Severe Thunderstorm Watch 231

Issued

May 3, 2012, 2:35 PM EDT (18:35 UTC)

Expired

May 3, 2012, 11:00 PM EDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Grand Rapids radar (KGRR), 52 km from the middle of the area, began a volume at 18:37 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

20%

One or more EF2 to EF5 tornadoes

5%

Ten or more severe wind reports

30%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

30%

One or more hailstones of 2 inches or more

20%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 674May 3, 11:34 AM EDT
• Mesoscale Discussion 677May 3, 3:53 PM EDT
• Mesoscale Discussion 678May 3, 4:33 PM EDT
• Mesoscale Discussion 682May 3, 6:57 PM EDT
• Mesoscale Discussion 686May 3, 8:36 PM EDT

802 
WWUS20 KWNS 031837
SEL1
SPC WW 031837
MIZ000-LMZ000-040100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 231
NWS STORM PREDICTION CENTER NORMAN OK
235 PM EDT THU MAY 3 2012

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

       SOUTHERN LOWER MICHIGAN
       LAKE MICHIGAN

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 235 PM UNTIL
900 PM EDT.

HAIL TO 2 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 40
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 10 MILES NORTH
NORTHWEST OF BENTON HARBOR MICHIGAN TO 25 MILES EAST SOUTHEAST OF
BAD AXE MICHIGAN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).

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 229...WW 230...

DISCUSSION...EXPECT TSTMS TO INCREASE ALONG WARM FRONT AND WITHIN
WARM SECTOR ESTABLISHED ACROSS SRN LOWER MI. TEMPS IN THE 80S AND
DEWPOINTS IN THE 60S WERE CONTRIBUTING TO MLCAPE VALUES AROUND 2000
J/KG. SHEAR AND FORCING NEAR/ALONG AND NORTH OF THE FRONT SHOULD BE
SUFFICIENT TO SUSTAIN INCREASINGLY PERSISTENT UPDRAFTS ALONG WITH
SOME POTENTIAL FOR SUPERCELL STRUCTURE AND LARGE HAIL. WITH
TIME...SHEAR AND DEEP-LAYER FLOW MAY ALSO STRENGTHEN ACROSS THE WARM
SECTOR WITH THE CHANCE FOR STORMS IN THE FORM OF LINE SEGMENTS
POSSIBLY  INCREASING AND POSING A DAMAGING WIND THREAT.

AVIATION...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 500. MEAN STORM
MOTION VECTOR 26025.


...CARBIN

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.