Severe Thunderstorm Watch 285

Issued

May 20, 2012, 1:24 PM EDT (17:24 UTC)

Expired

May 20, 2012, 8:35 PM EDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Marquette radar (KMQT), 141 km from the middle of the area, began a volume at 17:27 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

50%

One or more gusts of 65 knots or more

20%

Ten or more severe hail reports

60%

One or more hailstones of 2 inches or more

10%

Six or more combined severe hail and wind reports

80%

• Mesoscale Discussion 849May 20, 11:52 AM EDT
• Mesoscale Discussion 852May 20, 3:57 PM EDT

324 
WWUS20 KWNS 201727
SEL5
SPC WW 201727
MIZ000-WIZ000-LMZ000-LSZ000-210100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 285
NWS STORM PREDICTION CENTER NORMAN OK
1225 PM CDT SUN MAY 20 2012

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

       WESTERN AND CENTRAL UPPER MICHIGAN
       NORTHERN AND CENTRAL WISCONSIN
       LAKE MICHIGAN
       LAKE SUPERIOR

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 1225 PM UNTIL
800 PM CDT.

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 75
STATUTE MILES EAST AND WEST OF A LINE FROM 5 MILES NORTHEAST OF
HOUGHTON MICHIGAN TO 40 MILES WEST SOUTHWEST OF OSHKOSH
WISCONSIN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).

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.

DISCUSSION...STORMS ARE BEGINNING TO INCREASE IN COVERAGE AND
INTENSITY ALONG/AHEAD OF A COLD FRONT MOVING ACROSS WRN WI.  THE
ENVIRONMENT IN THE WARM SECTOR IS MODERATELY UNSTABLE WITH MLCAPE OF
1500-2000 J/KG AND CONTINUED AFTERNOON HEATING WILL FURTHER STEEPEN
LOW LEVEL LAPSE RATES. SWLY MID LEVEL WINDS OF 40-50 KT ARE
CONTRIBUTING TO FAVORABLE DEEP LAYER SHEAR SUPPORTIVE OF ORGANIZED
CONVECTIVE STRUCTURES INCLUDING A FEW SUPERCELLS AND/OR BOW ECHOES.
THIS WILL ENHANCE WIND GUST POTENTIAL WITH STRONGER STORMS...AND
STEEP MID LEVEL LAPSE RATES ABOVE THE PBL WILL ALSO PROMOTE LARGE
HAIL AS STORMS MOVE EWD/NEWD THIS AFTERNOON.

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 22030.


...WEISS

Severe Thunderstorm Watches in Wisconsin, 2012Severe 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.