Alert archive / Wisconsin / Mesoscale Discussions in 2012

Mesoscale Discussion 1369

July 2, 20129 counties in Michigan; 10 counties in Minnesota; 17 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 2, 2012, 10:17 PM EDT for 9 counties in Michigan; 10 counties in Minnesota; 17 counties in Wisconsin. It was in force for 118 min.

The area

The outline as issued.

The facts

Issued
Jul 2, 2012, 10:17 PM EDT (02:17 UTC)
Expired
Jul 3, 2012, 12:15 AM EDT
In force
118 min
Issued by
the Storm Prediction Center
All 36 counties

Baraga County, MI, Dickinson County, MI, Gogebic County, MI, Houghton County, MI, Iron County, MI, Keweenaw County, MI, Marquette County, MI, Menominee County, MI, Ontonagon County, MI, Aitkin County, MN, Carlton County, MN, Cook County, MN, Crow Wing County, MN, Kanabec County, MN, Lake County, MN, Mille Lacs County, MN, Morrison County, MN, Pine County, MN, Saint Louis County, MN, Ashland County, WI, Bayfield County, WI, Burnett County, WI, Douglas County, WI, Florence County, WI, Forest County, WI, Iron County, WI, Langlade County, WI, Lincoln County, WI, Marinette County, WI, Menominee County, WI, Oconto County, WI, Oneida County, WI, Price County, WI, Sawyer County, WI, Vilas County, WI, Washburn County, WI

The radar

The Duluth radar (KDLH), 161 km from the middle of the area, began a volume at 02:17 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, 2.3 hours before the alert went out and 285 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 2012-07-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2647 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 2012-07-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 134 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
2647 J/kg
Mixed-layer CIN
-104 J/kg
Mixed-layer LCL
1147 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
134 m²/s²
0-3 km storm-relative helicity
221 m²/s²
Significant tornado parameter
0.0
Supercell composite
12.7

Open this sounding in Storm Lab

The text

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

825 
ACUS11 KWNS 030218
SWOMCD
SPC MCD 030217
MIZ000-WIZ000-MNZ000-030415-

MESOSCALE DISCUSSION 1369
NWS STORM PREDICTION CENTER NORMAN OK
0917 PM CDT MON JUL 02 2012

AREAS AFFECTED...PORTIONS NERN MN...WRN LS...NRN WI...WRN-CENTRAL
UPPER MI.

CONCERNING...SEVERE THUNDERSTORM WATCH 455...

VALID 030217Z - 030415Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 455
CONTINUES.

SUMMARY...CONTINUE WW ALONG/AHEAD OF SVR BOW/MCS INITIALLY OVER NERN
MN.  ADDITIONAL WW APPEARS PROBABLE OVER PORTIONS NERN WI/UPPER MI.
ACTIVITY OVER NERN ND HAS DISSIPATED BEHIND ITS OWN GUST FRONT.
FURTHER CONVECTIVE DEVELOPMENT CANNOT BE RULED OUT OVER WRN PORTIONS
WW...WHETHER IN POCKETS OF UNDISTURBED BOUNDARY-LAYER AIR OVER RED
RIVER REGION...OR IN ELEVATED WAA REGIME ATOP EXPANDING MCS OUTFLOW.
 HOWEVER...BEST-ORGANIZED SVR THREAT BY FAR SHOULD REMAIN WITH MAIN
MCS.

DISCUSSION...DAMAGING BOW ECHO WILL CONTINUE TO POSE SVR WIND RISK
FROM DLH AREA ESEWD ACROSS ADJOINING PORTIONS LS/WI...DESPITE
PRESENCE OF SHALLOW MARINE LAYER.  SVR POTENTIAL THEREAFTER IS
SOMEWHAT MORE UNCERTAIN...BASED ON IMPACT OF MCS INTERACTION WITH
THAT LAYER...HOWEVER SURVIVING PORTION OF COMPLEX AGAIN WILL HAVE
ACCESS TO FAVORABLY MOIST/UNSTABLE AIR S OF LS.  COLD POOL AND
ATTENDANT ISALLOBARIC PERTURBATION ALREADY APPEARS SUFFICIENTLY
WELL-ORGANIZED THAT SVR GUSTS MAY BE FORCED DOWN THROUGH MARINE
LAYER OVER LAKE AND LAKE SHORE AS WELL.  SFC DEW POINTS 70S F S OF
LAKE-BREEZE FRONT WILL RESULT IN ONLY GRADUAL INCREASE IN
MLCINH...WHILE SUPPORTING MLCAPE 2500-4000 J/KG...BASED ON MODIFIED
MPX/GRB RAOBS AND MODEL SOUNDINGS.  TO EXTENT MEAN MOTION FOR PAST
COUPLE HOURS IS VALID...APEX OF BOW WOULD START TO EXIT ERN PORTIONS
WW AND REACH WRN UPPER MI AROUND 330Z.  SOME EWD TURN ALSO IS
POSSIBLE OVER UPPER MI BASED ON BACKING OF FORWARD-PROPAGATIONAL MCS
MOTION VECTORS IN BETWEEN LM-LS...INDICATED BY NEW NAM-BASED
GUIDANCE.

..EDWARDS.. 07/03/2012

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

ATTN...WFO...MQT...GRB...DLH...ARX...MPX...

LAT...LON   45809421 46779462 46669316 46819242 47169232 47379251
            47549310 47709180 48069120 48249088 48089080 48139060
            48089056 48109010 48008995 48038979 47998966 47998939
            47928923 48218848 48158843 47538762 47338783 46888772
            46678747 46498734 46488706 46498659 46508656 45838693
            44708802 45379011 45789374 45809421

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 2, 11:13 PM EDTSevere Thunderstorm WatchSPCBaraga, Dickinson, Gogebic, Houghton, Iron, Keweenaw and 3 more4 hr
Jul 3, 12:17 AM EDTMesoscale DiscussionSPCAlger, Baraga, Delta, Dickinson, Gogebic, Houghton and 6 more88 min
Jul 3, 3:24 AM EDTMesoscale DiscussionSPCAntrim, Bay, Benzie, Charlevoix, Cheboygan, Chippewa and 24 more96 min
Jul 3, 4:34 PM EDTMesoscale DiscussionSPCGenesee, Lapeer, Lenawee, Livingston, Macomb, Monroe and 4 more86 min
Jul 3, 3:00 AM EDTMesoscale DiscussionSPCAnoka, Benton, Carver, Chisago, Dakota, Hennepin and 11 more90 min
Jul 2, 8:23 PM EDTMesoscale DiscussionSPCBrown, Calumet, Columbia, Dane, Dodge, Florence and 18 more2 hr

Nearby

Mesoscale Discussions in Wisconsin, 2012Mesoscale Discussions in Minnesota, 2012Mesoscale Discussions in Michigan, 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.