Alert archive / Minnesota / Mesoscale Discussions in 2017

Mesoscale Discussion 941

June 2, 20177 counties in Iowa; 26 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Jun 2, 2017, 5:49 PM CDT for 7 counties in Iowa; 26 counties in Minnesota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jun 2, 2017, 5:49 PM CDT (22:49 UTC)
Expired
Jun 2, 2017, 8:15 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%
All 33 counties

Cerro Gordo County, IA, Floyd County, IA, Hancock County, IA, Kossuth County, IA, Mitchell County, IA, Winnebago County, IA, Worth County, IA, Blue Earth County, MN, Brown County, MN, Carver County, MN, Dakota County, MN, Dodge County, MN, Douglas County, MN, Faribault County, MN, Freeborn County, MN, Hennepin County, MN, Kandiyohi County, MN, Le Sueur County, MN, Martin County, MN, McLeod County, MN, Meeker County, MN, Mower County, MN, Nicollet County, MN, Pope County, MN, Renville County, MN, Rice County, MN, Scott County, MN, Sibley County, MN, Stearns County, MN, Steele County, MN, Waseca County, MN, Watonwan County, MN, Wright County, MN

The radar

The Minneapolis radar (KMPX), 74 km from the middle of the area, began a volume at 22:52 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 nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 10.8 hours before the alert went out and 73 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-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2017-06-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 2017-06-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 78 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
1706 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
78 m²/s²
0-3 km storm-relative helicity
90 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

127 
ACUS11 KWNS 022249
SWOMCD
SPC MCD 022249 
IAZ000-MNZ000-030115-

Mesoscale Discussion 0941
NWS Storm Prediction Center Norman OK
0549 PM CDT Fri Jun 02 2017

Areas affected...Portions of central/southern MN and northern IA

Concerning...Severe potential...Watch unlikely 

Valid 022249Z - 030115Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated severe thunderstorm potential will exist into the
evening hours from portions of central MN into northern IA, though
Watch issuance will not be needed.

DISCUSSION...Strong surface heating has allowed temperatures to warm
into the lower 90s in many areas west/southwest of a warm front
draped northwest-southeast from west-central MN to north-central IA.
This boundary will continue to advance eastward/northeastward into
the evening hours. Weak warm advection near this boundary, coupled
with diurnally bolstered baroclinic circulations across the
boundary, have promoted widely scattered thunderstorm development --
concentrated across the warm side of the frontal zone. Steep
tropospheric lapse rates are supporting 1000-2000 J/kg of MLCAPE
characterizing convective inflow, despite an overall paucity of
low-level moisture (surface dewpoints in the 50s). Large DCAPE will
support microbursts with an isolated damaging-wind risk, especially
where local cold-pool amalgamation occurs. Severe hail may also
accompany incipient intense updrafts. However, with stronger
effective shear -- and only reaching 20-25 kt -- displaced to the
cool side of the boundary, storms should remain disorganized while
slowly spreading eastward/southeastward into the evening hours.
Isolated severe hail potential may persist well into the evening
hours, as a cross-frontal low-level jet nocturnally strengthens
encouraging some increase in warm advection and elevated convection
potential.

..Cohen/Thompson.. 06/02/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...ARX...MPX...DMX...FGF...

LAT...LON   42789394 43839467 45299558 45959566 46179516 45699417
            44689301 43869249 43039251 42789291 42789394

Nearby

Mesoscale Discussions in Minnesota, 2017Mesoscale Discussions in Iowa, 2017Every mesoscale discussion in 2017

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.