Alert archive / Iowa / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 68, NWS Quad Cities, IA

May 17, 2017Benton County, Iowa County, Keokuk County, Iowa

NWS Quad Cities, IA issued this severe thunderstorm warning at May 17, 2017, 5:03 PM CDT for Benton County, Iowa County, Keokuk County, Iowa. It was in force for 57 min. 7 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
May 17, 2017, 5:03 PM CDT (22:03 UTC)
Expired
May 17, 2017, 6:00 PM CDT
In force
57 min
Issued by
NWS Quad Cities, IA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Benton County, IA, Iowa County, IA, Keokuk County, IA

The radar

The Des Moines radar (KDMX), 130 km from the middle of the area, began a volume at 22:06 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.

What was reported inside it

TimeReportWhereRemark
May 17, 5:42 PM CDTTSTM WND DMGMarengo, IARELAYED FROM DSM - LARGE TREE DOWN
May 17, 5:42 PM CDTTSTM WND GST 60Marengo, IARELAYED FROM DSM
May 17, 5:46 PM CDTTSTM WND GST 70Blairstown, IA
May 17, 5:52 PM CDTHAIL 1S North English, IAALSO REPORTING WINDS UP TO 55 MPH AND HEAVY RAIN.
May 17, 5:53 PM CDTTSTM WND GST 70Van Horne, IA
May 17, 5:57 PM CDTTSTM WND DMGNewhall, IAROOF BLOWN OFF HOME, PICTURE FROM TWITTER
May 17, 6:08 PM CDTTSTM WND GST 70Shellsburg, IA

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched 6 storm reports to this severe thunderstorm warning; the first came 39 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

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

IssuedProductOfficeLasted
May 17, 3:44 PM CDTTornado WatchSPC9 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 10.1 hours before the alert went out and 139 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 2017-05-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 103 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 2017-05-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 84 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
103 J/kg
Mixed-layer CIN
-348 J/kg
Mixed-layer LCL
1223 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
84 m²/s²
0-3 km storm-relative helicity
79 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

578 
WUUS53 KDVN 172203
SVRDVN
IAC011-095-107-172300-
/O.NEW.KDVN.SV.W.0068.170517T2203Z-170517T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Quad Cities IA/IL
503 PM CDT WED MAY 17 2017

The National Weather Service in the Quad Cities has issued a

* Severe Thunderstorm Warning for...
  Keokuk County in southeastern Iowa...
  Benton County in east central Iowa...
  Iowa County in east central Iowa...

* Until 600 PM CDT

* At 503 PM CDT, severe thunderstorms were located along a line
  extending from near Montezuma to near What Cheer to near Hedrick,
  moving northeast at 45 mph.

  HAZARD...60 mph wind gusts and quarter size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees. 

* Locations impacted include...
  Vinton, Marengo, Sigourney, Williamsburg, Belle Plaine, Atkins,
  Urbana, Dysart, North English, Shellsburg, Victor, Newhall,
  Hedrick, Blairstown, Van Horne, What Cheer, Keystone, Norway,
  Garrison and Delta.

This includes the following highways...
 Interstate 80 in Iowa between mile markers 205 and 227.
 Interstate 380 between mile markers 42 and 48.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
sturdy building.

&&

A tornado watch remains in effect until 1100 PM CDT for southeastern,
northeastern and east central Iowa.

LAT...LON 4151 9241 4153 9230 4230 9230 4230 9186
      4151 9185 4151 9195 4143 9195 4116 9226
      4116 9241
TIME...MOT...LOC 2203Z 220DEG 38KT 4159 9258 4142 9240 4116 9236 

HAIL...1.00IN
WIND...60MPH
 
$$

ERVIN
8 follow-up statements
497 
WWUS53 KDVN 172212
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
512 PM CDT WED MAY 17 2017

IAC011-095-107-172300-
/O.CON.KDVN.SV.W.0068.000000T0000Z-170517T2300Z/
Keokuk IA-Benton IA-Iowa IA-
512 PM CDT WED MAY 17 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM CDT
FOR KEOKUK...BENTON AND IOWA COUNTIES...

At 512 PM CDT, severe thunderstorms were located along a line
extending from near Brooklyn to 7 miles west of Millersburg to near
Hedrick, moving northeast at 50 mph.

HAZARD...60 mph wind gusts and quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees. 

Locations impacted include...
Vinton, Marengo, Sigourney, Williamsburg, Belle Plaine, Atkins,
Urbana, Dysart, North English, Shellsburg, Victor, Newhall, Hedrick,
Blairstown, Van Horne, What Cheer, Keystone, Norway, Garrison and
Delta.

This includes the following highways...
 Interstate 80 in Iowa between mile markers 205 and 227.
 Interstate 380 between mile markers 42 and 48.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

&&

A tornado watch remains in effect until 1100 PM CDT for southeastern,
northeastern and east central Iowa.

LAT...LON 4151 9241 4153 9230 4230 9230 4230 9186
      4151 9185 4151 9195 4143 9195 4116 9226
      4116 9241
TIME...MOT...LOC 2212Z 215DEG 44KT 4172 9250 4158 9230 4122 9236 

HAIL...1.00IN
WIND...60MPH
 
$$

ERVIN
380 
WWUS53 KDVN 172220
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
520 PM CDT WED MAY 17 2017

IAC011-095-107-172300-
/O.CON.KDVN.SV.W.0068.000000T0000Z-170517T2300Z/
Keokuk IA-Benton IA-Iowa IA-
520 PM CDT WED MAY 17 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM CDT
FOR KEOKUK...BENTON AND IOWA COUNTIES...

At 520 PM CDT, severe thunderstorms were located along a line
extending from 6 miles southeast of Tama to 6 miles southeast of
Victor to Delta, moving northeast at 50 mph.

HAZARD...70 mph wind gusts and quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings. 

Locations impacted include...
Vinton, Marengo, Sigourney, Williamsburg, Belle Plaine, Atkins,
Urbana, Dysart, North English, Shellsburg, Victor, Newhall, Hedrick,
Blairstown, Van Horne, What Cheer, Keystone, Norway, Garrison and
Delta.

This includes the following highways...
 Interstate 80 in Iowa between mile markers 205 and 227.
 Interstate 380 between mile markers 42 and 48.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

&&

A tornado watch remains in effect until 1100 PM CDT for southeastern,
northeastern and east central Iowa.

LAT...LON 4151 9241 4153 9230 4230 9230 4230 9186
      4151 9185 4151 9195 4143 9195 4116 9226
      4116 9241
TIME...MOT...LOC 2220Z 214DEG 44KT 4187 9252 4165 9224 4130 9232 

HAIL...1.00IN
WIND...70MPH
 
$$

ERVIN
838 
WWUS53 KDVN 172226
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
526 PM CDT WED MAY 17 2017

IAC011-095-107-172300-
/O.CON.KDVN.SV.W.0068.000000T0000Z-170517T2300Z/
Keokuk IA-Benton IA-Iowa IA-
526 PM CDT WED MAY 17 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM CDT
FOR KEOKUK...BENTON AND IOWA COUNTIES...

At 526 PM CDT, severe thunderstorms were located along a line
extending from 6 miles south of Traer to near Ladora to near
Hayesville, moving northeast at 50 mph.

HAZARD...70 mph wind gusts and quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings. 

Locations impacted include...
Vinton, Marengo, Sigourney, Williamsburg, Belle Plaine, Atkins,
Urbana, Dysart, North English, Shellsburg, Victor, Newhall, Hedrick,
Blairstown, Van Horne, What Cheer, Keystone, Norway, Garrison and
Delta.

This includes the following highways...
 Interstate 80 in Iowa between mile markers 205 and 227.
 Interstate 380 between mile markers 42 and 48.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

&&

A tornado watch remains in effect until 1100 PM CDT for southeastern,
northeastern and east central Iowa.

LAT...LON 4151 9241 4153 9230 4230 9230 4230 9186
      4151 9185 4151 9195 4143 9195 4116 9226
      4116 9241
TIME...MOT...LOC 2226Z 214DEG 44KT 4210 9244 4171 9218 4123 9226 

HAIL...1.00IN
WIND...70MPH
 
$$

ERVIN
238 
WWUS53 KDVN 172231
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
531 PM CDT WED MAY 17 2017

IAC011-095-107-172300-
/O.CON.KDVN.SV.W.0068.000000T0000Z-170517T2300Z/
Keokuk IA-Benton IA-Iowa IA-
531 PM CDT WED MAY 17 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM CDT
FOR KEOKUK...BENTON AND IOWA COUNTIES...

At 531 PM CDT, severe thunderstorms were located along a line
extending from near Traer to near Ladora to Hayesville, moving
northeast at 45 mph.

HAZARD...70 mph wind gusts and quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings. 

Locations impacted include...
Vinton, Marengo, Sigourney, Williamsburg, Belle Plaine, Atkins,
Urbana, Dysart, North English, Shellsburg, Victor, Newhall, Hedrick,
Blairstown, Van Horne, What Cheer, Keystone, Norway, Garrison and
Delta.

This includes the following highways...
 Interstate 80 in Iowa between mile markers 205 and 227.
 Interstate 380 between mile markers 42 and 48.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
sturdy building.

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

&&

A tornado watch remains in effect until 1100 PM CDT for southeastern,
northeastern and east central Iowa.

LAT...LON 4151 9241 4153 9230 4230 9230 4230 9186
      4151 9185 4151 9195 4143 9195 4116 9226
      4116 9241
TIME...MOT...LOC 2231Z 220DEG 38KT 4213 9241 4174 9215 4126 9223 

HAIL...1.00IN
WIND...70MPH
 
$$

ERVIN
515 
WWUS53 KDVN 172239
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
539 PM CDT WED MAY 17 2017

IAC011-095-107-172300-
/O.CON.KDVN.SV.W.0068.000000T0000Z-170517T2300Z/
Keokuk IA-Benton IA-Iowa IA-
539 PM CDT WED MAY 17 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM CDT
FOR KEOKUK...BENTON AND IOWA COUNTIES...

At 539 PM CDT, severe thunderstorms were located along a line
extending from near Traer to Blairstown to near Sigourney, moving
northeast at 50 mph.

HAZARD...70 mph wind gusts and quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings. 

Locations impacted include...
Vinton, Marengo, Sigourney, Williamsburg, Belle Plaine, Atkins,
Urbana, Dysart, North English, Shellsburg, Victor, Newhall, Hedrick,
Blairstown, Van Horne, What Cheer, Keystone, Norway, Garrison and
Delta.

This includes the following highways...
 Interstate 80 in Iowa between mile markers 205 and 227.
 Interstate 380 between mile markers 42 and 48.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

&&

A tornado watch remains in effect until 1100 PM CDT for southeastern,
northeastern and east central Iowa.

LAT...LON 4151 9241 4153 9230 4230 9230 4230 9186
      4151 9185 4151 9195 4143 9195 4116 9226
      4116 9241
TIME...MOT...LOC 2239Z 211DEG 43KT 4213 9241 4190 9211 4132 9216 

HAIL...1.00IN
WIND...70MPH
 
$$

ERVIN
860 
WWUS53 KDVN 172243
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
543 PM CDT WED MAY 17 2017

IAC011-095-107-172300-
/O.CON.KDVN.SV.W.0068.000000T0000Z-170517T2300Z/
Keokuk IA-Benton IA-Iowa IA-
543 PM CDT WED MAY 17 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM CDT
FOR KEOKUK...BENTON AND IOWA COUNTIES...

At 543 PM CDT, severe thunderstorms were located along a line
extending from near Traer to near Marengo to near Harper, moving
northeast at 40 mph.

HAZARD...70 mph wind gusts and quarter size hail. 

SOURCE...Trained weather spotters. 

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings. 

Locations impacted include...
Vinton, Marengo, Sigourney, Williamsburg, Belle Plaine, Atkins,
Urbana, Dysart, North English, Shellsburg, Victor, Newhall, Hedrick,
Blairstown, Van Horne, What Cheer, Keystone, Norway, Garrison and
Delta.

This includes the following highways...
 Interstate 80 in Iowa between mile markers 205 and 227.
 Interstate 380 between mile markers 42 and 48.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

&&

A tornado watch remains in effect until 1100 PM CDT for southeastern,
northeastern and east central Iowa.

LAT...LON 4151 9241 4153 9230 4230 9230 4230 9186
      4151 9185 4151 9195 4143 9195 4116 9226
      4116 9241
TIME...MOT...LOC 2243Z 219DEG 36KT 4217 9239 4183 9205 4138 9212 

HAIL...1.00IN
WIND...70MPH
 
$$

ERVIN
451 
WWUS53 KDVN 172251
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
551 PM CDT WED MAY 17 2017

IAC011-095-107-172300-
/O.CON.KDVN.SV.W.0068.000000T0000Z-170517T2300Z/
Keokuk IA-Benton IA-Iowa IA-
551 PM CDT WED MAY 17 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM CDT
FOR CENTRAL KEOKUK...BENTON AND IOWA COUNTIES...

At 551 PM CDT, severe thunderstorms were located along a line
extending from near Dysart to near Norway to near South English,
moving northeast at 45 mph.

HAZARD...70 mph wind gusts and quarter size hail. 

SOURCE...Trained weather spotters. 

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings. 

Locations impacted include...
Vinton, Marengo, Sigourney, Williamsburg, Belle Plaine, Atkins,
Urbana, North English, Shellsburg, Newhall, Hedrick, Blairstown, Van
Horne, Keystone, Norway, Garrison, Ladora, Keswick, South English and
Parnell.

This includes the following highways...
 Interstate 80 in Iowa between mile markers 208 and 227.
 Interstate 380 between mile markers 42 and 48.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
sturdy building.

Prepare immediately for large hail and damaging winds. People outside
should move to a shelter, inside a strong building and away from
windows.

&&

A tornado watch remains in effect until 1100 PM CDT for southeastern,
northeastern and east central Iowa.

LAT...LON 4136 9225 4151 9222 4230 9230 4230 9186
      4151 9185 4151 9195 4143 9195 4116 9226
      4116 9241
TIME...MOT...LOC 2251Z 220DEG 38KT 4223 9232 4189 9198 4144 9205 

HAIL...1.00IN
WIND...70MPH
 
$$

ERVIN
173 
WWUS53 KDVN 172258
SVSDVN

Severe Weather Statement
National Weather Service Quad Cities IA/IL
558 PM CDT WED MAY 17 2017

IAC011-095-107-172307-
/O.EXP.KDVN.SV.W.0068.000000T0000Z-170517T2300Z/
Keokuk IA-Benton IA-Iowa IA-
558 PM CDT WED MAY 17 2017

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL KEOKUK...BENTON AND
IOWA COUNTIES WILL EXPIRE AT 600 PM CDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.  However heavy rain
is still possible with these thunderstorms.

A tornado watch remains in effect until 1100 PM CDT for southeastern,
northeastern and east central Iowa.

Remember, a Severe Thunderstorm Warning still remains in effect for
eastern Benton and eastern Iowa county. 

LAT...LON 4136 9225 4151 9222 4230 9230 4230 9186
      4151 9185 4151 9195 4143 9195 4116 9226
      4116 9241
TIME...MOT...LOC 2257Z 220DEG 38KT 4227 9228 4193 9194 4148 9201 

$$

ERVIN

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 May 17, 2:24 PM CDT, 2 hours 39 minutes earlier.

Area forecast discussion, May 17, 2:24 PM CDT, 2 hours 39 minutes before
Area Forecast Discussion
National Weather Service Quad Cities IA IL
224 PM CDT Wed May 17 2017

.SYNOPSIS...
Issued at 221 PM CDT Wed May 17 2017

Abbreviated early issuance AFD to get ready for convective event.
Water vapor showing neg tilted upper wave on track acrs southeastern
Neb. After potentail convective severe event this afternoon and
evening, a reprieve with cooler conditions on Thu. Then the next
main upstream large cut-off upper low will roll out to the upper
Midwest for a wet end to the week and start to the weekend.
Generally cooler Sunday into earlier next week, with another wave
digging from the northwest for another precip event toward mid next
week.

&&

.SHORT TERM...(This Evening through Thursday)
ISSUED AT 221 PM CDT Wed May 17 2017

Will have to watch for isolated to sctrd elevated storms with
hail potential ahead of the "main show" for the rest of the
afternoon, but the main severe weather event currently gathering
steam/"bubbling" in sfc pressure falls max over the MO RVR
Valley. Strong wing of lift into current mesoanalysis-indicated
already strongly sheared environment in place acrs the local area,
supportive of enhanced severe weather risk acrs the area
especially along and west of the MS RVR. Most of latest run
HiRes/CAM's continue to suggest an arching wing or two of broken
line of supercells, mixed with a few strong convective clusters,
moving rapidly at 50-60 MPH in from the west- southwest mainly
after 21z, with prime impact window from 5 PM to 8 or 9 PM CDT
before the brunt of the activity blows eastward. Again speed of
storms to complicate matters and increase danger aspect. Current
CAPEs of 1000-1500 J/KG acrs the region may increase a bit more
through early evening, while brunt of Cap/EML starts to migrate
eastward. This should be adequate for such strong shear profiles
to work with for all modes of severe weather, with tornadoes and
large hail the prime threats. But lingering concern that limited
CAPE for such strong shear profiles, may actually limit a higher
end severe weather event such as if we had 3000+ CAPEs.

The tornado threat may be limited to the initial incoming line as
long as llvl winds have some type of southeasterly direction
component, but then switch to more hail and damaging winds, as llvl
ambient environmental winds go south-southwest making for a more
uniform vertical profile, but still very high in speed shear.

Some isolated to sctrd showers and storms may linger acrs the
northern half of the CWA after the main line exits off to the east-
northeast through midnight, but then mainly dry into Thu morning or
just some wrap-around showers in the far north as upper level
cyclone pivots acrs northern WI and induces wrap-around.

Thu...after wrap around showers decrease in the north, this day
mainly dry and cooler in between two upper cyclones, with varying
amounts of cloud cover. LLVL baroclinicity aligns and tightens along
and south of the DVN CWA into the evening, with northeast post-
frontal boundary layer winds keeping temps in the 60s to low 70s
acrs much of the area.    ..12..

.LONG TERM...(Thursday Night through next Wednesday)
ISSUED AT 221 PM CDT Wed May 17 2017

Active weather pattern to continue through the period with chances
of rain and thunderstorms through the beginning of the weekend and
then again midweek next week.  Previously discussed issues with
model inconsistency still remains with this package.  This, along
with the threat for severe weather today has led to heavy use of
blended guidance for the long term.  Overall agreement in the large
scale pattern through the period means that the mesoscale details
need to be worked out and thus lead to most of uncertainty
throughout the period.   Gibbs

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
ISSUED AT 1241 PM CDT Wed May 17 2017

Brisk southerly sfc winds gusting over 30 KTS along with passing
mainly VFR clouds will be the main story this afternoon before the
main line of storms is expected to move into the local area from
the southwest later this afternoon and evening. An isolated storm to
wdly sctrd storms, though, is possible over the area ahead of the
main line, thus may keep VCNTY wording although that may be heavy
handed if current RADAR trends remain consistent. Have tried to
time a 1-2 hour window when a passing line of severe storms will
move northeastward through the TAF sites again during late
afternoon into early-mid evening. Then VCNTY for a few hours for
lingering isolated to sctrd storms behind the main line through
mid to late evening, then trend dry from midnight into Thu
morning. Sfc winds veering to the west at 10-20 KTS late tonight
into Thu morning, with cigs lowering to low VFR to MVFR in the main
low pressure storm system's wrap around cloud deck.   ..12..

&&

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

SYNOPSIS...12
SHORT TERM...12
LONG TERM...Gibbs
AVIATION...12
Hazardous weather outlook, May 17, 3:02 AM CDT, 14 hours 1 minute before
Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
302 AM CDT Wed May 17 2017

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-180815-
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-
302 AM CDT Wed May 17 2017

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...TONIGHT

Scattered thunderstorms are expected this morning. The main
threats are lightning and hail to penny size.

More widespread thunderstorms are expected this afternoon and
evening. Fast-moving storms could produce damaging winds around 70
mph and tornadoes. A secondary threat is large hail.

A south wind will gust around 40 mph this afternoon. Drivers of
high profile vehicles should use caution.

Area rivers are experiencing flooding. Please see the
latest Flood Statements and Flood Warnings for details.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

There is a risk of thunderstorms late Thursday night through
Saturday evening. It is too early to determine the severe weather
risk.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is expected between 2 PM and 10 PM CDT today.

RP Kinney/08

In the hours before

Local storm report, May 17, 4:13 PM CDT, 50 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
413 PM CDT WED MAY 17 2017

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

0411 PM     TSTM WND DMG     FAIRFIELD               41.01N 91.97W
05/17/2017                   JEFFERSON          IA   TRAINED SPOTTER

            2 SEMIS ON HWY 34 BLOWN OVER

&&

TES
Special weather statement, May 17, 4:13 PM CDT, 50 minutes before
Special Weather Statement
National Weather Service Quad Cities IA IL
413 PM CDT Wed May 17 2017

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-172315-
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-
Including the cities of Independence, Manchester, Dubuque,
Vinton, Cedar Rapids, Anamosa, Maquoketa, Marengo, Iowa City,
Tipton, Clinton, Muscatine, Davenport, Bettendorf, Sigourney,
Washington, Wapello, Fairfield, Mount Pleasant, Burlington,
Keosauqua, Fort Madison, Galena, Freeport, Mount Carroll,
Sterling, Moline, Rock Island, Geneseo, Princeton, Hennepin,
Aledo, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka
413 PM CDT Wed May 17 2017

...STRONG WINDS OVER NORTHEAST MISSOURI...EASTERN IOWA AND
NORTHWEST ILLINOIS LATE THIS AFTERNOON...

At 4 pm CDT, south winds from 20 to 30 mph with gusts as high as
50 mph were occurring across portions of eastern Iowa, northwest
Illinois and far northeast Missouri through 7 pm. This will create
areas of blowing dust, bring down small tree branches and blow
around loose lawn items.

These strong winds are occurring outside scattered strong to
severe thunderstorms developing over eastern Iowa. A tornado watch
remains in effect for much of the area until 11 pm.

Drivers of vans, campers, trailers, and other high profile
vehicles should be extra cautious, especially on east-west roads.
Home owners should take steps to secure loose outdoor belongings.

Sheets
Local storm report, May 17, 4:24 PM CDT, 39 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
424 PM CDT WED MAY 17 2017

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

0420 PM     HAIL             MOUNT PLEASANT          40.96N 91.55W
05/17/2017  E0.50 INCH       HENRY              IA   TRAINED SPOTTER

0421 PM     HAIL             1 SW DYERSVILLE         42.47N 91.13W
05/17/2017  M1.00 INCH       DUBUQUE            IA   TRAINED SPOTTER

&&

GROSS
Local storm report, May 17, 4:29 PM CDT, 34 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
429 PM CDT WED MAY 17 2017

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

0410 PM     TSTM WND GST     FAIRFIELD               41.01N 91.97W
05/17/2017  M55 MPH          JEFFERSON          IA   AWOS

&&

GROSS
Local storm report, May 17, 4:31 PM CDT, 32 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
431 PM CDT WED MAY 17 2017

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

0428 PM     HAIL             MOUNT UNION             41.06N 91.39W
05/17/2017  M1.25 INCH       HENRY              IA   EMERGENCY MNGR

&&

GROSS
Local storm report, May 17, 4:44 PM CDT, 19 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
444 PM CDT WED MAY 17 2017

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

0411 PM     HAIL             1 NNW MOUNT PLEASANT    40.97N 91.56W
05/17/2017  M0.25 INCH       HENRY              IA   TRAINED SPOTTER

            PEA TO DIME SIZE HAIL

0356 PM     HAIL             FARMINGTON              40.64N 91.74W
05/17/2017  E0.25 INCH       VAN BUREN          IA   FIRE DEPT/RESCUE

            TIME ESTIMATED - PEA TO DIME SIZE HAIL DURING STORM

0356 PM     TSTM WND DMG     FARMINGTON              40.64N 91.74W
05/17/2017                   VAN BUREN          IA   FIRE DEPT/RESCUE

            BRANCHES DOWN

0430 PM     TSTM WND DMG     2 W YARMOUTH            41.03N 91.36W
05/17/2017                   DES MOINES         IA   TRAINED SPOTTER

            TIME IS ESTIMATED - LARGE TREE BRANCH APPROX 18 FEET LONG
            WAS TORN OFF TREE

&&

TES

The office that day

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

IssuedProductOfficeCountiesLasted
May 17, 1:23 AM CDTSpecial Weather StatementDVNBenton, Buchanan, Delaware, Iowa, Johnson, Jones and 3 more37 min
May 17, 8:50 AM CDTSpecial Weather StatementDVNScott25 min
May 17, 3:16 PM CDTSevere Thunderstorm WarningDVNBenton, Buchanan, Linn43 min
May 17, 3:36 PM CDTSevere Thunderstorm WarningDVNDelaware, Dubuque, Jones, Linn54 min
May 17, 3:38 PM CDTTornado WarningDVNJefferson, Keokuk, Washington52 min
May 17, 3:45 PM CDTSevere Thunderstorm WarningDVNDes Moines, Henry, Lee, Van Buren30 min
May 17, 3:49 PM CDTTornado WarningDVNHenry, Jefferson, Van Buren, Washington41 min
May 17, 3:55 PM CDTTornado WarningDVNDes Moines, Henry, Lee, Louisa, Van Buren50 min
May 17, 4:23 PM CDTSevere Thunderstorm WarningDVNIowa, Johnson, Washington44 min
May 17, 4:40 PM CDTTornado WarningDVNDes Moines, Henry, Louisa, Muscatine50 min
May 17, 5:24 PM CDTSevere Thunderstorm WarningDVNCedar, Clinton, Muscatine, Scott30 min
May 17, 5:39 PM CDTSevere Thunderstorm WarningDVNHenry, Jefferson, Keokuk, Van Buren, Washington66 min
May 17, 5:50 PM CDTSevere Thunderstorm WarningDVNBenton, Buchanan, Delaware, Iowa, Johnson, Linn and 1 more55 min
May 17, 5:54 PM CDTSevere Thunderstorm WarningDVNJefferson, Van Buren51 min
May 17, 6:01 PM CDTTornado WarningDVNHenry, Jefferson, Lee, Van Buren59 min
May 17, 6:19 PM CDTTornado WarningDVNJohnson, Louisa, Washington41 min
May 17, 6:28 PM CDTFlash Flood WarningDVNJohnson, Linn3 hr
May 17, 6:31 PM CDTSevere Thunderstorm WarningDVNBuchanan, Cedar, Clinton, Delaware, Dubuque, Jackson and 5 more59 min
May 17, 6:32 PM CDTTornado Warning Tornado observedDVNDelaware, Dubuque, Jones, Linn43 min
May 17, 6:38 PM CDTSevere Thunderstorm WarningDVNHenry, Louisa, Muscatine, Washington52 min
May 17, 6:48 PM CDTTornado WarningDVNCedar, Johnson, Muscatine42 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2017Every severe thunderstorm warning in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.