Alert archive / Iowa / Special Weather Statements in 2021

Special Weather Statement, NWS Quad Cities, IA

August 23, 20214 counties in Iowa

NWS Quad Cities, IA issued this special weather statement at Aug 23, 2021, 5:40 AM CDT for 4 counties in Iowa. It was in force for 65 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 23, 2021, 5:40 AM CDT (10:40 UTC)
Expired
Aug 23, 2021, 6:45 AM CDT
In force
65 min
Issued by
NWS Quad Cities, IA
Hail
0.25 in
Wind
40

Counties Benton County, IA, Buchanan County, IA, Delaware County, IA, Dubuque County, IA

The radar

The Quad Cities radar (KDVN), 110 km from the middle of the area, began a volume at 10:40 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, 10.7 hours before the alert went out and 113 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 00:00Z on 2021-08-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 00:00Z on 2021-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 46 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1587 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
46 m²/s²
0-3 km storm-relative helicity
120 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

<!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>

What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Aug 23, 3:49 AM CDT, 1 hour 51 minutes earlier.

Area forecast discussion, Aug 23, 3:49 AM CDT, 1 hour 51 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, Aug 23, 4:28 AM CDT, 1 hour 12 minutes before
Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
428 AM CDT Mon Aug 23 2021

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-240930-
Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson-
Cedar-Clinton-Muscatine-Scott-Keokuk-Washington-Louisa-Jefferson-
Henry IA-Des Moines-Van Buren-Lee-Jo Daviess-Stephenson-Carroll-
Whiteside-Rock Island-Henry IL-Bureau-Putnam-Mercer-Henderson-
Warren-Hancock-McDonough-Scotland-Clark-
428 AM CDT Mon Aug 23 2021

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

Expect scattered thunderstorms this morning over much of the
outlook area. The main threats will be pockets of heavy rain, and
possibly some small hail.

Afternoon heat indices in the 90s will be common across the
outlook area. Depending on the amount of cloud cover, some
locations west of Highway 218 and Interstate 380 could see values
around 100 degrees for a few hours.

More thunderstorms are possible tonight, mainly north of
Interstate 80. The main hazard will be heavy rain. There is a low
risk of damaging winds north of U.S. Highway 20.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

Thunderstorms are possible mainly north of Interstate 80 Tuesday
morning, and again Tuesday night. There is a low risk of damaging
winds. Depending on cloud cover, some locations could see heat
index readings in the range of 100 to 105 degrees Tuesday afternoon.

Periodic chances for storms will continue Wednesday through Sunday.
The threat of severe weather during this time period remains
uncertain.

.SPOTTER INFORMATION STATEMENT...

There is a low chance of spotter activation tonight, mainly north
of U.S. Highway 20.

RP Kinney/McClure

In the hours before

Special weather statement, Aug 23, 5:40 AM CDT, 0 minutes before
Special Weather Statement
National Weather Service Quad Cities IA/IL
540 AM CDT Mon Aug 23 2021

IAZ040>042-051>053-ILZ001-231145-
Jo Daviess IL-Linn IA-Buchanan IA-Delaware IA-Benton IA-Dubuque IA-
Jones IA-
540 AM CDT Mon Aug 23 2021

...Strong thunderstorms will impact portions of northwestern Jo
Daviess, Buchanan, Dubuque, Benton, northwestern Jones, Delaware and
northern Linn Counties through 645 AM CDT...

At 540 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Cassville to near La Porte City. Movement
was southeast at 20 mph.

HAZARD...Winds in excess of 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down small tree limbs and blow
         around unsecured objects. Minor damage to outdoor objects
         is possible.

Strong thunderstorms will be near...
  Luxemburg around 545 AM CDT.
  Holy Cross around 555 AM CDT.
  Mount Auburn and Balltown around 605 AM CDT.
  Rickardsville and Bankston around 610 AM CDT.
  Garrison and Sherrill around 615 AM CDT.
  Vinton and Epworth around 620 AM CDT.
  Dubuque, Centralia and Durango around 625 AM CDT.
  Asbury, Peosta and Sageville around 630 AM CDT.

Other locations impacted by these storms include Wapsipinicon Golf
Course, Bankston Park, Fillmore, Monti, Waupeton, Lattnerville,
Pinicon Ridge Park, Buck Creek, Baileys Ford Park and Petersburg.

This includes Interstate 380 between mile markers 27 and 55.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4263 9070 4254 9064 4248 9065 4242 9057
      4187 9230 4230 9230 4230 9206 4264 9208
      4265 9090 4267 9089
TIME...MOT...LOC 1040Z 311DEG 19KT 4268 9104 4228 9228

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

RP Kinney

The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 23, 6:49 AM CDTSpecial Weather StatementDVNJohnson, Jones56 min
Aug 23, 8:15 AM CDTSpecial Weather StatementDVNJohnson, Linn, Louisa, Muscatine, Washington45 min
Aug 23, 2:45 PM CDTHeat AdvisoryDVNBenton, Cedar, Clinton, Des Moines, Henry, Iowa and 12 more29 hr
Aug 23, 11:31 AM CDTSpecial Weather StatementDVNWarren29 min
Aug 23, 2:24 PM CDTSpecial Weather StatementDVNCarroll36 min

Nearby

Special Weather Statements in Iowa, 2021Every special weather statement in 2021

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.