Alert archive / Minnesota / Mesoscale Discussions in 2018

Mesoscale Discussion 1017

July 8, 201811 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Jul 8, 2018, 5:30 AM CDT for 11 counties in Minnesota. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued
Jul 8, 2018, 5:30 AM CDT (10:30 UTC)
Expired
Jul 8, 2018, 7:00 AM CDT
In force
90 min
Issued by
the Storm Prediction Center

Counties Beltrami County, MN, Clearwater County, MN, Itasca County, MN, Kittson County, MN, Koochiching County, MN, Lake of the Woods County, MN, Marshall County, MN, Pennington County, MN, Polk County, MN, Red Lake County, MN, Roseau County, MN

The radar

The Fargo/Grand Forks radar (KMVX), 174 km from the middle of the area, began a volume at 10:34 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.

The nearest sounding before it

International Fa, MN (KINL), launched 00:00Z, 10.5 hours before the alert went out and 152 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, International Fa, MN at 00:00Z on 2018-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1565 joules per kilogram.LCLLFCEL10008507005003002001001 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, International Fa, MN at 00:00Z on 2018-07-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 98 square meters per square second.193958Sfc1 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
1565 J/kg
Mixed-layer CIN
-140 J/kg
Mixed-layer LCL
1282 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
98 m²/s²
0-3 km storm-relative helicity
350 m²/s²
Significant tornado parameter
0.4
Supercell composite
13.6

Open this sounding in Storm Lab

The text

As transmitted.

844 
ACUS11 KWNS 081030
SWOMCD
SPC MCD 081030 
MNZ000-NDZ000-081200-

Mesoscale Discussion 1017
NWS Storm Prediction Center Norman OK
0530 AM CDT Sun Jul 08 2018

Areas affected...Portions of northern Minnesota

Concerning...Severe Thunderstorm Watch 265...

Valid 081030Z - 081200Z

The severe weather threat for Severe Thunderstorm Watch 265
continues.

SUMMARY...A few severe storms, primarily capable of severe gusts,
remain possible over northern Minnesota early this morning. Some of
these could develop east of ongoing Watch 265, but may be limited
enough in spatial extent to preclude downstream watch issuance. If
trends suggest otherwise, though, a watch could be issued for parts
of the Duluth, MN CWA later this morning.

DISCUSSION...A forward-propagating cluster of severe cells is
continuing east/northeast around 40-45 kt early this morning. This
cluster has been associated with a string of severe-wind reports
over North Dakota, and this trend may persist through sunrise,
especially given enhanced propagation from new warm-advection
development to the east. The 00Z INL sounding, modified for regional
surface observations, confirms considerable convective inhibition
exists ahead of the cluster, but strong forced ascent along the cold
pool and steep mid-level lapse rates continue to overcome this
impediment. 

At its current trajectory/speed, these cells should reach the
eastern edge of Watch 265 around 7-730am CDT. Additionally,
downstream warm-advection cells may depart the watch even sooner.
However, these cells appear to be weaker/more elevated, possibly due
to a lack of stronger forced ascent (unlike the upstream cluster).
Therefore, new watch issuance may not need to be considered until
the primary cluster approaches the edge of the watch. Even then, it
may only glance northwest portions of the DLH CWA (e.g., Koochiching
Co). Such a limited spatial extent outside of the ongoing watch may
not necessitate new watch issuance.

..Picca.. 07/08/2018

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

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

LAT...LON   48479709 48899718 49009676 49179538 49329484 48799374
            48559296 47849285 47449313 47309449 47389677 47969706
            48479709

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 8, 2:35 AM CDTMesoscale DiscussionSPCBeltrami, Clearwater, Kittson, Lake of the Woods, Marshall, Norman and 4 more85 min
Jul 8, 3:14 AM CDTSevere Thunderstorm WatchSPCBeltrami, Clearwater, Kittson, Lake of the Woods, Marshall, Pennington and 3 more5 hr
Jul 8, 6:59 AM CDTSevere Thunderstorm WatchSPCCook, Itasca, Koochiching, Lake, Saint Louis4 hr
Jul 8, 9:23 AM CDTMesoscale DiscussionSPCCook, Lake, Saint Louis97 min
Jul 8, 1:16 PM CDTMesoscale DiscussionSPCBecker, Beltrami, Clay, Clearwater, Hubbard, Mahnomen and 4 more2 hr
Jul 8, 3:52 PM CDTSevere Thunderstorm WatchSPCAitkin, Becker, Big Stone, Carlton, Cass, Clay and 15 more7 hr
Jul 8, 5:46 PM CDTMesoscale DiscussionSPCAitkin, Becker, Benton, Big Stone, Carlton, Cass and 22 more119 min

Nearby

Mesoscale Discussions in Minnesota, 2018Every mesoscale discussion in 2018

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.