Alert archive / Illinois / Flash Flood Watches in 2017

Flash Flood Watch 3, NWS Chicago, IL

July 12, 201716 counties in Illinois; 5 counties in Indiana

NWS Chicago, IL issued this flash flood watch at Jul 12, 2017, 2:32 PM CDT for 16 counties in Illinois; 5 counties in Indiana. It took effect at Jul 12, 2017, 9:00 PM CDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued: Jul 12, 2017, 2:32 PM CDT (19:32 UTC)
In effect from: Jul 12, 2017, 9:00 PM CDT
Expired: Jul 13, 2017, 2:57 AM CDT
In force: 6 hr
Issued by: NWS Chicago, IL
Flood severity: None

All 21 counties

Boone 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, LaSalle County, IL, Lee County, IL, Livingston County, IL, McHenry County, IL, Ogle County, IL, Winnebago County, IL, Benton County, IN, Jasper County, IN, Lake County, IN, Newton County, IN, Porter County, IN

The radar

The Chicago radar (KLOT), 15 km from the middle of the area, began a volume at 19:35 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

Lincoln, IL (KILX), launched 12:00Z, 7.5 hours before the alert went out and 156 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: 1083 J/kg
Mixed-layer CIN: -166 J/kg
Mixed-layer LCL: 1094 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 136 m²/s²
0-3 km storm-relative helicity: 85 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood watch 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 watch went out at Jul 12, 12:39 PM CDT, 1 hour 53 minutes earlier.

Area forecast discussion, Jul 12, 12:39 PM CDT, 1 hour 53 minutes before

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

Hazardous weather outlook, Jul 12, 2:18 PM CDT, 14 minutes before

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

In the hours before

Local storm report, Jul 12, 10:23 AM CDT, 4 hours 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1023 AM CDT WED JUL 12 2017

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

0913 AM     HAIL             LOMBARD                 41.87N 88.01W
07/12/2017  M0.25 INCH       DUPAGE             IL   PUBLIC

&&

ACS

Local storm report, Jul 12, 10:35 AM CDT, 3 hours 57 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1035 AM CDT WED JUL 12 2017

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

0950 AM     TSTM WND GST     4 NE CHICAGO            41.92N 87.57W
07/12/2017  M47.00 MPH       LMZ741             IL   C-MAN STATION

&&

MDB

Local storm report, Jul 12, 10:36 AM CDT, 3 hours 56 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1036 AM CDT WED JUL 12 2017

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

1035 AM     HAIL             ORLAND PARK             41.61N 87.85W
07/12/2017  E0.25 INCH       COOK               IL   PUBLIC

&&

ACS

Local storm report, Jul 12, 10:37 AM CDT, 3 hours 55 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1037 AM CDT WED JUL 12 2017

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

0940 AM     MARINE TSTM WIND 6 E GLENCOE             42.13N 87.65W
07/12/2017  M51 MPH          LMZ740             IL   BUOY

&&

MDB

Local storm report, Jul 12, 10:38 AM CDT, 3 hours 54 minutes before

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1038 AM CDT WED JUL 12 2017

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

1035 AM     HAIL             ORLAND PARK             41.61N 87.85W
07/12/2017  E0.25 INCH       COOK               IL   PUBLIC

1022 AM     FLOOD            CHICAGO                 41.88N 87.63W
07/12/2017                   COOK               IL   PUBLIC

            STANDING WATER OF TWO TO SIX INCHES NEAR LAKE SHORE DRIVE
            AND BELMONT.

0950 AM     MARINE TSTM WIND 4 NE CHICAGO            41.92N 87.57W
07/12/2017  M47.00 MPH       LMZ741             IL   C-MAN STATION

0943 AM     HEAVY RAIN       HOFFMAN ESTATES         42.06N 88.14W
07/12/2017  M1.70 INCH       COOK               IL   TRAINED SPOTTER

            RAIN FELL IN THE PAST 45 MINUTES. ALSO SMALL HAIL.

0940 AM     HAIL             ARLINGTON HEIGHTS       42.09N 87.98W
07/12/2017  M0.25 INCH       COOK               IL   TRAINED SPOTTER

0940 AM     MARINE TSTM WIND 6 E GLENCOE             42.13N 87.65W
07/12/2017  M51.00 MPH       LMZ740             IL   BUOY

0935 AM     HAIL             GLENVIEW                42.08N 87.82W
07/12/2017  E0.75 INCH       COOK               IL   PUBLIC

0921 AM     HAIL             1 N LINCOLNSHIRE        42.21N 87.92W
07/12/2017  M0.25 INCH       LAKE               IL   COCORAHS

0921 AM     HAIL             ROLLING MEADOWS         42.08N 88.03W
07/12/2017  M0.25 INCH       COOK               IL   TRAINED SPOTTER

0920 AM     TSTM WND DMG     BUFFALO GROVE           42.17N 87.96W
07/12/2017                   LAKE               IL   LAW ENFORCEMENT

            BRANCHES DOWN.

0920 AM     HAIL             CARPENTERSVILLE         42.12N 88.27W
07/12/2017  M0.25 INCH       KANE               IL   TRAINED SPOTTER

0919 AM     HAIL             MUNDELEIN               42.27N 88.00W
07/12/2017  M0.75 INCH       LAKE               IL   TRAINED SPOTTER

0915 AM     HAIL             CARY                    42.21N 88.25W
07/12/2017  M0.25 INCH       MCHENRY            IL   PUBLIC

0913 AM     HAIL             LOMBARD                 41.87N 88.01W
07/12/2017  M0.25 INCH       DUPAGE             IL   PUBLIC

0913 AM     HAIL             CARY                    42.21N 88.25W
07/12/2017  M0.75 INCH       MCHENRY            IL   TRAINED SPOTTER

0910 AM     HAIL             3 WNW BULL VALLEY       42.33N 88.40W
07/12/2017  M0.25 INCH       MCHENRY            IL   COCORAHS

0900 AM     HEAVY RAIN       1 N LINCOLNSHIRE        42.21N 87.92W
07/12/2017  M1.01 INCH       LAKE               IL   COCORAHS

            RAIN IN THE PAST HOUR

0850 AM     HEAVY RAIN       1 ESE BANNOCKBURN       42.19N 87.85W
07/12/2017  M0.97 INCH       LAKE               IL   COCORAHS

            RAIN FELL IN PAST 65 MINUTES

0849 AM     HAIL             WOOD DALE               41.97N 87.98W
07/12/2017  M0.25 INCH       DUPAGE             IL   TRAINED SPOTTER

0840 AM     HAIL             ELK GROVE VILLAGE       42.01N 87.99W
07/12/2017  M0.75 INCH       COOK               IL   TRAINED SPOTTER

0825 AM     HEAVY RAIN       2 W GURNEE              42.38N 87.98W
07/12/2017  M1.02 INCH       LAKE               IL   COCORAHS

            RAIN FELL IN THE PAST 1 HOUR.

0657 AM     HEAVY RAIN       ROUND LAKE PARK         42.32N 88.06W
07/12/2017  M7.13 INCH       LAKE               IL   PUBLIC

0648 AM     HEAVY RAIN       MUNDELEIN               42.27N 88.00W
07/12/2017  M6.75 INCH       LAKE               IL   PUBLIC

0638 AM     HEAVY RAIN       3 SE FOX LAKE           42.38N 88.14W
07/12/2017  M4.46 INCH       LAKE               IL   PUBLIC

0633 AM     HEAVY RAIN       2 SE LAKEMOOR           42.32N 88.18W
07/12/2017  M2.42 INCH       LAKE               IL   COCORAHS

0600 AM     FLASH FLOOD      MUNDELEIN               42.27N 88.00W
07/12/2017                   LAKE               IL   BROADCAST MEDIA

            WATER AT LEAST 8-10 INCHES DEEP AT LINCOLN AND DIVISION.
            NUMEROUS HOUSES FLOODED AND PEOPLE RESCUED BY RAFTS.

0600 AM     FLASH FLOOD      LIBERTYVILLE            42.28N 87.97W
07/12/2017                   LAKE               IL   BROADCAST MEDIA

            NORTHBOUND 45 BLOCKED AT IL-137 DUE TO HIGH STANDING
            WATER. BUTTERFIELD/VIRGINIA BLOCKED PETERSON RD BLOCKED
            BY INDEPENDENCE RT 21 BLOCKED NORTH OF IL-60

0557 AM     FLASH FLOOD      GURNEE                  42.38N 87.94W
07/12/2017                   LAKE               IL   DEPT OF HIGHWAYS

            IL-132 CLOSED BETWEEN OPLAINE RD AND FIRST ST DUE TO
            FLOODING

0545 AM     HEAVY RAIN       1 SSW LAKE VILLA        42.40N 88.09W
07/12/2017  M5.31 INCH       LAKE               IL   COCORAHS

0530 AM     FLASH FLOOD      2 SW NORTH CHICAGO      42.30N 87.89W
07/12/2017                   LAKE               IL   BROADCAST MEDIA

            HIGH FLOOD WATERS AT US-41 AND IL-137

0526 AM     HEAVY RAIN       GURNEE                  42.38N 87.94W
07/12/2017  M3.42 INCH       LAKE               IL   COCORAHS

0515 AM     HEAVY RAIN       1 W LAKE BLUFF          42.28N 87.87W
07/12/2017  M5.38 INCH       LAKE               IL   COCORAHS

0506 AM     HEAVY RAIN       LIBERTYVILLE            42.28N 87.97W
07/12/2017  M5.17 INCH       LAKE               IL   EMERGENCY MNGR

0455 AM     HEAVY RAIN       3 W ELGIN               42.04N 88.35W
07/12/2017  M4.29 INCH       KANE               IL   COCORAHS

0400 AM     HEAVY RAIN       2 W GURNEE              42.38N 87.98W
07/12/2017  M5.40 INCH       LAKE               IL   COCORAHS

0334 AM     HEAVY RAIN       1 NNW LINDENHURST       42.43N 88.04W
07/12/2017  M4.20 INCH       LAKE               IL   COCORAHS

0200 AM     FLASH FLOOD      LIBERTYVILLE            42.28N 87.97W
07/12/2017                   LAKE               IL   LAW ENFORCEMENT

            REPORTS OF SIGNIFICANT FLASH FLOODING WITH NUMERIOUS
            ROADS IMPASSABLE.

&&

ACS

Local storm report, Jul 12, 12:00 PM CDT, 2 hours 32 minutes before

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 11, 9:26 PM CDT	Special Weather Statement	LOT	Kane	19 min
Jul 11, 10:27 PM CDT	Special Weather Statement	LOT	Kane	18 min
Jul 11, 10:32 PM CDT	Special Marine Warning	LOT		88 min
Jul 11, 10:42 PM CDT	Severe Thunderstorm Warning	LOT	Kane	33 min
Jul 11, 10:44 PM CDT	Flash Flood Warning	LOT	Cook, DuPage, Kane, Lake, McHenry	16 hr
Jul 11, 11:37 PM CDT	Special Weather Statement	LOT	Kane	23 min
Jul 12, 12:57 AM CDT	Special Weather Statement	LOT	McHenry	33 min
Jul 12, 1:05 AM CDT	Severe Thunderstorm Warning	LOT	Lake, McHenry	40 min
Jul 12, 1:21 AM CDT	Special Marine Warning	LOT		84 min
Jul 12, 1:29 AM CDT	Flash Flood Warning Emergency	LOT	Lake, McHenry	10 hr
Jul 12, 1:51 AM CDT	Severe Thunderstorm Warning	LOT	Cook, Lake	28 min
Jul 12, 1:53 AM CDT	Special Marine Warning	LOT		67 min
Jul 12, 3:14 AM CDT	Special Weather Statement	LOT	Lake	46 min
Jul 12, 3:21 AM CDT	Special Marine Warning	LOT		84 min
Jul 12, 3:39 AM CDT	River Flood Warning	LOT	Lake	15 days
Jul 12, 3:41 AM CDT	Heat Advisory	LOT	Ford, Grundy, LaSalle, Livingston	12 hr
Jul 12, 4:15 AM CDT	River Flood Warning	LOT	Lake	14 days
Jul 12, 4:15 AM CDT	River Flood Warning	LOT	Cook	14 days
Jul 12, 4:38 AM CDT	Special Marine Warning	LOT		97 min
Jul 12, 7:04 AM CDT	Severe Thunderstorm Warning	LOT	Lake, McHenry	71 min
Jul 12, 7:23 AM CDT	Special Marine Warning	LOT		97 min
Jul 12, 7:32 AM CDT	River Flood Warning	LOT	Kane, Kendall	19 days
Jul 12, 8:38 AM CDT	Special Weather Statement	LOT	Cook, DuPage	52 min
Jul 12, 8:59 AM CDT	Special Marine Warning	LOT		2 hr
Jul 12, 9:24 AM CDT	Severe Thunderstorm Warning	LOT	Cook, DuPage, Lake	21 min
Jul 12, 10:14 AM CDT	Flash Flood Warning	LOT	Cook, DuPage, Kane, Kendall, Will	6 hr
Jul 12, 10:29 AM CDT	River Flood Advisory	LOT	Cook	36 hr
Jul 12, 10:57 AM CDT	Flash Flood Warning	LOT	Lake, McHenry	3 hr
Jul 12, 11:44 AM CDT	River Flood Warning	LOT	Cook	5 days
Jul 12, 11:44 AM CDT	River Flood Warning	LOT	Kane, McHenry	21 days
Jul 12, 11:44 AM CDT	River Flood Warning	LOT	Cook	4 days
Jul 12, 11:46 AM CDT	River Flood Warning	LOT	Cook	20 hr
Jul 12, 2:06 PM CDT	Areal Flood Warning	LOT	Cook, Kane, Lake, McHenry	3 hr
Jul 12, 5:05 PM CDT	River Flood Advisory	LOT	Cook	4 days

Nearby

Flash Flood Watches in Illinois, 2017 Flash Flood Watches in Indiana, 2017 Every flash flood watch in 2017

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.