Alert archive / Illinois / Special Weather Statements in 2018

Special Weather Statement, NWS St. Louis, MO

July 29, 2018Montgomery County, Illinois

NWS St. Louis, MO issued this special weather statement at Jul 29, 2018, 10:30 AM CDT for Montgomery County, Illinois. It was in force for 60 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: Jul 29, 2018, 10:30 AM CDT (15:30 UTC)
Expired: Jul 29, 2018, 11:30 AM CDT
In force: 60 min
Issued by: NWS St. Louis, MO

County Montgomery County, IL

The radar

The Lincoln radar (KILX), 103 km from the middle of the area, began a volume at 15:34 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

Lincoln, IL (KILX), launched 12:00Z, 3.5 hours before the alert went out and 126 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 990 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: 4 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 St. Louis, MO wrote its last area forecast discussion before this special weather statement went out at Jul 29, 7:13 AM CDT, 3 hours 17 minutes earlier.

Area forecast discussion, Jul 29, 7:13 AM CDT, 3 hours 17 minutes before

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Hazardous weather outlook, Jul 29, 3:56 AM CDT, 6 hours 34 minutes before

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In the hours before

Special weather statement, Jul 29, 10:30 AM CDT, 0 minutes before

Special Weather Statement
National Weather Service St Louis MO
1030 AM CDT SUN JUL 29 2018

ILZ059-060-291630-
Macoupin IL-Montgomery IL-
1030 AM CDT SUN JUL 29 2018

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN MACOUPIN AND MONTGOMERY
COUNTIES UNTIL 1130 AM CDT...

At 1029 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles south of Girard to near Staunton.
Movement was east at 40 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
Litchfield, Hillsboro, Staunton, Virden, Gillespie, Nokomis, Girard,
Mount Olive, Benld, Raymond, Witt, White Oak, Farmersville, Taylor
Springs, Coffeen, Wilsonville, Schram City, Sawyerville, Mount Clare
and East Gillespie.

This includes Interstate 55 in Illinois between exits 41 and 63.

This also includes  Lake Lou Yaeger.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3922 8925 3903 8925 3903 8959 3900 8959
      3900 8988 3952 8977 3952 8953 3935 8953
      3935 8914 3922 8914
TIME...MOT...LOC 1529Z 278DEG 18KT 3935 8977 3900 8983

Maples

The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 29, 3:25 PM CDT	Severe Thunderstorm Warning	LSX	Jefferson	50 min
Jul 29, 4:36 PM CDT	Special Weather Statement	LSX	Sainte Genevieve	39 min
Jul 29, 4:24 PM CDT	Severe Thunderstorm Warning	LSX	Randolph	51 min
Jul 29, 5:05 PM CDT	Tornado Warning	LSX	Randolph	25 min
Jul 29, 5:15 PM CDT	Flash Flood Warning	LSX	Randolph	3 hr

Nearby

Special Weather Statements in Illinois, 2018 Every special weather statement in 2018

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.