Alert archive / Illinois / Special Weather Statements in 2017

Special Weather Statement, NWS Quad Cities, IA

March 20, 2017Henry County, Illinois

NWS Quad Cities, IA issued this special weather statement at Mar 20, 2017, 12:29 AM CDT for Henry County, Illinois. It was in force for 46 min. 4 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
Mar 20, 2017, 12:29 AM CDT (05:29 UTC)
Expired
Mar 20, 2017, 1:15 AM CDT
In force
46 min
Issued by
NWS Quad Cities, IA

County Henry County, IL

The radar

The Quad Cities radar (KDVN), 47 km from the middle of the area, began a volume at 05:29 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
Mar 20, 12:45 AM CDTHAIL 0.751 N Cambridge, IL5 MINUTES...COVER THE GROUND
Mar 20, 12:45 AM CDTHAIL 0.751 W Cambridge, ILUP TO DIME SIZE HAIL.
Mar 20, 12:45 AM CDTHAIL 11 S Cambridge, ILFEW STONES TO 1 INCH.
Mar 20, 12:50 AM CDTHAIL 0.752 E Cambridge, ILALSO 30 MPH WINDS.

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

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 5.5 hours before the alert went out and 45 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 2017-03-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2017-03-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 299 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2365 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
299 m²/s²
0-3 km storm-relative helicity
483 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.9

Open this sounding in Storm Lab

The text

As transmitted.

469 
WWUS83 KDVN 200529
SPSDVN

Special Weather Statement
National Weather Service Quad Cities IA/IL
1229 AM CDT MON MAR 20 2017

ILC073-131-200615-
Mercer-Henry-
1229 AM CDT MON MAR 20 2017

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN MERCER AND SOUTHERN
HENRY COUNTIES UNTIL 115 AM CDT...

At 1227 AM CDT, a strong thunderstorm was located over Lynn Center, 
or 10 miles west of Cambridge, moving east at 35 mph. Dime size hail 
is possible with this storm over the next hour as it tracks across 
southern Henry County. 

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 4115 9044 4112 9044 4112 9048 4133 9051
      4133 9044 4136 9043 4142 8987 4115 8987
TIME...MOT...LOC 0527Z 262DEG 31KT 4127 9039 

$$

SHEETS

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 20, 12:41 AM CDTSevere Thunderstorm WarningDVNHenry34 min

Nearby

Special Weather Statements in Illinois, 2017Every special weather statement 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.