Alert archive / Minnesota / Mesoscale Discussions in 2012

Mesoscale Discussion 1539

July 22, 201213 counties in Minnesota; 8 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 22, 2012, 1:40 PM CDT for 13 counties in Minnesota; 8 counties in North Dakota. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued: Jul 22, 2012, 1:40 PM CDT (18:40 UTC)
Expired: Jul 22, 2012, 3:15 PM CDT
In force: 95 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 21 counties

Becker County, MN, Beltrami County, MN, Clay County, MN, Clearwater County, MN, Hubbard County, MN, Koochiching County, MN, Lake of the Woods County, MN, Mahnomen County, MN, Norman County, MN, Pennington County, MN, Polk County, MN, Red Lake County, MN, Wilkin County, MN, Barnes County, ND, Cass County, ND, Dickey County, ND, LaMoure County, ND, Ransom County, ND, Richland County, ND, Sargent County, ND, Traill County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 97 km from the middle of the area, began a volume at 18:42 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 502Jul 22, 3:25 PM CDT

The nearest sounding before it

International Fa, MN (KINL), launched 12:00Z, 6.7 hours before the alert went out and 239 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: 1489 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 76 m²/s²
0-3 km storm-relative helicity: 93 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.

209 
ACUS11 KWNS 221841
SWOMCD
SPC MCD 221840
MNZ000-NDZ000-222015-

MESOSCALE DISCUSSION 1539
NWS STORM PREDICTION CENTER NORMAN OK
0140 PM CDT SUN JUL 22 2012

AREAS AFFECTED...PARTS OF SERN NORTH DAKOTA THRU MUCH OF NWRN/N
CNTRL MN

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 221840Z - 222015Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...TRENDS ARE BEING MONITORED FOR THE POSSIBILITY OF AN
INCREASING SEVERE THREAT WHICH COULD REQUIRE A SEVERE WEATHER WATCH
WITHIN THE NEXT COUPLE OF HOURS.

DISCUSSION...LATEST OBJECTIVE ANALYSES INDICATE THAT MIXED LAYER
CAPE WITHIN A PRE-FRONTAL AXIS OF STRONGER SURFACE HEATING ACROSS
THE REGION IS BECOMING MODERATELY LARGE /ON THE ORDER OF 2000-3000 J
PER KG/.  AND A WEAKNESS IN MID-LEVEL INHIBITION APPEARS TO BE
DEVELOPING...SOUTH OF AN EAST SOUTHEASTWARD PROGRESSING SHORT WAVE
IMPULSE... NEAR/NORTH OF THE INTERNATIONAL BORDER.  GUIDANCE IS
SUGGESTIVE THAT SOME INCREASE IN MID-LEVEL FORCING FOR ASCENT MAY
OCCUR AS FAR SOUTH AS NORTHERN MINNESOTA...WHICH MAY CONTRIBUTE TO
THE INITIATION AND DEVELOPMENT OF STORMS DURING THE 20-22Z TIME
FRAME.  PRE-FRONTAL LOW-LEVEL CONVERGENCE APPEARS GENERALLY WEAK
...WHICH PROBABLY WILL LIMIT CONVECTIVE COVERAGE...BUT ISOLATED TO
WIDELY SCATTERED STORM DEVELOPMENT APPEARS POSSIBLE AT LEAST AS FAR
SOUTH AS SOUTHEASTERN NORTH DAKOTA INTO PORTIONS OF WEST CENTRAL
MINNESOTA.  THIS SEEMS TO BE SUPPORTED BY LATEST TRENDS IN VISIBLE
SATELLITE IMAGERY.

IF/WHEN STORMS BEGIN TO FORM...DEEP LAYER SHEAR...NEAR A 40-50 KT
WESTERLY 500 MB JET STREAK MIGRATING EASTWARD IN THE VICINITY OF THE
INTERNATIONAL BORDER AREA...WILL BE CONDUCIVE TO ORGANIZED
CONVECTIVE DEVELOPMENT...INCLUDING ISOLATED SUPERCELLS.  DAMAGING
WIND GUSTS APPEAR TO BE THE MOST PROMINENT SEVERE THREAT...IN
ADDITION TO THE POTENTIAL FOR LARGE HAIL.

..KERR/HART.. 07/22/2012

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

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

LAT...LON   48509303 47359377 46069665 46119907 46419908 47089785
            48119648 48899539 48509303

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 21, 10:51 PM CDT	Mesoscale Discussion	SPC	Lincoln, Lyon, Murray, Nobles, Pipestone, Redwood and 2 more	54 min
Jul 22, 2:32 PM CDT	Mesoscale Discussion	SPC	Blue Earth, Dodge, Faribault, Fillmore, Freeborn, Houston and 8 more	88 min
Jul 22, 3:25 PM CDT	Severe Thunderstorm Watch	SPC	Aitkin, Becker, Beltrami, Carlton, Cass, Clay and 18 more	6 hr
Jul 22, 5:45 PM CDT	Severe Thunderstorm Watch	SPC	Big Stone, Traverse	4 hr
Jul 22, 6:55 PM CDT	Mesoscale Discussion	SPC	Becker, Beltrami, Cass, Clay, Clearwater, Hubbard and 11 more	95 min
Jul 21, 9:27 PM CDT	Mesoscale Discussion	SPC	Adams, Billings, Bowman, Burke, Divide, Dunn and 14 more	63 min

Nearby

Mesoscale Discussions in Minnesota, 2012 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; radar from the NEXRAD Level II archive.