Alert archive / Michigan / Tornado Watches in 2012
Tornado Watch 74
The Storm Prediction Center issued this tornado watch at Mar 12, 2012, 7:36 PM EDT for 13 counties in Michigan; 8 counties in Ohio. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 12, 2012, 7:36 PM EDT (23:36 UTC)
- Expired
- Mar 13, 2012, 2:58 AM EDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 21 counties
Genesee County, MI, Huron 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, Tuscola County, MI, Washtenaw County, MI, Wayne County, MI, Defiance County, OH, Fulton County, OH, Henry County, OH, Lucas County, OH, Ottawa County, OH, Sandusky County, OH, Williams County, OH, Wood County, OH
The radar
The Detroit radar (KDTX), 26 km from the middle of the area, began a volume at 23:36 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 40%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 12, 8:40 PM EDT | Severe Thunderstorm Warning | DTX | Tuscola | 50 min |
| Mar 12, 8:47 PM EDT | Tornado Warning | DTX | Tuscola | 16 min |
| Mar 12, 9:01 PM EDT | Severe Thunderstorm Warning | DTX | Huron, Sanilac | 44 min |
| Mar 12, 9:40 PM EDT | Severe Thunderstorm Warning | DTX | Lenawee | 36 min |
| Mar 12, 11:37 PM EDT | Severe Thunderstorm Warning | CLE | Lucas | 53 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Detroit, MI (KDTX), launched 12:00Z, 11.6 hours before the alert went out and 24 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1981 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 124 m²/s²
- 0-3 km storm-relative helicity
- 86 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
419
WWUS20 KWNS 122336
SEL4
SPC WW 122336
MIZ000-OHZ000-LEZ000-LHZ000-130700-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 74
NWS STORM PREDICTION CENTER NORMAN OK
735 PM EDT MON MAR 12 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
EASTERN LOWER MICHIGAN
NORTHWEST OHIO
LAKE ERIE
LAKE HURON
EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 735 PM UNTIL
300 AM EDT.
TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 45 STATUTE
MILES EAST AND WEST OF A LINE FROM 20 MILES NORTH NORTHEAST OF
BAD AXE MICHIGAN TO 25 MILES SOUTH SOUTHWEST OF TOLEDO OHIO. FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU4).
REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.
OTHER WATCH INFORMATION...CONTINUE...WW 73...
DISCUSSION...MIGRATORY SHORT-WAVE TROUGH WILL PROGRESS ACROSS THE
WATCH AREA TONIGHT...FOCUSING A BAND OF TSTMS ALONG AND AHEAD OF
ATTENDANT SURFACE COLD FRONT. THOUGH INSTABILITY WILL REMAIN QUITE
MARGINAL...THE DEGREE OF FORCING FOR ASCENT AND RATHER STRONG LOW-
AND DEEP-LAYER SHEAR WILL MAINTAIN A RISK FOR EMBEDDED SUPERCELL
AND/OR BOWING STRUCTURES CAPABLE OF DAMAGING WINDS AND PERHAPS A
COUPLE OF TORNADOES.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
350. MEAN STORM MOTION VECTOR 23040.
...MEADSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 12, 12:03 PM EDT | Mesoscale Discussion | SPC | Allegan, Berrien, Cass, Van Buren | 57 min |
| Mar 12, 4:22 PM EDT | Tornado Watch | SPC | Allegan, Arenac, Barry, Bay, Berrien, Branch and 25 more | 7 hr |
| Mar 12, 6:29 PM EDT | Mesoscale Discussion | SPC | Arenac, Bay, Branch, Calhoun, Clinton, Eaton and 18 more | 91 min |
Nearby
Tornado Watches in Michigan, 2012Tornado Watches in Ohio, 2012Every tornado watch 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.