Alert archive / Colorado / Special Weather Statements in 2021

Special Weather Statement, NWS Denver/Boulder, CO

June 19, 2021Arapahoe County, Colorado

NWS Denver/Boulder, CO issued this special weather statement at Jun 19, 2021, 1:25 PM MDT for Arapahoe County, Colorado. It was in force for 35 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: Jun 19, 2021, 1:25 PM MDT (19:25 UTC)
Expired: Jun 19, 2021, 2:00 PM MDT
In force: 35 min
Issued by: NWS Denver/Boulder, CO

County Arapahoe County, CO

The radar

The Denver radar (KFTG), 48 km from the middle of the area, began a volume at 19:25 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
Jun 19, 2:06 PM MDT	TORNADO	1 E Leader, CO	FIRST REPORT OF LANDSPOUT. LOCATION ESTIMATED.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 7.4 hours before the alert went out and 90 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: 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.

472 
WWUS85 KBOU 191925
SPSBOU

Special Weather Statement
National Weather Service Denver CO
125 PM MDT Sat Jun 19 2021

COZ045-046-192000-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County CO-Central and East Adams and Arapahoe Counties CO-
125 PM MDT Sat Jun 19 2021

...Brief Landspout Tornadoes Possible...

At 122 PM MDT, conditions are becoming favorable for the development 
of landspout tornadoes over eastern portions of Adams and Arapahoe 
counties and northeast Elbert county.  However, at this time it is 
unknown which if any storm would produce a landspout. Any landspouts 
which develop are expected to pose a limited threat.

Locations impacted include...
Deer Trail, Agate, Cottonwood Valley, Shamrock, Leader and Byers. 

Landspout tornadoes can form with a developing thunderstorm before
rain, hail, and even thunder is observed. Landspout tornadoes are not
usually associated with a wall cloud and are often difficult to
detect with weather radar.

&&

LAT...LON 3940 10424 3939 10422 3943 10417 3945 10417
      3946 10419 3949 10421 3944 10423 3944 10424
      4000 10420 4000 10373 3939 10375 3938 10413
      3941 10414 3938 10416 3940 10420 3938 10422
      3938 10424

$$

RPK

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 18, 8:57 PM MDT	Severe Thunderstorm Warning	BOU	Weld	33 min
Jun 19, 11:54 AM MDT	Fire Weather Watch	BOU	Grand, Jackson, Summit	15 hr
Jun 19, 1:57 PM MDT	Special Weather Statement	BOU	Denver	33 min
Jun 19, 2:09 PM MDT	Tornado Warning Tornado observed	BOU	Adams	36 min
Jun 19, 2:40 PM MDT	Tornado Warning	BOU	Morgan	35 min
Jun 19, 2:52 PM MDT	Tornado Warning	BOU	Adams	23 min
Jun 19, 2:54 PM MDT	Tornado Warning	BOU	Elbert	21 min
Jun 19, 3:14 PM MDT	Severe Thunderstorm Warning	BOU	Weld	31 min
Jun 19, 3:26 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Washington	34 min
Jun 19, 3:33 PM MDT	Severe Thunderstorm Warning	BOU	Washington	27 min
Jun 19, 3:35 PM MDT	Special Weather Statement	BOU	Washington	55 min
Jun 19, 3:41 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	49 min
Jun 19, 3:55 PM MDT	Severe Thunderstorm Warning	BOU	Washington	50 min
Jun 19, 4:04 PM MDT	Severe Thunderstorm Warning	BOU	Logan	41 min
Jun 19, 4:09 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	51 min
Jun 19, 4:12 PM MDT	Tornado Warning	BOU	Washington	33 min
Jun 19, 4:15 PM MDT	Tornado Warning	BOU	Logan	30 min
Jun 19, 4:37 PM MDT	Severe Thunderstorm Warning	BOU	Washington	38 min
Jun 19, 4:49 PM MDT	Severe Thunderstorm Warning	BOU	Logan, Phillips, Sedgwick	41 min
Jun 19, 4:57 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	33 min
Jun 19, 5:16 PM MDT	Severe Thunderstorm Warning	BOU	Phillips, Sedgwick	29 min

Nearby

Special Weather Statements in Colorado, 2021 Every special weather statement 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.