Severe Thunderstorm Watch 76

Issued

Mar 15, 2012, 4:28 PM EDT (20:28 UTC)

Expired

Mar 15, 2012, 11:00 PM EDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

1.5 in

Strongest gust expected

60 kt

Counties Bay County, MI, Genesee County, MI, Huron County, MI, Lapeer County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Midland 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

The Detroit radar (KDTX), 36 km from the middle of the area, began a volume at 20:29 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.

Two or more tornadoes

10%

One or more EF2 to EF5 tornadoes

5%

Ten or more severe wind reports

30%

One or more gusts of 65 knots or more

10%

Ten or more severe hail reports

50%

One or more hailstones of 2 inches or more

10%

Six or more combined severe hail and wind reports

60%

• Mesoscale Discussion 258Mar 15, 3:52 PM EDT
• Mesoscale Discussion 260Mar 15, 5:44 PM EDT
• Mesoscale Discussion 263Mar 15, 8:02 PM EDT

675 
WWUS20 KWNS 152029
SEL6
SPC WW 152029
MIZ000-LEZ000-LHZ000-160100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 76
NWS STORM PREDICTION CENTER NORMAN OK
430 PM EDT THU MAR 15 2012

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

       SOUTHEAST LOWER MICHIGAN
       LAKE ERIE
       LAKE HURON

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 430 PM UNTIL
900 PM EDT.

HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50
STATUTE MILES EAST AND WEST OF A LINE FROM 10 MILES NORTHWEST OF
BAD AXE MICHIGAN TO 35 MILES SOUTH OF ANN ARBOR MICHIGAN.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU6).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 75...

DISCUSSION...STORMS ARE INTENSIFYING ALONG A CONVERGENCE ZONE FROM
JUST WEST OF SAGINAW BAY TO NORTHWEST OF TOLEDO.  ANOMALOUSLY WARM
AND MOIST LOW LEVEL AIR MASS WITH SEASONABLY COOL MID LEVEL
TEMPERATURES ARE RESULTING IN STEEP LAPSE RATES AND STRONG
INSTABILITY WITH MLCAPE OF 2000 J PER KG /SEE 18Z DTX RAOB/.
ALTHOUGH WINDS ALOFT ARE NOT PARTICULARLY STRONG, 30 KT WESTERLY MID
LEVEL FLOW IS ASSOCIATED WITH SUFFICIENT DEEP LAYER SHEAR FOR
ORGANIZED UPDRAFTS AND THREAT FOR LARGE HAIL AND ISOLATED DAMAGING
WIND GUSTS.

AVIATION...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 450. MEAN STORM
MOTION VECTOR 26020.


...WEISS

Severe Thunderstorm Watches in Michigan, 2012Every severe thunderstorm watch in 2012

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.