Alert archive / Colorado / Special Weather Statements in 2021

Special Weather Statement, NWS Denver/Boulder, CO

October 12, 2021Logan County, Colorado

NWS Denver/Boulder, CO issued this special weather statement at Oct 12, 2021, 5:05 PM MDT for Logan County, Colorado. It was in force for 25 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
Oct 12, 2021, 5:05 PM MDT (23:05 UTC)
Expired
Oct 12, 2021, 5:30 PM MDT
In force
25 min
Issued by
NWS Denver/Boulder, CO
Hail
0.88 in
Wind
50

County Logan County, CO

The radar

The Cheyenne radar (KCYS), 152 km from the middle of the area, began a volume at 23:07 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, 11.1 hours before the alert went out and 99 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 2021-10-12Temperature 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°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2021-10-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 170 square meters per square second.1939587897117Sfc1 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
1285 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
170 m²/s²
0-3 km storm-relative helicity
335 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

399 
WWUS85 KBOU 122305
SPSBOU

Special Weather Statement
National Weather Service Denver CO
505 PM MDT Tue Oct 12 2021
 
COZ048-122330-
Logan County CO-
505 PM MDT Tue Oct 12 2021

...A strong thunderstorm will impact portions of central Logan County
through 530 PM MDT...

At 505 PM MDT, Doppler radar was tracking a strong thunderstorm 4
miles northeast of Sterling, moving north at 50 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around 
         unsecured objects. Minor damage to outdoor objects is 
         possible.

Locations impacted include...
Sterling, Iliff, Peetz and Padroni. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building. 

&&

LAT...LON 4059 10296 4058 10323 4100 10328 4100 10296
TIME...MOT...LOC 2305Z 179DEG 44KT 4065 10312 

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

$$

MEIER

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 12, 3:56 AM MDTHigh Wind WatchBOUBoulder, Larimer11 hr
Oct 12, 3:56 AM MDTHigh Wind WarningBOUArapahoe, Douglas, Elbert, Lincoln14 hr
Oct 12, 2:47 PM MDTHigh Wind WarningBOUBoulder, Larimer, Logan, Phillips, Sedgwick, Weld24 hr
Oct 12, 5:18 PM MDTSevere Thunderstorm WarningBOULogan, Phillips, Sedgwick42 min
Oct 12, 5:54 PM MDTTornado WarningBOUPhillips36 min

Nearby

Special Weather Statements in Colorado, 2021Every special weather statement in 2021

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.