Alert archive / Iowa / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 81, NWS Quad Cities, IA

July 10, 20094 counties in Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Jul 10, 2009, 10:52 PM CDT for 4 counties in Iowa. It was in force for 53 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: Jul 10, 2009, 10:52 PM CDT (03:52 UTC)
Expired: Jul 10, 2009, 11:45 PM CDT
In force: 53 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon

Counties Benton County, IA, Iowa County, IA, Johnson County, IA, Linn County, IA

The radar

The Quad Cities radar (KDVN), 108 km from the middle of the area, began a volume at 03:56 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 00:00Z, 3.9 hours before the alert went out and 332 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: 448 J/kg
Mixed-layer CIN: -172 J/kg
Mixed-layer LCL: 1300 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 98 m²/s²
0-3 km storm-relative helicity: 318 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.5

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 Quad Cities, IA wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 10, 4:00 PM CDT, 6 hours 52 minutes earlier.

Area forecast discussion, Jul 10, 4:00 PM CDT, 6 hours 52 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 10, 4:40 AM CDT, 18 hours 12 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
440 AM CDT FRI JUL 10 2009

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-111000-
BENTON IA-BUCHANAN IA-BUREAU IL-CARROLL IL-CEDAR IA-CLARK MO-
CLINTON IA-DELAWARE IA-DES MOINES IA-DUBUQUE IA-HANCOCK IL-
HENDERSON IL-HENRY IA-HENRY IL-IOWA IA-JACKSON IA-JEFFERSON IA-
JO DAVIESS IL-JOHNSON IA-JONES IA-KEOKUK IA-LEE IA-LINN IA-LOUISA IA-
MCDONOUGH IL-MERCER IL-MUSCATINE IA-PUTNAM IL-ROCK ISLAND IL-
SCOTLAND MO-SCOTT IA-STEPHENSON IL-VAN BUREN IA-WARREN IL-
WASHINGTON IA-WHITESIDE IL-
440 AM CDT FRI JUL 10 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
ILLINOIS...NORTHWEST ILLINOIS...WEST CENTRAL ILLINOIS...EAST
CENTRAL IOWA...NORTHEAST IOWA...SOUTHEAST IOWA AND NORTHEAST
MISSOURI.

.DAY ONE...TODAY AND TONIGHT

A THUNDERSTORM COMPLEX ACROSS THE NORTHERN PORTIONS OF THE OUTLOOK
AREA MAY PRODUCE WIND GUSTS UP TO 60 MPH AND HAIL UP TO THE SIZE OF
QUARTERS ALONG AND NORTH OF HIGHWAY 30 THROUGH MID MORNING. IF THIS
STORM SYSTEM CAN MAINTAIN ITS STRENGTH...IT MAY BE ABLE TO PRODUCE
STRONG WINDS AND HAIL AS FAR SOUTH AS THE INTERSTATE 80 CORRIDOR
THROUGH LATE MORNING. OTHER STORMS MAY DEVELOP IN SOUTH CENTRAL IOWA
EARLY THIS MORNING AND EVENTUALLY MOVE ACROSS AREAS SOUTH OF
INTERSTATE 80 THROUGH MIDDAY. IF THIS OCCURS...THESE STORMS WOULD
ALSO HAVE THE POTENTIAL TO PRODUCE WIND GUSTS OF 45 TO 60 MPH AND
HAIL UP TO THE SIZE OF QUARTERS. VERY HEAVY RAINFALL AT RATES OF UP
TO 2 INCHES AN HOUR MAY PRODUCE LOCALIZED URBAN AND SMALL STREAM
FLOODING AS THESE STORMS PASS THROUGH.

AS FOR THE STORM POTENTIAL FOR THIS AFTERNOON AND EVENING...MUCH
WILL DEPEND ON HOW MUCH THE ATMOSPHERE CAN RECOVER AND HEAT UP
AFTER THE MORNING STORMS EITHER MOVE OUT OF THE AREA OR FALL
APART. IF SOME SUNSHINE CAN BREAK OUT FOR TEMPERATURES TO WARM
INTO THE 80S...A VERY UNSTABLE AIRMASS WILL BECOME ESTABLISHED ACROSS
THE REGION. THEN A COLD FRONT APPROACHING FROM THE WEST SHOULD
TRIGGER THUNDERSTORMS BY THIS EVENING. WITH DEEP LAYER SHEAR AND
STRENGTHENING MID LEVEL WINDS THERE WILL BE A THREAT FOR SUPERCELL
TYPE THUNDERSTORMS WITH DAMAGING WINDS...LARGE HAIL AND A FEW
TORNADOES DEVELOPING IN THE OUTLOOK AREA. WIDESPREAD DAMAGING WINDS
IN EXCESS OF 70 MPH WILL BECOME THE PRIMARY THREAT IF THE INITIAL
STORMS FORM INTO A LINE DURING THE EVENING. LATEST INDICATIONS
SUGGEST THAT THIS LINE OF STORMS WILL MAINLY IMPACT AREAS ALONG AND
EAST OF THE MISSISSIPPI RIVER TONIGHT. LOCALLY HEAVY RAINFALL WILL
AGAIN BE LIKELY WITH ANY STRONG STORMS...AND COMBINED WITH THE RECENT
BOUTS OF RAIN MAY CAUSE FLASH FLOODING DUE TO SATURATED SOILS. MANY
AREA RIVER AND STREAMS WILL ALSO EXPERIENCE SUBSTANTIAL RISES.

THE STORM PREDICTION CENTER HAS THE ENTIRE OUTLOOK AREA UNDER A
SLIGHT RISK FOR SEVERE WEATHER TODAY AND TONIGHT.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THUNDERSTORMS MAY BE ONGOING OVER PORTIONS OF THE OUTLOOK AREA
SATURDAY MORNING ESPECIALLY ALONG AND SOUTH OF INTERSTATE 80. THERE
IS A LOW CHANCE THAT A FEW STORMS WILL RE-STRENGTHEN AND REACH SEVERE
LIMITS ALONG AND SOUTH OF THE HIGHWAY 34 CORRIDOR.

LATEST INDICATIONS THEN SUGGEST THAT THE NEXT MAIN CHANCE FOR
THUNDERSTORMS AFTER THE WEEKEND WILL BE LATE TUESDAY AND TUESDAY
NIGHT. IT IS STILL TOO EARLY TO DETERMINE THE THREAT FOR SEVERE
WEATHER FOR TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS LIKELY TODAY AND TONIGHT.

12

In the hours before

Local storm report, Jul 10, 6:24 PM CDT, 4 hours 28 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>

Local storm report, Jul 10, 6:31 PM CDT, 4 hours 21 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 Quad Cities, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 10, 9:10 PM CDT	River Flood Warning	DVN	Clinton, Scott	47 hr
Jul 11, 12:06 AM CDT	Special Weather Statement	DVN	Cedar, Johnson, Muscatine	54 min
Jul 11, 12:45 AM CDT	Special Weather Statement	DVN	Muscatine	60 min
Jul 11, 1:33 AM CDT	Special Weather Statement	DVN	Rock Island	57 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2009 Every severe thunderstorm warning in 2009

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.