Alert archive / Iowa / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 122, NWS Quad Cities, IA

September 2, 2018Buchanan County, Delaware County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Sep 2, 2018, 3:01 PM CDT for Buchanan County, Delaware County, Iowa. It was in force for 44 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
Sep 2, 2018, 3:01 PM CDT (20:01 UTC)
Expired
Sep 2, 2018, 3:45 PM CDT
In force
44 min
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

Counties Buchanan County, IA, Delaware County, IA

The radar

The Quad Cities radar (KDVN), 127 km from the middle of the area, began a volume at 20:01 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, 8.0 hours before the alert went out and 131 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 2018-09-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 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 2018-09-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 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
20 J/kg
Mixed-layer CIN
-242 J/kg
Mixed-layer LCL
1345 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
58 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

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 Sep 2, 2:12 PM CDT, 49 minutes earlier.

Area forecast discussion, Sep 2, 2:12 PM CDT, 49 minutes before
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Hazardous weather outlook, Sep 2, 5:38 AM CDT, 9 hours 23 minutes before
Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
538 AM CDT Sun Sep 2 2018

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-031000-
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-
538 AM CDT Sun Sep 2 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...TODAY AND TONIGHT

Showers and thunderstorms are expected again this afternoon and
tonight across portions of the Outlook Area. Current indications
suggest the storm coverage may be higher along and north of the
Interstate 80 corridor especially by tonight, but scattered
storms may still occur to the south of I-80 as well. Some of these
storms may be strong to possibly severe with damaging winds and
large hail the main threats. But with all the recent heavy
rainfall, today will be another day with an elevated risk of
flooding and flash flooding where new storms develop and move
across areas already rain-soaked and saturated. Once these areas
of concern are better defined, a new Flash Flood Watch may be
needed for later today and tonight. Stay tuned for updates.

The Storm Prediction Center has placed a Marginal Risk for severe
weather this afternoon and tonight for areas generally along and
northwest of a line from Keosauqua Iowa, to Burlington Iowa, and
to Sterling Illinois.

Some area rivers are experiencing rising water levels and
flooding. Please see the latest Flood Statements and Flood
Warnings for details.

Away from the storms and cloud cover, unseasonably warm
temperatures and high humidity will combine to produce heat index
readings as high as the 90s during the afternoon and early evening
hours.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

There will be a chance of thunderstorms almost every day through
the period, with them being more common during the evening and
night time hours. It is too soon to determine the risk of severe
weather. But the storms will have the potential to produce more
heavy rain which could lead to additional flash flooding and
river flooding.

Several area rivers will likely continue to experience high water
levels and flooding for much of the upcoming week, especially if
rounds of storms continue to effect portions of the Outlook Area.

Very warm temperatures and higher than normal humidity will
continue for much of the upcoming week, sending heat index
readings as high as the 90s during the afternoon and early evening
hours.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and tonight. Any
reports of new flooding or flash flooding would be appreciated.

12

In the hours before

Special weather statement, Sep 2, 2:39 PM CDT, 22 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 7:32 PM CDTSpecial Weather StatementDVNKeokuk28 min
Sep 1, 7:39 PM CDTSevere Thunderstorm WarningDVNKeokuk36 min
Sep 1, 7:52 PM CDTTornado WarningDVNKeokuk23 min
Sep 1, 8:14 PM CDTSevere Thunderstorm WarningDVNJefferson, Keokuk46 min
Sep 1, 8:23 PM CDTSevere Thunderstorm WarningDVNKeokuk37 min
Sep 1, 8:56 PM CDTSpecial Weather StatementDVNWashington49 min
Sep 1, 9:05 PM CDTSevere Thunderstorm WarningDVNHenry, Jefferson, Washington40 min
Sep 1, 9:08 PM CDTSevere Thunderstorm WarningDVNHenry, Jefferson, Washington52 min
Sep 1, 9:22 PM CDTSevere Thunderstorm WarningDVNJefferson38 min
Sep 1, 9:52 PM CDTSpecial Weather StatementDVNIowa53 min
Sep 1, 9:56 PM CDTSpecial Weather StatementDVNLouisa49 min
Sep 1, 10:04 PM CDTSpecial Weather StatementDVNWashington26 min
Sep 1, 10:08 PM CDTFlash Flood WarningDVNKeokuk5 hr
Sep 1, 11:20 PM CDTFlash Flood WarningDVNIowa, Keokuk, Washington4 hr
Sep 1, 11:29 PM CDTSpecial Weather StatementDVNScott46 min
Sep 1, 11:50 PM CDTSpecial Weather StatementDVNDubuque25 min
Sep 2, 9:26 AM CDTFlash Flood WatchDVNBenton, Buchanan, Cedar, Clinton, Delaware, Des Moines and 15 more39 hr
Sep 2, 9:53 AM CDTRiver Flood WarningDVNCedar, Jones, Linn11 days
Sep 2, 10:22 AM CDTRiver Flood WarningDVNLouisa16 days
Sep 2, 10:22 AM CDTRiver Flood WarningDVNDes Moines, Louisa16 days
Sep 2, 10:22 AM CDTRiver Flood WarningDVNDes Moines17 days
Sep 2, 10:22 AM CDTRiver Flood WarningDVNDes Moines, Lee17 days
Sep 2, 2:39 PM CDTSpecial Weather StatementDVNBuchanan111 min
Sep 2, 3:41 PM CDTTornado WarningDVNDelaware, Dubuque22 min
Sep 2, 4:31 PM CDTSpecial Weather StatementDVNDubuque74 min
Sep 2, 5:32 PM CDTSpecial Weather StatementDVNJones43 min
Sep 2, 6:18 PM CDTSpecial Weather StatementDVNJackson42 min
Sep 2, 6:25 PM CDTSpecial Weather StatementDVNCedar, Muscatine, Scott, Washington50 min
Sep 2, 6:48 PM CDTSpecial Weather StatementDVNJefferson, Van Buren42 min
Sep 1, 8:42 PM CDTSpecial Weather StatementDVNWhiteside33 min
Sep 1, 9:33 PM CDTSpecial Weather StatementDVNRock Island42 min
Sep 1, 9:36 PM CDTSpecial Weather StatementDVNRock Island39 min
Sep 1, 10:01 PM CDTSpecial Weather StatementDVNWhiteside29 min
Sep 1, 11:02 PM CDTSpecial Weather StatementDVNCarroll, Stephenson43 min
Sep 2, 8:53 AM CDTRiver Flood WarningDVNHenry, Rock Island, Whiteside25 days
Sep 2, 8:53 AM CDTRiver Flood WarningDVNHenry, Rock Island14 days
Sep 2, 10:22 AM CDTRiver Flood WarningDVNHancock17 days

Nearby

Severe Thunderstorm Warnings in Iowa, 2018Every severe thunderstorm 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.