Alert archive / Illinois / Severe Thunderstorm Warnings in 2000

Severe Thunderstorm Warning 87, NWS Chicago, IL

August 5, 2000Boone County, McHenry County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Aug 5, 2000, 4:19 PM CDT for Boone County, McHenry County, Illinois. It was in force for 56 min. No storm report in the archive falls 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.

The facts

Issued
Aug 5, 2000, 4:19 PM CDT (21:19 UTC)
Expired
Aug 5, 2000, 5:15 PM CDT
In force
56 min
Issued by
NWS Chicago, IL
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Boone County, IL, McHenry County, IL

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 9.3 hours before the alert went out and 178 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 12:00Z on 2000-08-05Temperature 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 12:00Z on 2000-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 148 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
1330 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
148 m²/s²
0-3 km storm-relative helicity
231 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
WUUS53 KLOT 052121
SVRCHI
ILC007-111-052215-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
ISSUED BY MILWAUKEE/SULLIVAN WI
419 PM CDT SAT AUG 5 2000

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN BOONE COUNTY IN NORTH CENTRAL ILLINOIS
  MCHENRY COUNTY IN NORTHEAST ILLINOIS

* UNTIL 515 PM CDT

* AT 420 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 12 MILES NORTHWEST OF POPLAR GROVE...OR ABOUT 4
  MILES EAST OF BELOIT...MOVING SOUTHEAST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  POPLAR GROVE AT 430 PM CDT.
  CAPRON AT 435 PM CDT.
  HARVARD AT 440 PM CDT.
  HEBRON AT 455 PM CDT.

IF YOU ARE IN THE PATH OF THIS STORM...YOU SHOULD PREPARE FOR
DAMAGING WINDS IN EXCESS OF 60 MPH...LARGE HAIL...AND DEADLY
LIGHTNING. SEEK SHELTER IMMEDIATELY!

LAT...LON 4264 8896 4237 8895 4216 8823 4249 8824

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 Chicago, IL wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 5, 3:30 AM CDT, 12 hours 49 minutes earlier.

Area forecast discussion, Aug 5, 3:30 AM CDT, 12 hours 49 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
330 AM CDT SAT AUG 5 2000

MDLS SHOWING FAIRLY DECENT CONTINUITY PAST FEW RUNS IN HANDLING OF
NXT WX SYS DUE TO AFFECT FA TNGT-ERLY SUN.  GOOD CONSISTENCEY BTWN
MDLS AS WELL.  WL MAKE NO LRG SCALE CHGS TO GOING FCST.

IR SATLT LOOPS SHOW MAIN MCS COVERING ERN SD.  HARD TO DETERMINE DIR
OF PROPAGATION ATTM BUT DTN LOOPS SHOW INDIVIDUAL CONVECTIVE
ELEMENTS DVLPG SWD TWD NERN NE AND PERHAPS NWRN IA.  THIS IS
CONSISTENT WITH FCST THICKNESS FIELD.  PROFILERS PAST SVRL HRS ALSO
SUG THIS SYS SHUD CONT FAIRLY INTACT AS IT DROPS SSEWD TO W OF IL.
BASED ON THIS EXPECTR CONVECTIVE DEBRIS/ANVIL CANOPY WL OVRSPRD AREA
TDY.  SIG VORT MAX TO MOV FM NRN PLAINS TO UPR GRTLKS TNGT.  THIS WL
SHFT TSTM GENERATION AREA EWD INTO UPR MIDWEST/UPR GRTLKS RGN WITH
THIS ACTIVITY THEN DROPPING SEWD INTO NRN IL.  SHWRS COULD MOV INTO
NRN IL AS EARLY AS LATE AFTN...BUT BASED ON FCST WIND PROFILES AND
MDL SOUNDINGS SHOWING SIGNIFICANT DESTBLZN...BEST CHC FOR TSTMS
STILL LUKS LIKE TNGT.  WUD LIKE TO SEE FCST ISENTROPIC DATA BUT ONLY
BITS AND PIECES OF 00Z SAT ISENTROPIC GRAPHICS HAVE LOADED TO AWIPS.
BY SUN MRNG...BEST LO LVL FORCING/ MOISTURE CONVERGENCE SHIFTS EWD.
DFUS SFC BNDRY FCST TO HANG UP TO N/NW OF FA.  EVENTHOUGH BEST LIFT
SHIFTS E OF AREA AND LO LVL FLO BCMS A/CYCLNC...ENUF INSTBY FCST
THAT LO CHC POPS APPEAR BEST ROUTE TO GO.  NONETHELESS...AFTER WAA
TSTMS MOVE THRU TNGT-ERLY SUN THERE SHUD BE A BRK IN THE ACTION WITH
PCPN BCMG ISOLD UNTIL SUN NGT-MON WHEN NXT DSTBC INDUCES BETTER LO
LVL FLO FIELD FOR NOCTURNAL TSTM DVLPMT.

MOS TEMPS STILL IN RESONABLY CLOSE AGREEMENT AND WL DEVIATE LTL FM
GUID FOR FCST TEMPS.

.CHI...NONE

MERZLOCK

In the hours before

Special weather statement, Aug 5, 12:09 PM CDT, 4 hours 10 minutes before
ILZ003>006-008-010>014-019>023-032>033-039-INZ001>002-010>011-019-
061100-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHICAGO IL
NOON CDT/EST SAT AUG 5 2000

FOR NORTH CENTRAL AND NORTHEAST ILLINOIS AND NORTHWEST INDIANA.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE REGION
TONIGHT.

AS AN UPPER LEVEL WEATHER DISTURBANCE IS MOVING INTO THE UPPER GREAT
LAKES TODAY. AN INCREASING SOUTH FLOW OF WARMER AND MORE HUMID AIR
WILL PUSH INTO THE REGION...HELPING MORE THUNDERSTORMS TO DEVELOP
THIS AFTERNOON AND TONIGHT. SOME OF THESE STORMS MAY CONTAIN
DAMAGING STRAIGHT-LINE WINDS AND HAIL. THE MAIN THREAT FOR SEVERE
ACTIVITY WILL REMAIN WEST AND SOUTH OF THE AREA TONIGHT.

A COLD FRONT WILL DROP SOUTHEAST OUT OF IOWA AND WISCONSIN TONIGHT
AND BECOME STATIONARY OVER NORTHERN ILLINOIS ON SUNDAY. HIGH
DEWPOINTS AND A LINGERING UNSTABLE ENVIRONMENT SOUTH OF THIS FRONT
COULD FEED REDEVELOPMENT OF THUNDERSTORMS ON SUNDAY. THESE COULD
LIKELY BE TRIGGERED BY DAYTIME HEATING...AND COULD REACH SEVERE
STRENGTH. THIS POTENTIALLY SEVERE AREA WOULD GENERALLY LIE OVER
SOUTH AND EASTERN PORTIONS OF THE AREA.

BRUMER

Nearby

Severe Thunderstorm Warnings in Illinois, 2000Every 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; the sounding from the Mesonet's radiosonde archive.