Alert archive / Iowa / Special Weather Statements in 2021

Special Weather Statement, NWS Quad Cities, IA

July 29, 2021Clinton County, Scott County, Iowa; Henry County, Whiteside County, Illinois

NWS Quad Cities, IA issued this special weather statement at Jul 29, 2021, 4:47 AM CDT for Clinton County, Scott County, Iowa; Henry County, Whiteside County, Illinois. It was in force for 43 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 29, 2021, 4:47 AM CDT (09:47 UTC)
Expired
Jul 29, 2021, 5:30 AM CDT
In force
43 min
Issued by
NWS Quad Cities, IA

Counties Clinton County, IA, Scott County, IA, Henry County, IL, Whiteside County, IL

The radar

The Quad Cities radar (KDVN), 34 km from the middle of the area, began a volume at 09:49 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 00:00Z, 9.8 hours before the alert went out and 27 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 2021-07-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4022 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 2021-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 52 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
4022 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
1022 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
52 m²/s²
0-3 km storm-relative helicity
90 m²/s²
Significant tornado parameter
1.0
Supercell composite
6.8

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Jul 29, 3:57 AM CDT, 50 minutes earlier.

Area forecast discussion, Jul 29, 3:57 AM CDT, 50 minutes before
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Hazardous weather outlook, Jul 28, 2:45 PM CDT, 14 hours 2 minutes before
Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
245 PM CDT Wed Jul 28 2021

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-291945-
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-
245 PM CDT Wed Jul 28 2021

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

Hot and humid conditions will continue this afternoon and tonight
with heat indices in the 100 to 105 range. A Heat Advisory
remains in effect. There is a chance for thunderstorms overnight
tonight mainly north of a line from La Crosse Wisconsin, to
Freeport Illinois. The main threats will be lightning, damaging
wind, and heavy downpours.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

Hot and humid conditions will be seen Thursday for areas along
and south of I-80. Heat indices will rise above 100 degrees in the
afternoon at times. There is a chance for thunderstorms along and
south of highway 34 in Iowa Thursday evening and again Friday
evening. The severe risk is marginal at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected today and tonight.

GROSS

In the hours before

Local storm report, Jul 29, 2:16 AM CDT, 2 hours 31 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
216 AM CDT THU JUL 29 2021

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

0204 AM     TSTM WND GST     1 ESE NORA              42.46N 89.93W
07/29/2021  M51 MPH          JO DAVIESS         IL   TRAINED SPOTTER

&&

RPK
Special weather statement, Jul 29, 2:35 AM CDT, 2 hours 12 minutes before
Special Weather Statement
National Weather Service Quad Cities IA/IL
235 AM CDT Thu Jul 29 2021

ILC015-085-177-IAC045-055-061-097-105-290830-
Jo Daviess-Carroll-Stephenson-Jackson-Dubuque-Jones-Delaware-Clinton-
235 AM CDT Thu Jul 29 2021

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT JO DAVIESS...CARROLL...
SOUTHERN STEPHENSON...JACKSON...DUBUQUE...NORTHEASTERN JONES...
EASTERN DELAWARE AND NORTHEASTERN CLINTON COUNTIES UNTIL 330 AM
CDT...

At 235 AM CDT, radar indicated strong thunderstorms were located
along a line extending from near Dyersville to Bellevue to near
German Valley. Movement was south at 25 mph.

Wind gusts up to 50 mph and pea size hail are possible with these
storms.

Locations impacted include...
Dubuque, Freeport, Maquoketa, Galena, Mount Carroll, Asbury,
Dyersville, Savanna, Lena, Bellevue, Cascade, Stockton, Epworth, East
Dubuque, Farley, Lanark, Peosta, Milledgeville, Preston and Hanover.

Torrential rainfall is also occurring with these storms. Minor
flooding of low lying areas, creeks, streams and urban areas is
possible. If you encounter water over a roadway, do not drive through
it.

Persons in campgrounds should consider seeking sturdy shelter until
these storms pass.

LAT...LON 4264 9072 4251 9064 4251 9045 4240 9031
      4234 8940 4220 8940 4220 8969 4195 8969
      4198 9039 4222 9115 4265 9114 4265 9090
      4268 9090
TIME...MOT...LOC 0735Z 352DEG 21KT 4250 9108 4228 9041 4223 8940

RP Kinney
Local storm report, Jul 29, 2:45 AM CDT, 2 hours 2 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
245 AM CDT THU JUL 29 2021

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

0143 AM     TSTM WND DMG     1 ENE DUBUQUE           42.51N 90.67W
07/29/2021                   DUBUQUE            IA   LAW ENFORCEMENT

            2 TREES DOWN FROM THUNDERSTORM OUTFLOW
            WINDS. TREES WERE ABOUT 2 FEET IN DIAMETER.

&&

RPK
Special weather statement, Jul 29, 3:31 AM CDT, 1 hour 16 minutes before
Special Weather Statement
National Weather Service Quad Cities IA/IL
331 AM CDT Thu Jul 29 2021

ILC015-085-IAC045-055-061-097-105-290900-
Jo Daviess-Carroll-Jackson-Dubuque-Jones-Delaware-Clinton-
331 AM CDT Thu Jul 29 2021

...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL JO DAVIESS...
WESTERN CARROLL...JACKSON...DUBUQUE...NORTHEASTERN JONES...EASTERN
DELAWARE AND NORTHEASTERN CLINTON COUNTIES UNTIL 400 AM CDT...

At 329 AM CDT, strong thunderstorms were clustered Dyersville to
Springbrook, moving southeast at 35 mph.

Wind gusts of 50 to 55 mph and penny size hail are possible with the
most intense storms.

A strong storm will be near...
 Preston, Spragueville and Green Island around 340 AM CDT.
  Miles around 350 AM CDT.
  Savanna, Sabula and Andover around 355 AM CDT.

Other locations impacted by this storm include Otter Creek, North
Hanover, South Gary Owen, Bankston Park, Fillmore, Teeds Grove,
Maquoketa Caves State Park, Waupeton, Lattnerville and Reeceville.

Torrential rainfall is also occurring with this storm. Minor flooding
of low lying areas, creeks, streams and urban areas is possible. If
you encounter water over a roadway, do not drive through it.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 4264 9073 4262 9070 4254 9064 4251 9064
      4251 9052 4214 8997 4184 9026 4232 9120
      4265 9118 4265 9090 4268 9089
TIME...MOT...LOC 0829Z 305DEG 29KT 4216 9045

RP Kinney
Special weather statement, Jul 29, 4:04 AM CDT, 43 minutes before
Special Weather Statement
National Weather Service Quad Cities IA/IL
404 AM CDT Thu Jul 29 2021

ILC015-161-195-IAC045-097-105-163-290945-
Rock Island-Whiteside-Carroll-Jackson-Scott-Jones-Clinton-
404 AM CDT Thu Jul 29 2021

...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT NORTHEASTERN ROCK
ISLAND...NORTHWESTERN WHITESIDE...WESTERN CARROLL...JACKSON...
NORTHEASTERN SCOTT...EAST CENTRAL JONES AND CLINTON COUNTIES UNTIL
445 AM CDT...

At 402 AM CDT, strong thunderstorms were clustered from Maquoketa to
near Clinton, moving southeast at 30 mph.

Winds in excess of 40 mph and half inch hail are possible with these
storms. Torrential rainfall is also occurring with these storms.
Minor flooding of low lying areas, creeks, streams and urban areas
is possible. If you encounter water over a roadway, do not drive
through it.

Locations impacted include...
Clinton, Maquoketa, Morrison, DeWitt, Camanche, Savanna, Bellevue,
Erie, Garden Plain, Preston, Fairhaven, Albany, Cordova, Sabula,
Delmar, Lost Nation, Miles, Andrew, Charlotte and Low Moor.

This includes Interstate 88 between mile markers 11 and 27.

LAT...LON 4233 9042 4228 9043 4221 9037 4219 9032
      4220 9021 4187 8973 4158 9014 4213 9110
      4230 9085 4230 9067 4238 9066 4238 9049
TIME...MOT...LOC 0902Z 316DEG 28KT 4194 9024

RP Kinney
Special weather statement, Jul 29, 4:47 AM CDT, 0 minutes before
Special Weather Statement
National Weather Service Quad Cities IA/IL
447 AM CDT Thu Jul 29 2021

ILC011-015-073-161-195-IAC031-045-097-105-163-291030-
Rock
Island-Whiteside-Henry-Carroll-Bureau-Jackson-Cedar-Scott-Jones-
Clinton-
447 AM CDT Thu Jul 29 2021

...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT NORTHEASTERN ROCK
ISLAND...WHITESIDE...NORTHERN HENRY...SOUTH CENTRAL CARROLL...
NORTHWESTERN BUREAU...SOUTHWESTERN JACKSON...NORTHERN CEDAR...
SCOTT...SOUTHEASTERN JONES AND CLINTON COUNTIES UNTIL 530 AM CDT...

At 445 AM CDT, strong thunderstorms extended from southeast Jones
County, into Whiteside County, moving southeast at 30 mph.

Winds in excess of 40 mph and pea size hail are possible with the
strongest storms. Torrential rainfall is also occurring with these
storms. Minor flooding of low lying areas, creeks, streams and urban
areas is possible. If you encounter water over a roadway, do not
drive through it.

Locations impacted include...
Davenport, Moline, Bettendorf, Clinton, East Moline, Sterling, Rock
Falls, Maquoketa, Morrison, Mechanicsville, Stanwood, Silvis,
Geneseo, Eldridge, DeWitt, Colona, Camanche, Le Claire, Coal Valley
and Fulton.

This includes the following highways...
 Interstate 74 in Iowa between mile markers 1 and 5.
 Interstate 80 in Iowa between mile markers 289 and 306.
 Interstate 80 in Illinois between mile markers 1 and 33.
 Interstate 74 in Illinois near mile marker 1, and between mile
markers 9 and 16.
 Interstate 88 between mile markers 1 and 44.
 Interstate 280 near mile marker 1.

LAT...LON 4130 9011 4191 9132 4218 9087 4179 8963
      4159 8963 4158 8958
TIME...MOT...LOC 0945Z 304DEG 26KT 4172 9004

RP Kinney

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 29, 1:42 AM CDTSpecial Weather StatementDVNDelaware, Dubuque63 min
Jul 29, 2:35 AM CDTSpecial Weather StatementDVNDubuque, Jackson55 min
Jul 29, 3:31 AM CDTSpecial Weather StatementDVNDubuque, Jackson29 min
Jul 29, 4:04 AM CDTSpecial Weather StatementDVNClinton, Jackson41 min
Jul 29, 8:36 AM CDTSpecial Weather StatementDVNMuscatine24 min
Jul 29, 9:27 AM CDTSpecial Weather StatementDVNWashington33 min
Jul 29, 9:55 AM CDTSpecial Weather StatementDVNLouisa35 min
Jul 29, 10:11 AM CDTSpecial Weather StatementDVNWashington34 min
Jul 29, 10:27 AM CDTSpecial Weather StatementDVNDes Moines, Louisa33 min
Jul 29, 10:48 AM CDTSpecial Weather StatementDVNHenry27 min
Jul 29, 11:03 AM CDTSpecial Weather StatementDVNDes Moines27 min
Jul 29, 11:16 AM CDTSpecial Weather StatementDVNDes Moines29 min
Jul 29, 11:31 AM CDTSpecial Weather StatementDVNVan Buren29 min
Jul 29, 12:15 PM CDTSpecial Weather StatementDVNLee30 min
Jul 29, 1:30 AM CDTSevere Thunderstorm WarningDVNJo Daviess, Stephenson60 min
Jul 29, 7:24 AM CDTSpecial Weather StatementDVNHenry66 min
Jul 29, 8:59 AM CDTSpecial Weather StatementDVNMercer31 min
Jul 29, 9:18 AM CDTSpecial Weather StatementDVNWarren27 min
Jul 29, 9:23 AM CDTSpecial Weather StatementDVNMercer52 min
Jul 29, 10:56 AM CDTSpecial Weather StatementDVNHenderson34 min
Jul 29, 11:25 AM CDTSpecial Weather StatementDVNHenderson, Warren50 min
Jul 29, 11:43 AM CDTSpecial Weather StatementDVNHenderson32 min
Jul 29, 12:10 PM CDTSpecial Weather StatementDVNHenderson35 min

Nearby

Special Weather Statements in Iowa, 2021Special Weather Statements in Illinois, 2021Every special weather statement in 2021

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.