Severe Thunderstorm Watch 435

Issued

Jun 29, 2012, 10:49 AM CDT (15:49 UTC)

Expired

Jun 29, 2012, 4:19 PM CDT

In force

6 hr

Issued by

the Storm Prediction Center

Largest hail expected

2.5 in

Strongest gust expected

60 kt

The Chicago radar (KLOT), 87 km from the middle of the area, began a volume at 15:52 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

70%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

70%

One or more hailstones of 2 inches or more

60%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 1305Jun 29, 9:22 AM CDT
• Mesoscale Discussion 1306Jun 29, 1:01 PM CDT
• Mesoscale Discussion 1308Jun 29, 2:07 PM CDT
• Mesoscale Discussion 1310Jun 29, 3:22 PM CDT

907 
WWUS20 KWNS 291549
SEL5
SPC WW 291549
ILZ000-INZ000-LMZ000-292300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 435
NWS STORM PREDICTION CENTER NORMAN OK
1150 AM EDT FRI JUN 29 2012

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

       EXTREME NORTHEASTERN ILLINOIS
       NORTHERN AND CENTRAL INDIANA
       LAKE MICHIGAN

EFFECTIVE THIS FRIDAY MORNING AND EVENING FROM 1150 AM UNTIL 700
PM EDT.

HAIL TO 2.5 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 60
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 15 MILES NORTH OF
MARSEILLES ILLINOIS TO 35 MILES EAST NORTHEAST OF MUNCIE INDIANA.
 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...CLUSTER OF TSTMS OVER NCNTRL IL HAS BECOME MORE N-S
ORIENTED WITH RESPECT TO THE DEEP LAYER MEAN FLOW AND WILL LIKELY
EVOLVE INTO SFC-BASED STORMS EARLY THIS AFTN IN SRN CHICAGO METRO
AREA.  STORMS WILL THEN PROPAGATE ESE INTO NRN/CNTRL IND THROUGH THE
AFTN WHERE MLCAPES WILL BE IN EXCESS OF 5000 J/KG.  VERY STEEP LAPSE
RATES AND AT LEAST 35-40 KTS OF MID-LVL FLOW WILL BE FAVORABLE FOR
VERY LARGE HAIL AND DMGG WIND GUSTS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 29040.


...RACY

Severe Thunderstorm Watches in Indiana, 2012Severe Thunderstorm Watches in Illinois, 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.