Alert archive / Illinois / Flash Flood Warnings in 2007

Flash Flood Warning 15, NWS Chicago, IL

July 9, 2007McHenry County, Illinois

NWS Chicago, IL issued this flash flood warning at Jul 9, 2007, 2:54 PM CDT for McHenry County, Illinois. It was in force for 5 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
Jul 9, 2007, 2:54 PM CDT (19:54 UTC)
Expired
Jul 9, 2007, 8:00 PM CDT
In force
5 hr
Issued by
NWS Chicago, IL
Area
Whole counties

County McHenry County, IL

The radar

The Milwaukee radar (KMKX), 72 km from the middle of the area, began a volume at 19:57 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 12:00Z, 7.9 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, Davenport, at 12:00Z on 2007-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1065 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, Davenport, at 12:00Z on 2007-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 square meters per square second.1939Sfc1 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
1065 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
1222 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
27 m²/s²
0-3 km storm-relative helicity
-19 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 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 Jul 9, 1:00 PM CDT, 1 hour 54 minutes earlier.

Area forecast discussion, Jul 9, 1:00 PM CDT, 1 hour 54 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 9, 11:50 AM CDT, 3 hours 4 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1150 AM CDT MON JUL 9 2007

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
092130-
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-
1150 AM CDT MON JUL 9 2007/1250 PM CDT MON JUL 9 2007

THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR NORTH
CENTRAL AND NORTHEAST ILLINOIS...AND NORTHWEST INDIANA.

.DAY ONE...TODAY AND TONIGHT.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
ILLINOIS AND EXTREME NORTHERN INDIANA THIS AFTERNOON AND EVENING.
THE RISK AREA IS GENERALLY ALONG AND NORTH OF INTERSTATE 80.

SCATTERED STORMS MAY DEVELOP ACROSS NORTHEAST ILLINOIS AND NORTHWEST
INDIANA AFTER 2 PM CDT OR 3 PM EDT. A WEAK FRONT WILL MOVE SOUTH TO
THE ILLINOIS AND WISCONSIN BORDER. A LAKE BREEZE FROM LAKE MICHIGAN
MAY MOVE WEST TOWARDS ROCKFORD. THESE TWO FRONTS MAY PROVIDE ENOUGH
LIFT TO INITIATE THE SCATTERED THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

A SLIGHT RISK OF SEVERE THUNDERSTORMS EXISTS AGAIN TUESDAY AFTERNOON
AND EVENING OVER MUCH OF NORTHERN ILLINOIS.  A STRONGER COLD FRONT
IS FORECAST TO SWEEP ACROSS THE MIDWEST TUESDAY EVENING.  WITH
STRONGER WIND PROFILES ASSOCIATED WITH THIS SYSTEM...AND WITH AMPLE
INSTABILITY IN PLACE AHEAD OF THE FRONT...STORMS ARE EXPECTED TO
HAVE MORE COVERAGE AND A GREATER POTENTIAL FOR DEVELOPING DAMAGING
WIND GUSTS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED THROUGH TONIGHT.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

LMZ740>745-766-092130-
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 INDIANA TO BURNS HARBOR-
BURNS HARBOR TO MICHIGAN CITY-
LAKE MICHIGAN, WINTHROP HARBOR IL EASTWARD TO THE MID-
POINT OF THE LAKE AND SOUTHWARD TO MICHIGAN CITY MI BEYOND 5 NM
OFFSHORE-
430 AM CDT MON JUL 9 2007

THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS
AND INDIANA WATERS OF LAKE MICHIGAN.

.DAY ONE... TODAY AND TONIGHT.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN LAKE
MICHIGAN THIS AFTERNOON AND EVENING.

SCATTERED STORMS MAY DEVELOP ACROSS THE LAKE THIS AFTERNOON AND
EVENING.  A FEW STORMS MAY BE CAPABLE OF PRODUCING MARGINALLY SEVERE
HAIL AND WIND GUSTS IN EXCESS OF 34 KNOTS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

A SLIGHT RISK OF SEVERE THUNDERSTORMS EXISTS AGAIN TUESDAY AFTERNOON
AND EVENING.  A COLD FRONT IS FORECAST TO SWEEP ACROSS THE SOUTHERN
END OF LAKE MICHIGAN TUESDAY EVENING.  THE PRIMARY THREAT FROM THESE
STORMS WILL BE DAMAGING WIND GUSTS.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 9, 2:14 PM CDTSevere Thunderstorm WarningLOTMcHenry61 min
Jul 9, 2:34 PM CDTSevere Thunderstorm WarningLOTLake56 min
Jul 9, 2:37 PM CDTSpecial Marine WarningLOT83 min
Jul 9, 3:19 PM CDTSevere Thunderstorm WarningLOTKane, McHenry56 min
Jul 9, 3:38 PM CDTSevere Thunderstorm WarningLOTDeKalb, Kane52 min
Jul 9, 3:44 PM CDTSevere Thunderstorm WarningLOTCook, DuPage, Kane61 min
Jul 9, 4:07 PM CDTSevere Thunderstorm WarningLOTWill23 min
Jul 9, 4:25 PM CDTFlash Flood WarningLOTDeKalb4 hr
Jul 9, 4:27 PM CDTSevere Thunderstorm WarningLOTDeKalb41 min
Jul 9, 4:48 PM CDTSevere Thunderstorm WarningLOTWill36 min
Jul 9, 4:59 PM CDTSevere Thunderstorm WarningLOTLee46 min
Jul 9, 5:38 PM CDTFlash Flood WarningLOTLee4 hr
Jul 9, 5:49 PM CDTSevere Thunderstorm WarningLOTDeKalb, Kane29 min
Jul 9, 5:56 PM CDTRiver Flood WarningLOTDeKalb3 hr

Nearby

Flash Flood Warnings in Illinois, 2007Every flash flood warning in 2007

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.