Alert archive / Iowa / Special Weather Statements in 2021

Special Weather Statement, NWS Quad Cities, IA

August 11, 2021Washington County, Iowa

NWS Quad Cities, IA issued this special weather statement at Aug 11, 2021, 3:36 PM CDT for Washington County, Iowa. It was in force for 24 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: Aug 11, 2021, 3:36 PM CDT (20:36 UTC)
Expired: Aug 11, 2021, 4:00 PM CDT
In force: 24 min
Issued by: NWS Quad Cities, IA
Hail: 0.75 in
Wind: 40

County Washington County, IA

The radar

The Quad Cities radar (KDVN), 99 km from the middle of the area, began a volume at 20:37 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 12:00Z, 8.6 hours before the alert went out and 106 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2852 J/kg
Mixed-layer CIN: -107 J/kg
Mixed-layer LCL: 1040 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 170 m²/s²
0-3 km storm-relative helicity: 193 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.7

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 Aug 11, 1:03 PM CDT, 2 hours 33 minutes earlier.

Area forecast discussion, Aug 11, 1:03 PM CDT, 2 hours 33 minutes before

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Hazardous weather outlook, Aug 11, 3:28 AM CDT, 12 hours 8 minutes before

Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
328 AM CDT Wed Aug 11 2021

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-120830-
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-
328 AM CDT Wed Aug 11 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...TODAY AND TONIGHT

A heat advisory is in effect for the entire area from noon to 7 PM
this evening. Heat index values of 100 to 106 are expected this
afternoon into the early evening hours.

There is also a Slight Risk for severe thunderstorms across the
entire area today and tonight. The primary threats are damaging
winds, hail, heavy rainfall, and frequent lightning.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

Severe storms are possible late Thursday afternoon and evening,
mainly south of a line from Stockton, Illinois to Cedar Rapids,
Iowa where the Storm Prediction Center has a Marginal Risk. The
main severe weather threat will be damaging winds. Heavy rainfall
and frequent lightning will also be possible.

Very warm and humid conditions will linger through Thursday with
heat index readings near 100 in the afternoon and early evening
hours.

.SPOTTER INFORMATION STATEMENT...

Storm spotter activation may be needed this afternoon and evening.

Cousins/Sheets

In the hours before

Local storm report, Aug 11, 11:35 AM CDT, 4 hours 1 minute before

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Local storm report, Aug 11, 12:05 PM CDT, 3 hours 31 minutes before

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Local storm report, Aug 11, 12:10 PM CDT, 3 hours 26 minutes before

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Local storm report, Aug 11, 12:27 PM CDT, 3 hours 9 minutes before

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Local storm report, Aug 11, 1:40 PM CDT, 1 hour 56 minutes before

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Special weather statement, Aug 11, 3:36 PM CDT, 0 minutes before

Special Weather Statement
National Weather Service Quad Cities IA/IL
336 PM CDT Wed Aug 11 2021

IAZ067-077-078-087-088-112100-
Henry IA-Washington IA-Muscatine IA-Louisa IA-Jefferson IA-
336 PM CDT Wed Aug 11 2021

...A strong thunderstorm will impact portions of northern Henry,
western Louisa, southeastern Washington, southwestern Muscatine and
northeastern Jefferson Counties through 400 PM CDT...

At 336 PM CDT, Doppler radar was tracking a strong thunderstorm over
Coppock, or 10 miles south of Washington, moving east at 30 mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

This strong thunderstorm will be near...
  Wayland around 340 PM CDT.
  Ainsworth, Crawfordsville and Olds around 355 PM CDT.

Other locations in the path of this storm include Winfield, Cotter
and Wyman.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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.

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 4103 9176 4120 9183 4136 9137 4110 9126
TIME...MOT...LOC 2036Z 252DEG 25KT 4114 9170

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

Ervin

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 11, 5:38 AM CDT	Special Weather Statement	DVN	Lee	37 min
Aug 11, 5:56 AM CDT	Severe Thunderstorm Warning	DVN	Des Moines, Lee	19 min
Aug 11, 6:10 AM CDT	Severe Thunderstorm Warning	DVN	Des Moines, Henry, Lee	20 min
Aug 11, 6:24 AM CDT	Severe Thunderstorm Warning	DVN	Des Moines	22 min
Aug 11, 6:38 AM CDT	Severe Thunderstorm Warning	DVN	Des Moines, Louisa	37 min
Aug 11, 6:59 AM CDT	Flash Flood Warning	DVN	Des Moines, Lee	3 hr
Aug 11, 7:04 AM CDT	Special Weather Statement	DVN	Muscatine	26 min
Aug 11, 8:16 AM CDT	High Wind Warning	DVN	Clinton, Des Moines, Louisa, Muscatine, Scott	104 min
Aug 11, 9:46 AM CDT	Areal Flood Warning	DVN	Des Moines, Lee	3 hr
Aug 11, 10:24 AM CDT	Special Weather Statement	DVN	Lee	21 min
Aug 11, 4:26 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque	49 min
Aug 11, 5:11 PM CDT	Severe Thunderstorm Warning	DVN	Delaware, Dubuque, Jackson, Jones	49 min
Aug 11, 5:38 PM CDT	Tornado Warning	DVN	Dubuque	13 min
Aug 11, 6:24 AM CDT	Special Weather Statement	DVN	McDonough	36 min
Aug 11, 7:32 AM CDT	Special Weather Statement	DVN	Rock Island	28 min
Aug 11, 7:55 AM CDT	Special Weather Statement	DVN	Bureau, Henry, Whiteside	65 min
Aug 11, 8:07 AM CDT	Severe Thunderstorm Warning	DVN	Bureau, Henry, Rock Island, Whiteside	53 min
Aug 11, 8:33 AM CDT	Severe Thunderstorm Warning Considerable damage threat	DVN	Bureau, Putnam, Whiteside	57 min
Aug 11, 9:59 AM CDT	Special Weather Statement	DVN	McDonough	31 min
Aug 11, 10:45 AM CDT	Special Weather Statement	DVN	Henderson, Warren	30 min
Aug 11, 10:57 AM CDT	Severe Thunderstorm Warning	DVN	Henderson, McDonough, Warren	33 min
Aug 11, 5:11 AM CDT	Special Weather Statement	DVN	Clark	34 min

Nearby

Special Weather Statements in Iowa, 2021 Every 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.