Alert archive / Colorado / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 39, NWS Denver/Boulder, CO

June 7, 2017Logan County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 7, 2017, 5:31 PM MDT for Logan County, Colorado. It was in force for 44 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jun 7, 2017, 5:31 PM MDT (23:31 UTC)
Expired
Jun 7, 2017, 6:15 PM MDT
In force
44 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Hail
1.5 in
Wind
60.0 mph

County Logan County, CO

The radar

The Cheyenne radar (KCYS), 145 km from the middle of the area, began a volume at 23:31 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.

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 11.5 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-pSkew-T log-p diagram, Denver, CO at 12:00Z on 2017-06-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2017-06-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -6 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
1579 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
-6 m²/s²
0-3 km storm-relative helicity
82 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

120 
WUUS55 KBOU 072331
SVRBOU
COC075-080015-
/O.NEW.KBOU.SV.W.0039.170607T2331Z-170608T0015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Denver CO
531 PM MDT WED JUN 7 2017

The National Weather Service in Denver Colorado has issued a

* Severe Thunderstorm Warning for...
  Central Logan County in northeastern Colorado...

* Until 615 PM MDT

* At 530 PM MDT, a severe thunderstorm was located near Padroni, or 6
  miles north of Sterling, moving south at 15 mph.

  HAZARD...Ping pong ball size hail and 60 mph wind gusts. 

  SOURCE...Radar indicated. 

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Expect 
           wind damage to roofs, siding, and trees. 

* Locations impacted include...
  Sterling, Padroni and Atwood. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move immediately to shelter inside a strong building. Stay
away from windows.

&&

LAT...LON 4078 10327 4079 10314 4059 10299 4054 10315
      4058 10335
TIME...MOT...LOC 2330Z 349DEG 13KT 4075 10321 

HAIL...1.50IN
WIND...60MPH
 
$$

GIMMESTAD
2 follow-up statements
683 
WWUS55 KBOU 080004
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
604 PM MDT WED JUN 7 2017

COC075-080015-
/O.CON.KBOU.SV.W.0039.000000T0000Z-170608T0015Z/
Logan CO-
604 PM MDT WED JUN 7 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM MDT
FOR SOUTH CENTRAL LOGAN COUNTY...

At 603 PM MDT, a severe thunderstorm was located 5 miles northeast of
Atwood, or 5 miles south of Sterling, moving south at 15 mph.

HAZARD...60 mph wind gusts and quarter size hail. 

SOURCE...Radar indicated. 

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

Locations impacted include...
Southeastern Sterling.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4060 10322 4065 10311 4057 10304 4054 10315
      4056 10324
TIME...MOT...LOC 0003Z 351DEG 14KT 4058 10318 

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

GIMMESTAD
848 
WWUS55 KBOU 080020
SVSBOU

Severe Weather Statement
National Weather Service Denver CO
620 PM MDT WED JUN 7 2017

COC075-080030-
/O.EXP.KBOU.SV.W.0039.000000T0000Z-170608T0015Z/
Logan CO-
620 PM MDT WED JUN 7 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL LOGAN COUNTY HAS
EXPIRED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore the warning has
been allowed to expire.

LAT...LON 4060 10322 4065 10311 4057 10304 4054 10315
      4056 10324
TIME...MOT...LOC 0020Z 349DEG 13KT 4052 10317 

$$

GIMMESTAD

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 6, 8:19 PM MDTSpecial Weather StatementBOULincoln41 min
Jun 7, 2:39 PM MDTSevere Thunderstorm WarningBOULogan31 min
Jun 7, 3:08 PM MDTSevere Thunderstorm WarningBOULogan52 min
Jun 7, 3:21 PM MDTSpecial Weather StatementBOUDenver39 min
Jun 7, 3:36 PM MDTSpecial Weather StatementBOUBoulder24 min
Jun 7, 4:06 PM MDTSevere Thunderstorm WarningBOULogan54 min
Jun 7, 4:32 PM MDTSevere Thunderstorm WarningBOULogan58 min
Jun 7, 4:52 PM MDTSevere Thunderstorm WarningBOUWeld21 min
Jun 7, 4:57 PM MDTSevere Thunderstorm WarningBOUWashington48 min
Jun 7, 5:04 PM MDTSpecial Weather StatementBOUAdams41 min
Jun 7, 5:37 PM MDTSevere Thunderstorm WarningBOUMorgan53 min
Jun 7, 5:43 PM MDTSevere Thunderstorm WarningBOUWashington47 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2017Every severe thunderstorm warning in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.