Alert archive / Colorado / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 252, NWS Denver/Boulder, CO

July 29, 2018Lincoln County, Washington County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 29, 2018, 6:25 PM MDT for Lincoln County, Washington County, Colorado. It was in force for 50 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: Jul 29, 2018, 6:25 PM MDT (00:25 UTC)
Expired: Jul 29, 2018, 7:15 PM MDT
In force: 50 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

Counties Lincoln County, CO, Washington County, CO

The radar

The Denver radar (KFTG), 98 km from the middle of the area, began a volume at 00:25 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
Jul 29, 6:52 PM MDT	HAIL 1.75	10 Ne Cedar Point, CO
Jul 29, 6:55 PM MDT	TSTM WND GST 68	Limon, CO
Jul 29, 7:06 PM MDT	TSTM WND GST 70	Limon, 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
Jul 29, 1:07 PM MDT	Tornado Watch	SPC	8 hr

The nearest sounding before it

Denver, CO (KDEN), launched 00:00Z, 0.4 hours before the alert went out and 45 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: 943 J/kg
Mixed-layer CIN: -220 J/kg
Mixed-layer LCL: 1653 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 101 m²/s²
0-3 km storm-relative helicity: 191 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.8

Open this sounding in Storm Lab

The text

As transmitted.

037 
WUUS55 KBOU 300025
SVRBOU
COC073-121-300115-
/O.NEW.KBOU.SV.W.0252.180730T0025Z-180730T0115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
625 PM MDT SUN JUL 29 2018

The National Weather Service in Denver Colorado has issued a

* Severe Thunderstorm Warning for...
  Southwestern Washington County in northeastern Colorado...
  Northeastern Lincoln County in east central Colorado...

* Until 715 PM MDT.

* At 624 PM MDT, a severe thunderstorm was located 9 miles south of
  Last Chance, or 23 miles north of Limon, moving southeast at 35
  mph.

  HAZARD...60 mph wind gusts and half dollar size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees. Hail damage to 
           vehicles is expected.

* Locations impacted include...
  Limon, Arriba and Genoa. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect for the warned area. Tornadoes can
develop quickly from severe thunderstorms. Although a tornado is not
immediately likely, if one is spotted, act quickly and move to a
place of safety inside a sturdy structure such as a basement or small
interior room.

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.

&&

A Tornado Watch remains in effect until 900 PM MDT for northeastern
and east central Colorado.

LAT...LON 3973 10370 3970 10345 3950 10335 3948 10317
      3918 10317 3926 10369
TIME...MOT...LOC 0024Z 337DEG 31KT 3959 10358 

HAIL...1.25IN
WIND...60MPH
 
$$

RJK

1 follow-up statement

331 
WWUS55 KBOU 300111
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
711 PM MDT SUN JUL 29 2018

COC073-121-300121-
/O.EXP.KBOU.SV.W.0252.000000T0000Z-180730T0115Z/
Washington CO-Lincoln CO-
711 PM MDT SUN JUL 29 2018

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN WASHINGTON AND
NORTHEASTERN LINCOLN COUNTIES WILL EXPIRE AT 715 PM MDT...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning will be allowed to expire.

A Tornado Watch remains in effect until 900 PM MDT for northeastern
and east central Colorado.

LAT...LON 3973 10370 3970 10345 3950 10335 3948 10317
      3918 10317 3926 10369
TIME...MOT...LOC 0111Z 337DEG 31KT 3923 10338 

$$

RJK

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 29, 6:43 PM MDT	Severe Thunderstorm Warning	BOU	Larimer, Weld	32 min
Jul 29, 7:04 PM MDT	Severe Thunderstorm Warning	BOU	Weld	26 min
Jul 29, 7:04 PM MDT	Tornado Warning	BOU	Elbert, Lincoln	26 min
Jul 29, 7:28 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Weld	32 min
Jul 29, 7:59 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe	31 min
Jul 29, 8:27 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe, Elbert	33 min
Jul 29, 8:58 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	32 min
Jul 29, 9:25 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	35 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.