Severe Thunderstorm Watch 540

Issued

Jul 30, 2012, 2:28 PM EDT (18:28 UTC)

Expired

Jul 30, 2012, 10:00 PM EDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

60 kt

The Marquette radar (KMQT), 107 km from the middle of the area, began a volume at 18:30 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

20%

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

50%

• Mesoscale Discussion 1650Jul 30, 1:26 PM EDT
• Mesoscale Discussion 1652Jul 30, 4:49 PM EDT
• Mesoscale Discussion 1655Jul 30, 7:16 PM EDT

622 
WWUS20 KWNS 301832
SEL0
SPC WW 301832
MIZ000-WIZ000-LMZ000-LSZ000-310100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 540
NWS STORM PREDICTION CENTER NORMAN OK
130 PM CDT MON JUL 30 2012

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

       UPPER PENINSULA OF MICHIGAN
       NORTHEAST WISCONSIN
       LAKE MICHIGAN
       LAKE SUPERIOR

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 130 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 20 MILES NORTHEAST OF
MARQUETTE MICHIGAN TO 40 MILES SOUTHWEST OF GREEN BAY WISCONSIN.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU0).

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 EXPECTED TO INITIATE SHORTLY AHEAD OF A COLD
FRONT SPREADING EAST FROM NRN WI AND LAKE SUPERIOR. A CORRIDOR OF
UNSTABLE AIR HAS DEVELOPED FROM CNTRL WI NEWD ACROSS THE MIDDLE
PORTION OF THE LOWER PENINSULA OF MI. SBCAPE IN THIS CORRIDOR HAS
CLIMBED TO OVER 2000 J/KG WHERE SFC TEMPERATURES WERE IN THE LOWER
TO MIDDLE 80S F AND DEWPOINTS WERE HOLDING IN THE MID TO UPPER 60S
F. STORMS INITIATING ALONG OR JUST AHEAD OF THE FRONT SHOULD
INCREASE IN INTENSITY AS GREATER INSTABILITY IS REALIZED.
STRENGTHENING MID LEVEL FLOW OF AROUND 40KT WILL LEND SUFFICIENT
SHEAR FOR STORMS TO ORGANIZE INTO LONGER LIVED LINES/CLUSTERS AND
PERHAPS EVEN A SUPERCELL OR TWO. DAMAGING WINDS AND SOME HAIL WOULD
BE LIKELY WITH THIS ACTIVITY. EVENTUALLY...FOCUSED LINEAR ASCENT
ALONG THE ADVANCING FRONT MAY BE SUFFICIENT TO INDUCE A SQUALL LINE
LATER TODAY ACROSS ERN WI...THE MIDDLE PORTION OF THE U.P. OF
MI...AND PORTIONS OF NRN LAKE MICHIGAN.

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 450. MEAN STORM
MOTION VECTOR 31025.


...CARBIN

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.