Alert archive / Iowa / Special Weather Statements in 2020

Special Weather Statement, NWS Quad Cities, IA

August 9, 2020Buchanan County, Iowa

NWS Quad Cities, IA issued this special weather statement at Aug 9, 2020, 8:39 AM CDT for Buchanan County, Iowa. It was in force for 66 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 9, 2020, 8:39 AM CDT (13:39 UTC)
Expired: Aug 9, 2020, 9:45 AM CDT
In force: 66 min
Issued by: NWS Quad Cities, IA

County Buchanan County, IA

The radar

The Quad Cities radar (KDVN), 145 km from the middle of the area, began a volume at 13:41 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, 1.7 hours before the alert went out and 149 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: 1113 J/kg
Mixed-layer CIN: -172 J/kg
Mixed-layer LCL: 885 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -18 m²/s²
0-3 km storm-relative helicity: -14 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 9, 5:42 AM CDT, 2 hours 57 minutes earlier.

Area forecast discussion, Aug 9, 5:42 AM CDT, 2 hours 57 minutes before

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Hazardous weather outlook, Aug 9, 4:06 AM CDT, 4 hours 33 minutes before

Hazardous Weather Outlook
National Weather Service Quad Cities IA IL
406 AM CDT Sun Aug 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-
406 AM CDT Sun Aug 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

Hot and humid conditions will increase today, with heat index
levels this afternoon and early evening ranging from 95 to 100.
Some spots may exceed 100 heat index this afternoon, and a heat
advisory may be required. In any case, those outside working
should plan on frequent breaks and make sure to drink plenty of
water.

The Storm Prediction Center is forecasting a Slight risk for
severe storms in areas north of Interstate 80 through tonight,
and a marginal risk farther south. While a warm layer of air above
the ground may prevent storms from forming today and tonight,
there is a chance that storms over Minnesota build south towards
the area this afternoon and evening. If that happens, then these
storms will bring the threat of damaging winds and heavy rainfall.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

There will be a chance for more thunderstorms on Monday and
Monday evening. Strong to severe thunderstorms will be possible
with damaging wind and large hail the primary threats. Locally
heavy rainfall and flash flooding in areas that experience
repeated thunderstorms will also be a concern. The Storm
Prediction Center has a marginal risk of severe thunderstorms
across most of the Outlook Area for Monday.

There will be periodic chances for thunderstorms from Tuesday
night through Friday, but severe weather potential appears low at
this time.

Very warm and humid conditions will continue on Monday with heat
index readings ranging from the mid 90s to near 100 degrees.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and tonight.

Ervin/12

In the hours before

Special weather statement, Aug 9, 8:06 AM CDT, 33 minutes before

Special Weather Statement
National Weather Service Quad Cities IA/IL
806 AM CDT Sun Aug 9 2020

IAC011-019-091345-
Buchanan-Benton-
806 AM CDT Sun Aug 9 2020

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT WESTERN BUCHANAN AND
NORTHERN BENTON COUNTIES UNTIL 845 AM CDT...

At 806 AM CDT, radar indicated strong thunderstorms were located
along a line extending from near Tripoli to near Dysart. Movement was
east at 25 mph.

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

Locations impacted include...
Independence, Jesup, Urbana, Fairbank, Hazleton, Brandon, Rowley,
Mount Auburn, Lime Creek County Park, Wapsipinicon Golf Course,
Rodgers Park, Fontana County Park, Littleton, Buchanan County
Fairgrounds, Otterville, Spencers Grove, Minne Estema Park,
Independence Airport, Wildcat Bluff Park and Fontana Park.

This includes Interstate 380 between mile markers 40 and 55.

If outdoors, consider seeking shelter inside a building.

LAT...LON 4219 9184 4218 9230 4230 9230 4230 9206
      4247 9206 4247 9208 4264 9208 4264 9183
TIME...MOT...LOC 1306Z 274DEG 23KT 4283 9230 4220 9228

Speck

Special weather statement, Aug 9, 8:39 AM CDT, 0 minutes before

Special Weather Statement
National Weather Service Quad Cities IA/IL
839 AM CDT Sun Aug 9 2020

IAC019-091445-
Buchanan-
839 AM CDT Sun Aug 9 2020

...A STRONG THUNDERSTORM WILL AFFECT BUCHANAN COUNTY UNTIL 945 AM
CDT...

At 839 AM CDT, a strong thunderstorm was located over Jesup, or 11
miles west of Independence, moving east at 20 mph.

Winds of 40 to 50 mph and half inch hail are possible with this
storm.

Locations impacted include...
Independence, Jesup, Fairbank, Winthrop, Hazleton, Quasqueton,
Lamont, Brandon, Rowley, Aurora, Stanley, Lime Creek County Park,
Winthrop Golf Course, Wapsipinicon Golf Course, Fontana County Park,
Littleton, Monti, Buchanan County Fairgrounds, Otterville and
Independence Airport.

This includes Interstate 380 between mile markers 49 and 55.

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.

LAT...LON 4264 9161 4230 9160 4230 9206 4247 9206
      4247 9208 4264 9208
TIME...MOT...LOC 1339Z 270DEG 18KT 4243 9210

Speck

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 8:06 AM CDT	Special Weather Statement	DVN	Buchanan	39 min
Aug 9, 9:16 AM CDT	Special Weather Statement	DVN	Delaware	44 min
Aug 9, 9:55 AM CDT	Special Weather Statement	DVN	Dubuque	65 min
Aug 9, 12:49 PM CDT	Special Weather Statement	DVN	Delaware	41 min
Aug 9, 1:28 PM CDT	Special Weather Statement	DVN	Delaware	47 min
Aug 9, 5:23 PM CDT	Special Weather Statement	DVN	Stephenson	7 min

Nearby

Special Weather Statements in Iowa, 2020 Every special weather statement 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.