Alert archive / North Dakota / Mesoscale Discussions in 2012

Mesoscale Discussion 1471

July 15, 20128 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 15, 2012, 4:00 PM CDT for 8 counties in North Dakota. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued: Jul 15, 2012, 4:00 PM CDT (21:00 UTC)
Expired: Jul 15, 2012, 5:30 PM CDT
In force: 90 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Bottineau County, ND, Burke County, ND, McHenry County, ND, McLean County, ND, Mountrail County, ND, Pierce County, ND, Renville County, ND, Ward County, ND

The watches that followed

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

Tornado Watch 486Jul 15, 5:30 PM CDT

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 9.0 hours before the alert went out and 171 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: 312 J/kg
Mixed-layer CIN: -301 J/kg
Mixed-layer LCL: 1428 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 339 m²/s²
0-3 km storm-relative helicity: 822 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

249 
ACUS11 KWNS 152101
SWOMCD
SPC MCD 152100
NDZ000-152230-

MESOSCALE DISCUSSION 1471
NWS STORM PREDICTION CENTER NORMAN OK
0400 PM CDT SUN JUL 15 2012

AREAS AFFECTED...PARTS OF NWRN THROUGH N CNTRL NORTH DAKOTA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 152100Z - 152230Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...ISOLATED SEVERE STORM DEVELOPMENT APPEARS POSSIBLE WITHIN
THE NEXT COUPLE OF HOURS...AND TRENDS ARE BEING MONITORED FOR AN
INCREASING SEVERE THREAT THAT COULD REQUIRE A WW LATER THIS
AFTERNOON.

DISCUSSION...ALTHOUGH AN 18Z SOUNDING FROM BISMARCK IS SUGGESTIVE OF
SUPPRESSED CONVECTIVE POTENTIAL DUE TO CAPPING ISSUES...RELATIVELY
LOW MOISTURE VALUES AND MODEST MIXED LAYER CAPE...OBSERVATIONAL AND
MODEL DATA INDICATE POTENTIALLY GREATER INSTABILITY ASSOCIATED WITH
HIGHER MOISTURE CONTENT AIR ALONG THE WARM FRONT IN CLOSER PROXIMITY
TO THE SURFACE LOW OVER NORTHWESTERN NORTH DAKOTA.  AND IT APPEARS
THAT A ZONE OF ENHANCED LOW-LEVEL CONVERGENCE COUPLED WITH STRONG
LOW-LEVEL WARM ADVECTION COULD BECOME SUPPORTIVE OF AT LEAST
ISOLATED STORM DEVELOPMENT BY 22-23Z...WITH HIGHEST PROBABILITIES
NEAR/NORTH THROUGH EAST OF MINOT.  IF THIS OCCURS... VERTICAL SHEAR
BENEATH 30-40 KT SOUTHWESTERLY 500 MB FLOW WILL BE SUPPORTIVE OF
ORGANIZED CONVECTIVE DEVELOPMENT...INCLUDING SUPERCELLS.  CLOCKWISE
CURVED LOW-LEVEL HODOGRAPHS ARE SIZABLE... AND SUPPORTIVE OF SOME
TORNADIC POTENTIAL...BUT THIS THREAT MAY BE LIMITED BY SIZABLE
SUB-CLOUD TEMPERATURE/DEW POINT SPREADS.  LOCALLY STRONG DAMAGING
WIND GUSTS MAY BECOME THE MORE PROMINENT SEVERE THREAT...WITH LARGE
HAIL ALSO POSSIBLE.

..KERR/CARBIN.. 07/15/2012

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

ATTN...WFO...FGF...BIS...

LAT...LON   48510275 48910256 48850019 48579941 48119936 47650010
            47550097 47830224 48510275

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 15, 5:31 PM CDT	Tornado Watch	SPC	Benson, Bottineau, Burke, Cavalier, Eddy, McHenry and 10 more	6 hr

Nearby

Mesoscale Discussions in North Dakota, 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.