Alert archive / Michigan / Tornado Watches in 2011

Tornado Watch 125

April 10, 201110 counties in Michigan

The Storm Prediction Center issued this tornado watch at Apr 10, 2011, 9:17 PM EDT for 10 counties in Michigan. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Apr 10, 2011, 9:17 PM EDT (01:17 UTC)
Expired
Apr 11, 2011, 1:05 AM EDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
50 kt

Counties Alger County, MI, Baraga County, MI, Chippewa County, MI, Delta County, MI, Dickinson County, MI, Luce County, MI, Mackinac County, MI, Marquette County, MI, Menominee County, MI, Schoolcraft County, MI

The radar

The Marquette radar (KMQT), 87 km from the middle of the area, began a volume at 01:20 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
30%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
50%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 10, 9:41 PM EDTSevere Thunderstorm WarningMQTDelta, Dickinson, Marquette, Menominee34 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

Green Bay/Straub, WI (KGRB), launched 00:00Z, 1.3 hours before the alert went out and 211 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 00:00Z on 2011-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1647 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 00:00Z on 2011-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 399 square meters per square second.1939587897117Sfc1 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
1647 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
1073 m above ground
0-6 km bulk shear
74 kt
0-1 km storm-relative helicity
399 m²/s²
0-3 km storm-relative helicity
397 m²/s²
Significant tornado parameter
4.2
Supercell composite
11.4

Open this sounding in Storm Lab

The text

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

478 
WWUS20 KWNS 110119
SEL5
SPC WW 110119
MIZ000-LHZ000-LMZ000-LSZ000-110600-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 125
NWS STORM PREDICTION CENTER NORMAN OK
920 PM EDT SUN APR 10 2011

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

       CENTRAL AND EASTERN UPPER MICHIGAN
       LAKE HURON
       LAKE MICHIGAN
       LAKE SUPERIOR

EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 920 PM UNTIL
200 AM EDT.

TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 60 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 85 STATUTE
MILES EAST AND WEST OF A LINE FROM 40 MILES EAST SOUTHEAST OF
ESCANABA MICHIGAN TO 70 MILES EAST NORTHEAST OF MARQUETTE
MICHIGAN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).

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 120...WW 121...WW
122...WW 123...WW 124...

DISCUSSION...SUSTAINED SUPERCELLS OVER NRN AND ERN WI EXPECTED TO
CONTINUE RAPIDLY ENE ACROSS CNTRL AND PERHAPS ERN PARTS OF THE UPR
PENINSULA OF MI.  WHILE NEAR-SFC LAYER IS RELATIVELY STABLE GIVEN
FLOW OFF THE LAKES...KGRB SOUNDING AND VWP DATA SUGGEST
SHEAR/INSTABILITY ENVIRONMENT IMMEDIATELY ABOVE THE SFC COULD
SUPPORT SUSTENANCE OF EXISTING LOW-LVL MESOCYCLONES AND POSSIBLE
TORNADOES THAT MOVE INTO REGION FROM THE WSW.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 50 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 26050.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 10, 9:55 PM EDTMesoscale DiscussionSPCAlger, Alpena, Antrim, Benzie, Charlevoix, Cheboygan and 26 more95 min
Apr 11, 12:03 AM EDTMesoscale DiscussionSPCAllegan, Barry, Berrien, Calhoun, Cass, Clinton and 12 more87 min
Apr 11, 1:48 AM EDTMesoscale DiscussionSPCBranch, Hillsdale, Lenawee, Saint Joseph87 min

Nearby

Tornado Watches in Michigan, 2011Every tornado watch in 2011

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.