Alert archive / Colorado / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 12, NWS Denver/Boulder, CO

April 27, 2021Washington County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Apr 27, 2021, 5:19 PM MDT for Washington County, Colorado. It was in force for 26 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: Apr 27, 2021, 5:19 PM MDT (23:19 UTC)
Expired: Apr 27, 2021, 5:45 PM MDT
In force: 26 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), 147 km from the middle of the area, began a volume at 23:22 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

Time	Report	Where	Remark
Apr 27, 5:22 PM MDT	HAIL 1	2 Ese Lone Star, CO	HAIL STILL FALLING AT THE TIME OF REPORT. HAIL ACCUMULATION OF UP TO TWO INCHES ON THE GROUND AT 5:40PM.

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.

Issued	Product	Office	Lasted
Apr 27, 11:45 AM MDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 11.3 hours before the alert went out and 63 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 3214 m above ground
0-6 km bulk shear: 67 kt
0-1 km storm-relative helicity: 51 m²/s²
0-3 km storm-relative helicity: 72 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

404 
WUUS55 KBOU 272319
SVRBOU
COC121-272345-
/O.NEW.KBOU.SV.W.0012.210427T2319Z-210427T2345Z/

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

The National Weather Service in Denver Colorado has issued a

* Severe Thunderstorm Warning for...
  Northeastern Washington County in northeastern Colorado...

* Until 545 PM MDT.

* At 519 PM MDT, a severe thunderstorm was located 4 miles east of
  Lone Star, or 15 miles north of Yuma, moving northwest at 5 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...
  Lone Star.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and deadly cloud to ground
lightning. Seek shelter inside a well-built structure. Stay away from
windows.

&&

LAT...LON 4035 10280 4026 10280 4029 10300 4044 10292
      4044 10278 4035 10278
TIME...MOT...LOC 2319Z 117DEG 3KT 4035 10277 

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

DANIELSON

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 27, 1:52 AM MDT	Severe Thunderstorm Warning	BOU	Washington	23 min
Apr 27, 3:16 AM MDT	Winter Storm Warning	BOU	Boulder, Clear Creek, Gilpin, Grand, Jackson, Jefferson and 3 more	30 hr
Apr 27, 11:35 AM MDT	Special Weather Statement	BOU	Douglas	25 min
Apr 27, 11:55 AM MDT	Special Weather Statement	BOU	Elbert	50 min
Apr 27, 11:59 AM MDT	Special Weather Statement	BOU	Denver	31 min
Apr 27, 12:49 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Weld	26 min
Apr 27, 1:15 PM MDT	Special Weather Statement	BOU	Adams	45 min
Apr 27, 1:51 PM MDT	Special Weather Statement	BOU	Lincoln	39 min
Apr 27, 1:53 PM MDT	Special Weather Statement	BOU	Weld	37 min
Apr 27, 1:59 PM MDT	Severe Thunderstorm Warning	BOU	Weld	31 min
Apr 27, 2:02 PM MDT	Severe Thunderstorm Warning	BOU	Elbert	28 min
Apr 27, 2:08 PM MDT	Winter Weather Advisory	BOU	Clear Creek, Douglas, Gilpin, Jefferson, Park	20 hr
Apr 27, 2:23 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	52 min
Apr 27, 2:43 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Morgan	32 min
Apr 27, 2:49 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	41 min
Apr 27, 3:00 PM MDT	Special Weather Statement	BOU	Lincoln	45 min
Apr 27, 3:10 PM MDT	Special Weather Statement	BOU	Morgan	20 min
Apr 27, 3:13 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Morgan, Washington	32 min
Apr 27, 3:28 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	47 min
Apr 27, 3:32 PM MDT	Special Weather Statement	BOU	Morgan	28 min
Apr 27, 3:41 PM MDT	Tornado Warning	BOU	Lincoln	34 min
Apr 27, 4:12 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	33 min
Apr 27, 4:16 PM MDT	Severe Thunderstorm Warning	BOU	Logan, Morgan, Washington	17 min
Apr 27, 4:36 PM MDT	Tornado Warning	BOU	Lincoln	24 min
Apr 27, 5:51 PM MDT	Special Weather Statement	BOU	Phillips	24 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2021 Every 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.