Alert archive / Colorado / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 101, NWS Denver/Boulder, CO

July 2, 2011Larimer County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 2, 2011, 12:17 AM MDT for Larimer County, Colorado. It was in force for 43 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: Jul 2, 2011, 12:17 AM MDT (06:17 UTC)
Expired: Jul 2, 2011, 1:00 AM MDT
In force: 43 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Hail: 1.0 in
Wind: 50.0 mph

County Larimer County, CO

The radar

The Cheyenne radar (KCYS), 75 km from the middle of the area, began a volume at 06:21 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
Jul 2, 12:55 AM MDT	HAIL 1.25	Fort Collins, CO

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

The nearest sounding before it

Denver, CO (KDNR), launched 00:00Z, 6.3 hours before the alert went out and 181 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 3222 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 23 m²/s²
0-3 km storm-relative helicity: 223 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.

385 
WUUS55 KBOU 020617
SVRBOU
COC069-020700-
/O.NEW.KBOU.SV.W.0101.110702T0617Z-110702T0700Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
1217 AM MDT SAT JUL 2 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EAST CENTRAL LARIMER COUNTY IN NORTH CENTRAL COLORADO

* UNTIL 100 AM MDT

* AT 1217 AM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING ONE INCH DIAMETER HAIL. 
  THIS STORM WAS LOCATED 3 MILES SOUTHWEST OF MASONVILLE...OR 12
  MILES SOUTHWEST OF FORT COLLINS...MOVING NORTHEAST AT 20 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO MASONVILLE
  AND FORT COLLINS.

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 4066 10513 4052 10497 4039 10525 4046 10538
TIME...MOT...LOC 0617Z 226DEG 16KT 4046 10525
WIND...HAIL <50MPH 1.00IN

$$

2 follow-up statements

878 
WWUS55 KBOU 020636
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
1236 AM MDT SAT JUL 2 2011

COC069-020700-
/O.CON.KBOU.SV.W.0101.000000T0000Z-110702T0700Z/
LARIMER CO-
1236 AM MDT SAT JUL 2 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 100 AM MDT
FOR EAST CENTRAL LARIMER COUNTY...

AT 1235 AM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING ONE INCH DIAMETER HAIL. 
THIS STORM WAS LOCATED 2 MILES SOUTHWEST OF HORSETOOTH MOUNTAIN...OR
8 MILES SOUTHWEST OF FORT COLLINS...MOVING NORTHEAST AT 15 MPH.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
TIMNATH...MASONVILLE AND FORT COLLINS.

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 4042 10521 4048 10534 4066 10513 4052 10497
TIME...MOT...LOC 0635Z 214DEG 14KT 4052 10522
WIND...HAIL <50MPH 1.00IN

$$

385 
WWUS55 KBOU 020659
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
1259 AM MDT SAT JUL 2 2011

COC069-020708-
/O.EXP.KBOU.SV.W.0101.000000T0000Z-110702T0700Z/
LARIMER CO-
1259 AM MDT SAT JUL 2 2011

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL LARIMER COUNTY 
WILL BE ALLOWED TO EXPIRED AT 1 AM MDT...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS WEAKENED AND IS NO 
LONGER EXPECTED TO PRODUCE SEVERE WEATHER. HEAVY RAIN AND SMALL HAIL 
ARE STILL POSSIBLE WITH THIS STORM. 

LAT...LON 4042 10521 4048 10534 4066 10513 4052 10497
TIME...MOT...LOC 0658Z 221DEG 14KT 4059 10514

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 2, 1:23 AM MDT	Severe Thunderstorm Warning	BOU	Lincoln, Washington	52 min
Jul 2, 12:16 PM MDT	Areal Flood Advisory	BOU	Jackson	71 hr
Jul 2, 2:14 PM MDT	Special Weather Statement	BOU	Jefferson	31 min
Jul 2, 3:18 PM MDT	Special Weather Statement	BOU	Douglas	27 min
Jul 2, 3:46 PM MDT	Special Weather Statement	BOU	Logan	29 min
Jul 2, 3:52 PM MDT	Severe Thunderstorm Warning	BOU	Logan	38 min
Jul 2, 3:54 PM MDT	Special Weather Statement	BOU	Elbert	36 min
Jul 2, 4:22 PM MDT	Special Weather Statement	BOU	Morgan	23 min
Jul 2, 4:27 PM MDT	Special Weather Statement	BOU	Adams	33 min
Jul 2, 4:45 PM MDT	Severe Thunderstorm Warning	BOU	Adams	30 min
Jul 2, 5:05 PM MDT	Tornado Warning	BOU	Washington	25 min
Jul 2, 5:16 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Morgan, Washington	59 min
Jul 2, 5:31 PM MDT	Severe Thunderstorm Warning	BOU	Washington	44 min
Jul 2, 5:44 PM MDT	Tornado Warning	BOU	Washington	31 min
Jul 2, 5:49 PM MDT	Special Weather Statement	BOU	Lincoln	26 min
Jul 2, 5:58 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	62 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.