Alert archive / Iowa / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 179, NWS Quad Cities, IA

September 6, 2020Buchanan County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Sep 6, 2020, 12:58 AM CDT for Buchanan County, Iowa. It was in force for 62 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 6, 2020, 12:58 AM CDT (05:58 UTC)
Expired
Sep 6, 2020, 2:00 AM CDT
In force
62 min
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Hail
1.5 in
Wind
50.0 mph

County Buchanan County, IA

The radar

The Quad Cities radar (KDVN), 141 km from the middle of the area, began a volume at 05:58 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 5, 9:34 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 6.0 hours before the alert went out and 145 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 2020-09-06Temperature 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 2020-09-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 square meters per square second.19395878Sfc1 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
2140 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
269 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 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 6, 12:04 AM CDT, 54 minutes earlier.

Area forecast discussion, Sep 6, 12:04 AM CDT, 54 minutes before
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Hazardous weather outlook, Sep 5, 3:31 AM CDT, 21 hours 27 minutes before
Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
331 AM CDT Sat Sep 5 2020

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-060845-
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-
331 AM CDT Sat Sep 5 2020

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

Thunderstorms will be possible across the area late tonight, with
some having the potential to become severe. The Storm Prediction
Center has a slight risk of severe thunderstorms north of a line
from Manchester Iowa to Williamsburg Iowa, with a marginal risk
for the rest of eastern Iowa into northwest Illinois. The primary
threats with storms, will be damaging wind gusts and large hail.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

Southwest winds could gust to 40 mph at times Sunday afternoon.

Thunderstorms could redevelop over portions of the area late
Sunday afternoon and evening ahead of a cold front. There is
some uncertainty regarding how widespread these storms will be,
but any storms that are able to form will be capable of producing
large hail and damaging winds.

Isolated thunderstorms will be possible at times next week. The
threat for severe weather appears low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed late tonight and early Sunday
morning.

McClure/Speck

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 6, 1:35 AM CDTSevere Thunderstorm WarningDVNBuchanan, Delaware55 min
Sep 6, 2:17 AM CDTSevere Thunderstorm WarningDVNDelaware, Dubuque, Jones, Linn58 min
Sep 6, 3:14 AM CDTSevere Thunderstorm WarningDVNDelaware, Dubuque, Jones32 min
Sep 6, 4:04 AM CDTSevere Thunderstorm WarningDVNClinton, Scott41 min
Sep 6, 4:28 AM CDTSevere Thunderstorm WarningDVNCedar, Delaware, Jones, Linn47 min
Sep 6, 5:14 AM CDTSpecial Weather StatementDVNScott31 min
Sep 6, 9:03 AM CDTSpecial Weather StatementDVNLinn42 min
Sep 6, 1:57 AM CDTSevere Thunderstorm WarningDVNCarroll, Jo Daviess, Stephenson29 min
Sep 6, 4:40 AM CDTSevere Thunderstorm WarningDVNBureau, Henry, Rock Island, Whiteside65 min
Sep 6, 5:44 AM CDTSevere Thunderstorm WarningDVNBureau, Henry31 min
Sep 6, 7:19 AM CDTSpecial Weather StatementDVNMercer26 min
Sep 6, 8:10 AM CDTSpecial Weather StatementDVNHenderson, McDonough, Warren50 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2020Every severe thunderstorm warning in 2020

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.