Alert archive / Iowa / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 48, NWS Quad Cities, IA

April 4, 2023Buchanan County, Delaware County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at Apr 4, 2023, 9:43 PM CDT for Buchanan County, Delaware County, Iowa. It was in force for 17 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
Apr 4, 2023, 9:43 PM CDT (02:43 UTC)
Expired
Apr 4, 2023, 10:00 PM CDT
In force
17 min
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Tornado
Possible
Damage threat
Considerable
Hail
1.75 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 02:47 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
Apr 4, 2:48 PM CDTTornado WatchSPC7 hr
Apr 4, 6:34 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 2.7 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 00:00Z on 2023-04-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1391 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 00:00Z on 2023-04-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 677 square meters per square second.1939587897117Sfc1 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
1391 J/kg
Mixed-layer CIN
-149 J/kg
Mixed-layer LCL
935 m above ground
0-6 km bulk shear
89 kt
0-1 km storm-relative helicity
677 m²/s²
0-3 km storm-relative helicity
837 m²/s²
Significant tornado parameter
0.0
Supercell composite
30.3

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 Apr 4, 6:52 PM CDT, 2 hours 51 minutes earlier.

Area forecast discussion, Apr 4, 6:52 PM CDT, 2 hours 51 minutes before
Area Forecast Discussion
National Weather Service Quad Cities IA IL
652 PM CDT Tue Apr 4 2023

.UPDATE...
Issued at 643 PM CDT Tue Apr 4 2023

The warm front appears to have stalled roughly along a line from
KDSM east to KIKK. Based on available data it appears the warm
front will remain nearly stationary until the LLJ strengthens
after sunset and the surface low in southwest Iowa begins moving
more rapidly east northeast.

Based on this the tornado watch along the highway 20 corridor has
been replaced with a severe thunderstorm watch until 1 AM. Once
the LLJ strengthens after sunset elevated storms should begin
developing north of the warm front as forcing increases. Primary
risk in this area would be large hail.

After midnight the discrete storms along/ahead of the eastward
moving cold front should form into a broken line. Hail and
damaging winds would be the primary risks. Given the large amount
of wind shear in the atmosphere, brief spin up tornadoes along the
cold front cannot be ruled out.

&&

.SYNOPSIS...
Issued at 313 PM CDT Tue Apr 4 2023

18z surface data has the warm front running from the highway 34
corridor in Iowa east through central Illinois. Dew points north of
the front ranged from the 30s to the 50s with 60s south of the front.

&&

.SHORT TERM...(This evening through Wednesday)
Issued at 313 PM CDT Tue Apr 4 2023

Storm initiation south of the warm front will occur rapidly between
4 and 6 PM. Discrete cells will dominate the second round of severe
storms late this afternoon and evening. Thus large hail and
tornadoes will be the primary risks with damaging winds a secondary
risk. The tornado risk will be the highest with storms along and
near the warm front.

There may or may not be a brief lull in storm activity late this
evening before storms along the cold front arrive after midnight.

The storms along the cold front will be capable of damaging winds
and brief spin up tornadoes. The most likely time frame for these
storms will be roughly 3 AM to 10 AM Wednesday.

Late Wednesday morning and continuing into the afternoon dry
conditions will be seen with steady or slowly falling temperatures.
Very windy conditions will develop with sustained winds of 20 to 35
mph with gusts to 45 mph.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 313 PM CDT Tue Apr 4 2023

Quiet with a warmup into early next week

Wednesday night through Saturday night
Assessment...high confidence

Windy conditions will continue Wednesday night and into Thursday
morning as the cool Canadian high builds into the Midwest. Otherwise
expect quiet and dry conditions through Saturday night.

Temperatures will be below normal for Thursday with a warm up
commencing on Friday.

Sunday and Sunday night
Assessment...low to medium confidence

The model consensus has slight chance to chance pops for the area.
However there is a question of moisture availability with the
passage of the upper level disturbance.

The operational GFS/CMC/ECMWF models show dry conditions for the
area. Some members of the GEFS/CMCE/EPS show a risk of rain with the
passage of the upper level disturbance.

Monday through Tuesday
Assessment...high confidence

Quiet, dry and warm conditions will be seen across the area as
southerly flow pulls warm air into the area. Temperatures are
expected to average well above normal.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 638 PM CDT Tue Apr 4 2023

VFR/MVFR conditions will be seen south of I-80 while IFR
conditions continue along and north of I-80 with LLWS developing.
Isolated to perhaps scattered strong to severe TSRA will continue
through 05z/05. After 05z/05 the cold front will move through
eastern Iowa and northern Illinois with strong to severe TSRA.
VFR/MVFR conditions will be seen with IFR associated with TSRA.
After 12z/05 conditions will slowly improve to MVFR.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...08
AVIATION...08
Hazardous weather outlook, Apr 4, 3:53 PM CDT, 5 hours 50 minutes before
Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
353 PM CDT Tue Apr 4 2023

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-052100-
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-
353 PM CDT Tue Apr 4 2023

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

Two additional rounds of strong to severe storms are expected.
The Storm Prediction Center has a moderate risk of severe storms
for the entire area.

The first round is expected between 4 and 10 PM. Large hail and
tornadoes are the primary risks with damaging winds a secondary
risk.

After midnight a strong cold front will sweep through the area.
Strong to severe storms are expected between 3 and 10 AM Wednesday.
Damaging winds and brief spin up tornadoes will be the primary
risks with hail a secondary risk.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Very windy conditions will develop on Wednesday and continue into
Wednesday night. Wind gusts up to 45 mph will be possible.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is likely this afternoon and evening.

In the hours before

Local storm report, Apr 4, 9:11 PM CDT, 32 minutes before
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Local storm report, Apr 4, 9:15 PM CDT, 28 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
915 PM CDT TUE APR 4 2023

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

0902 PM     HAIL             1 WNW VINTON            42.17N 92.04W
04/04/2023  U1.00 INCH       BENTON             IA   PUBLIC

            REPORT FROM MPING: QUARTER (1.00 IN.).

&&

ARG
Local storm report, Apr 4, 9:29 PM CDT, 14 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
929 PM CDT TUE APR 4 2023

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

0923 PM     HAIL             2 NE PLUM RIVER         42.33N 89.96W
04/04/2023  M1.75 INCH       JO DAVIESS         IL   PUBLIC

&&

ARG
Local storm report, Apr 4, 9:38 PM CDT, 5 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
938 PM CDT TUE APR 4 2023

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

0930 PM     HAIL             WINTHROP                42.47N 91.73W
04/04/2023  E1.75 INCH       BUCHANAN           IA   EMERGENCY MNGR

&&

ARG
Local storm report, Apr 4, 9:40 PM CDT, 3 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
940 PM CDT TUE APR 4 2023

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

0937 PM     HAIL             1 WSW RED OAK           42.39N 89.69W
04/04/2023  M1.75 INCH       STEPHENSON         IL   PUBLIC

&&

ARG
Local storm report, Apr 4, 9:43 PM CDT, 0 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
943 PM CDT TUE APR 4 2023

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

0940 PM     HAIL             1 S WINSLOW             42.47N 89.80W
04/04/2023  M1.75 INCH       STEPHENSON         IL   PUBLIC

&&

ARG

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 4, 8:21 PM CDTSevere Thunderstorm WarningDVNBenton39 min
Apr 4, 8:49 PM CDTSevere Thunderstorm WarningDVNClinton, Jackson26 min
Apr 4, 8:55 PM CDTSevere Thunderstorm WarningDVNBenton, Buchanan, Delaware, Linn50 min
Apr 4, 10:29 PM CDTSevere Thunderstorm WarningDVNBenton, Buchanan, Delaware, Linn46 min
Apr 4, 11:15 PM CDTSevere Thunderstorm WarningDVNBenton, Buchanan, Delaware, Linn45 min
Apr 5, 12:14 AM CDTSpecial Weather StatementDVNIowa, Johnson, Keokuk, Washington46 min
Apr 5, 12:56 AM CDTSpecial Weather StatementDVNJones34 min
Apr 5, 1:08 AM CDTSpecial Weather StatementDVNJohnson37 min
Apr 5, 1:10 AM CDTSevere Thunderstorm WarningDVNJohnson, Washington35 min
Apr 5, 1:43 AM CDTSevere Thunderstorm WarningDVNCedar, Jones47 min
Apr 5, 1:50 AM CDTSpecial Weather StatementDVNLouisa40 min
Apr 5, 1:54 AM CDTSevere Thunderstorm WarningDVNJohnson, Louisa, Muscatine, Washington36 min
Apr 5, 3:10 AM CDTSpecial Weather StatementDVNHenry, Jefferson, Johnson, Keokuk, Lee, Van Buren and 1 more35 min
Apr 5, 3:23 AM CDTSevere Thunderstorm WarningDVNHenry, Jefferson, Lee, Louisa, Van Buren, Washington37 min
Apr 5, 4:22 AM CDTSpecial Weather StatementDVNClinton, Jackson38 min
Apr 5, 4:28 AM CDTSpecial Weather StatementDVNScott62 min
Apr 4, 8:48 PM CDTRiver Flood WatchDVNHenry, Rock Island13 hr
Apr 4, 8:48 PM CDTRiver Flood WarningDVNHenry, Rock Island, Whiteside6 days
Apr 4, 9:09 PM CDTSevere Thunderstorm WarningDVNCarroll, Jo Daviess, Stephenson36 min
Apr 4, 9:33 PM CDTSevere Thunderstorm WarningDVNStephenson27 min
Apr 5, 1:57 AM CDTSpecial Weather StatementDVNJo Daviess33 min
Apr 5, 3:40 AM CDTSpecial Weather StatementDVNHancock50 min
Apr 5, 3:42 AM CDTSevere Thunderstorm WarningDVNHancock, McDonough48 min
Apr 5, 4:03 AM CDTSpecial Weather StatementDVNHenderson, Warren27 min
Apr 5, 4:09 AM CDTSevere Thunderstorm WarningDVNHenderson, Mercer, Warren51 min
Apr 5, 4:50 AM CDTSevere Thunderstorm WarningDVNHenry, Rock Island, Whiteside40 min
Apr 5, 4:51 AM CDTTornado WarningDVNHenry24 min
Apr 5, 4:55 AM CDTSpecial Weather StatementDVNCarroll, Stephenson50 min
Apr 5, 5:01 AM CDTSevere Thunderstorm WarningDVNJo Daviess, Stephenson26 min
Apr 5, 5:11 AM CDTSevere Thunderstorm WarningDVNBureau, Carroll, Whiteside34 min
Apr 5, 5:15 AM CDTTornado WarningDVNBureau, Henry11 min
Apr 5, 5:36 AM CDTTornado WarningDVNBureau24 min
Apr 5, 5:38 AM CDTSevere Thunderstorm WarningDVNBureau, Putnam, Whiteside38 min
Apr 5, 9:57 AM CDTRiver Flood WarningDVNHenry, Rock Island4 days
Apr 5, 2:32 AM CDTSpecial Weather StatementDVNClark43 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2023Every severe thunderstorm warning in 2023

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.