Alert archive / Colorado / Mesoscale Discussions in 2014

Mesoscale Discussion 421

April 27, 20144 counties in Colorado; Keith County, Nebraska

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2014, 11:48 AM MDT for 4 counties in Colorado; Keith County, Nebraska. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 27, 2014, 11:48 AM MDT (17:48 UTC)
Expired: Apr 27, 2014, 2:15 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Kit Carson County, CO, Phillips County, CO, Sedgwick County, CO, Yuma County, CO, Keith County, NE

The radar

The Goodland radar (KGLD), 97 km from the middle of the area, began a volume at 17:49 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, 5.8 hours before the alert went out and 73 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: 1820 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: -107 m²/s²
0-3 km storm-relative helicity: 57 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.

611 
ACUS11 KWNS 271749
SWOMCD
SPC MCD 271748 
NEZ000-COZ000-272015-

MESOSCALE DISCUSSION 0421
NWS STORM PREDICTION CENTER NORMAN OK
1248 PM CDT SUN APR 27 2014

AREAS AFFECTED...NERN CO...FAR SW NEB

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 271748Z - 272015Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...ISOLATED BRIEF TORNADOES WILL BE POSSIBLE WITH A BAND OF
CONVECTION ON THE CUSP OF THE LOW-LEVEL DRY SLOT. WW ISSUANCE IS NOT
ANTICIPATED.

DISCUSSION...CONVECTION HAS RECENTLY INCREASED IN A NARROW BAND
ALONG THE LEADING EDGE OF THE DRY SLOT ACROSS NERN CO...COINCIDENT
WITH A NARROW AXIS OF 500 J/KG SBCAPE NOTED BY RECENT OBJECTIVE
MESOANALYSIS. DEEP-LAYER WIND PROFILES WILL NOT FAVOR ORGANIZED
STORM STRUCTURES...BUT STEEP LOW-LEVEL LAPSE RATES COMBINED WITH
RICH SURFACE VORTICITY IN THE VICINITY OF THE SFC LOW WILL RESULT IN
A THREAT OF ISOLATED BRIEF TORNADOES THROUGH THE AFTERNOON.

..DEAN/THOMPSON.. 04/27/2014

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LBF...GLD...BOU...

LAT...LON   39160281 39510301 39950296 40500279 40780256 41020230
            41370200 41240135 40620186 40060225 39920233 39690238
            39410237 39230235 39160237 39160281

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 27, 6:55 AM MDT	Mesoscale Discussion	SPC	Pawnee	95 min
Apr 27, 10:54 AM MDT	Mesoscale Discussion	SPC	Adams, Antelope, Blaine, Boone, Brown, Buffalo and 36 more	96 min
Apr 27, 11:16 AM MDT	Tornado Watch	SPC	Adams, Blaine, Boyd, Brown, Buffalo, Cherry and 31 more	7 hr
Apr 27, 2:19 PM MDT	Mesoscale Discussion	SPC	Adams, Arthur, Blaine, Brown, Buffalo, Cherry and 19 more	86 min
Apr 27, 5:28 PM MDT	Mesoscale Discussion	SPC	Blaine, Boyd, Brown, Cherry, Custer, Garfield and 13 more	62 min

Nearby

Mesoscale Discussions in Colorado, 2014 Mesoscale Discussions in Nebraska, 2014 Every mesoscale discussion in 2014

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.