Alert archive / Minnesota / Mesoscale Discussions in 2011

Mesoscale Discussion 2091

September 1, 20117 counties in Minnesota

The Storm Prediction Center issued this mesoscale discussion at Sep 1, 2011, 6:39 AM CDT for 7 counties in Minnesota. It was in force for 36 min.

The area

The outline as issued.

The facts

Issued
Sep 1, 2011, 6:39 AM CDT (11:39 UTC)
Expired
Sep 1, 2011, 7:15 AM CDT
In force
36 min
Issued by
the Storm Prediction Center

Counties Beltrami County, MN, Cass County, MN, Clearwater County, MN, Hubbard County, MN, Itasca County, MN, Koochiching County, MN, Wadena County, MN

The radar

The Duluth radar (KDLH), 195 km from the middle of the area, began a volume at 11:40 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

International Fa, MN (KINL), launched 00:00Z, 11.7 hours before the alert went out and 155 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 2011-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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 2011-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 59 square meters per square second.19395878Sfc1 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
4 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
463 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
59 m²/s²
0-3 km storm-relative helicity
145 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.

666 
ACUS11 KWNS 011140
SWOMCD
SPC MCD 011139
MNZ000-011215-

MESOSCALE DISCUSSION 2091
NWS STORM PREDICTION CENTER NORMAN OK
0639 AM CDT THU SEP 01 2011

AREAS AFFECTED...NRN MN

CONCERNING...SEVERE THUNDERSTORM WATCH 820...

VALID 011139Z - 011215Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 820
CONTINUES.

WW 820 WILL BE ALLOWED TO EXPIRE AT 12Z...AND A NEW WW ISSUANCE IS
UNLIKELY AT THIS TIME.

AN ISOLATED SEVERE WEATHER THREAT REMAINS ACROSS THE ERN EXTENT OF
WW 820 ACROSS NORTH CENTRAL MN /CLEARWATER AND BELTRAMI COUNTIES/
AND INTO ADJACENT COUNTIES OF NRN CASS TO KOOCHICHING.
HOWEVER...EVEN THIS THREAT APPEARS TO BE WANING PER A DECREASING
TREND IN LIGHTNING STRIKES AND WARMING CLOUD TOPS ALONG THE
ATTENDANT SRN PERIPHERY OF THE MCS CONVECTIVE CLOUD/PRECIPITATION
SHIELD ADVANCING EWD ACROSS NRN MN EARLY THIS MORNING.

LOW LEVEL WAA SHOULD GRADUALLY WEAKEN ACROSS MUCH OF NORTH
CENTRAL-NERN MN AS THE SWLY LLJ ALSO DECREASES IN SPEED.  THIS
ASCENT COMBINED WITH DIFFLUENT FLOW REGIME ALOFT OVER NRN MN WILL
PROVIDE SUFFICIENT DEEP LAYER UVVS FOR CONTINUED SHOWERS/TSTMS THIS
MORNING.  HOWEVER...WEAKENING WAA/INSTABILITY SUGGEST A LOWER
POTENTIAL FOR THE DEVELOPMENT OF MORE ROBUST UPDRAFTS AND SUBSEQUENT
SEVERE WEATHER THREAT.

..PETERS.. 09/01/2011

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

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

LAT...LON   47169533 47689559 48139546 48489421 48439322 47709327
            46949397 46579457 46569507 47169533

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 1, 12:48 AM CDTSevere Thunderstorm WatchSPCBeltrami, Clearwater, Kittson, Lake of the Woods, Mahnomen, Marshall and 5 more6 hr
Sep 1, 3:40 AM CDTMesoscale DiscussionSPCBeltrami, Clearwater, Itasca, Kittson, Koochiching, Lake of the Woods and 7 more65 min

Nearby

Mesoscale Discussions in Minnesota, 2011Every 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.