Alert archive / Illinois / Red Flag Warnings in 2012

Red Flag Warning 2, NWS Chicago, IL

March 20, 201218 counties in Illinois; 5 counties in Indiana

NWS Chicago, IL issued this red flag warning at Mar 20, 2012, 1:08 PM CDT for 18 counties in Illinois; 5 counties in Indiana. It was in force for 6 hr. 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 20, 2012, 1:08 PM CDT (18:08 UTC)
Expired
Mar 20, 2012, 7:02 PM CDT
In force
6 hr
Issued by
NWS Chicago, IL
All 23 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, McHenry County, IL, Ogle County, IL, Will County, IL, Winnebago County, IL, Benton County, IN, Jasper County, IN, Lake County, IN, Newton County, IN, Porter County, IN

The radar

The Chicago radar (KLOT), 12 km from the middle of the area, began a volume at 18:13 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, 6.1 hours before the alert went out and 158 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, Lincoln, IL at 12:00Z on 2012-03-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 16 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2012-03-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 131 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
16 J/kg
Mixed-layer CIN
-218 J/kg
Mixed-layer LCL
1084 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
131 m²/s²
0-3 km storm-relative helicity
136 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.

942 
WWUS83 KLOT 201808
RFWLOT

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE CHICAGO IL
108 PM CDT TUE MAR 20 2012

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
210100-
/O.NEW.KLOT.FW.W.0002.120320T1808Z-120321T0100Z/
WINNEBAGO-BOONE-MCHENRY-LAKE IL-OGLE-LEE-DE KALB-KANE-DUPAGE-COOK-
LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-IROQUOIS-FORD-
LAKE IN-PORTER-NEWTON-JASPER-BENTON-
108 PM CDT TUE MAR 20 2012 /208 PM EDT TUE MAR 20 2012/

...RED FLAG WARNING IN EFFECT UNTIL 8 PM CDT /9 PM EDT/ THIS
EVENING...

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A RED FLAG
WARNING FOR LOW RELATIVE HUMIDITY AND STRONG WINDS FOR ALL OF 
NORTH CENTRAL AND NORTHERN ILLINOIS ALONG WITH NORTHWEST INDIANA
WHICH IS IN EFFECT UNTIL 8 PM CDT /9 PM EDT/ THIS EVENING.

* AFFECTED AREA...ALL OF NORTH CENTRAL AND NORTHEAST ILLINOIS
  ALONG WITH NORTHWEST INDIANA.

* WINDS...SOUTH 15 TO 25 MPH WITH GUSTS UP TO 35 MPH.

* TIMING...THROUGH EARLY THIS EVENING.

* RELATIVE HUMIDITY...AS LOW AS 20 PERCENT.

* IMPACTS...CONDITIONS ARE FAVORABLE FOR RAPID GROWTH OF WILD
  FIRES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A RED FLAG WARNING MEANS THAT CRITICAL FIRE WEATHER CONDITIONS
ARE EITHER OCCURRING NOW...OR WILL SHORTLY. A COMBINATION OF
STRONG WINDS...LOW RELATIVE HUMIDITY...AND WARM TEMPERATURES WILL
CREATE EXPLOSIVE FIRE GROWTH POTENTIAL.

&&

$$
CMS
1 follow-up statement
330 
WWUS83 KLOT 210002
RFWLOT

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE CHICAGO IL
702 PM CDT TUE MAR 20 2012

...WINDS DIMINISHING AND HUMIDITY SLOWLY INCREASING...


ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
210115-
/O.CAN.KLOT.FW.W.0002.000000T0000Z-120321T0100Z/
WINNEBAGO-BOONE-MCHENRY-LAKE IL-OGLE-LEE-DE KALB-KANE-DUPAGE-COOK-
LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-IROQUOIS-FORD-
LAKE IN-PORTER-NEWTON-JASPER-BENTON-
702 PM CDT TUE MAR 20 2012 /802 PM EDT TUE MAR 20 2012/

...RED FLAG WARNING IS CANCELLED FOR LOW RELATIVE HUMIDITY AND 
STRONG WINDS FOR NORTHERN ILLINOIS AND NORTHWEST INDIANA...

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS CANCELLED THE RED
FLAG WARNING.

SOUTHERLY WIND SPEEDS HAVE DIMINISHED AND SHOULD CONTINUE SUCH A
TREND THROUGH THE EVENING...WHILE HUMIDITY WILL GRADUALLY RISE.
THUS RED FLAG CONDITIONS ARE NO LONG PRESENT...AND THE RED FLAG
WARNING HAS BEEN CANCELLED.

GUSTY SOUTHERLY WINDS WILL AGAIN BE PRESENT BY MID MORNING ON
WEDNESDAY AND PERSIST THROUGH THE AFTERNOON. WHILE HUMIDITY VALUES
ARE EXPECTED TO BE SLIGHTLY HIGHER...MAINLY BETWEEN 30 AND 40
PERCENT...CONDITIONS FOR BURNING STILL MAY BE CHALLENGING.

$$

The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 20, 3:50 AM CDTSmall Craft AdvisoryLOT18 hr

Nearby

Red Flag Warnings in Illinois, 2012Red Flag Warnings in Indiana, 2012Every red flag warning in 2012

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.