Alert archive / Michigan / Tornado Watches in 2008

Tornado Watch 481

June 7, 200813 counties in Michigan

The Storm Prediction Center issued this tornado watch at Jun 7, 2008, 6:42 PM EDT for 13 counties in Michigan. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jun 7, 2008, 6:42 PM EDT (22:42 UTC)
Expired: Jun 8, 2008, 12:00 AM EDT
In force: 5 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

Counties Allegan County, MI, Barry County, MI, Calhoun County, MI, Clinton County, MI, Eaton County, MI, Gratiot County, MI, Ionia County, MI, Kalamazoo County, MI, Kent County, MI, Montcalm County, MI, Muskegon County, MI, Ottawa County, MI, Van Buren County, MI

The radar

The Grand Rapids radar (KGRR), 68 km from the middle of the area, began a volume at 23:01 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: 10%
Ten or more severe wind reports: 50%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 60%
One or more hailstones of 2 inches or more: 30%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jun 7, 8:16 PM EDT	Severe Thunderstorm Warning	GRR	Allegan, Ottawa	44 min
Jun 7, 8:28 PM EDT	Severe Thunderstorm Warning	GRR	Barry, Ionia, Kent	35 min
Jun 7, 9:00 PM EDT	Severe Thunderstorm Warning	GRR	Ottawa	60 min
Jun 7, 9:24 PM EDT	Severe Thunderstorm Warning	GRR	Allegan	81 min
Jun 7, 9:58 PM EDT	Flash Flood Warning	GRR	Allegan, Barry, Eaton, Ionia, Kent, Ottawa	6 hr
Jun 7, 10:14 PM EDT	Severe Thunderstorm Warning	GRR	Barry, Eaton, Ionia, Kent	46 min
Jun 7, 10:43 PM EDT	Severe Thunderstorm Warning	GRR	Eaton, Ingham	62 min
Jun 7, 10:57 PM EDT	Severe Thunderstorm Warning	GRR	Clinton	18 min
Jun 7, 11:47 PM EDT	Severe Thunderstorm Warning	GRR	Kalamazoo, Van Buren	47 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, 10.7 hours before the alert went out and 218 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: 181 J/kg
Mixed-layer CIN: -78 J/kg
Mixed-layer LCL: 677 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 40 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.

000
WWUS20 KWNS 072240
SEL1  
SPC WW 072240
INZ000-MIZ000-LMZ000-080400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 481
NWS STORM PREDICTION CENTER NORMAN OK
640 PM EDT SAT JUN 7 2008

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       PARTS OF NORTHERN INDIANA
       PARTS OF SOUTHERN AND WESTERN LOWER MICHIGAN
       LAKE MICHIGAN

EFFECTIVE THIS SATURDAY NIGHT FROM 640 PM UNTIL MIDNIGHT EDT.

TORNADOES...HAIL TO 2 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 55 STATUTE
MILES EAST AND WEST OF A LINE FROM 35 MILES NORTH OF GRAND RAPIDS
MICHIGAN TO 50 MILES SOUTHEAST OF VALPARAISO INDIANA.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU1).

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 478...WW 479...WW 480...

DISCUSSION...SEVERE THUNDERSTORMS INCLUDING TORNADIC SUPERCELLS OVER
NRN IL AND SRN WI MOVING E/NE.  WHILE CONDITIONS ARE NOT QUITE AS
FAVORABLE E OF LM THERE IS STILL FAVORABLE DEEP LAYER SHEAR AND MDT
INSTABILITY...THUS THREAT OF SUPERCELLS INCLUDING TORNADOES IS
EXPECTED TO CONTINUE UNTIL AT LEAST SUNSET ACROSS WATCH AREA.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 24030.


...HALES

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 7, 3:31 AM EDT	Mesoscale Discussion	SPC	Brown, Clay, Greene, Hendricks, Johnson, Monroe and 6 more	119 min
Jun 7, 3:01 PM EDT	Tornado Watch	SPC	Benton, Jasper, Lake, Newton, Porter	6 hr
Jun 7, 7:34 PM EDT	Mesoscale Discussion	SPC	Lake, Porter	56 min
Jun 6, 9:47 PM EDT	Mesoscale Discussion	SPC	Alcona, Arenac, Bay, Clare, Gladwin, Iosco and 7 more	58 min
Jun 7, 3:27 PM EDT	Mesoscale Discussion	SPC	Antrim, Benzie, Cheboygan, Clare, Crawford, Gladwin and 23 more	93 min

Nearby

Tornado Watches in Michigan, 2008 Every tornado watch in 2008

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.