Alert archive / Michigan / Mesoscale Discussions in 2012

Mesoscale Discussion 674

May 3, 201234 counties in Michigan; 14 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 3, 2012, 11:34 AM EDT for 34 counties in Michigan; 14 counties in Wisconsin. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
May 3, 2012, 11:34 AM EDT (15:34 UTC)
Expired
May 3, 2012, 1:00 PM EDT
In force
86 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 48 counties

Arenac County, MI, Bay County, MI, Clare County, MI, Clinton County, MI, Genesee County, MI, Gladwin County, MI, Gratiot County, MI, Huron County, MI, Ionia County, MI, Iosco County, MI, Isabella County, MI, Kent County, MI, Lake County, MI, Lapeer County, MI, Manistee County, MI, Mason County, MI, Mecosta County, MI, Midland County, MI, Missaukee County, MI, Montcalm County, MI, Muskegon County, MI, Newaygo County, MI, Oceana County, MI, Ogemaw County, MI, Osceola County, MI, Oscoda County, MI, Ottawa County, MI, Roscommon County, MI, Saginaw County, MI, Saint Clair County, MI, Sanilac County, MI, Shiawassee County, MI, Tuscola County, MI, Wexford County, MI, Calumet County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Green Lake County, WI, Jefferson County, WI, Manitowoc County, WI, Milwaukee County, WI, Outagamie County, WI, Ozaukee County, WI, Sheboygan County, WI, Washington County, WI, Waukesha County, WI, Winnebago County, WI

The radar

The Grand Rapids radar (KGRR), 96 km from the middle of the area, began a volume at 15:35 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

Green Bay/Straub, WI (KGRB), launched 12:00Z, 3.6 hours before the alert went out and 190 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, Green Bay/Straub, WI at 12:00Z on 2012-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 321 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, Green Bay/Straub, WI at 12:00Z on 2012-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 160 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
321 J/kg
Mixed-layer CIN
-146 J/kg
Mixed-layer LCL
565 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
160 m²/s²
0-3 km storm-relative helicity
220 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.8

Open this sounding in Storm Lab

The text

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

954 
ACUS11 KWNS 031534
SWOMCD
SPC MCD 031534 
MIZ000-WIZ000-031700-

MESOSCALE DISCUSSION 0674
NWS STORM PREDICTION CENTER NORMAN OK
1034 AM CDT THU MAY 03 2012

AREAS AFFECTED...ECNTRL WI...LOWER MI

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 031534Z - 031700Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...THUNDERSTORMS ARE EXPECTED TO INCREASE ALONG A CORRIDOR
FROM ECNTRL WI INTO LOWER MI LATE THIS MORNING INTO THE EARLY
AFTERNOON.  LARGE HAIL AND GUSTY WINDS MAY BE NOTED.

DISCUSSION...REMNANT MCV IS LIFTING NEWD ACROSS SWRN WI AND
CONVECTION IS BEGINNING TO INCREASE A BIT JUST AHEAD OF THIS FEATURE
ACROSS ADAMS/SAUK COUNTIES IN SWRN WI.  THIS TREND IS EXPECTED TO
CONTINUE OVER THE NEXT FEW HOURS AND THERE IS INCREASING CONCERN
THAT AN ELONGATED CORRIDOR OF CONVECTION WILL EVOLVE...INITIALLY
SOMEWHAT ELEVATED TO THE NORTH OF THE WARM FRONT...ACROSS ECNTRL WI
INTO LOWER MI.  THE STRONGEST BOUNDARY LAYER HEATING IS OCCURRING
FROM SERN WI INTO SRN LOWER MI AND THIS WILL AID DESTABILIZATION FOR
ROBUST NEAR-SFC BASED STORMS NEAR THE WARM FRONT.  CLUSTERS OF
THUNDERSTORMS WILL GRADUALLY INCREASE IN AREAL COVERAGE/INTENSITY
INTO THE EARLY AFTERNOON AND THE PROBABILITY OF A SEVERE
THUNDERSTORM WATCH NEEDED ACROSS THIS REGION IS INCREASING.

..DARROW.. 05/03/2012

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

ATTN...WFO...DTX...APX...GRR...GRB...MKX...

LAT...LON   44418869 44718389 43928220 42698263 42678636 43068946
            44418869

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 3, 12:51 AM EDTMesoscale DiscussionSPCManistee, Mason, Oceana54 min
May 3, 12:41 PM EDTSevere Thunderstorm WatchSPCAlcona, Alpena, Antrim, Arenac, Bay, Benzie and 23 more5 hr
May 3, 2:35 PM EDTSevere Thunderstorm WatchSPCAllegan, Barry, Berrien, Branch, Calhoun, Cass and 27 more8 hr
May 3, 2:39 PM EDTMesoscale DiscussionSPCAntrim, Arenac, Bay, Benzie, Clare, Crawford and 18 more66 min
May 3, 3:53 PM EDTMesoscale DiscussionSPCBerrien67 min
May 3, 4:33 PM EDTMesoscale DiscussionSPCAllegan, Barry, Bay, Calhoun, Cass, Clinton and 15 more57 min
May 3, 6:57 PM EDTMesoscale DiscussionSPCAllegan, Barry, Berrien, Branch, Calhoun, Cass and 28 more63 min
May 2, 8:38 PM EDTMesoscale DiscussionSPCAdams, Buffalo, Jackson, Juneau, La Crosse, Monroe and 4 more37 min
May 2, 8:47 PM EDTSevere Thunderstorm WatchSPCAdams, Buffalo, Clark, Jackson, Juneau, La Crosse and 3 more5 hr
May 3, 9:43 AM EDTMesoscale DiscussionSPCAdams, Brown, Buffalo, Calumet, Clark, Columbia and 26 more92 min
May 3, 2:07 PM EDTSevere Thunderstorm WatchSPCColumbia, Dane, Dodge, Green, Jefferson, Kenosha and 7 more6 hr

Nearby

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