Alert archive / Colorado / Mesoscale Discussions in 2011

Mesoscale Discussion 1513

July 5, 20119 counties in Colorado; Cheyenne County, Nebraska

The Storm Prediction Center issued this mesoscale discussion at Jul 5, 2011, 5:19 PM MDT for 9 counties in Colorado; Cheyenne County, Nebraska. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: Jul 5, 2011, 5:19 PM MDT (23:19 UTC)
Expired: Jul 5, 2011, 6:15 PM MDT
In force: 56 min
Issued by: the Storm Prediction Center

Counties Adams County, CO, Arapahoe County, CO, Elbert County, CO, Logan County, CO, Morgan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Yuma County, CO, Cheyenne County, NE

The radar

The Denver radar (KFTG), 136 km from the middle of the area, began a volume at 23:19 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 602Jul 5, 6:00 PM MDT

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 11.3 hours before the alert went out and 40 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: 45 J/kg
Mixed-layer CIN: -407 J/kg
Mixed-layer LCL: 1874 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 5 m²/s²
0-3 km storm-relative helicity: -34 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.

787 
ACUS11 KWNS 052319
SWOMCD
SPC MCD 052319 
NEZ000-COZ000-060015-

MESOSCALE DISCUSSION 1513
NWS STORM PREDICTION CENTER NORMAN OK
0619 PM CDT TUE JUL 05 2011

AREAS AFFECTED...PORTIONS NERN CO AND SRN PANHANDLE OF
NEB...ADJOINING W SIDE OF WW 600.

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 052319Z - 060015Z

SVR POTENTIAL IS INCREASING ACROSS PORTIONS CENTRAL HIGH PLAINS
MAINLY W OF WW 600...WITH DAMAGING GUSTS AND LARGE HAIL POSSIBLE.

COMPLEX SFC MESOANALYSIS FEATURES HEAT LOW OVER SERN CO NEAR
LAA...AND S OF  QUASISTATIONARY FRONTAL/CONVERGENCE BOUNDARY
ANALYZED FROM NEAR COS-LIC-MCK-CNK.  N OF THIS
BOUNDARY...DEEP/PERSISTENT NELY FLOW IN BOUNDARY LAYER CONTINUES TO
ADVECT/TRANSPORT FAVORABLE MOISTURE UPSLOPE...MAINTAINED IN PART BY
SERN CO LOW.  THIS PROCESS ALSO ENHANCES BOTH LOW-LEVEL SHEAR AND
STORM-RELATIVE INFLOW FOR EWD-MOVING CONVECTION N OF FRONT.  DESPITE
MODEST 700-500 MB LAYER WINDS...STG DIRECTIONAL SHEAR CONTRIBUTES TO
35-40 KT EFFECTIVE SHEAR MAGNITUDES IN SUPPORT OF STORM
ORGANIZATION.  BOUNDARY WILL ACT AS EFFECTIVE SRN BOUND FOR SVR
THREAT...GIVEN HOT/DEEPLY-MIXED AIR TO ITS S WHERE MODIFIED RAOBS
AND FCST SOUNDINGS SUGGEST VERY LITTLE CAPE.  BY CONTRAST...ZONAL
SFC MOIST AXIS EXTENDING FROM CYS RIDGE EWD SUPPORTS MLCAPE RANGING
FROM AROUND 3500 J/KG OVER SWRN NEB TO 1500 J/KG OVER IBM/SNY
REGION.  AS OF 23Z...CONVECTION WAS STRENGTHENING AND BECOMING MORE
DENSE IN COVERAGE ACROSS ERN WELD COUNTY...WITH POTENTIAL FOR
UPSCALE GROWTH AND FURTHER INTENSIFICATION AS IT MOVES INTO
PROGRESSIVELY MORE BUOYANT ENVIRONMENT.

..EDWARDS.. 07/05/2011

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

ATTN...WFO...LBF...GLD...PUB...BOU...CYS...

LAT...LON   39770250 39010467 41060398 41540261 40050201 39770250

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 5, 3:47 PM MDT	Severe Thunderstorm Watch	SPC	Yuma	8 hr
Jul 4, 10:14 PM MDT	Mesoscale Discussion	SPC	Boyd, Brown, Holt, Keya Paha, Rock	91 min
Jul 5, 1:17 PM MDT	Mesoscale Discussion	SPC	Dawes, Sheridan	73 min
Jul 5, 1:49 PM MDT	Mesoscale Discussion	SPC	Adams, Boone, Buffalo, Butler, Cass, Clay and 36 more	86 min
Jul 5, 2:32 PM MDT	Mesoscale Discussion	SPC	Dakota, Dixon	88 min

Nearby

Mesoscale Discussions in Colorado, 2011 Mesoscale Discussions in Nebraska, 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.