Alert archive / Illinois / Blizzard Watches in 2009

Blizzard Watch 2, NWS Chicago, IL

January 12, 200916 counties in Illinois; 5 counties in Indiana

NWS Chicago, IL issued this blizzard watch at Jan 12, 2009, 3:40 PM CST for 16 counties in Illinois; 5 counties in Indiana. It took effect at Jan 14, 2009, 12:00 PM CST. It was in force for .

The area

The counties it named.

The facts

Issued
Jan 12, 2009, 3:40 PM CST (21:40 UTC)
In effect from
Jan 14, 2009, 12:00 PM CST
Expired
Jan 13, 2009, 10:48 AM CST
In force
Issued by
NWS Chicago, IL
All 21 counties

Boone 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, Winnebago County, IL, Benton County, IN, Jasper County, IN, Lake County, IN, Newton County, IN, Porter County, IN

The radar

The Chicago radar (KLOT), 15 km from the middle of the area, began a volume at 21:43 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

Davenport, (KDVN), launched 12:00Z, 9.7 hours before the alert went out and 190 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 2009-01-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 joules per kilogram.LCLEL10008507005003002001001 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 2009-01-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 0 square meters per square second.1939Sfc1 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
1 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
484 m above ground
0-6 km bulk shear
0 kt
0-1 km storm-relative helicity
0 m²/s²
0-3 km storm-relative helicity
0 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 12, 4:21 AM CSTBlizzard WatchLOTBoone, DeKalb, DuPage, Grundy, Kane, Kendall and 6 more7 hr
Jan 12, 4:21 AM CSTWinter Weather AdvisoryLOTBoone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more28 hr
Jan 12, 4:33 AM CSTGale WarningLOT34 hr
Jan 12, 4:33 AM CSTHeavy Freezing Spray WarningLOT34 hr
Jan 12, 11:49 AM CSTBlizzard WarningLOTBoone, DeKalb, DuPage, Grundy, Kane, Kendall and 6 more16 hr

Nearby

Blizzard Watches in Illinois, 2009Blizzard Watches in Indiana, 2009Every blizzard watch in 2009

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.