Alert archive / Minnesota / Mesoscale Discussions in 2012

Mesoscale Discussion 1677

August 1, 201233 counties in Minnesota; 9 counties in South Dakota

The Storm Prediction Center issued this mesoscale discussion at Aug 1, 2012, 7:35 PM CDT for 33 counties in Minnesota; 9 counties in South Dakota. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued
Aug 1, 2012, 7:35 PM CDT (00:35 UTC)
Expired
Aug 1, 2012, 8:30 PM CDT
In force
55 min
Issued by
the Storm Prediction Center
All 42 counties

Anoka County, MN, Blue Earth County, MN, Brown County, MN, Carver County, MN, Chippewa County, MN, Cottonwood County, MN, Dakota County, MN, Dodge County, MN, Goodhue County, MN, Hennepin County, MN, Kandiyohi County, MN, Lac qui Parle County, MN, Le Sueur County, MN, Lincoln County, MN, Lyon County, MN, McLeod County, MN, Meeker County, MN, Murray County, MN, Nicollet County, MN, Pipestone County, MN, Ramsey County, MN, Redwood County, MN, Renville County, MN, Rice County, MN, Scott County, MN, Sibley County, MN, Steele County, MN, Swift County, MN, Waseca County, MN, Washington County, MN, Watonwan County, MN, Wright County, MN, Yellow Medicine County, MN, Brookings County, SD, Codington County, SD, Deuel County, SD, Grant County, SD, Hamlin County, SD, Kingsbury County, SD, Lake County, SD, Miner County, SD, Moody County, SD

The radar

The Minneapolis radar (KMPX), 92 km from the middle of the area, began a volume at 00:39 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 00:00Z, 0.6 hours before the alert went out and 89 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 00:00Z on 2012-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2247 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, Minneapolis, MN at 00:00Z on 2012-08-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 51 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
2247 J/kg
Mixed-layer CIN
-65 J/kg
Mixed-layer LCL
1724 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
101 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.9

Open this sounding in Storm Lab

The text

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

936 
ACUS11 KWNS 020036
SWOMCD
SPC MCD 020035
WIZ000-MNZ000-SDZ000-020130-

MESOSCALE DISCUSSION 1677
NWS STORM PREDICTION CENTER NORMAN OK
0735 PM CDT WED AUG 01 2012

AREAS AFFECTED...SRN MN...ERN SD

CONCERNING...SEVERE THUNDERSTORM WATCH 549...

VALID 020035Z - 020130Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 549
CONTINUES.

SUMMARY...CLUSTER OF SVR TSTMS NEAR RWF WILL LIKELY CONTINUE WITH A
THREAT OF WIND DAMAGE THROUGH AT LEAST 03Z. BEYOND
THAT...UNCERTAINTY EXISTS DUE TO THE DEGREE TO WHICH THE COLD
POOL/SHEAR BALANCE CAN BE MAINTAINED. STRONGER UPDRAFTS WITHIN THIS
CLUSTER WILL ALSO HAVE THE POTENTIAL TO PRODUCE LARGE HAIL.

DISCUSSION...SVR TSTMS VICINITY RWF HAVE DEVELOPED A SMALL COLD POOL
AND ARE PRODUCING DAMAGING WINDS...REF G69KT AT RWF...THAT WILL
LIKELY CONTINUE THROUGH AT LEAST 03Z. ENVIRONMENT AHEAD OF THIS
CLUSTER IS CHARACTERIZED BY MLCAPE IN EXCESS OF 3000 J/KG AND A
LARGELY UNIDIRECTIONAL WIND PROFILE ABOVE THE BOUNDARY LAYER.
SHORT-TERM ENVIRONMENT APPEARS FAVORABLE FOR ADDITIONAL ENHANCED
WIND DAMAGE THREAT. BEYOND 03Z...THERE IS SOME QUESTION WHETHER THE
COLD POOL/SHEAR BALANCE CAN BE MAINTAINED AND SUSTAIN THE WIND
DAMAGE THREAT. IN ADDITION...THE LOSS OF DIURNAL HEATING WILL LIKELY
LEAD TO INCREASING CINH WITH TIME LATER THIS EVENING.

..BUNTING/HART.. 08/02/2012

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

ATTN...WFO...ARX...MPX...FSD...ABR...

LAT...LON   45309269 43719270 43719771 45319770 45309269

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 1, 10:11 PM CDTMesoscale DiscussionSPCFillmore, Houston, Olmsted, Wabasha, Winona94 min
Aug 1, 8:19 PM CDTMesoscale DiscussionSPCBon Homme, Clay, Union, Yankton56 min
Aug 2, 2:44 PM CDTMesoscale DiscussionSPCButte, Harding, Lawrence, Meade, Perkins31 min
Aug 2, 3:03 PM CDTSevere Thunderstorm WatchSPCButte, Harding, Lawrence, Meade, Perkins7 hr

Nearby

Mesoscale Discussions in Minnesota, 2012Mesoscale Discussions in South Dakota, 2012Every 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.