Alert archive / Colorado / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 166, NWS Denver/Boulder, CO

July 17, 2011Gilpin County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 17, 2011, 2:25 PM MDT for Gilpin County, Colorado. It was in force for 35 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: Jul 17, 2011, 2:25 PM MDT (20:25 UTC)
Expired: Jul 17, 2011, 3:00 PM MDT
In force: 35 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.25 in
Wind: 50.0 mph

County Gilpin County, CO

The radar

The Denver radar (KFTG), 88 km from the middle of the area, began a volume at 20:29 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 (KDNR), launched 12:00Z, 8.4 hours before the alert went out and 199 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: 94 J/kg
Mixed-layer CIN: -352 J/kg
Mixed-layer LCL: 1885 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 22 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

954 
WUUS55 KBOU 172025
SVRBOU
COC047-172100-
/O.NEW.KBOU.SV.W.0166.110717T2025Z-110717T2100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
225 PM MDT SUN JUL 17 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL GILPIN COUNTY IN CENTRAL COLORADO

* UNTIL 300 PM MDT

* AT 225 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING HALF DOLLAR SIZE HAIL. 
  THIS STORM WAS LOCATED 5 MILES SOUTHEAST OF TOLLAND...OR 32 MILES
  WEST OF DENVER...MOVING NORTH AT 10 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO TOLLAND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF SEVERE WEATHER APPROACHES YOUR AREA...GO INSIDE A STURDY SHELTER
AWAY FROM CREEK BEDS AND OTHER FLOOD-PRONE AREAS. REMEMBER...A SEVERE
THUNDERSTORM CAN PRODUCE LARGE DAMAGING HAIL...DAMAGING WINDS IN
EXCESS OF 58 MPH...DEADLY LIGHTNING...AND VERY HEAVY RAIN.

&&

LAT...LON 3992 10561 3991 10546 3981 10552 3984 10562
TIME...MOT...LOC 2025Z 184DEG 9KT 3986 10555
WIND...HAIL <50MPH 1.25IN

$$

2 follow-up statements

312 
WWUS55 KBOU 172035
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
235 PM MDT SUN JUL 17 2011

COC047-172100-
/O.CON.KBOU.SV.W.0166.000000T0000Z-110717T2100Z/
GILPIN CO-
235 PM MDT SUN JUL 17 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM MDT
FOR CENTRAL GILPIN COUNTY...

AT 235 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING HALF DOLLAR SIZE HAIL.  THIS
STORM WAS LOCATED 3 MILES SOUTHEAST OF TOLLAND...OR 33 MILES WEST OF
DENVER...MOVING NORTH AT 10 MPH.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
TOLLAND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

HEAVY RAINS MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED ROADS AS THEY
MAY BE WASHED OUT. WATER LEVELS OF SMALL STREAMS AND RIVERS MAY ALSO
RISE...THEREFORE SEEK HIGHER GROUND IF THREATENED BY FLOOD WATERS.

IF SEVERE WEATHER APPROACHES YOUR AREA...GO INSIDE A STURDY SHELTER
AWAY FROM CREEK BEDS AND OTHER FLOOD-PRONE AREAS. REMEMBER...A SEVERE
THUNDERSTORM CAN PRODUCE LARGE DAMAGING HAIL...DAMAGING WINDS IN
EXCESS OF 58 MPH...DEADLY LIGHTNING...AND VERY HEAVY RAIN.

&&

LAT...LON 3992 10561 3991 10546 3981 10552 3984 10562
TIME...MOT...LOC 2035Z 184DEG 9KT 3987 10556
WIND...HAIL <50MPH 1.25IN

$$

986 
WWUS55 KBOU 172058
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
258 PM MDT SUN JUL 17 2011

COC047-172108-
/O.EXP.KBOU.SV.W.0166.000000T0000Z-110717T2100Z/
GILPIN CO-
258 PM MDT SUN JUL 17 2011

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL GILPIN COUNTY WILL
EXPIRE AT 300 PM MDT...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS WEAKENED SOME AND NO
LONGER EXPECTED TO PRODUCE SEVERE WEATHER.

LAT...LON 3992 10561 3991 10546 3981 10552 3984 10562
TIME...MOT...LOC 2058Z 184DEG 9KT 3993 10555

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 6:33 PM MDT	River Flood Advisory	BOU	Morgan	40 hr
Jul 16, 6:33 PM MDT	River Flood Advisory	BOU	Logan, Morgan, Washington	63 hr
Jul 16, 9:37 PM MDT	Severe Thunderstorm Warning	BOU	Weld	35 min
Jul 17, 12:55 PM MDT	Areal Flood Advisory	BOU	Boulder, Grand, Larimer	80 min
Jul 17, 2:20 PM MDT	Special Weather Statement	BOU	Gilpin	25 min
Jul 17, 2:29 PM MDT	Areal Flood Advisory	BOU	Clear Creek, Gilpin	91 min
Jul 17, 2:57 PM MDT	Flash Flood Warning	BOU	Clear Creek, Gilpin	3 hr
Jul 17, 3:33 PM MDT	Special Weather Statement	BOU	Boulder	27 min
Jul 17, 3:37 PM MDT	Areal Flood Advisory	BOU	Boulder	83 min
Jul 17, 3:44 PM MDT	Flash Flood Warning	BOU	Boulder	3 hr
Jul 17, 3:59 PM MDT	Special Weather Statement	BOU	Boulder	31 min
Jul 17, 4:16 PM MDT	Areal Flood Advisory	BOU	Boulder	89 min
Jul 17, 4:31 PM MDT	Special Weather Statement	BOU	Boulder	29 min
Jul 17, 4:57 PM MDT	Special Weather Statement	BOU	Boulder	33 min
Jul 17, 5:01 PM MDT	Areal Flood Advisory	BOU	Boulder	89 min
Jul 17, 5:25 PM MDT	Special Weather Statement	BOU	Boulder	35 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2011 Every severe thunderstorm warning in 2011

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.