Alert archive / Illinois / Severe Thunderstorm Warnings in 2001
Severe Thunderstorm Warning 35, NWS Chicago, IL
NWS Chicago, IL issued this severe thunderstorm warning at Jul 21, 2001, 6:34 PM CDT for Will County, Illinois. It was in force for 41 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Jul 21, 2001, 6:34 PM CDT (23:34 UTC)
- Expired
- Jul 21, 2001, 7:15 PM CDT
- In force
- 41 min
- Issued by
- NWS Chicago, IL
- Area
- Whole counties
County Will County, IL
The radar
The Chicago radar (KLOT), 20 km from the middle of the area, began a volume at 23:36 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, 11.6 hours before the alert went out and 153 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
- 883 J/kg
- Mixed-layer CIN
- -87 J/kg
- Mixed-layer LCL
- 1001 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 80 m²/s²
- 0-3 km storm-relative helicity
- 115 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 3.2
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 Jul 21, 2:45 PM CDT, 3 hours 49 minutes earlier.
Area forecast discussion, Jul 21, 2:45 PM CDT, 3 hours 49 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 245 PM CDT SAT JUL 21 2001 THE NUMBERS ARE IN FOR TOMORROW AND MAY BE A BIT OVERDONE CONSIDERING RH AND RANDOM CLOUD COVER. MCS DEVELPMENT IN SRN MN AND IA NOT PICKED UP ON MODELS. CORFIDI VECTORS WOULD SUGGEST STUFF IN SRN MN EARMARKED FOR NRN IL THIS EVENING AND ERLY TONIGHT. IF LITTLE PCPN BY THE TIME IT ARRIVES...WILL BE MORE CLOUD COVER TO KEEP TEMPS UP TONIGHT AND DEPARTING BY MRNG TO ALLOW GOOD AMOUNT OF SUNSHINE. WITH THAT IN MIND...TEMPS SHOULD HAVE LITTLE PROBLEM REACHING 90+ AGAIN ON SUNDAY. THUS WILL UPGRADE EXCESSIVE HEAT WATCH TO WARNING TO BE IN EFFECT SUNDAY. 850 THERMAL RIDGE EDGING EAST OVER NWRN IL TMRW AND JUSTIFYING WARMER TEMPS FOR THE AREA WEST OF CHI. RFD ALREADY REACHED 92 WITH GOOD PROSPECT OF 95 TMRW. THIS CUD MEAN HI VALUES AROUND 105. COORDINATION WITH SURROUNDING WFO'S SUGGEST ADVISORY FOR ALL CWA WITH WARNING CRITERIA FOR THE 8 COUNTY CHICAGO AREA. THIS RIDGE EDGES FURTHER EAST MONDAY WITH ENHANCED 850 JET. IF NO PCPN OR THICK CLOUD COVER...CUD CONTINUE HEAT WRNG/ADV INTO MONDAY. NOW FOR PCPN. STILL SOME SPORADIC SHOWERS DEVELOPING IN AREA...BUT LARGER CONCERN IS AREA IN MN AND IA...WHICH APPEARS TO BE DYING. WLL PUT IN CHC TNGT FOR SHWERS 30%...BUT LEAVE OUT TOMORROW. BETTER DYNAMICS APPEARING SUNDAY NIGHT WITH NEARLY ADIABATIC LAPSE BELOW 800 MB...SHEARED WIND PROFILE...AND CAPES AROUND 4K. QUESTION IS WILL IT CONT (CLDS AND/OR PCPN) INTO MONDAY. MODELS SAY THERE IS A CHC ON MONDAY WITH TROF MOVING THRU MONDAY EVENING. THERMAL RIDGE NOT MOVING SOUTH OF AREA UNTIL TUESDAY NIGHT WITH ACTUAL PASSAGE OF COLD FRONT. THUS TUESDAY COULD BE ANOTHER EXTENSION OF HOT WEATHER. AVN BRING FNT THRU DRY ON TUESDAY WHICH SEEMS ODD AND WILL KEEP CHC GOING. NE WINDS OVER AREA THRU FRIDAY SHUD KEEP RETURN MOISTURE SOUTH OF AREA...PSBLY RAINING ACRS NWRN AND CNTL IL. MAY RETURN CHC RAIN TO AREA FRIDAY NIGHT AND SATURDAY. .CHI...EXCESSIVE HEAT WARNING FOR SUNDAY CHICAGO AREA/EXCESSIVE HEAT ADV FOR SUNDAY REST OF CWA. BRUMER
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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.