Alert archive / Michigan / Mesoscale Discussions in 2012

Mesoscale Discussion 258

March 15, 201218 counties in Michigan; 14 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at Mar 15, 2012, 3:52 PM EDT for 18 counties in Michigan; 14 counties in Ohio. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Mar 15, 2012, 3:52 PM EDT (19:52 UTC)
Expired: Mar 15, 2012, 5:15 PM EDT
In force: 83 min
Issued by: the Storm Prediction Center

All 32 counties

Bay County, MI, Genesee County, MI, Hillsdale County, MI, Ingham County, MI, Jackson County, MI, Lapeer County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Monroe County, MI, Oakland County, MI, Saginaw County, MI, Saint Clair County, MI, Sanilac County, MI, Shiawassee County, MI, Tuscola County, MI, Washtenaw County, MI, Wayne County, MI, Allen County, OH, Defiance County, OH, Fulton County, OH, Hancock County, OH, Henry County, OH, Lucas County, OH, Ottawa County, OH, Paulding County, OH, Putnam County, OH, Sandusky County, OH, Seneca County, OH, Van Wert County, OH, Williams County, OH, Wood County, OH

The radar

The Detroit radar (KDTX), 34 km from the middle of the area, began a volume at 19:52 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.

Severe Thunderstorm Watch 76Mar 15, 4:30 PM EDT

The nearest sounding before it

Detroit, MI (KDTX), launched 12:00Z, 7.9 hours before the alert went out and 38 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2007 J/kg
Mixed-layer CIN: -65 J/kg
Mixed-layer LCL: 802 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 78 m²/s²
0-3 km storm-relative helicity: 66 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.

801 
ACUS11 KWNS 151953
SWOMCD
SPC MCD 151952
MIZ000-OHZ000-INZ000-152115-

MESOSCALE DISCUSSION 0258
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT THU MAR 15 2012

AREAS AFFECTED...SERN LOWER MI...NWRN OH

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 151952Z - 152115Z

THREAT FOR AT LEAST ISOLATED SEVERE STORMS PRIMARILY PRODUCING LARGE
HAIL SHOULD INCREASE ACROSS SERN LOWER MI. A SEVERE TSTM WATCH
ISSUANCE IS BEING CONSIDERED FOR THIS AREA.

A FEW TSTMS HAVE FORMED ALONG QUASI-STATIONARY FRONT EXTENDING W/E
THROUGH CNTRL LOWER MI...AND WITHIN A CONFLUENCE ZONE EXTENDING N/S
INTO NWRN OH. MODIFIED 18Z DTX RAOB SUGGESTS THE ENVIRONMENT IS
RATHER UNSTABLE WITH MLCAPE AROUND 2500 J/KG. 30 KT WLY FLOW AT 500
MB SHOULD BE SUFFICIENT FOR ORGANIZED UPDRAFTS. GIVEN THE STEEP
LAPSE RATE ENVIRONMENT...LARGE HAIL WILL BE THE PRIMARY SEVERE
THREAT. DESPITE THE LACK OF APPARENT LARGE-SCALE FORCING FOR
ASCENT...THE MODERATE TO STRONG INSTABILITY AND LACK OF MLCIN MAY
RESULT IN A GROWING CONVECTIVE CLUSTER DEVELOPING E/SEWD THROUGH
LATE AFTERNOON.

..GRAMS.. 03/15/2012

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

ATTN...WFO...CLE...ILN...DTX...IWX...GRR...

LAT...LON   43768406 43968300 43648241 42618242 41118312 40718374
            40768456 41638487 42488470 43768406

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 15, 3:19 AM EDT	Mesoscale Discussion	SPC	Monroe	86 min
Mar 15, 4:28 PM EDT	Severe Thunderstorm Watch	SPC	Bay, Genesee, Huron, Lapeer, Lenawee, Livingston and 11 more	7 hr
Mar 15, 5:44 PM EDT	Mesoscale Discussion	SPC	Genesee, Hillsdale, Ingham, Jackson, Lapeer, Lenawee and 10 more	61 min
Mar 15, 4:44 PM EDT	Mesoscale Discussion	SPC	Butler, Clermont, Hamilton, Preble	61 min
Mar 15, 5:28 PM EDT	Severe Thunderstorm Watch	SPC	Auglaize, Brown, Butler, Champaign, Clark, Clermont and 13 more	3 hr
Mar 15, 6:02 PM EDT	Mesoscale Discussion	SPC	Allen, Defiance, Fulton, Henry, Lucas, Paulding and 4 more	2 hr
Mar 15, 7:23 PM EDT	Mesoscale Discussion	SPC	Adams, Auglaize, Brown, Butler, Champaign, Clark and 12 more	97 min

Nearby

Mesoscale Discussions in Michigan, 2012 Mesoscale Discussions in Ohio, 2012 Every 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.