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The expiration time in the watch graphic is amended if the watch is
replaced, cancelled or extended.
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Watch Status Reports.
SEL2
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 512
NWS STORM PREDICTION CENTER NORMAN OK
355 PM CDT THU JUN 25 2009
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
NORTHEAST ILLINOIS
NORTHWEST INDIANA
LAKE MICHIGAN
EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 355 PM UNTIL
900 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 45
STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTHEAST OF
ROCKFORD ILLINOIS TO 80 MILES SOUTHEAST OF MARSEILLES ILLINOIS.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU2).
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 508...WW 509...WW
510...WW 511...
DISCUSSION...A VERY UNSTABLE AIR MASS HAS DEVELOPED ACROSS THIS
REGION THIS AFTERNOON WITH NO CAPPING. DESPITE THE WEAK LOW LEVEL
FLOW/FOCUS... LAKE BREEZE AND OUTFLOW BOUNDARIES SHOULD FOCUS RAPID
THUNDERSTORM DEVELOPMENT THROUGH THE EVENING. SHEAR REMAINS
SUPPORTIVE OF SUSTAINED/ORGANIZED SEVERE...INCLUDING BRIEF
SUPERCELLS...WITH PRIMARY THREATS OF LARGE HAIL AND DAMAGING WINDS.
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 32015.
...EVANS
Note:
The Aviation Watch (SAW) product is an approximation to the watch area.
The actual watch is depicted by the shaded areas.
SAW2
WW 512 SEVERE TSTM IL IN LM 252055Z - 260200Z
AXIS..45 STATUTE MILES EAST AND WEST OF LINE..
30NE RFD/ROCKFORD IL/ - 80SE MMO/MARSEILLES IL/
..AVIATION COORDS.. 40NM E/W /41SSW BAE - 24W BVT/
HAIL SURFACE AND ALOFT..2 INCHES. WIND GUSTS..60 KNOTS.
MAX TOPS TO 500. MEAN STORM MOTION VECTOR 32015.
LAT...LON 42508780 40548675 40548845 42508956
THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS
FOR WOU2.
Watch 512 Status Report Messages:
STATUS REPORT #2 ON WW 512
VALID 252245Z - 252340Z
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..MEAD..06/25/09
ATTN...WFO...LOT...
&&
STATUS REPORT FOR WS 512
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
ILC007-031-037-043-053-063-075-089-091-093-097-099-103-105-111-
141-197-201-252340-
IL
. ILLINOIS COUNTIES INCLUDED ARE
BOONE COOK DEKALB
DUPAGE FORD GRUNDY
IROQUOIS KANE KANKAKEE
KENDALL LAKE LA SALLE
LEE LIVINGSTON MCHENRY
OGLE WILL WINNEBAGO
$$
INC007-073-089-111-127-252340-
IN
. INDIANA COUNTIES INCLUDED ARE
BENTON JASPER LAKE
NEWTON PORTER
$$
LMZ740-741-742-743-744-745-777-779-252340-
CW
. ADJACENT COASTAL WATERS INCLUDED ARE
WINTHROP HARBOR TO WILMETTE HARBOR IL
WILMETTE HARBOR TO NORTHERLY ISLAND IL
NORTHERLY ISLAND TO CALUMET HARBOR IL
CALUMET HARBOR IL TO GARY IN
GARY TO BURNS HARBOR IN
BURNS HARBOR TO MICHIGAN CITY IN
LAKE MICHIGAN FROM WINTHROP HARBOR TO WILMETTE HARBOR IL 5NM OFF
SHORE TO MID LAKE
LAKE MICHIGAN FROM WILMETTE HARBOR TO MICHIGAN CITY IN 5NM OFF
SHORE TO MID LAKE
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
STATUS REPORT #1 ON WW 512
VALID 252140Z - 252240Z
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..MEAD..06/25/09
ATTN...WFO...LOT...
&&
STATUS REPORT FOR WS 512
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
ILC007-031-037-043-053-063-075-089-091-093-097-099-103-105-111-
141-197-201-252240-
IL
. ILLINOIS COUNTIES INCLUDED ARE
BOONE COOK DEKALB
DUPAGE FORD GRUNDY
IROQUOIS KANE KANKAKEE
KENDALL LAKE LA SALLE
LEE LIVINGSTON MCHENRY
OGLE WILL WINNEBAGO
$$
INC007-073-089-111-127-252240-
IN
. INDIANA COUNTIES INCLUDED ARE
BENTON JASPER LAKE
NEWTON PORTER
$$
LMZ740-741-742-743-744-745-777-779-252240-
CW
. ADJACENT COASTAL WATERS INCLUDED ARE
WINTHROP HARBOR TO WILMETTE HARBOR IL
WILMETTE HARBOR TO NORTHERLY ISLAND IL
NORTHERLY ISLAND TO CALUMET HARBOR IL
CALUMET HARBOR IL TO GARY IN
GARY TO BURNS HARBOR IN
BURNS HARBOR TO MICHIGAN CITY IN
LAKE MICHIGAN FROM WINTHROP HARBOR TO WILMETTE HARBOR IL 5NM OFF
SHORE TO MID LAKE
LAKE MICHIGAN FROM WILMETTE HARBOR TO MICHIGAN CITY IN 5NM OFF
SHORE TO MID LAKE
$$
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
$$
Note:
Click for Complete Product Text.
Tornadoes
Probability of 2 or more tornadoes
|
Low (20%)
|
Probability of 1 or more strong (F2-F5) tornadoes
|
Low (5%)
|
Wind
Probability of 10 or more severe wind events
|
Mod (30%)
|
Probability of 1 or more wind events > 65 knots
|
Mod (30%)
|
Hail
Probability of 10 or more severe hail events
|
Mod (30%)
|
Probability
of 1 or
more hailstones > 2 inches
|
Low (20%)
|
Combined Severe Hail/Wind
Probability of 6 or more combined severe hail/wind events
|
High (70%)
|
For each watch, probabilities for particular events inside the watch
(listed above in each table) are determined by the issuing forecaster.
The "Low" category contains probability values ranging from less than 2%
to 20% (F2-F5 tornadoes), less than 5% to 20% (all other probabilities),
"Moderate" from 30% to 60%, and "High" from 70% to greater than 95%.
High values are bolded and lighter in color to provide awareness of
an increased threat for a particular event.
weather.gov 
