Alert archive / Illinois / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 27, NWS Chicago, IL

May 14, 2018Lee County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at May 14, 2018, 4:00 PM CDT for Lee County, Illinois. It was in force for 45 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 14, 2018, 4:00 PM CDT (21:00 UTC)
Expired
May 14, 2018, 4:45 PM CDT
In force
45 min
Issued by
NWS Chicago, IL
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

County Lee County, IL

The radar

The Chicago radar (KLOT), 102 km from the middle of the area, began a volume at 21:00 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 14, 2:54 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 9.0 hours before the alert went out and 187 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 12:00Z on 2018-05-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 962 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 12:00Z on 2018-05-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -23 square meters per square second.193958Sfc1 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
962 J/kg
Mixed-layer CIN
-160 J/kg
Mixed-layer LCL
1462 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
-23 m²/s²
0-3 km storm-relative helicity
86 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Chicago, IL wrote its last area forecast discussion before this severe thunderstorm warning went out at May 14, 2:16 PM CDT, 1 hour 44 minutes earlier.

Area forecast discussion, May 14, 2:16 PM CDT, 1 hour 44 minutes before
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Hazardous weather outlook, May 14, 3:05 PM CDT, 55 minutes before
Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
305 PM CDT Mon May 14 2018

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
152015-
Winnebago-Boone-McHenry-Lake Illinois-Ogle-Lee-De Kalb-Kane-
DuPage-Cook-La Salle-Kendall-Grundy-Will-Kankakee-Livingston-
Iroquois-Ford-Lake Indiana-Porter-Newton-Jasper-Benton-
305 PM CDT Mon May 14 2018 /405 PM EDT Mon May 14 2018/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR North Central Illinois...
Northeast Illinois AND Northwest Indiana.

.DAY ONE...Tonight.

WEATHER HAZARDS EXPECTED:
  Significant Thunderstorm Risk...with an associated:
      Elevated Hail Risk...up to golf ball size.
      Elevated Thunderstorm Wind Damage Risk...up to 60 mph.
  Elevated Flooding Risk.

DISCUSSION:

Additional scattered thunderstorms expected this afternoon
into the evening across the entire outlook area. Expect
thunderstorms to develop along and west of I-39 in northern IL,
with continued scattered thunderstorm development expected to move
east into other areas in northern IL and northwest IN soon there
after. This thunderstorm development is expected to persist
through early evening, shifting focus more into northwest IN
during that time, before exiting by mid to late evening. With any
storms that will occur today, large hail, damaging winds, and
heavy rainfall remain the primary hazards.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Tuesday...
  Limited Flooding Risk.
  Limited Thunderstorm Risk.
Wednesday through Sunday...
  Limited Thunderstorm Risk.

DISCUSSION:

Thunderstorm chances continue this week but with lower
probabilities.

.SPOTTER INFORMATION STATEMENT...

Spotters will likely be needed this afternoon and evening.

GENERAL STORM MOTION OF THE DAY:

Moving east northeast at 30 to 40 mph.

&&

LMZ740>745-152015-
Winthrop Harbor to Wilmette Harbor-
Wilmette Harbor to Northerly Island-
Northerly Island to Calumet Harbor-Calumet Harbor to Gary-
Gary to Burns Harbor-Burns Harbor to Michigan City-
305 PM CDT Mon May 14 2018

THIS HAZARDOUS WEATHER OUTLOOK IS FOR the Illinois nearshore
waters of Lake Michigan AND the Indiana nearshore waters of Lake
Michigan.

.DAY ONE...Tonight.

  Significant Thunderstorm Risk.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Tuesday...
  Limited Thunderstorm Risk.
Saturday and Sunday...
  Limited Thunderstorm Risk.

&&

LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868-
870-872-874-876-878-152015-
Lake Michigan from Michigan City IN to St. Joseph MI 5 NM
offshore to Mid Lake-
Lake Michigan from Seul Choix Point to Rock Island Passage 5 NM
offshore to Mid Lake-
Lake Michigan South of a line from Seul Choix Point to the
Mackinac Bridge and north of a line from Charlevoix MI to South
Fox Island 5 NM offshore-
Lake Michigan from Charlevoix to Point Betsie MI 5 NM offshore to
Mid Lake-
Lake Michigan from Point Betsie to Manistee MI 5 NM offshore to
Mid Lake-
Lake Michigan from Rock Island Passage to Sturgeon Bay WI-
Lake Michigan from Sturgeon Bay to Two Rivers WI 5 NM offshore to
Mid Lake-
Lake Michigan from Two Rivers to Sheboygan WI 5 NM offshore to
Mid Lake-
Lake Michigan from Sheboygan to Port Washington WI 5 NM offshore
to Mid Lake-
Lake Michigan from Port Washington to North Point Light WI 5 NM
offshore to Mid Lake-
Lake Michigan from North Point Light to Wind Point WI 5 NM
offshore to Mid Lake-
Lake Michigan from Wind Point WI to Winthrop Harbor IL 5 NM
offshore to Mid Lake-
Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5 NM
offshore to Mid Lake-
Lake Michigan from Wilmette Harbor IL to Michigan City IN 5 NM
offshore to Mid Lake-
Lake Michigan from Pentwater to Manistee MI 5 NM offshore to Mid
Lake-
Lake Michigan from Whitehall to Pentwater MI 5 NM offshore to Mid
Lake-
Lake Michigan from Grand Haven to Whitehall MI 5 NM offshore to
Mid Lake-
Lake Michigan from Holland to Grand Haven MI 5 NM offshore to Mid
Lake-
Lake Michigan from South Haven to Holland MI 5 NM offshore to Mid
Lake-
Lake Michigan from St. Joseph to South Haven MI 5 NM offshore to
Mid Lake-
305 PM CDT Mon May 14 2018

THIS HAZARDOUS WEATHER OUTLOOK IS FOR the open waters of Lake
Michigan.

.DAY ONE...Tonight.

Significant Thunderstorm Risk for the south half of the lake.

Areas of fog are possible across the south half.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Limited Thunderstorm Risk Tuesday for the south half, and
again Saturday and Sunday for the entire lake.

&&

Rodriguez

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In the hours before

Local storm report, May 14, 10:23 AM CDT, 5 hours 37 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1023 AM CDT MON MAY 14 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0714 AM     MARINE TSTM WIND 2 NNW BURNS HARBOR      41.65N 87.15W
05/14/2018  M60 MPH          PORTER             IN   C-MAN STATION

            MEASURED GUST TO 60 MPH.

&&
Local storm report, May 14, 12:22 PM CDT, 3 hours 38 minutes before
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Special weather statement, May 14, 3:39 PM CDT, 21 minutes before
Special Weather Statement
National Weather Service Chicago/Romeoville Il
339 PM CDT MON MAY 14 2018

ILZ010-142100-
Lee IL-
339 PM CDT MON MAY 14 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN LEE COUNTY UNTIL 400
PM CDT...

At 339 PM CDT, Doppler radar was tracking a strong thunderstorm near
Deer Grove, or 8 miles southeast of Rock Falls, moving northeast at
40 mph.

Nickel size hail and wind gusts up to 50 mph will be possible with
this storm.

Locations impacted include...
Harmon.

A severe thunderstorm watch remains in effect until 1000 PM CDT for
north central Illinois.

LAT...LON 4174 8963 4182 8954 4158 8937 4159 8963
TIME...MOT...LOC 2039Z 227DEG 33KT 4167 8962

BMD
Special weather statement, May 14, 3:50 PM CDT, 10 minutes before
Special Weather Statement
National Weather Service Chicago/Romeoville Il
350 PM CDT MON MAY 14 2018

ILZ011-012-142115-
Kane IL-De Kalb IL-
350 PM CDT MON MAY 14 2018

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL DE KALB AND
NORTHWESTERN KANE COUNTIES UNTIL 415 PM CDT...

At 349 PM CDT, Doppler radar was tracking a strong thunderstorm near
Cortland, or near Sycamore, moving northeast at 30 mph.

Half inch hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
DeKalb, Elburn, Cortland, Maple Park, Lily Lake, Virgil and
Burlington.

A severe thunderstorm watch remains in effect until 1000 PM CDT for
north central and northeastern Illinois.

LAT...LON 4181 8873 4189 8879 4208 8851 4185 8836
TIME...MOT...LOC 2049Z 245DEG 27KT 4188 8868

BMD
Special weather statement, May 14, 3:57 PM CDT, 3 minutes before
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The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 14, 3:43 AM CDTSpecial Weather StatementLOTOgle32 min
May 14, 4:42 AM CDTSevere Thunderstorm WarningLOTOgle, Winnebago48 min
May 14, 5:09 AM CDTSpecial Weather StatementLOTBoone, Lee, Ogle, Winnebago36 min
May 14, 6:41 AM CDTAreal Flood AdvisoryLOTCook, DuPage3 hr
May 14, 6:43 AM CDTAreal Flood WarningLOTLake6 hr
May 14, 8:13 AM CDTSpecial Weather StatementLOTLee32 min
May 14, 10:50 AM CDTMarine Dense Fog AdvisoryLOT10 hr
May 14, 11:28 AM CDTRiver Flood WarningLOTLake6 days
May 14, 11:28 AM CDTRiver Flood WarningLOTLake11 days
May 14, 11:28 AM CDTRiver Flood WarningLOTLake56 hr
May 14, 11:28 AM CDTRiver Flood WarningLOTCook68 hr
May 14, 11:28 AM CDTRiver Flood WarningLOTKane, McHenry46 hr
May 14, 11:28 AM CDTRiver Flood WarningLOTKane, Kendall5 days
May 14, 11:42 AM CDTRiver Flood AdvisoryLOTCook3 days
May 14, 11:42 AM CDTRiver Flood AdvisoryLOTCook65 hr
May 14, 11:42 AM CDTRiver Flood AdvisoryLOTLake45 hr
May 14, 3:39 PM CDTSpecial Weather StatementLOTLee21 min
May 14, 3:50 PM CDTSpecial Weather StatementLOTDeKalb, Kane25 min
May 14, 3:57 PM CDTSpecial Weather StatementLOTOgle33 min
May 14, 4:23 PM CDTSevere Thunderstorm WarningLOTDeKalb, Kane52 min
May 14, 5:29 PM CDTSpecial Marine WarningLOT3 hr
May 14, 5:39 PM CDTSpecial Weather StatementLOTDuPage36 min
May 14, 6:10 PM CDTSpecial Weather StatementLOTCook, DuPage20 min
May 14, 7:27 AM CDTSpecial Weather StatementLOTPorter33 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2018Every severe thunderstorm warning in 2018

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.