Alert archive / Colorado / Tornado Warnings in 2018

Tornado Warning 7, NWS Denver/Boulder, CO

May 28, 2018Washington County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 28, 2018, 5:04 PM MDT for Washington County, Colorado. It was in force for 26 min. 5 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: May 28, 2018, 5:04 PM MDT (23:04 UTC)
Expired: May 28, 2018, 5:30 PM MDT
In force: 26 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Tornado: Observed
Hail: 1.75 in

County Washington County, CO

The radar

The Goodland radar (KGLD), 117 km from the middle of the area, began a volume at 23:08 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
May 28, 5:11 PM MDT	TORNADO	5 Wsw Cope, CO	THIS REPORT IS FOR ONE OF THREE TORNADOES ON THE GROUND SIMULTANEOUSLY SOUTHWEST OF COPE BETWEEN 511 AND 539 PM MDT. THIS TORNADO WAS ANTICYCLONIC AND REMAINED OVER AN OPEN FIELD, LASTING 16 MINUTES. THE DURATION OF THE TORNADO EVENT WAS 16 MINUTES.
May 28, 5:15 PM MDT	TORNADO	5 Wsw Cope, CO	TWO AND POTENTIALLY 3 TORNADOES ON THE GROUND IN OPEN FIELDS. NO DAMAGE REPORTED. BOTH TORNADOES ON THE GROUND FOR SEVERAL MINUTES WITH ONE LASTING NEAR 30 MINUTES.
May 28, 5:15 PM MDT	TORNADO	5 Wsw Cope, CO	TWO TORNADOES ON THE GROUND IN OPEN FIELD. NO DAMAGE REPORTED. BOTH TORNADOES ON THE GROUND FOR SEVERAL MINUTES.
May 28, 5:15 PM MDT	TORNADO	8 Ene Thurman, CO	THIS REPORT COVERS 1 OF 3 TORNADOES THAT WERE VISIBLE WITH A THIRD IN OPEN FIELDS SOUTHWEST OF COPE. A CYCLONIC TORNADO FORMED AT 515 AND LASTED FOR 24 MINUTES TOTAL AND CROSSED INTO KIT CARSON COUNTY. NO DAMAGE REPORTED. THE DURATION OF THE TORNADO EVENT WAS
May 28, 5:29 PM MDT	TORNADO	9 E Thurman, CO	THIS IS THE THIRD TORNADO VISIBLE SIMULTANEOUSLY SOUTHWEST OF COPE. IT LASTED A FEW MINUTES. THE DURATION OF THE TORNADO EVENT WAS 3 MINUTES.

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
May 28, 1:12 PM MDT	Tornado Watch	SPC	8 hr

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 11.1 hours before the alert went out and 28 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: 69 J/kg
Mixed-layer CIN: -104 J/kg
Mixed-layer LCL: 854 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: -4 m²/s²
0-3 km storm-relative helicity: 173 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted.

090 
WFUS55 KBOU 282304
TORBOU
COC121-282330-
/O.NEW.KBOU.TO.W.0007.180528T2304Z-180528T2330Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Denver CO
504 PM MDT MON MAY 28 2018

The National Weather Service in Denver Colorado has issued a

* Tornado Warning for...
  Southeastern Washington County in northeastern Colorado...

* Until 530 PM MDT.

* At 503 PM MDT, a confirmed tornado was located near Arickaree
  School, or 27 miles north of Flagler, moving north at 15 mph.

  HAZARD...Tornado and golf ball size hail.

  SOURCE...Weather spotters confirmed tornado.

  IMPACT...Expect damage to mobile homes, roofs, and vehicles.

* Locations impacted include...
  Arickaree School.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. TAKE COVER NOW! Move to a
basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.

&&

LAT...LON 3957 10293 3957 10314 3988 10315 3988 10284
TIME...MOT...LOC 2303Z 198DEG 11KT 3970 10303 

TORNADO...OBSERVED
HAIL...1.75IN

$$

MEIER

1 follow-up statement

453 
WWUS55 KBOU 282319
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
519 PM MDT MON MAY 28 2018

COC121-282330-
/O.CON.KBOU.TO.W.0007.000000T0000Z-180528T2330Z/
Washington CO-
519 PM MDT MON MAY 28 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 530 PM MDT FOR
SOUTHEASTERN WASHINGTON COUNTY...
    
At 518 PM MDT, a confirmed tornado was located 4 miles southwest of 
Cope, or 22 miles north of Seibert, moving east at 10 mph.

HAZARD...TORNADO and golf ball size hail.

SOURCE...Weather spotters confirmed tornado.

IMPACT...Expect damage to mobile homes, roofs, and vehicles.

Locations impacted include...
Arickaree School.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. TAKE COVER NOW! Move to a
basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.

&&

LAT...LON 3957 10293 3957 10314 3988 10315 3988 10284
TIME...MOT...LOC 2318Z 275DEG 8KT 3962 10295 

TORNADO...OBSERVED
HAIL...1.75IN

$$

MEIER

The office that day

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

Issued	Product	Office	Counties	Lasted
May 27, 6:09 PM MDT	Severe Thunderstorm Warning	BOU	Phillips, Sedgwick	33 min
May 27, 6:19 PM MDT	Severe Thunderstorm Warning	BOU	Sedgwick	26 min
May 28, 1:14 PM MDT	Areal Flood Advisory	BOU	Clear Creek, Park	91 min
May 28, 1:52 PM MDT	Severe Thunderstorm Warning	BOU	Park	23 min
May 28, 2:05 PM MDT	Flash Flood Warning	BOU	Jackson	85 min
May 28, 2:38 PM MDT	Flash Flood Watch	BOU	Logan, Morgan, Phillips, Sedgwick, Washington	6 hr
May 28, 2:55 PM MDT	Special Weather Statement	BOU	Jefferson	50 min
May 28, 3:25 PM MDT	Severe Thunderstorm Warning	BOU	Clear Creek, Jefferson, Park	50 min
May 28, 4:03 PM MDT	Severe Thunderstorm Warning	BOU	Weld	42 min
May 28, 4:13 PM MDT	Severe Thunderstorm Warning	BOU	Arapahoe, Denver, Jefferson	47 min
May 28, 4:18 PM MDT	Severe Thunderstorm Warning	BOU	Washington	42 min
May 28, 4:21 PM MDT	Special Weather Statement	BOU	Weld	39 min
May 28, 4:40 PM MDT	Severe Thunderstorm Warning	BOU	Arapahoe, Douglas	50 min
May 28, 4:46 PM MDT	Severe Thunderstorm Warning	BOU	Weld	44 min
May 28, 4:59 PM MDT	Severe Thunderstorm Warning	BOU	Washington	46 min
May 28, 5:11 PM MDT	Tornado Warning	BOU	Morgan	34 min
May 28, 5:15 PM MDT	Tornado Warning	BOU	Weld	30 min
May 28, 5:27 PM MDT	Tornado Warning	BOU	Logan, Washington	33 min
May 28, 5:36 PM MDT	Tornado Warning	BOU	Weld	24 min
May 28, 5:38 PM MDT	Tornado Warning	BOU	Weld	37 min
May 28, 5:47 PM MDT	Tornado Warning	BOU	Morgan, Weld	28 min

Nearby

Tornado Warnings in Colorado, 2018 Every tornado warning in 2018 Tornadoes in 2018

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.