Alert archive / Iowa / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 142, NWS Quad Cities, IA

September 12, 2019Buchanan County, Delaware County, Linn County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Sep 12, 2019, 4:50 PM CDT for Buchanan County, Delaware County, Linn County, Iowa. It was in force for 40 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 12, 2019, 4:50 PM CDT (21:50 UTC)
Expired
Sep 12, 2019, 5:30 PM CDT
In force
40 min
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Buchanan County, IA, Delaware County, IA, Linn County, IA

The radar

The Quad Cities radar (KDVN), 117 km from the middle of the area, began a volume at 21:52 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 12, 3:40 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.8 hours before the alert went out and 121 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 2019-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1327 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 2019-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 61 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
1327 J/kg
Mixed-layer CIN
-55 J/kg
Mixed-layer LCL
805 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
61 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.1

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 12, 1:59 PM CDT, 2 hours 51 minutes earlier.

Area forecast discussion, Sep 12, 1:59 PM CDT, 2 hours 51 minutes before
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Hazardous weather outlook, Sep 12, 4:26 AM CDT, 12 hours 24 minutes before
Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
426 AM CDT Thu Sep 12 2019

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-130930-
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-
426 AM CDT Thu Sep 12 2019

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

This afternoon and evening: The Storm Prediction Center has a
slight risk for severe thunderstorms across the entire outlook
area. A strong cold front will sweep a line of thunderstorms,
some possibly severe, across the outlook area. The main risk will
be damaging winds and possible large hail. However, a stalled
boundary in eastern Iowa may serve as a focus for discrete
supercells which may produce tornadoes. This risk is greatest
north of Interstate 80 in eastern Iowa.

In addition: due to the intense rainfall rates that will accompany
these storms, there is the potential for flash flooding especially
along the Highway 20 corridor in Iowa and Illinois. This area has
received several inches of rain in the past week and is the most
vulnerable to flash flooding. A flash flood watch is in effect
through this evening for that area.

Heat index values in the lower to mid 90s can be expected this
afternoon mainly along and south of Interstate 80.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

Friday: West winds will gust up to 35 mph especially north of
Interstate 80.

Saturday night: Scattered thunderstorms are expected to develop
as a warm front returns to the area. The Storm Prediction Center
has a marginal risk for severe storms in eastern Iowa, northwest
of a Dubuque to Sigourney line.

.SPOTTER INFORMATION STATEMENT...

Spotter and amateur radio activation may be needed this afternoon
and evening.

Haase

In the hours before

Local storm report, Sep 12, 12:00 PM CDT, 4 hours 50 minutes before
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Special weather statement, Sep 12, 12:43 PM CDT, 4 hours 7 minutes before
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Special weather statement, Sep 12, 4:35 PM CDT, 15 minutes before
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Local storm report, Sep 12, 4:43 PM CDT, 7 minutes before
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Special weather statement, Sep 12, 4:45 PM CDT, 5 minutes before
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Local storm report, Sep 12, 4:47 PM CDT, 3 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
447 PM CDT THU SEP 12 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0442 PM     TSTM WND GST     1 N INDEPENDENCE        42.49N 91.89W
09/12/2019  E50 MPH          BUCHANAN           IA   TRAINED SPOTTER

            SUSTAINED AT 45 MPH FOLLOWING THE GUST.

&&

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 11, 7:11 PM CDTSevere Thunderstorm WarningDVNDubuque, Jackson, Jones34 min
Sep 11, 7:40 PM CDTSpecial Weather StatementDVNJackson50 min
Sep 11, 10:08 PM CDTFlash Flood WarningDVNDubuque6 hr
Sep 11, 11:38 PM CDTFlash Flood WarningDVNDubuque5 hr
Sep 12, 1:46 AM CDTFlash Flood WatchDVNBuchanan, Delaware, Dubuque23 hr
Sep 12, 4:35 PM CDTSpecial Weather StatementDVNLinn25 min
Sep 12, 4:45 PM CDTSpecial Weather StatementDVNBuchanan30 min
Sep 12, 6:06 PM CDTSpecial Weather StatementDVNJones39 min
Sep 12, 6:19 PM CDTSevere Thunderstorm WarningDVNCedar, Johnson, Jones, Linn41 min
Sep 11, 7:50 PM CDTSpecial Weather StatementDVNJo Daviess40 min
Sep 11, 8:28 PM CDTSpecial Weather StatementDVNStephenson47 min
Sep 11, 8:31 PM CDTSpecial Weather StatementDVNCarroll44 min
Sep 11, 10:56 PM CDTFlash Flood WarningDVNStephenson5 hr
Sep 11, 11:44 PM CDTFlash Flood WarningDVNStephenson2 hr
Sep 12, 10:02 AM CDTRiver Flood WarningDVNStephenson39 days
Sep 12, 12:43 PM CDTSpecial Weather StatementDVNCarroll32 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2019Every severe thunderstorm warning in 2019

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.