Alert archive / Colorado / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 310, NWS Denver/Boulder, CO

August 14, 2018Adams County, Weld County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 14, 2018, 5:47 PM MDT for Adams County, Weld County, Colorado. It was in force for 28 min. 6 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 14, 2018, 5:47 PM MDT (23:47 UTC)
Expired: Aug 14, 2018, 6:15 PM MDT
In force: 28 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Adams County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 42 km from the middle of the area, began a volume at 23:48 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 14, 5:52 PM MDT	HAIL 0.5	1 W Firestone, CO	MARBLE AND PEA SIZED HAIL ACCUMULATING.
Aug 14, 5:58 PM MDT	HAIL 0.88	2 Ese Wattenburg, CO	HAIL SHREDDED LEAVES.
Aug 14, 6:00 PM MDT	HAIL 0.5	2 W Firestone, CO	3 TO 6 INCHES OF PEA TO MARBLE HAIL OVER AN INCH OF RAIN IN 30 MIN.
Aug 14, 6:05 PM MDT	HAIL 1	2 Ese Brighton, CO	0.63 INCHES OF RAIN IN 7 MINUTES.
Aug 14, 6:05 PM MDT	HAIL 1	2 Ese Brighton, CO	CORRECTS PREVIOUS HAIL REPORT FROM 2 ESE BRIGHTON. 0.63 INCHES OF RAIN IN 7 MINUTES.
Aug 14, 6:16 PM MDT	HAIL 0.5	Brighton, CO	LOTS OF MARBLE HAIL AND STREET FLOODING.

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

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 11.8 hours before the alert went out and 145 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: 283 J/kg
Mixed-layer CIN: -212 J/kg
Mixed-layer LCL: 1251 m above ground
0-6 km bulk shear: 7 kt
0-1 km storm-relative helicity: -18 m²/s²
0-3 km storm-relative helicity: -5 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

715 
WUUS55 KBOU 142347
SVRBOU
COC001-123-150015-
/O.NEW.KBOU.SV.W.0310.180814T2347Z-180815T0015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
547 PM MDT TUE AUG 14 2018

The National Weather Service in Denver Colorado has issued a

* Severe Thunderstorm Warning for...
  Southwestern Weld County in northeastern Colorado...
  Northwestern Adams County in northeastern Colorado...

* Until 615 PM MDT.

* At 546 PM MDT, a severe thunderstorm was located over Dacono, or 24
  miles north of Denver, moving southeast at 25 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...
  Northeastern Thornton, northern Commerce City, Brighton, Erie,
  Firestone, Frederick, Fort Lupton, Lochbuie, Dacono and Barr Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4002 10460 3986 10486 4000 10498 4000 10496
      4004 10496 4004 10498 4003 10497 4003 10498
      4001 10499 4002 10499 4008 10506 4011 10506
      4019 10490
TIME...MOT...LOC 2346Z 316DEG 23KT 4008 10491 

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

BOWEN

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 14, 3:12 PM MDT	Special Weather Statement	BOU	Larimer	48 min
Aug 14, 3:44 PM MDT	Severe Thunderstorm Warning	BOU	Weld	46 min
Aug 14, 4:25 PM MDT	Severe Thunderstorm Warning	BOU	Weld	50 min
Aug 14, 4:30 PM MDT	Severe Thunderstorm Warning	BOU	Larimer	27 min
Aug 14, 4:56 PM MDT	Severe Thunderstorm Warning	BOU	Jefferson	49 min
Aug 14, 4:56 PM MDT	Severe Thunderstorm Warning	BOU	Boulder, Larimer	22 min
Aug 14, 5:08 PM MDT	Severe Thunderstorm Warning	BOU	Park	52 min
Aug 14, 5:16 PM MDT	Severe Thunderstorm Warning	BOU	Boulder, Weld	29 min
Aug 14, 5:39 PM MDT	Severe Thunderstorm Warning	BOU	Arapahoe, Denver, Douglas, Jefferson	51 min
Aug 14, 5:51 PM MDT	Areal Flood Advisory	BOU	Adams, Boulder, Weld	114 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2018 Every severe thunderstorm warning 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.