Alert archive / Colorado / Tornado Warnings in 2018

Tornado Warning 9, NWS Denver/Boulder, CO

May 28, 2018Weld County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 28, 2018, 5:15 PM MDT for Weld County, Colorado. It was in force for 30 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: May 28, 2018, 5:15 PM MDT (23:15 UTC)
Expired: May 28, 2018, 5:45 PM MDT
In force: 30 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.0 in

County Weld County, CO

The radar

The Cheyenne radar (KCYS), 62 km from the middle of the area, began a volume at 23:19 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, 5:34 PM MDT	TORNADO	7 S Grover, CO	BRIEF TORNADO. POWERS LINES WERE TAKEN OUT IN VICINITY.

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, 2:01 PM MDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 11.3 hours before the alert went out and 133 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.

781 
WFUS55 KBOU 282315
TORBOU
COC123-282345-
/O.NEW.KBOU.TO.W.0009.180528T2315Z-180528T2345Z/

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

The National Weather Service in Denver Colorado has issued a

* Tornado Warning for...
  North central Weld County in northeastern Colorado...

* Until 545 PM MDT.
    
* At 515 PM MDT, a severe thunderstorm capable of producing a tornado
  was located 6 miles southwest of Grover, or 34 miles northeast of
  Greeley, moving northeast at 15 mph.

  HAZARD...Tornado and quarter size hail.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* Locations impacted include...
  Grover.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4068 10424 4077 10444 4093 10432 4081 10409
TIME...MOT...LOC 2315Z 211DEG 14KT 4079 10430 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

KRIEDERMAN

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, 5:04 PM MDT	Tornado Warning Tornado observed	BOU	Washington	26 min
May 28, 5:11 PM MDT	Tornado Warning	BOU	Morgan	34 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.