Alert archive / Illinois / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 252, NWS Quad Cities, IA

July 31, 2008Stephenson County, Illinois

NWS Quad Cities, IA issued this severe thunderstorm warning at Jul 31, 2008, 12:34 PM CDT for Stephenson County, Illinois. It was in force for 46 min. 2 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: Jul 31, 2008, 12:34 PM CDT (17:34 UTC)
Expired: Jul 31, 2008, 1:20 PM CDT
In force: 46 min
Issued by: NWS Quad Cities, IA
Area: Storm-based polygon

County Stephenson County, IL

The radar

The Milwaukee radar (KMKX), 110 km from the middle of the area, began a volume at 17:34 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.

What was reported inside it

Time	Report	Where	Remark
Jul 31, 12:54 PM CDT	TSTM WND GST 49	Freeport, IL
Jul 31, 12:54 PM CDT	NON-TSTM WND GST 49	Freeport, IL

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

The watch it was issued in

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

Issued	Product	Office	Lasted
Jul 31, 7:18 AM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 5.6 hours before the alert went out and 110 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: 718 J/kg
Mixed-layer CIN: -163 J/kg
Mixed-layer LCL: 1016 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 89 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS53 KDVN 311734
SVRDVN
ILC177-311830-
/O.NEW.KDVN.SV.W.0252.080731T1734Z-080731T1830Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1234 PM CDT THU JUL 31 2008

THE NATIONAL WEATHER SERVICE IN THE QUAD CITIES HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN STEPHENSON COUNTY IN NORTHWEST ILLINOIS...

* UNTIL 130 PM CDT.

* AT 1229 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DESTRUCTIVE WINDS
  IN EXCESS OF 70 MPH.  THESE STORMS WERE LOCATED APPROXIMATELY ALONG
  A LINE EXTENDING FROM 8 MILES NORTH OF CEDARVILLE TO 21 MILES
  SOUTHWEST OF FREEPORT...OR ALONG A LINE EXTENDING FROM 8 MILES
  SOUTH OF MONROE TO MOUNT CARROLL...AND MOVING SOUTHEAST AT 49 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  FREEPORT AND DAKOTA AROUND 1240 PM CDT...
  ROCK CITY AND DAVIS AROUND 1245 PM CDT...
  RIDOTT AND GERMAN VALLEY AROUND 1250 PM CDT...

THIS IS A DANGEROUS STORM. MOVE IMMEDIATELY INDOORS AND STAY AWAY
FROM WINDOWS.

LAT...LON 4220 8940 4219 8941 4219 8949 4219 8950
      4220 8970 4250 8969 4249 8940
TIME...MOT...LOC 1734Z 301DEG 43KT 4245 8962 4208 8988

$$

08

3 follow-up statements

000 
WWUS53 KDVN 311748
SVSDVN

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1248 PM CDT THU JUL 31 2008

ILC177-311830-
/O.CON.KDVN.SV.W.0252.000000T0000Z-080731T1830Z/
STEPHENSON IL-
1248 PM CDT THU JUL 31 2008

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 130 PM CDT
FOR EASTERN STEPHENSON COUNTY...

AT 1243 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING
DESTRUCTIVE WINDS IN EXCESS OF 70 MPH.  THESE STORMS WERE LOCATED
APPROXIMATELY ALONG A LINE EXTENDING FROM DAKOTA TO 17 MILES
SOUTHWEST OF OAKDALE NATURE PRESERVE...OR ALONG A LINE EXTENDING FROM
10 MILES NORTHEAST OF FREEPORT TO 12 MILES SOUTHEAST OF MOUNT
CARROLL...MOVING SOUTHEAST AT 49 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  RURAL SOUTHEASTERN STEPHENSON COUNTY AT 100 PM CDT

THIS IS A DANGEROUS STORM. MOVE IMMEDIATELY INDOORS AND STAY AWAY
FROM WINDOWS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 100 PM CDT
THURSDAY AFTERNOON FOR NORTHEASTERN IOWA AND NORTHWEST ILLINOIS.

LAT...LON 4220 8940 4219 8941 4219 8949 4219 8950
      4220 8970 4250 8969 4249 8940
TIME...MOT...LOC 1748Z 301DEG 43KT 4236 8943 4199 8969

$$

08

000 
WWUS53 KDVN 311801
SVSDVN

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
101 PM CDT THU JUL 31 2008

ILC177-311830-
/O.CON.KDVN.SV.W.0252.000000T0000Z-080731T1830Z/
STEPHENSON IL-
101 PM CDT THU JUL 31 2008

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 130 PM CDT
FOR EASTERN STEPHENSON COUNTY...

AT 1257 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING
DESTRUCTIVE WINDS IN EXCESS OF 70 MPH.  THESE STORMS WERE LOCATED
APPROXIMATELY ALONG A LINE EXTENDING FROM 9 MILES EAST OF RIDOTT TO
20 MILES SOUTH OF GERMAN VALLEY...OR ALONG A LINE EXTENDING FROM 13
MILES WEST OF ROCKFORD TO 7 MILES NORTHWEST OF DIXON...MOVING
SOUTHEAST AT 49 MPH.

THIS IS A DANGEROUS STORM. MOVE IMMEDIATELY INDOORS AND STAY AWAY
FROM WINDOWS.

LAT...LON 4220 8940 4219 8941 4219 8949 4219 8950
      4220 8970 4250 8969 4249 8940
TIME...MOT...LOC 1801Z 301DEG 43KT 4228 8925 4191 8952

$$

08

000 
WWUS53 KDVN 311820
SVSDVN

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
120 PM CDT THU JUL 31 2008

ILC177-311830-
/O.CAN.KDVN.SV.W.0252.000000T0000Z-080731T1830Z/
STEPHENSON IL-
120 PM CDT THU JUL 31 2008

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN STEPHENSON COUNTY IS
CANCELLED...

THE SEVERE THUNDERSTORM THAT WAS CAPABLE OF PRODUCING SEVERE WEATHER 
HAS MOVED OUT OF THE WARNED AREA. THEREFORE THE SEVERE THUNDERSTORM 
WARNING HAS BEEN CANCELLED.

LAT...LON 4220 8940 4219 8941 4219 8949 4219 8950
      4220 8970 4250 8969 4249 8940
TIME...MOT...LOC 1820Z 301DEG 43KT 4216 8899 4179 8926

$$

08

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 31, 3:24 AM CDT	Dense Fog Advisory	DVN	Bureau, Hancock, Henderson, Henry, McDonough, Mercer and 4 more	7 hr
Jul 31, 11:55 AM CDT	Severe Thunderstorm Warning	DVN	Carroll, Jo Daviess, Stephenson	65 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2008 Every severe thunderstorm warning in 2008

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.