Alert archive / Illinois / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 45

March 15, 201613 counties in Illinois; 13 counties in Indiana; Berrien County, Michigan

The Storm Prediction Center issued this severe thunderstorm watch at Mar 15, 2016, 8:40 PM CDT for 13 counties in Illinois; 13 counties in Indiana; Berrien County, Michigan. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Mar 15, 2016, 8:40 PM CDT (01:40 UTC)
Expired
Mar 16, 2016, 12:24 AM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 27 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, McHenry County, IL, Will County, IL, Benton County, IN, Cass County, IN, Fulton County, IN, Jasper County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Newton County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, White County, IN, Berrien County, MI

The radar

The Chicago radar (KLOT), 45 km from the middle of the area, began a volume at 01:43 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
10%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Mar 15, 9:13 PM CDTSevere Thunderstorm WarningLOTGrundy, LaSalle, Livingston47 min
Mar 15, 9:21 PM CDTSevere Thunderstorm WarningLOTFord, Iroquois, Livingston39 min
Mar 15, 9:28 PM CDTSevere Thunderstorm WarningLOTDeKalb, Lee, Ogle32 min
Mar 15, 9:52 PM CDTSevere Thunderstorm WarningLOTFord, Iroquois, Kankakee38 min
Mar 15, 9:54 PM CDTSevere Thunderstorm WarningLOTGrundy, Kendall, LaSalle, Will36 min
Mar 15, 10:22 PM CDTTornado WarningLOTIroquois, Kankakee23 min
Mar 15, 10:34 PM CDTTornado WarningLOTKankakee26 min
Mar 15, 10:58 PM CDTSevere Thunderstorm WarningLOTKankakee, Will34 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 1.7 hours before the alert went out and 146 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Lincoln, IL at 00:00Z on 2016-03-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1364 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 00:00Z on 2016-03-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 135 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1364 J/kg
Mixed-layer CIN
-54 J/kg
Mixed-layer LCL
1257 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
135 m²/s²
0-3 km storm-relative helicity
241 m²/s²
Significant tornado parameter
1.2
Supercell composite
8.9

Open this sounding in Storm Lab

The text

As transmitted.

867 
WWUS20 KWNS 160138
SEL5  
SPC WW 160138
ILZ000-INZ000-MIZ000-LMZ000-160800-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 45
NWS STORM PREDICTION CENTER NORMAN OK
835 PM CDT TUE MAR 15 2016

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
  NORTHEASTERN ILLINOIS
  NORTHERN INDIANA
  EXTREME SOUTHWESTERN LOWER MICHIGAN
  LAKE MICHIGAN

* EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 835 PM
  UNTIL 300 AM CDT.

* PRIMARY THREATS INCLUDE...
  SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2
    INCHES IN DIAMETER POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

SUMMARY...A BAND OF SEVERE THUNDERSTORMS...WITH A FEW EMBEDDED
SUPERCELLS AND BOW ECHOES...WILL OFFER A RISK FOR DAMAGING WIND IN
THE WESTERN AND SOUTHERN PARTS OF THE WATCH AREA OVER A SLIVER OF
NORTHEASTERN ILLINOIS.  LARGE HAIL IS POSSIBLE ANYWHERE IN THE WATCH
INCLUDING THE CHICAGO AREA...SOUTHERN LAKE MICHIGAN AND NORTHWESTERN
INDIANA.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60
STATUTE MILES EITHER SIDE OF A LINE FROM 70 MILES SOUTH SOUTHWEST
OF VALPARAISO INDIANA TO 60 MILES WEST NORTHWEST OF BENTON HARBOR
MICHIGAN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 44...

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 24030.


...EDWARDS

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 15, 8:07 PM CDTMesoscale DiscussionSPCCook, DuPage, Iroquois, Kankakee, Lake, Vermilion and 1 more53 min
Mar 15, 10:58 PM CDTMesoscale DiscussionSPCCass, Fulton, Jasper, Lake, LaPorte, Marshall and 6 more92 min
Mar 16, 5:42 AM CDTMesoscale DiscussionSPCGogebic6 hr

Nearby

Severe Thunderstorm Watches in Illinois, 2016Severe Thunderstorm Watches in Indiana, 2016Severe Thunderstorm Watches in Michigan, 2016Every severe thunderstorm watch in 2016

Sources

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.