Alert archive / Illinois / Mesoscale Discussions in 2003

Mesoscale Discussion 2049

August 1, 200335 counties in Illinois; 5 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Aug 1, 2003, 5:49 PM CDT for 35 counties in Illinois; 5 counties in Iowa. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
Aug 1, 2003, 5:49 PM CDT (22:49 UTC)
Expired
Aug 1, 2003, 7:15 PM CDT
In force
86 min
Issued by
the Storm Prediction Center
All 40 counties

Des Moines County, IA, Henry County, IA, Lee County, IA, Louisa County, IA, Scott County, IA, Boone County, IL, Brown County, IL, Bureau County, IL, Cass County, IL, DeKalb County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Schuyler County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Woodford County, IL

The radar

The Lincoln radar (KILX), 87 km from the middle of the area, began a volume at 22:52 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, 10.8 hours before the alert went out and 103 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 2003-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1279 joules per kilogram.LCLLFCEL10008507005003002001001 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 2003-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 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
1279 J/kg
Mixed-layer CIN
-100 J/kg
Mixed-layer LCL
1232 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
56 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

994 
ACUS11 KWNS 012249
SWOMCD
SPC MCD 012249 
ILZ000-IAZ000-020015-

MESOSCALE DISCUSSION 2049
NWS STORM PREDICTION CENTER NORMAN OK
0549 PM CDT FRI AUG 01 2003

AREAS AFFECTED...FAR SERN IA/WRN AND NRN IL

CONCERNING...SEVERE THUNDERSTORM WATCH 824...

VALID 012249Z - 020015Z

CLUSTER OF STRONG CONVECTION OVER THE ERN PORTION OF WW 824 WILL
HAVE THE POTENTIAL FOR WIND DAMAGE AND/OR LARGE HAIL OVER THE NEXT
FEW HOURS.

ANALYSIS SHOWS A SFC LOW OVER LOWER MI AND A TRAILING WEAK COLD
FRONT ACROSS NRN IND AND NCNTRL IL. CONVECTION IS ONGOING ACROSS NRN
IL ALONG A BAND OF STRONG LOW-LEVEL CONVERGENCE EXTENDING SEWD INTO
CNTRL IND. THE LOW-LEVEL CONVERGENCE AND STRONG LARGE-SCALE LIFT
AHEAD OF SHORTWAVE TROUGH ACROSS WRN IL WILL HELP THE CONVECTION TO
REMAIN INTENSE OVER THE NEXT FEW HOURS. IN ADDITION...THE VERY
UNSTABLE AIR AHEAD THE CONVECTION WILL HELP SUSTAIN THE CONVECTION
AS IT MOVES ACROSS THE ERN PORTION OF WW 824. NEW CELLS DEVELOPING
ACROSS SERN IA WILL LIKELY MOVE INTO THE FAR WRN PORTION OF WW 824.
THE STRONG INSTABILITY AND 30 KT OF DEEP LAYER SHEAR ACROSS THE
REGION WILL ENHANCE THE POTENTIAL FOR LARGE HAIL AND/OR DAMAGING
WINDS.

..BROYLES.. 08/01/2003

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LOT...ILX...LSX...DVN...

39589063 40169133 40989176 41749051 42428892 41838812
40988771 40098931

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 31, 8:19 PM CDTMesoscale DiscussionSPCBoone, Carroll, Jo Daviess, Ogle, Stephenson, Winnebago116 min
Aug 1, 10:59 AM CDTMesoscale DiscussionSPCBureau, DeKalb, Ford, Fulton, Grundy, Henderson and 20 more2 hr
Aug 1, 2:00 PM CDTSevere Thunderstorm WatchSPCAdams, Boone, Brown, Bureau, Cass, DeKalb and 35 more6 hr
Aug 1, 2:58 PM CDTMesoscale DiscussionSPCAlexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 13 more2 hr
Aug 1, 3:20 PM CDTSevere Thunderstorm WatchSPCAlexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 13 more6 hr
Jul 31, 11:14 PM CDTMesoscale DiscussionSPCBenton, Black Hawk, Boone, Bremer, Buchanan, Butler and 13 more2 hr

Nearby

Mesoscale Discussions in Illinois, 2003Mesoscale Discussions in Iowa, 2003Every mesoscale discussion in 2003

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.