Alert archive / Missouri / Mesoscale Discussions in 2005

Mesoscale Discussion 607

April 20, 200519 counties in Illinois; 36 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2005, 1:52 PM CDT for 19 counties in Illinois; 36 counties in Missouri. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
Apr 20, 2005, 1:52 PM CDT (18:52 UTC)
Expired
Apr 20, 2005, 3:45 PM CDT
In force
113 min
Issued by
the Storm Prediction Center
All 55 counties

Adams County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Fulton County, IL, Greene County, IL, Hancock County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Mason County, IL, McDonough County, IL, Menard County, IL, Monroe County, IL, Morgan County, IL, Pike County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, Camden County, MO, City of Saint Louis, MO, Cole County, MO, Cooper County, MO, Crawford County, MO, Dallas County, MO, Dent County, MO, Franklin County, MO, Gasconade County, MO, Howard County, MO, Jefferson County, MO, Laclede County, MO, Lewis County, MO, Lincoln County, MO, Maries County, MO, Marion County, MO, Miller County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Morgan County, MO, Osage County, MO, Phelps County, MO, Pike County, MO, Pulaski County, MO, Ralls County, MO, Randolph County, MO, Saint Charles County, MO, Saint Louis County, MO, Shelby County, MO, Texas County, MO, Warren County, MO, Washington County, MO

The radar

The St Louis radar (KLSX), 83 km from the middle of the area, began a volume at 18:55 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, 6.9 hours before the alert went out and 264 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 2005-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 107 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 2005-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 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
107 J/kg
Mixed-layer CIN
-174 J/kg
Mixed-layer LCL
1360 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
37 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.

000 
ACUS11 KWNS 201852
SWOMCD
SPC MCD 201852 
ILZ000-MOZ000-IAZ000-202045-

MESOSCALE DISCUSSION 0607
NWS STORM PREDICTION CENTER NORMAN OK
0152 PM CDT WED APR 20 2005

AREAS AFFECTED...ERN MO/WCNTRL IL

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 201852Z - 202045Z

THREAT FOR ISOLD SEVERE WIND/HAIL INCREASING ACROSS ERN MO INTO
WCNTRL IL. ALTHOUGH NOT CURRENTLY ANTICIPATED...WILL CONTINUE TO
MONITOR TRENDS FOR POSSIBLE WW.

ORGANIZED MCS CONTINUES TO PROPAGATE SEWD AT AROUND 25 KTS ACROSS
ECNTRL MO...ALONG A LINE FROM WEST OF QUINCY IL TO NEAR COLUMBIA MO.
AHEAD OF THIS MCS...DOWNSTREAM AIRMASS CHARACTERIZED BY MODERATE
INSTABILITY...WITH UPPER 70S/LOWER 80S TEMPS CONTRIBUTING TO 
1000-1500 J/KG MLCAPE AMIDST NEGLIGIBLE CINH BASED UPON RUC
PROXIMITY SOUNDINGS. IN SPITE OF RATHER WEAK VERTICAL SHEAR /DEEP
LAYER SHEAR 20 KTS OR LESS/...ORGANIZATION OF MCS AND MODEST SWLY
INFLOW WILL CONTINUE TO SUPPORT PROPAGATION THROUGH MODERATELY
UNSTABLE AIRMASS...WITH THREAT FOR AT LEAST ISOLD DAMAGING
WINDS/LARGE HAIL THROUGH THE AFTERNOON.

..GUYER.. 04/20/2005

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

ATTN...WFO...ILX...LSX...DVN...SGF...EAX...

40479135 40639036 39998957 38189001 37169141 37559310
38649320 39579240

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 20, 12:21 PM CDTMesoscale DiscussionSPCChampaign, Douglas, Ford, Iroquois, Piatt, Vermilion114 min
Apr 20, 5:07 PM CDTMesoscale DiscussionSPCClinton, Franklin, Jackson, Jefferson, Madison, Monroe and 5 more113 min

Nearby

Mesoscale Discussions in Missouri, 2005Mesoscale Discussions in Illinois, 2005Every mesoscale discussion in 2005

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.