Alert archive / Iowa / Flash Flood Watches in 2020

Flash Flood Watch 4, NWS Quad Cities, IA

June 10, 20209 counties in Iowa

NWS Quad Cities, IA issued this flash flood watch at Jun 10, 2020, 3:49 AM CDT for 9 counties in Iowa. It took effect at Jun 10, 2020, 6:00 AM CDT. It was in force for 10 hr.

The area

The counties it named.

The facts

Issued
Jun 10, 2020, 3:49 AM CDT (08:49 UTC)
In effect from
Jun 10, 2020, 6:00 AM CDT
Expired
Jun 10, 2020, 4:00 PM CDT
In force
10 hr
Issued by
NWS Quad Cities, IA
Flood severity
None

Counties Benton County, IA, Buchanan County, IA, Cedar County, IA, Delaware County, IA, Dubuque County, IA, Iowa County, IA, Johnson County, IA, Jones County, IA, Linn County, IA

The radar

The Quad Cities radar (KDVN), 94 km from the middle of the area, began a volume at 08:49 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, 8.8 hours before the alert went out and 99 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 2020-06-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 104 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 2020-06-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 203 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
104 J/kg
Mixed-layer CIN
-63 J/kg
Mixed-layer LCL
582 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
203 m²/s²
0-3 km storm-relative helicity
260 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.3

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood watch 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 flash flood watch went out at Jun 10, 3:44 AM CDT, 5 minutes earlier.

Area forecast discussion, Jun 10, 3:44 AM CDT, 5 minutes before
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Hazardous weather outlook, Jun 9, 4:47 AM CDT, 23 hours 2 minutes before
Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
447 AM CDT Tue Jun 9 2020

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-101000-
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-
447 AM CDT Tue Jun 9 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

Periods of heavy rain are likely Today from the remnants of
tropical storm Cristobal. A Flash Flood Watch is in effect for
the counties along and west of the Mississippi River. Rainfall
rates up to 2 inches per hour are possible with the heaviest bands
of rain. There is a Moderate risk for flash flooding roughly for
areas west of the Mississippi River and a Slight risk to the east.

A widespread 1 to 3 inches of rain is anticipated along and west
of a line from Dubuque, Iowa to Keokuk, Iowa. Isolated amounts
near 4 or 5 inches are possible. There is a low risk for a few
brief spin up tornadoes area-wide through the afternoon.

A Wind Advisory is in effect for Bureau and Putnam Counties
through the evening for east to southeast wind gusts of 40 to 50
mph. Gusts up to 40 mph are possible futher west, extending toward
the Mississippi River. The winds will turn to the southwest late
this afternoon and evening.

Flooding continues along portions of the Wapsipinicon River and
Mississippi River. Please see the latest Flood Statements and
Flood Warnings for details.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed today. Rainfall amounts over 1
inch and reports of flash flooding would be appreciated.

Uttech

In the hours before

Special weather statement, Jun 10, 12:23 AM CDT, 3 hours 26 minutes before
Special Weather Statement
National Weather Service Quad Cities IA/IL
1223 AM CDT Wed Jun 10 2020

IAC095-101-103-107-183-100545-
Keokuk-Johnson-Washington-Jefferson-Iowa-
1223 AM CDT Wed Jun 10 2020

...A STRONG THUNDERSTORM WILL AFFECT KEOKUK...SOUTHWESTERN JOHNSON...
NORTHWESTERN WASHINGTON...NORTH CENTRAL JEFFERSON AND SOUTHERN IOWA
COUNTIES UNTIL 1245 AM CDT...

At 1222 AM CDT, a strong thunderstorm was located over Sigourney,
moving northeast at 50 mph.

Winds in excess of 40 mph and pea size hail are possible with this
storm. Torrential rainfall is also occurring with this storm.

Locations impacted include...
Sigourney, Wellman, North English, Richland, Delta, Keswick, South
English, Parnell, Millersburg, Harper, Kinross, Hayesville, Keota,
Ollie, Webster, Frytown, Lancaster, Lake Iowa Park, Keokuk County
Expo and Lake Belva Deer Park.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4112 9202 4126 9239 4166 9222 4157 9166
TIME...MOT...LOC 0522Z 209DEG 45KT 4132 9217

Uttech
Special weather statement, Jun 10, 12:45 AM CDT, 3 hours 4 minutes before
Special Weather Statement
National Weather Service Quad Cities IA/IL
1245 AM CDT Wed Jun 10 2020

IAC095-103-107-183-100630-
Keokuk-Johnson-Washington-Iowa-
1245 AM CDT Wed Jun 10 2020

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT NORTHEASTERN KEOKUK...
CENTRAL JOHNSON...NORTHERN WASHINGTON AND SOUTHEASTERN IOWA COUNTIES
UNTIL 130 AM CDT...

At 1244 AM CDT, radar indicated strong thunderstorms were located
along a line extending from North English to near Washington.
Movement was northeast at 40 mph.

Winds in excess of 30 mph are possible. Torrential rainfall is also
occurring with these storms.

Locations impacted include...
Iowa City, Washington, Coralville, Williamsburg, Kalona, Tiffin,
Wellman, University Heights, North English, Riverside, Oxford, Hills,
South English, Parnell, Kinross, Richmond, West Chester, Frytown,
Windham and Johnson County Fairgrounds.

This includes Interstate 80 in Iowa between mile markers 220 and 240.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 4179 9190 4162 9138 4128 9175 4150 9223
TIME...MOT...LOC 0544Z 219DEG 37KT 4153 9211 4137 9175

Uttech
Special weather statement, Jun 10, 1:09 AM CDT, 2 hours 40 minutes before
Special Weather Statement
National Weather Service Quad Cities IA/IL
109 AM CDT Wed Jun 10 2020

ILC131-161-195-IAC031-139-163-100645-
Rock Island-Mercer-Whiteside-Cedar-Scott-Muscatine-
109 AM CDT Wed Jun 10 2020

...A STRONG THUNDERSTORM WILL AFFECT ROCK ISLAND...NORTHWESTERN
MERCER...WESTERN WHITESIDE...SOUTHEASTERN CEDAR...SCOTT AND
NORTHEASTERN MUSCATINE COUNTIES UNTIL 145 AM CDT...

At 108 AM CDT, a strong thunderstorm was located over Andalusia, or 9
miles southwest of Rock Island, moving northeast at 50 mph.

Winds in excess of 30 mph and brief heavy rain are possible with
this storm.

Locations impacted include...
Davenport, Moline, Rock Island, Bettendorf, East Moline, Durant,
Silvis, Eldridge, Milan, Le Claire, Hampton, Port Byron, Walcott,
Blue Grass, Buffalo, Andalusia, Rapids City, Princeton, Long Grove
and Cordova.

This includes the following highways...
 Interstate 74 in Iowa between mile markers 1 and 5.
 Interstate 80 in Iowa between mile markers 277 and 306.
 Interstate 74 in Illinois between mile markers 1 and 5.
 Interstate 280 between mile markers 1 and 18.

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.

LAT...LON 4127 9067 4130 9106 4168 9091 4174 9033
      4173 9032 4174 9031 4175 9017
TIME...MOT...LOC 0608Z 220DEG 42KT 4142 9074

Uttech
Special weather statement, Jun 10, 1:13 AM CDT, 2 hours 36 minutes before
Special Weather Statement
National Weather Service Quad Cities IA/IL
113 AM CDT Wed Jun 10 2020

IAC031-103-105-139-100645-
Cedar-Johnson-Jones-Muscatine-
113 AM CDT Wed Jun 10 2020

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT CEDAR...NORTHEASTERN
JOHNSON...SOUTHEASTERN JONES AND NORTHWESTERN MUSCATINE COUNTIES
UNTIL 145 AM CDT...

At 112 AM CDT, radar indicated strong thunderstorms were located
along a line extending from near Oakdale to near Atalissa. Movement
was northeast at 45 mph.

Winds in excess of 30 mph and brief heavy rain are possible with
these storms.

Locations impacted include...
Iowa City, Muscatine, Tipton, West Branch, Mechanicsville, Stanwood,
Coralville, West Liberty, Wilton, University Heights, Lowden,
Bennett, Atalissa, Rochester, Buchanan, Clarence, Newport, Cedar
Valley, Muscatine County Fairgrounds and Johnson County Fairgrounds.

This includes Interstate 80 in Iowa between mile markers 243 and 274.

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.

LAT...LON 4186 9142 4186 9137 4193 9136 4195 9134
      4195 9090 4173 9090 4143 9109 4165 9161
TIME...MOT...LOC 0612Z 203DEG 39KT 4172 9154 4154 9115

Uttech
Special weather statement, Jun 10, 1:38 AM CDT, 2 hours 11 minutes before
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Special weather statement, Jun 10, 2:05 AM CDT, 1 hour 44 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jun 9, 7:21 PM CDTAreal Flood WarningDVNBenton, Buchanan, Linn12 hr
Jun 9, 8:19 PM CDTRiver Flood WarningDVNBenton, Iowa7 days
Jun 9, 8:19 PM CDTRiver Flood WarningDVNJohnson, Washington62 hr
Jun 9, 8:47 PM CDTRiver Flood WatchDVNLouisa21 days
Jun 9, 8:47 PM CDTRiver Flood WatchDVNLouisa21 days
Jun 9, 8:47 PM CDTRiver Flood WarningDVNCedar, Louisa, Muscatine21 days
Jun 9, 8:47 PM CDTRiver Flood WarningDVNJohnson, Louisa, Washington48 hr
Jun 9, 9:01 PM CDTRiver Flood WarningDVNBuchanan, Linn3 days
Jun 9, 9:01 PM CDTRiver Flood WarningDVNCedar, Jones, Linn7 days
Jun 9, 9:35 PM CDTRiver Flood WarningDVNDes Moines, Louisa21 days
Jun 9, 10:38 PM CDTAreal Flood WarningDVNBuchanan12 hr
Jun 9, 11:38 PM CDTSpecial Weather StatementDVNJefferson, Van Buren37 min
Jun 10, 12:02 AM CDTSpecial Weather StatementDVNKeokuk28 min
Jun 10, 12:15 AM CDTRiver Flood WarningDVNLee22 hr
Jun 10, 12:23 AM CDTSpecial Weather StatementDVNKeokuk22 min
Jun 10, 12:45 AM CDTSpecial Weather StatementDVNJohnson, Washington45 min
Jun 10, 1:09 AM CDTSpecial Weather StatementDVNScott36 min
Jun 10, 1:13 AM CDTSpecial Weather StatementDVNCedar, Johnson, Muscatine32 min
Jun 10, 9:36 AM CDTSpecial Weather StatementDVNLinn54 min
Jun 10, 9:44 AM CDTFlash Flood WarningDVNLinn5 hr
Jun 10, 10:10 AM CDTRiver Flood WarningDVNLouisa21 days
Jun 10, 10:10 AM CDTRiver Flood WarningDVNLouisa21 days
Jun 10, 10:16 AM CDTRiver Flood WarningDVNDes Moines, Henry, Lee65 hr
Jun 10, 10:31 AM CDTAreal Flood WarningDVNBuchanan48 hr
Jun 10, 11:12 AM CDTSpecial Weather StatementDVNBenton, Delaware93 min
Jun 10, 1:00 PM CDTSpecial Weather StatementDVNLouisa, Muscatine60 min
Jun 10, 1:11 PM CDTSpecial Weather StatementDVNClinton, Scott64 min
Jun 10, 2:20 PM CDTAreal Flood WarningDVNBenton, Linn24 hr
Jun 9, 11:41 PM CDTSpecial Weather StatementDVNMcDonough34 min
Jun 10, 1:38 AM CDTSpecial Weather StatementDVNWhiteside37 min
Jun 10, 2:05 AM CDTSpecial Weather StatementDVNWhiteside25 min

Nearby

Flash Flood Watches in Iowa, 2020Every flash flood watch 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.