Alert archive / Illinois / Severe Thunderstorm Warnings in 2001
Severe Thunderstorm Warning 66, NWS Chicago, IL
NWS Chicago, IL issued this severe thunderstorm warning at Sep 6, 2001, 7:11 PM CDT for DuPage County, Kendall County, Will County, Illinois. It was in force for 34 min. 3 reports came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- Sep 6, 2001, 7:11 PM CDT (00:11 UTC)
- Expired
- Sep 6, 2001, 7:45 PM CDT
- In force
- 34 min
- Issued by
- NWS Chicago, IL
- Area
- Whole counties
Counties DuPage County, IL, Kendall County, IL, Will County, IL
The radar
The Chicago radar (KLOT), 7 km from the middle of the area, began a volume at 00:14 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 |
|---|---|---|---|
| Sep 6, 7:20 PM CDT | Thunderstorm Wind 50 E | Oswego, IL | |
| Sep 6, 7:25 PM CDT | Thunderstorm Wind 50 E | Naperville, IL | |
| Sep 6, 7:25 PM CDT | Thunderstorm Wind 50 E | Plainfield, IL |
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 nearest sounding before it
Lincoln, IL (KILX), launched 00:00Z, 0.2 hours before the alert went out and 169 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.
- Mixed-layer CAPE
- 200 J/kg
- Mixed-layer CIN
- -148 J/kg
- Mixed-layer LCL
- 1364 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 163 m²/s²
- 0-3 km storm-relative helicity
- 199 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.
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 Sep 6, 3:00 PM CDT, 4 hours 11 minutes earlier.
Area forecast discussion, Sep 6, 3:00 PM CDT, 4 hours 11 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 300 PM CDT THU SEP 6 2001 WATER VAPOR LOOP SHOWS SHORT WAVE LIFTING NORTHEAST ACROSS KANSAS AND MISSOURI THIS AFTERNOON...WITH SCATTERED SHOWERS AND THUNDERSTORMS INCREASING IN COVERAGE INTO WESTERN PORTIONS OF THE FORECAST AREA. PLENTY OF MOISTURE AVAILABLE...WITH SURFACE DEWPOINTS SURGING INTO THE UPPER 60S AND LOWER 70S. MODELS IN GOOD AGREEMENT IN TAKING THIS FIRST WAVE NORTHEAST INTO THE GREAT LAKES REGION TONIGHT...DAMPING AND WEAKENING IT IN THE PROCESS AS IT RIDES INTO THE RIDGE OVER THE EASTERN PORTION OF THE NATION. SOMEWHAT OF A LULL IN THE ACTION FRIDAY IN THE WAKE OF THIS FIRST SYSTEM...ALHTOUGH WILL KEEP CHANCE POPS IN FOR SCATTERED PRECIP POSSIBLE IN MOIST AIRMASS AND POSSIBLE SMALL RIPPLES IN UPPER FLOW. BETTER CHANCE FOR PRECIPITATION RETURN SATURDAY...AS NEXT SIGNIFICANT SHORT WAVE ROUNDS THE BASE OF THE TROF AND LIFTS TOWARD ILLINOIS. SOME DIFFERENCES IN TIMING BETWEEN MODELS WITH THIS ONE...WITH AVN ABOUT 6 HOURS FASTER THAN THE SLOWER ETA. AT THIS DISTANCE WILL GO WITH A BLEND...AND GO WITH LIKELY POPS SATURDAY. WILL KEEP CHANCE FOR SATURDAY NIGHT...AS ETA HOLDS ON TO POST FRONTAL PRECIP IN VICINITY OF LOW LEVEL BAROCLINIC ZONE AND RIGHT ENTRANCE TO UPPER JET MAX WHILE AVN ATTEMPTS TO BRING IN DRY SLOT. MAIN UPPER TROF MOVES ACROSS SUNDAY...AND ALTHOUGH SURFACE FRONT AND MOIST AXIS PASSES TO THE EAST...WILL HANG ON TO CHANCE POPS FOR SHOWERS ON SUNDAY AS VORT PASSES OVERHEAD. SURFACE HIGH THEN BUILDS IN EARLY NEXT WEEK...WITH MRF INDICATING FLOW TO BECOME A BIT FLATTER BEHIND EXITING TROF. WARM ADVECTION PRECIP RETURNS TO NORTHERN PLAINS AND UPPER MIDWEST ON BACK SIDE OF HIGH BY MID WEEK...BUT LOOKS TO STAY NORTH AND WEST OF FORECAST AREA INTO THURSDAY. TEMPERATURE GUIDANCE PRETTY CLOSE BETWEEN FWC/FAN AND APPEARS REASONABLE. WILL GO WITH HIGHER MINS WITH DEWPOINTS NEAR 70 NEXT TWO NIGHTS. BIG DIFFERENCES SHOW UP BY 120 HOURS BETWEEN AVN AND MRF HOWEVER...WITH 850 TEMPS OF +10 AND +4 RESPECTIVELY BY 12Z MONDAY. CURRENT FORECAST TRENDS COOLER BUT A LITTLE ABOVE MRF MEX GUIDANCE. THIS IN LINE WITH NCEP MANUAL NUMBERS AND WILL CONTINUE. .CHI...NONE RATZER
In the hours before
Local storm report, Sep 6, 5:16 PM CDT, 1 hour 55 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
516 PM CDT THU SEP 06 2001
TIME(CDT) .....CITY LOCATION..... STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0330 PM POLO IL 45 MPH TSTM GUST
09/06/01 OGLE ONE TREE DOWN. 5-8
INCH BRANCHES DOWN IN
CITY. REPORTED BY
EMERGENCY MANAGEMENT.Nearby
Severe Thunderstorm Warnings in Illinois, 2001Every severe thunderstorm warning in 2001
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; radar from the NEXRAD Level II archive.