere Thunderstorm WarningBOUWashington27 min
Jun 19, 3:35 PM MDTSpecial Weather StatementBOUWashington55 min
Jun 19, 3:41 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln49 min
Jun 19, 3:55 PM MDTSevere Thunderstorm WarningBOUWashington50 min
Jun 19, 4:09 PM MDTSevere Thunderstorm WarningBOULincoln51 min
Jun 19, 4:12 PM MDTTornado WarningBOUWashington33 min
Jun 19, 4:15 PM MDTTornado WarningBOULogan30 min
Jun 19, 4:37 PM MDTSevere Thunderstorm WarningBOUWashington38 min
Jun 19, 4:49 PM MDTSevere Thunderstorm WarningBOULogan, Phillips, Sedgwick41 min
Jun 19, 4:57 PM MDTSevere Thunderstorm WarningBOULincoln33 min
Jun 19, 5:16 PM MDTSevere Thunderstorm WarningBOUPhillips, Sedgwick29 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2021Every severe thunderstorm warning in 2021

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.