Alert archive / Iowa / Areal Flood Warnings in 2018

Areal Flood Warning 13, NWS Quad Cities, IA

October 7, 2018Johnson County, Iowa

NWS Quad Cities, IA issued this areal flood warning at Oct 7, 2018, 7:34 PM CDT for Johnson County, Iowa. It was in force for 18 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
Oct 7, 2018, 7:34 PM CDT (00:34 UTC)
Expired
Oct 8, 2018, 1:30 PM CDT
In force
18 hr
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Flood severity
None

County Johnson County, IA

The radar

The Quad Cities radar (KDVN), 84 km from the middle of the area, began a volume at 00:33 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

Minneapolis, MN (KMPX), launched 00:00Z, 0.6 hours before the alert went out and 389 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, Minneapolis, MN at 00:00Z on 2018-10-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 5 joules per kilogram.LCLEL10008507005003002001001 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, Minneapolis, MN at 00:00Z on 2018-10-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 129 square meters per square second.1939587897Sfc1 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
5 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
446 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
129 m²/s²
0-3 km storm-relative helicity
246 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 areal flood 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 areal flood warning went out at Oct 7, 6:56 PM CDT, 38 minutes earlier.

Area forecast discussion, Oct 7, 6:56 PM CDT, 38 minutes before
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Hazardous weather outlook, Oct 7, 3:14 PM CDT, 4 hours 20 minutes before
Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
314 PM CDT Sun Oct 7 2018

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-082015-
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-
314 PM CDT Sun Oct 7 2018

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...THIS AFTERNOON AND TONIGHT

Soils remain completely saturated and unable to absorb heavy
rainfall in the entire outlook area. Rain and thunderstorms are
possible over the entire area this afternoon and tonight. Heavy
rains are most likely this afternoon and tonight, along and east
of the Mississippi River. There is now a flash flood watch in
effect through mid morning Monday for locations in extreme eastern
an southeastern Iowa, northeast Missouri, and all of west central
and northwest Illinois. Warm moist air aloft will allow for
thunderstorms to bring heavy rainfall, with rains tonight
possibly between 1 and 3 inches. This rain will could lead to
flash flooding and increased river flooding.

Area rivers are experiencing flooding. Please see the
latest Flood Statements and Flood Warnings for details.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

A flash flood watch will continue for portions of the area through
10 AM Monday morning.

There are periodic chances for showers and thunderstorms through
the middle of next week. The primary threat is expected to be
heavy rainfall, which could lead to flash flooding and aggravate
ongoing river flooding. However, a few severe thunderstorms are
also possible Tuesday night, mainly west of the Mississippi River.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated this afternoon or tonight.

ERVIN

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 7, 8:47 PM CDTRiver Flood WarningDVNDes Moines, Henry, Lee10 days
Oct 7, 9:16 PM CDTRiver Flood WatchDVNClinton, Scott15 hr
Oct 8, 2:30 AM CDTSpecial Weather StatementDVNHenry, Jefferson, Keokuk, Washington60 min
Oct 8, 3:34 AM CDTSpecial Weather StatementDVNCedar, Iowa, Johnson, Keokuk, Muscatine, Washington56 min
Oct 8, 4:29 AM CDTSpecial Weather StatementDVNBenton, Cedar, Iowa, Johnson, Jones, Linn61 min
Oct 8, 9:16 AM CDTRiver Flood WarningDVNBenton, Linn6 days
Oct 8, 9:16 AM CDTRiver Flood WarningDVNCedar, Johnson, Linn9 days
Oct 8, 9:16 AM CDTRiver Flood WarningDVNJohnson, Washington49 hr
Oct 8, 10:58 AM CDTRiver Flood WarningDVNLee6 days
Oct 8, 11:01 AM CDTRiver Flood WatchDVNJackson5 hr
Oct 8, 11:49 AM CDTRiver Flood WarningDVNClinton5 days
Oct 8, 11:49 AM CDTRiver Flood WarningDVNClinton, Scott17 days
Oct 8, 11:49 AM CDTRiver Flood WarningDVNScott6 days
Oct 8, 3:18 PM CDTSpecial Weather StatementDVNDes Moines, Henry, Lee, Louisa, Muscatine87 min
Oct 8, 3:36 PM CDTRiver Flood WarningDVNJackson5 days
Oct 7, 8:26 PM CDTRiver Flood WarningDVNHancock, McDonough24 hr
Oct 8, 12:20 AM CDTSpecial Weather StatementDVNMcDonough85 min

Nearby

Areal Flood Warnings in Iowa, 2018Every areal flood warning in 2018

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.