Alert archive / Colorado / Mesoscale Discussions in 2012

Mesoscale Discussion 1653

July 30, 201211 counties in Colorado

The Storm Prediction Center issued this mesoscale discussion at Jul 30, 2012, 3:45 PM MDT for 11 counties in Colorado. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Jul 30, 2012, 3:45 PM MDT (21:45 UTC)
Expired: Jul 30, 2012, 4:45 PM MDT
In force: 60 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Adams County, CO, Arapahoe County, CO, Cheyenne County, CO, Denver County, CO, El Paso County, CO, Elbert County, CO, Kit Carson County, CO, Lincoln County, CO, Morgan County, CO, Washington County, CO, Yuma County, CO

The radar

The Denver radar (KFTG), 60 km from the middle of the area, began a volume at 21:46 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 541Jul 30, 6:30 PM MDT

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 9.8 hours before the alert went out and 55 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: 36 J/kg
Mixed-layer CIN: -260 J/kg
Mixed-layer LCL: 2058 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 4 m²/s²
0-3 km storm-relative helicity: 48 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.

972 
ACUS11 KWNS 302145
SWOMCD
SPC MCD 302145 
COZ000-302245-

MESOSCALE DISCUSSION 1653
NWS STORM PREDICTION CENTER NORMAN OK
0445 PM CDT MON JUL 30 2012

AREAS AFFECTED...E-CNTRL AND NERN CO HIGH PLAINS

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 302145Z - 302245Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...AN ISOLD SEVERE WIND GUST THREAT WILL CONTINUE TO DEVELOP
AND MOVE EWD INTO PARTS OF ERN CO THIS EVENING.

DISCUSSION...SCTD STORMS HAVE DEVELOPED DURING THE PAST FEW HOURS
AND MORE RECENTLY MOVED EWD INTO THE ADJACENT HIGH PLAINS.  THESE
STORMS ARE ROUNDING THE NRN PERIPHERY OF THE S-CNTRL U.S.
ANTICYCLONE AND ARE WITHIN A BELT OF MODESTLY STRONG WLY FLOW /35
KTS AT 6 KM AGL/ PER THE PLT VWP.  WEAK ELY LOW LEVEL COMPONENT TO
THE FLOW HAS MAINTAINED 50-55 DEG F DEWPOINTS WITH TEMPS RISING INTO
THE 90S DOWNSTREAM OF THE ONGOING STORMS.  MODIFYING THE 12Z DNR
RAOB FOR A 90 TEMP AND 50 DEWPOINT YIELDS 1200 J/KG SBCAPE ATOP A
DRY ADIABATIC LAPSE RATE FROM THE SURFACE-600 MB LEVEL.  AS
SUCH...APPRECIABLE PW /AROUND 1 INCH/ AND ADEQUATE FLOW FOR SOME
STORM ORGANIZATION ALONG WITH STORM MERGERS/COLD POOL CONSOLIDATION
WILL PROBABLY PROMOTE UPSCALE GROWTH INTO 1 OR MORE SMALL LINEAR
CLUSTERS CAPABLE OF ISOLD SEVERE WIND GUSTS AS THEY MOVE EWD DURING
THE LATE AFTERNOON INTO THE EVENING HOURS.

..SMITH/MEAD.. 07/30/2012

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

ATTN...WFO...GLD...PUB...BOU...

LAT...LON   40510500 40630242 38440214 38530469 40510500

Nearby

Mesoscale Discussions in Colorado, 2012 Every mesoscale discussion in 2012

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.