Alert archive / Colorado / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 141, NWS Denver/Boulder, CO

August 19, 2021Phillips County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 19, 2021, 4:25 PM MDT for Phillips County, Colorado. It was in force for 35 min. 3 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: Aug 19, 2021, 4:25 PM MDT (22:25 UTC)
Expired: Aug 19, 2021, 5:00 PM MDT
In force: 35 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Damage threat: Considerable
Hail: 1.75 in
Wind: 60.0 mph

County Phillips County, CO

The radar

The Goodland radar (KGLD), 132 km from the middle of the area, began a volume at 22:25 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
Aug 19, 5:07 PM MDT	TORNADO	6 S Pleasant Valley, CO	2 OUTBUILDINGS DESTROYED, SEMI TRAILER ROLLED. TIME OF TORNADO WAS FROM 507 PM TO 512 PM.
Aug 19, 5:10 PM MDT	TORNADO	4 S Pleasant Valley, CO	&&
Aug 19, 5:10 PM MDT	TORNADO	4 S Pleasant Valley, 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.

Issued	Product	Office	Lasted
Aug 19, 1:14 PM MDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 10.4 hours before the alert went out and 118 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: 246 J/kg
Mixed-layer CIN: -241 J/kg
Mixed-layer LCL: 927 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: -59 m²/s²
0-3 km storm-relative helicity: 35 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

317 
WUUS55 KBOU 192225
SVRBOU
COC095-192300-
/O.NEW.KBOU.SV.W.0141.210819T2225Z-210819T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
425 PM MDT Thu Aug 19 2021

The National Weather Service in Denver Colorado has issued a

* Severe Thunderstorm Warning for...
  Southeastern Phillips County in northeastern Colorado...

* Until 500 PM MDT.

* At 425 PM MDT, a severe thunderstorm was located 5 miles southwest
  of Pleasant Valley, or 9 miles southeast of Holyoke, moving
  northeast at 25 mph.

  HAZARD...Golf ball size hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees. People and 
           animals outdoors will be injured. Expect hail damage to 
           roofs, siding, windows, and vehicles.

* This severe thunderstorm will be near...
  Pleasant Valley around 440 PM MDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4044 10208 4044 10218 4055 10229 4071 10205
      4045 10205
TIME...MOT...LOC 2225Z 230DEG 21KT 4050 10216 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

RPK

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 19, 1:23 PM MDT	Special Weather Statement	BOU	Logan	22 min
Aug 19, 2:01 PM MDT	Special Weather Statement	BOU	Logan	29 min
Aug 19, 2:13 PM MDT	Special Weather Statement	BOU	Broomfield	17 min
Aug 19, 2:17 PM MDT	Special Weather Statement	BOU	Broomfield	28 min
Aug 19, 2:24 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Boulder, Broomfield, Jefferson	36 min
Aug 19, 2:30 PM MDT	Severe Thunderstorm Warning	BOU	Douglas	30 min
Aug 19, 2:39 PM MDT	Tornado Warning	BOU	Adams, Broomfield, Jefferson	36 min
Aug 19, 2:46 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Weld	29 min
Aug 19, 2:59 PM MDT	Areal Flood Advisory	BOU	Adams	61 min
Aug 19, 3:05 PM MDT	Tornado Warning	BOU	Adams, Weld	25 min
Aug 19, 3:12 PM MDT	Tornado Warning	BOU	Douglas	18 min
Aug 19, 3:14 PM MDT	Severe Thunderstorm Warning	BOU	Weld	31 min
Aug 19, 3:35 PM MDT	Severe Thunderstorm Warning	BOU	Douglas, Elbert	25 min
Aug 19, 3:42 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Weld	33 min
Aug 19, 3:44 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe	31 min
Aug 19, 3:46 PM MDT	Tornado Warning	BOU	Douglas, Elbert	14 min
Aug 19, 3:49 PM MDT	Severe Thunderstorm Warning	BOU	Phillips	41 min
Aug 19, 3:51 PM MDT	Severe Thunderstorm Warning	BOU	Sedgwick	24 min
Aug 19, 3:55 PM MDT	Areal Flood Advisory	BOU	Arapahoe, Denver, Douglas	22 min
Aug 19, 3:58 PM MDT	Areal Flood Advisory	BOU	Weld	30 min
Aug 19, 4:04 PM MDT	Severe Thunderstorm Warning	BOU	Arapahoe, Elbert	41 min
Aug 19, 4:06 PM MDT	Areal Flood Advisory	BOU	Logan	54 min
Aug 19, 4:07 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Morgan	32 min
Aug 19, 4:10 PM MDT	Areal Flood Advisory	BOU	Phillips	95 min
Aug 19, 4:17 PM MDT	Severe Thunderstorm Warning	BOU	Adams	43 min
Aug 19, 4:18 PM MDT	Severe Thunderstorm Warning	BOU	Elbert	42 min
Aug 19, 4:32 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Arapahoe	28 min
Aug 19, 4:34 PM MDT	Tornado Warning	BOU	Phillips	26 min
Aug 19, 4:52 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Arapahoe, Elbert	23 min
Aug 19, 4:57 PM MDT	Areal Flood Advisory	BOU	Logan	50 min
Aug 19, 4:57 PM MDT	Tornado Warning	BOU	Phillips	33 min
Aug 19, 5:00 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Morgan	30 min
Aug 19, 5:04 PM MDT	Severe Thunderstorm Warning	BOU	Logan	25 min
Aug 19, 5:09 PM MDT	Flash Flood Warning	BOU	Phillips	3 hr
Aug 19, 5:34 PM MDT	Severe Thunderstorm Warning	BOU	Phillips	26 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.