Alert archive / North Dakota / Mesoscale Discussions in 2011

Mesoscale Discussion 1721

July 24, 201119 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 24, 2011, 12:04 PM MDT for 19 counties in North Dakota. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued: Jul 24, 2011, 12:04 PM MDT (18:04 UTC)
Expired: Jul 24, 2011, 1:30 PM MDT
In force: 86 min
Issued by: the Storm Prediction Center

Counties Adams County, ND, Billings County, ND, Bowman County, ND, Burleigh County, ND, Dunn County, ND, Emmons County, ND, Grant County, ND, Hettinger County, ND, Kidder County, ND, Logan County, ND, McLean County, ND, Mercer County, ND, Morton County, ND, Oliver County, ND, Sheridan County, ND, Sioux County, ND, Slope County, ND, Stark County, ND, Wells County, ND

The radar

The Bismarck radar (KBIS), 73 km from the middle of the area, began a volume at 18:06 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 681Jul 24, 1:45 PM MDT

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 6.1 hours before the alert went out and 77 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: 51 J/kg
Mixed-layer CIN: -148 J/kg
Mixed-layer LCL: 1184 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 122 m²/s²
0-3 km storm-relative helicity: 150 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.

063 
ACUS11 KWNS 241805
SWOMCD
SPC MCD 241804
NDZ000-SDZ000-MTZ000-241930-

MESOSCALE DISCUSSION 1721
NWS STORM PREDICTION CENTER NORMAN OK
0104 PM CDT SUN JUL 24 2011

AREAS AFFECTED...SWRN/CNTRL ND

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 241804Z - 241930Z

ISOLATED THUNDERSTORMS ARE FORECAST TO DEVELOP BY EARLY/MID
AFTERNOON...AND MAY POSE A THREAT FOR DAMAGING WINDS AND LARGE HAIL.
ATTM...A WW DOES NOT APPEAR LIKELY DUE TO LIMITED SVR WEATHER
COVERAGE. HOWEVER...CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED.


MID-DAY SURFACE ANALYSIS SHOWS A WEAK AREA OF CONVERGENCE LOCATED
FROM PORTIONS OF FAR WRN ND E-NEWD TO DVL. TEMPERATURES ALONG AND S
OF THIS BOUNDARY ARE WARMING INTO THE UPPER 70S TO LOW 80S...WHILE
LOW-LEVEL MOISTURE ADVECTION HAS BOOSTED SURFACE DEWPOINTS INTO THE
MID 60S. THE WARMING BOUNDARY LAYER IS AIDING IN STEEPENING
LOW-LEVEL LAPSE RATES/DESTABILIZATION...WITH A GRADUAL DECREASE IN
MLCIN OBSERVED IN OBJECTIVE ANALYSIS GUIDANCE DURING THE PAST FEW
HOURS. AS A RESULT...SURFACE BASED CUMULUS GROWTH IS OCCURRING NEAR
THE LOW-LEVEL CONVERGENCE ZONE. DESPITE A LACK OF STRONG LARGE-SCALE
ASCENT...OBSERVATIONAL TRENDS ALONG WITH RECENT RUC AND 3KM HRRR
GUIDANCE SUGGEST ISOLATED STORMS MAY FORM DURING THE NEXT FEW HOURS
OVER PORTIONS OF SWRN AND CNTRL ND. THE PRESENCE OF STRONG 40+ KT
DEEP LAYER WLY SHEAR AND MLCAPE VALUES UP TO 1500 J/KG SUGGEST A
SUPERCELL WILL BE POSSIBLE...POSING MAINLY A DAMAGING WIND/LARGE
HAIL THREAT. DUE TO ISOLATED STORM COVERAGE...THE SVR WEATHER THREAT
MAY NOT BE WIDESPREAD ENOUGH TO SUPPORT A WW...BUT CONVECTIVE TRENDS
WILL CONTINUE TO BE MONITORED.

..GARNER.. 07/24/2011

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

ATTN...WFO...FGF...ABR...BIS...UNR...BYZ...

LAT...LON   47860211 48199945 47169877 45999997 45760284 46150419
            46860392 47860211

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 24, 1:43 PM MDT	Severe Thunderstorm Watch	SPC	Adams, Barnes, Billings, Bowman, Burleigh, Cass and 26 more	6 hr
Jul 24, 4:26 PM MDT	Mesoscale Discussion	SPC	Adams, Barnes, Benson, Bowman, Burleigh, Cass and 22 more	94 min

Nearby

Mesoscale Discussions in North Dakota, 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.