Alert archive / Illinois / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 1, NWS Chicago, IL

March 9, 2002DeKalb County, LaSalle County, Illinois

NWS Chicago, IL issued this severe thunderstorm warning at Mar 9, 2002, 4:58 AM CST for DeKalb County, LaSalle County, Illinois. It was in force for 32 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: Mar 9, 2002, 4:58 AM CST (10:58 UTC)
Expired: Mar 9, 2002, 5:30 AM CST
In force: 32 min
Issued by: NWS Chicago, IL
Area: Whole counties

Counties DeKalb County, IL, LaSalle County, IL

The watch it was issued in

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

Issued	Product	Office	Lasted
Mar 9, 4:00 AM CST	Severe Thunderstorm Watch	SPC	4 hr

The nearest sounding before it

Davenport, (KDVN), launched 00:00Z, 11.0 hours before the alert went out and 139 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: 184 J/kg
Mixed-layer CIN: -106 J/kg
Mixed-layer LCL: 1023 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 192 m²/s²
0-3 km storm-relative helicity: 264 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.4

Open this sounding in Storm Lab

The text

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

000 
WUUS53 KLOT 091058
SVRCHI
ILC037-099-091130-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE CHICAGO IL
457 AM CST SAT MAR 9 2002

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  DE KALB COUNTY IN NORTH CENTRAL ILLINOIS
  LA SALLE COUNTY IN NORTH CENTRAL ILLINOIS

* UNTIL 530 AM CST

* AT 455 AM CST...DOPPLER RADAR INDICATED SEVERE THUNDERSTORMS OVER
  NORTH UTICA...OR ABOUT 5 MILES NORTHEAST OF LA SALLE...MOVING
  NORTHEAST AT 50 MPH.

THE SEVERE THUNDERSTORMS ARE CAPABLE OF PRODUCING
 DAMAGING WINDS GREATER THAN 60 MILES AN HOUR.
$$
LAT...LON 4161 8916 4118 8915 4134 8860 4183 8862
          4163 8893

NNNN

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 Mar 9, 2:25 AM CST, 2 hours 33 minutes earlier.

Area forecast discussion, Mar 9, 2:25 AM CST, 2 hours 33 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO IL
225 AM CST SAT MAR 9 2002

SYNOPSIS...A DEEPENING STORM SYSTEM OVER NORTHEAST IOWA WILL MOVE
RAPIDLY INTO EASTERN ONTARIO EARLY TONIGHT.  THE ASSOCIATED COLD FRONT
SHOULD BLOW THROUGH NORTHERN ILLINOIS SHORTLY AFTER SUNRISE WITH MUCH
COLDER AIR IN STORE THE REMAINDER OF THE WEEKEND.

DISCUSSION...DEEPENING LOW OVER EASTERN IOWA MOVING NEWD RAPIDLY AS
UPPER TROUGH BECOMES MORE POS TILTED OVER NRN GT LAKES LATER TODAY.
SCT SHOWERS AND TSTMS BREAKING OUT OVER CENTRAL AND NORTHERN IILINOIS
NOW WHILE NARROW CONVECTIVE LINE PUSHES TWD MISS RIVER.  DUE TO VERY
STRONG WIND FIELD ELEMENTS IN THIS LINE MAY PRODUCE ISOLD WIND GUSTS
EXCEEDING SEVERE LIMITS. FLOOD WATCH WILL BE DROPPED. AMOUNT OF PRECIP
SHOULD BE LIMITED BY RAPID MOVEMENT OF SYSTEM.  SOME RIVERS IN MINOR
FLOOD BUT NOT EXCESSIVE AND RUNOFF WILL BE SLOWED BY COOLING NEXT DAY
OR TWO.

WIND ADVISORY IS ANOTHER MATTER AND WITH STEEP LAPSE RATES AND PROGGED
WINDS OVER 50 MPH IN THE BOUNDARY LAYER LOCAL GUSTS TO AROUND 50 MPH
LIKELY FROM MIDDAY THROUGH EARLY EVENING.  GRADIENT WILL RELAX
TONIGHT.  INCOMING AIRMASS NOT NEARLY AS COLD AS PREV ONE AND WILL
MOVE ON QUICKLY AS SWLYS RETURN SUN NIGHT AND MON.  MORE ZONAL PATTERN
FORECAST THE MAJORITY OF NEXT WEEK WITH PERIODIC SHORT WAVES ZIPPING
BY.  NEW MRF SUGGESTS MORE TROUGHING OVER THE WESTERN STATES OVER NEXT
WKEND WHICH WOULD ALLOW MORE SUSTAINED WARMING THROUGH MIDWEST.  MOS
TEMPS DO NO REFLECT WARM AIRMASS IN PLACE AND RESULTANT 12UTC TEMPS SO
THAT PART OF GUIDANCE WILL BE DISMISSED.  OTHER TEMPS REASONABLE FOR
NXT 48HRS OR SO. KML

.CHI...WIND ADVZY NERN IL AND NW INDIANA TODAY
       STORM WARNING NRN LK MICH THIS AFTERNOON AND TNGT
       GALE WARNING SRN LK MICH THIS AFTERNOON AND TNGT

Nearby

Severe Thunderstorm Warnings in Illinois, 2002 Every severe thunderstorm warning in 2002

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.