Alert archive / Michigan / Mesoscale Discussions in 2012

Mesoscale Discussion 260

March 15, 201216 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at Mar 15, 2012, 5:44 PM EDT for 16 counties in Michigan. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued
Mar 15, 2012, 5:44 PM EDT (21:44 UTC)
Expired
Mar 15, 2012, 6:45 PM EDT
In force
61 min
Issued by
the Storm Prediction Center

Counties 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, Saint Clair County, MI, Sanilac County, MI, Shiawassee County, MI, Tuscola County, MI, Washtenaw County, MI, Wayne County, MI

The radar

The Detroit radar (KDTX), 13 km from the middle of the area, began a volume at 21:48 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

Detroit, MI (KDTX), launched 12:00Z, 9.7 hours before the alert went out and 13 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, Detroit, MI at 12:00Z on 2012-03-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2007 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, Detroit, MI at 12:00Z on 2012-03-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 78 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
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.

626 
ACUS11 KWNS 152144
SWOMCD
SPC MCD 152144 
MIZ000-152245-

MESOSCALE DISCUSSION 0260
NWS STORM PREDICTION CENTER NORMAN OK
0444 PM CDT THU MAR 15 2012

AREAS AFFECTED...ERN MI

CONCERNING...SEVERE THUNDERSTORM WATCH 76...

VALID 152144Z - 152245Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 76
CONTINUES.

THREAT OF PRIMARILY LARGE HAIL AND PERHAPS AN ISOLATED TORNADO
PERSISTS ACROSS THE WW AREA.

SEVERE THUNDERSTORMS CONTINUE TO INCREASE IN COVERAGE ACROSS ERN
MI...PRIMARILY ALONG: 

1. A SWD SAGGING COLD FRONT NOTED FROM MANISTEE EWD TO BAD AXE
2. A SURFACE CONFLUENCE ZONE FROM SOUTH BEND NEWD TO BAD AXE
3. A SURFACE CONFLUENCE ZONE FROM NEAR TOLEDO NWD TO BAD AXE

ADDITIONALLY...A DISTINCT SUPERCELL HAS FORMED IN WASHTENAW COUNTY
NEAR A SURFACE LOW NOTED NEAR LANSING...WHERE SEVERAL OF THE
AFOREMENTIONED CONFLUENCE ZONES INTERSECT. HERE...ALTHOUGH DEEP
LAYER SHEAR VALUES REMAIN SOMEWHAT ON THE LOWER THRESHOLDS FOR
SUPERCELL FORMATION...LOCAL ENHANCEMENTS TO LOW-LEVEL SRH VALUES IN
ADDITION TO FAVORABLE THERMODYNAMICS HAVE COMPENSATED SUFFICIENTLY
AND AN ISOLATED TORNADO CANNOT BE RULED OUT. ADDITIONALLY...AN AXIS
OF 60S F DEW POINTS REMAINS OVER THIS AREA...WHICH WILL CONTINUE TO
BE SUPPORTIVE OF VIGOROUS UPDRAFTS GIVEN THE STEEP LOW-MID LEVEL
LAPSE RATE ENVIRONMENT NOTED ON THE 18Z DETROIT SOUNDING.

..HURLBUT.. 03/15/2012

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

ATTN...WFO...DTX...IWX...GRR...

LAT...LON   41748335 41878473 42498467 43258411 43758358 43898301
            43508265 42958251 41748335

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 15, 3:19 AM EDTMesoscale DiscussionSPCMonroe86 min
Mar 15, 3:52 PM EDTMesoscale DiscussionSPCBay, Genesee, Hillsdale, Ingham, Jackson, Lapeer and 12 more83 min
Mar 15, 4:28 PM EDTSevere Thunderstorm WatchSPCBay, Genesee, Huron, Lapeer, Lenawee, Livingston and 11 more7 hr

Nearby

Mesoscale 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.