Alert archive / Nebraska / Mesoscale Discussions in 2011

Mesoscale Discussion 2021

August 19, 2011Logan County, Morgan County, Weld County, Colorado; 5 counties in Nebraska; Goshen County, Laramie County, Platte County, Wyoming

The Storm Prediction Center issued this mesoscale discussion at Aug 19, 2011, 4:01 PM MDT for Logan County, Morgan County, Weld County, Colorado; 5 counties in Nebraska; Goshen County, Laramie County, Platte County, Wyoming. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: Aug 19, 2011, 4:01 PM MDT (22:01 UTC)
Expired: Aug 19, 2011, 5:00 PM MDT
In force: 59 min
Issued by: the Storm Prediction Center

Counties Logan County, CO, Morgan County, CO, Weld County, CO, Banner County, NE, Cheyenne County, NE, Kimball County, NE, Scotts Bluff County, NE, Sioux County, NE, Goshen County, WY, Laramie County, WY, Platte County, WY

The radar

The Cheyenne radar (KCYS), 71 km from the middle of the area, began a volume at 22:04 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, 10.0 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: 3547 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: -59 m²/s²
0-3 km storm-relative helicity: -17 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.

026 
ACUS11 KWNS 192201
SWOMCD
SPC MCD 192201 
NEZ000-COZ000-WYZ000-192300-

MESOSCALE DISCUSSION 2021
NWS STORM PREDICTION CENTER NORMAN OK
0501 PM CDT FRI AUG 19 2011

AREAS AFFECTED...SERN WY / NEB PANHANDLE / NERN CO

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 192201Z - 192300Z

WHILE STORM COVERAGE IS EXPECTED TO INCREASE THROUGH THE LATE
AFTERNOON SPILLING EWD FROM THE HIGHER TERRAIN INTO THE CNTRL HIGH
PLAINS...THE NEED FOR A WW IS CURRENTLY ANTICIPATED TO BE UNLIKELY. 

SURFACE ANALYSIS PLACES A SURFACE RIDGE EXTENDING SWWD FROM THE NRN
PLAINS INTO THE CNTRL HIGH PLAINS...N OF A FRONT EXTENDING W TO E
FROM SERN CO INTO WRN MO.  N OF THE BOUNDARY...MOIST NELY UPSLOPE
FLOW AND AN EXTENSIVE MID-HIGH CLOUD CANOPY ARE BOTH LIMITING THE
MAGNITUDE OF SURFACE HEATING AS TEMPS ACROSS THE NEB PANHANDLE
REMAIN AOB 80 DEG F.  DESPITE STRONG SHEAR PROFILES IN PLACE /35-50
KTS 0-6 KM SHEAR/...FORECAST SOUNDINGS SHOW SUBSTANTIAL CAPPING OVER
THE DISCUSSION AREA.  A WEAK DISTURBANCE ANALYZED BY THE RUC MOVING
EWD ACROSS THE ERN UT/WRN CO APPEARS TO BE PARTLY RESPONSIBLE FOR AN
INCREASE IN STORM ACTIVITY TO THE W ACROSS NWRN CO AND S-CNTRL WY. 
AS THIS DISTURBANCES MOVES EWD...STORM COVERAGE SHOULD INCREASE
ACROSS THE REGION FROM W TO E. 

TRENDS IN RADAR MOSAIC THE PAST FEW HOURS HAVE SHOWN CONVECTION
STRUGGLING TO MAINTAIN VIGOR AS IT MOVES EWD ALONG AND E OF THE I-25
CORRIDOR--LIKELY DUE TO THE EXISTING INVERSION INHIBITING SUSTAINED
SURFACE-BASED PARCEL INFLOW.  STORM INTENSITY/SEVERITY SEEMS TO BE
HIGHLY DEPENDENT UPON STORMS REMAINING SURFACE-BASED OVER THE HIGH
PLAINS...AND CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED OVER
THE NEXT FEW HOURS.

..SMITH.. 08/19/2011

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

ATTN...WFO...BOU...CYS...

LAT...LON   40150435 40330457 42550516 42780481 42860421 42790372
            42620345 40610276 40290301 40100375 40150435

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 18, 7:29 PM MDT	Mesoscale Discussion	SPC	Antelope, Boone, Butler, Cass, Colfax, Cuming and 17 more	61 min
Aug 18, 8:52 PM MDT	Mesoscale Discussion	SPC	Boone, Butler, Cass, Clay, Colfax, Fillmore and 23 more	53 min

Nearby

Mesoscale Discussions in Nebraska, 2011 Mesoscale Discussions in Colorado, 2011 Mesoscale Discussions in Wyoming, 2011 Every mesoscale discussion 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.