Alert archive / Illinois / Severe Thunderstorm Warnings in 2000

Severe Thunderstorm Warning 399, NWS St. Louis, MO

August 17, 2000Saint Clair County, Illinois

NWS St. Louis, MO issued this severe thunderstorm warning at Aug 17, 2000, 8:54 PM CDT for Saint Clair County, Illinois. It was in force for 51 min. 1 report came from inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties, with what was reported inside it.

The facts

Issued: Aug 17, 2000, 8:54 PM CDT (01:54 UTC)
Expired: Aug 17, 2000, 9:45 PM CDT
In force: 51 min
Issued by: NWS St. Louis, MO
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Saint Clair County, IL

What was reported inside it

Time	Report	Where	Remark
Aug 17, 8:55 PM CDT	Thunderstorm Wind 61 E	Lebanon, IL	Thunderstorm wind gusts estimated at 70 mph flattened a corn field near Lebanon.

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

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

Issued	Product	Office	Lasted
Aug 17, 5:30 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 1.9 hours before the alert went out and 219 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: 4438 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 1011 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 145 m²/s²
Significant tornado parameter: 3.1
Supercell composite: 18.2

Open this sounding in Storm Lab

The text

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

827 
WUUS53 KLSX 180156
SVRSTL
ILC163-180245-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE ST LOUIS MO
854 PM CDT THU AUG 17 2000

THE NATIONAL WEATHER SERVICE IN ST LOUIS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  ST. CLAIR COUNTY IN SOUTHWEST ILLINOIS

* UNTIL 945 PM CDT

* AT 854 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 6 MILES SOUTHWEST OF CENTREVILLE...MOVING
  EAST NORTHEAST AT 25 MPH.

* LOCATIONS IN THE PATH...
  CENTREVILLE
  FAIRVIEW HEIGHTS
  OFALLON
  BELLEVILLE
  
THE PRIMARY THREAT POSED BY THIS STORM IS DAMAGING WINDS. MOVE
QUICKLY TO THE INTERIOR PORTION OF A STURDY SHELTER...AND STAY AWAY
FROM OUTSIDE WALLS AND WINDOWS.

LAT...LON 3866 9016 3844 9017 3828 8988 3822 8972
          3867 8971

GKS

What forecasters said that day

The local office's own words before this severe thunderstorm warning 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 severe thunderstorm warning went out at Aug 17, 4:00 PM CDT, 4 hours 54 minutes earlier.

Area forecast discussion, Aug 17, 4:00 PM CDT, 4 hours 54 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
400 PM CDT THU AUG 17 2000

20Z MSAS DATA INDICATES CDFNT ENTERING NRN SXNS OF FA...EXTDG FM
NERN MO (JUST E OF KIRK) SWWD THRU W CNTRL MO INTO SERN KS.  MDT-STG
LLVL CONV IND ALG/JUST AHD OF FNT WITH LI/S AOB -10 AND CAPES ARND
5000 J/KG.  BAND OF LLVL CONV FINALLY ENTERING RGN OF WK ENUF
SFC-BASED CAP TO BEGIN TO DVLP CU FIELDS ACRS CNTRL/NERN MO.  TSTM
DVLPMT XPCTD TO BE IMMINENT.  SUM POST-FNTL PCPN ALSO EXISTS OVR NRN
MO/SRN IA AS A RESULT OF MID LVL S/W.

FCST PROB FOR THE AFTN PACKAGE IS PCPN CHCS TNGT AND THEN TEMPS FRI
THRU SAT.

12Z MODELS IN GOOD AGRMT THRU 48HRS.  S/W OVR NRN MO/SRN IA WL MOV
EWD THRU CNTRL IL TNGT.  RDG AXIS OVR ERN ROCKIES WL SLIDE EWD INTO
PLNS BY SAT...PROMOTING A W TO NWLY UPR FLO THRU PD.  APPEARS A
CONVECTIVELY INDUCED VORT MX WL TRY TO UNDERCUT RDG ON SAT AND MOV
INTO NRN/WRN ZONES.  ON SFC FEATURES...CDFNT WL MOV THRU MOST OF FA
THIS EVNG...AND THEN THRU RMNDR SRN ZONES OVRNGT.  CANADIAN HI PRES
WL THEN DOMINATE RGN THRU FRI NGT...WITH A WRMFNT THEN SLIDING INTO
WRN MO ON SAT.

FOR TNGT...HAVE EVERY REASON TO BELIEVE BKN LN OF CONVECTION WL DVLP
SOON...ACRS CNTRL-NERN MO AND THIS LN WL TRACK W/ FNT THRU MOST OF
FA.  PWAT VALUES ARND 2 INCHES...MDT-STG LLVL CONV...AND HI INSTAB
AIRMASS SHD FAVOR THAT SCENARIO.  VORT MX WL KEEP POST-FNTL PCPN
GOING ACRS NRN ZONES THIS EVNG...THOUGH THEY MISS MUCH OF THE BKN LN
OF TSTMS THAT SHD DVLP SOON.  WENT MUCH ABV GUIDANCE POPS...BUT
TENDED TO FOLLOW GUIDANCE TEMPS.

FOR FRI...CANADIAN AIRMASS TO DOMINATE WX-SCENE...WITH VERY AUTUMN
LIKE SITN SETTING UP.  SHD SEE EXTENSIVE MVFR CIG DECK ACRS
CNTRL/NRN ZONES IN MRNG...AND WL BREAK UP SOMEWHAT FM S TO N DURG
AFTN.  N-NELY SFC WNDS AND CLDS SHD RESULT IN TEMPS ABT 20 DEG
COOLER THAN TDA...AND TENDED TO GO AOB GUIDANCE TEMPS.

FOR SAT...CONVECTION TO OUR W WL SPREAD HI CLD DECK OVR ERL IN PD.
MODELS ALL INDICATING TO ENUF MOISTURE RTRN IN WRN/NRN ZONES WITH
UPR LVL DYNAMICS TO WARRANT RAIN CHCS IN AFTN THESE AREAS.  OTRW...
ELY LLVL FLOW/CLDS WL KEEP TEMPS IN CHECK.

.STL...NONE
TES

In the hours before

Special weather statement, Aug 17, 8:10 PM CDT, 44 minutes before

MOZ018-019-026-027-034-035-180500-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ST LOUIS MO
810 PM CDT THU AUG 17 2000

THE THREAT OF SEVERE WEATHER HAS DIMINISHED ACROSS THE REGION.
THE COLD FRONT HAS PUSHED THROUGH AND STABLE AND COOLER AIR
WILL BE MOVING INTO THE AREA.

THE SEVERE THUNDERSTORM WATCH HAS BEEN CANCELLED FOR THE FOLLOWING
COUNTIES

IN MISSOURI - KNOX...LEWIS...SHELBY...MARION...MONROE AND RALLS

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 17, 8:04 PM CDT	Severe Thunderstorm Warning	LSX	Saint Clair	41 min
Aug 17, 8:20 PM CDT	Severe Thunderstorm Warning	LSX	Clinton	40 min
Aug 17, 8:28 PM CDT	Severe Thunderstorm Warning	LSX	Fayette, Montgomery	47 min
Aug 17, 8:29 PM CDT	Severe Thunderstorm Warning	LSX	Madison	46 min
Aug 17, 8:58 PM CDT	Severe Thunderstorm Warning	LSX	Bond	47 min
Aug 17, 9:15 PM CDT	Severe Thunderstorm Warning	LSX	Madison	45 min
Aug 17, 9:43 PM CDT	Severe Thunderstorm Warning	LSX	Clinton, Marion	47 min
Aug 17, 9:50 PM CDT	Severe Thunderstorm Warning	LSX	Madison, Saint Clair	40 min
Aug 17, 10:25 PM CDT	Severe Thunderstorm Warning	LSX	Clinton	50 min
Aug 17, 10:46 PM CDT	Severe Thunderstorm Warning	LSX	Bond	44 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2000 Every severe thunderstorm warning in 2000

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.