Alert archive / Illinois / Flash Flood Warnings in 2019

Flash Flood Warning 18, NWS Chicago, IL

September 13, 20197 counties in Illinois

NWS Chicago, IL issued this flash flood warning at Sep 13, 2019, 12:38 AM CDT for 7 counties in Illinois. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Sep 13, 2019, 12:38 AM CDT (05:38 UTC)
Expired: Sep 13, 2019, 6:45 AM CDT
In force: 6 hr
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Flood severity: None

Counties Boone County, IL, DeKalb County, IL, Kane County, IL, Lake County, IL, McHenry County, IL, Ogle County, IL, Winnebago County, IL

The radar

The Chicago radar (KLOT), 81 km from the middle of the area, began a volume at 05:43 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.

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 5.6 hours before the alert went out and 162 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1935 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 1302 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 96 m²/s²
0-3 km storm-relative helicity: 234 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 6.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood 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 flash flood warning went out at Sep 12, 8:14 PM CDT, 4 hours 24 minutes earlier.

Area forecast discussion, Sep 12, 8:14 PM CDT, 4 hours 24 minutes before

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Hazardous weather outlook, Sep 12, 2:32 PM CDT, 10 hours 6 minutes before

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
232 PM CDT Thu Sep 12 2019

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
131945-
Winnebago-Boone-McHenry-Lake IL-Ogle-Lee-De Kalb-Kane-DuPage-Cook-
La Salle-Kendall-Grundy-Will-Kankakee-Livingston-Iroquois-Ford-
Lake IN-Porter-Newton-Jasper-Benton-
232 PM CDT Thu Sep 12 2019 /332 PM EDT Thu Sep 12 2019/

This Hazardous Weather Outlook is for portions of North Central
Illinois...Northeast Illinois and Northwest Indiana.

.DAY ONE...Tonight.

Weather hazards expected...

  Significant Thunderstorm Risk...with an associated:
     Elevated damaging wind risk...up to 60 mph.
     Limited hail risk...up to quarter sized.
     Limited Tornado risk.
  Elevated Flooding Risk.
  Limited Excessive heat Risk south of I-80.
  High Swim Risk

DISCUSSION...

Showers and thunderstorms will be possible this afternoon. Some of
these storms could be strong to severe with a threat for large
hail and strong wind gusts. In addition, there will be a tornado
threat roughly either side of a Rochelle to Aurora to Monee line.

Additional showers and thunderstorms are expected to move into the
region after 10 PM this evening. A threat for strong wind gusts
will exist with this activity, but the severe weather potential
is expected to diminish with eastward extent into the evening.

Locally heavy rain will also be possible which may lead to some
instances of flooding, particularly across parts of far northeast
Illinois which received significant rainfall last night.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Friday...
  High Swim Risk
Saturday and Sunday...
  Limited Thunderstorm Risk.

.SPOTTER INFORMATION STATEMENT...

  Spotters may be needed this afternoon and evening.

GENERAL STORM MOTION OF THE DAY:

  Moving toward the east at 20 to 25 mph.

LMZ740>745-131945-
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-
232 PM CDT Thu Sep 12 2019

This Hazardous Weather Outlook is for portions of the Illinois
nearshore waters of Lake Michigan and the Indiana nearshore
waters of Lake Michigan.

.DAY ONE...Tonight.

Weather hazards expected...

  Hazardous conditions for small craft.
  Significant Thunderstorm Risk...with an associated:
    Elevated thunderstorm wind gust risk...up to 50 kts.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Friday...
  Hazardous conditions for small craft are likely.
Saturday and Sunday...
  Limited Thunderstorm Risk.

Carlaw

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In the hours before

Special weather statement, Sep 12, 6:40 PM CDT, 5 hours 58 minutes before

Special Weather Statement
National Weather Service Chicago/Romeoville
640 PM CDT Thu Sep 12 2019

INZ001-002-130030-
Porter IN-Lake IN-
640 PM CDT Thu Sep 12 2019

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN PORTER AND
NORTHEASTERN LAKE COUNTIES UNTIL 730 PM CDT...

At 639 PM CDT, Doppler radar was tracking a strong thunderstorm over
New Chicago, or over Lake Station, moving northeast at 15 mph.

Penny size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Gary, Portage, Merrillville, Schererville, Hobart, Griffith,
Chesterton, Lake Station, Porter, Burns Harbor, South Haven, Wheeler,
Lakes Of The Four Seasons, Winfield, New Chicago, Ogden Dunes, Town
Of Pines, Beverly Shores and Dune Acres.

This includes...  Indiana University Northwest, Indiana Dunes State
Park, and South Shore Rail Cats Baseball.

LAT...LON 4140 8717 4148 8741 4163 8735 4162 8728
      4163 8716 4164 8715 4165 8715 4165 8710
      4170 8695
TIME...MOT...LOC 2339Z 204DEG 13KT 4155 8724

RODRIGUEZ

Special weather statement, Sep 12, 9:44 PM CDT, 2 hours 54 minutes before

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Special weather statement, Sep 12, 10:43 PM CDT, 1 hour 55 minutes before

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Special weather statement, Sep 13, 12:37 AM CDT, 1 minute before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 12, 7:02 PM CDT	Special Marine Warning	LOT		88 min
Sep 12, 9:44 PM CDT	Special Weather Statement	LOT	Ogle, Winnebago	46 min
Sep 12, 10:43 PM CDT	Special Weather Statement	LOT	Lee, Ogle, Winnebago	62 min
Sep 12, 11:01 PM CDT	Areal Flood Advisory	LOT	Lee, Ogle, Winnebago	3 hr
Sep 12, 11:28 PM CDT	Severe Thunderstorm Warning	LOT	Lee, Ogle	47 min
Sep 12, 11:58 PM CDT	Severe Thunderstorm Warning	LOT	DeKalb, Lee, Ogle	62 min
Sep 13, 12:11 AM CDT	Areal Flood Advisory	LOT	Boone, DeKalb, Kane, Kendall, Lee, McHenry and 2 more	3 hr
Sep 13, 12:37 AM CDT	Special Weather Statement	LOT	Kane	38 min
Sep 13, 12:52 AM CDT	Severe Thunderstorm Warning	LOT	DuPage, Kane	25 min
Sep 13, 12:59 AM CDT	Special Weather Statement	LOT	Lake	46 min
Sep 13, 1:09 AM CDT	Special Marine Warning	LOT		81 min
Sep 13, 2:58 AM CDT	Areal Flood Advisory	LOT	DeKalb, Kane	3 hr
Sep 13, 3:28 AM CDT	Areal Flood Advisory	LOT	Cook	3 hr
Sep 13, 3:45 AM CDT	River Flood Advisory	LOT	Boone	24 hr
Sep 13, 4:08 AM CDT	Special Weather Statement	LOT	DuPage	37 min
Sep 13, 4:40 AM CDT	Special Weather Statement	LOT	Cook	50 min
Sep 13, 5:41 AM CDT	River Flood Advisory	LOT	Ogle	49 hr
Sep 13, 6:28 AM CDT	Areal Flood Warning	LOT	Boone, McHenry	3 hr
Sep 13, 7:40 AM CDT	River Flood Warning	LOT	Winnebago	41 days
Sep 13, 8:04 AM CDT	River Flood Warning	LOT	Winnebago	60 hr
Sep 13, 8:04 AM CDT	River Flood Warning	LOT	Winnebago	37 hr
Sep 13, 8:04 AM CDT	River Flood Warning	LOT	Ogle	61 hr
Sep 13, 8:13 AM CDT	River Flood Advisory	LOT	Winnebago	51 hr
Sep 13, 8:13 AM CDT	River Flood Advisory	LOT	Lee	4 days
Sep 13, 9:42 AM CDT	River Flood Watch	LOT		7 hr
Sep 13, 10:15 AM CDT	River Flood Advisory	LOT	Cook	6 days
Sep 13, 10:15 AM CDT	River Flood Advisory	LOT	Cook	72 hr
Sep 13, 10:15 AM CDT	River Flood Advisory	LOT	LaSalle	57 hr

Nearby

Flash Flood Warnings in Illinois, 2019 Every flash flood warning in 2019

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.