Alert archive / Colorado / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 1, NWS Denver/Boulder, CO

April 27, 2021Washington County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Apr 27, 2021, 1:52 AM MDT for Washington County, Colorado. It was in force for 23 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
Apr 27, 2021, 1:52 AM MDT (07:52 UTC)
Expired
Apr 27, 2021, 2:15 AM MDT
In force
23 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Washington County, CO

The radar

The Goodland radar (KGLD), 124 km from the middle of the area, began a volume at 07:55 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 nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 7.9 hours before the alert went out and 21 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 00:00Z on 2021-04-27Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 00:00Z on 2021-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 square meters per square second.1939587897117Sfc1 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
4461 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
109 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

271 
WUUS55 KBOU 270752
SVRBOU
COC121-270815-
/O.NEW.KBOU.SV.W.0001.210427T0752Z-210427T0815Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
152 AM MDT Tue Apr 27 2021

The National Weather Service in Denver Colorado has issued a

* Severe Thunderstorm Warning for...
  East central Washington County in northeastern Colorado...

* Until 215 AM MDT.

* At 152 AM MDT, a severe thunderstorm was located 4 miles south of
  Elba, or 20 miles south of Akron, moving east at 40 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...
  Elba.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3977 10280 3976 10323 3993 10332 4011 10279
TIME...MOT...LOC 0752Z 260DEG 34KT 3986 10316 

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

MEIER
1 follow-up statement
904 
WWUS55 KBOU 270815
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
215 AM MDT Tue Apr 27 2021

COC121-270825-
/O.EXP.KBOU.SV.W.0001.000000T0000Z-210427T0815Z/
Washington CO-
215 AM MDT Tue Apr 27 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL WASHINGTON COUNTY
HAS EXPIRED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been allowed to expire.  However small
hail is still possible with this thunderstorm.

LAT...LON 3977 10280 3976 10323 3993 10332 4011 10279
TIME...MOT...LOC 0815Z 260DEG 34KT 3987 10305 

$$

MEIER

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 27, 3:16 AM MDTWinter Storm WarningBOUBoulder, Clear Creek, Gilpin, Grand, Jackson, Jefferson and 3 more30 hr
Apr 27, 11:35 AM MDTSpecial Weather StatementBOUDouglas25 min
Apr 27, 11:55 AM MDTSpecial Weather StatementBOUElbert50 min
Apr 27, 11:59 AM MDTSpecial Weather StatementBOUDenver31 min
Apr 27, 12:49 PM MDTSevere Thunderstorm WarningBOUAdams, Weld26 min
Apr 27, 1:15 PM MDTSpecial Weather StatementBOUAdams45 min
Apr 27, 1:51 PM MDTSpecial Weather StatementBOULincoln39 min
Apr 27, 1:53 PM MDTSpecial Weather StatementBOUWeld37 min
Apr 27, 1:59 PM MDTSevere Thunderstorm WarningBOUWeld31 min
Apr 27, 2:02 PM MDTSevere Thunderstorm WarningBOUElbert28 min
Apr 27, 2:08 PM MDTWinter Weather AdvisoryBOUClear Creek, Douglas, Gilpin, Jefferson, Park20 hr
Apr 27, 2:23 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln52 min
Apr 27, 2:43 PM MDTSevere Thunderstorm WarningBOUAdams, Morgan32 min
Apr 27, 2:49 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln41 min
Apr 27, 3:00 PM MDTSpecial Weather StatementBOULincoln45 min
Apr 27, 3:10 PM MDTSpecial Weather StatementBOUMorgan20 min
Apr 27, 3:13 PM MDTSevere Thunderstorm WarningBOUAdams, Morgan, Washington32 min
Apr 27, 3:28 PM MDTSevere Thunderstorm WarningBOULincoln47 min
Apr 27, 3:32 PM MDTSpecial Weather StatementBOUMorgan28 min
Apr 27, 3:41 PM MDTTornado WarningBOULincoln34 min
Apr 27, 4:12 PM MDTSevere Thunderstorm WarningBOULincoln33 min
Apr 27, 4:16 PM MDTSevere Thunderstorm WarningBOULogan, Morgan, Washington17 min
Apr 27, 4:36 PM MDTTornado WarningBOULincoln24 min
Apr 27, 5:19 PM MDTSevere Thunderstorm WarningBOUWashington26 min
Apr 27, 5:51 PM MDTSpecial Weather StatementBOUPhillips24 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.