Alert archive / Illinois / Mesoscale Discussions in 2017
Mesoscale Discussion 577
The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2017, 1:10 PM CDT for 4 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 28, 2017, 1:10 PM CDT (18:10 UTC)
- Expired
- Apr 28, 2017, 3:15 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 60%
All 96 counties
Alexander County, IL, Bond County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jasper County, IL, Jefferson County, IL, Jersey County, IL, Johnson County, IL, Lawrence County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Massac County, IL, Monroe County, IL, Montgomery County, IL, Perry County, IL, Pope County, IL, Pulaski County, IL, Randolph County, IL, Richland County, IL, Saint Clair County, IL, Saline County, IL, Shelby County, IL, Union County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Brown County, IN, Clay County, IN, Crawford County, IN, Daviess County, IN, Dubois County, IN, Floyd County, IN, Gibson County, IN, Greene County, IN, Harrison County, IN, Jackson County, IN, Jennings County, IN, Knox County, IN, Lawrence County, IN, Martin County, IN, Monroe County, IN, Orange County, IN, Owen County, IN, Perry County, IN, Pike County, IN, Posey County, IN, Scott County, IN, Spencer County, IN, Sullivan County, IN, Vanderburgh County, IN, Vigo County, IN, Warrick County, IN, Washington County, IN, Ballard County, KY, Breckinridge County, KY, Crittenden County, KY, Daviess County, KY, Hancock County, KY, Henderson County, KY, Livingston County, KY, McLean County, KY, Meade County, KY, Union County, KY, Webster County, KY, Bollinger County, MO, Cape Girardeau County, MO, City of Saint Louis, MO, Franklin County, MO, Iron County, MO, Jefferson County, MO, Madison County, MO, Perry County, MO, Reynolds County, MO, Saint Charles County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Scott County, MO, Warren County, MO, Washington County, MO, Wayne County, MO
The nearest sounding before it
Lincoln, IL (KILX), launched 12:00Z, 6.2 hours before the alert went out and 207 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 912 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 114 m²/s²
- 0-3 km storm-relative helicity
- 218 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
549
ACUS11 KWNS 281811
SWOMCD
SPC MCD 281810
INZ000-KYZ000-ILZ000-MOZ000-282015-
Mesoscale Discussion 0577
NWS Storm Prediction Center Norman OK
0110 PM CDT Fri Apr 28 2017
Areas affected...southeast Missouri and into southern portions of
Illinois and Indiana and vicinity
Concerning...Severe potential...Watch possible
Valid 281810Z - 282015Z
Probability of Watch Issuance...60 percent
SUMMARY...Elevated storms developing over the southeast Missouri
vicinity should gradually increase in coverage, and pose a severe
risk -- mainly in the form of large hail. WW may be required in the
next 1-2 hours.
DISCUSSION...Latest radar loop shows storms increasing across the
southeast MO vicinity, likely associated with a zone of ascent
associated with a weak/subtle wave evident in water vapor imagery
moving northeast across eastern portions of KS/OK and into MO at
this time. A slow increase in storm coverage and intensity is
expected over the next few hours given gradual mid-level
destabilization in conjunction with the existing, amply sheared
environment (and as hinted at by visible imagery and the latest HRRR
runs). As such, we will continue to monitor convective evolution
and need for a possible WW. Though risk would likely remain
primarily hail, any storm development farther south -- i.e. nearer
the warm front -- would require additional attention, with respect
to possible surface-based severe risk. While capping (with respect
to a surface-based parcel) is expected to persist, we continue to
monitor areas near/south of the boundary as well -- i.e. eastward
across western and into central KY and vicinity.
..Goss/Grams.. 04/28/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ILN...LMK...IND...PAH...ILX...LSX...SGF...
LAT...LON 39058532 37718639 36908941 36938989 37319125 38759124
39308992 39628745 39058532SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 28, 4:59 PM CDT | Mesoscale Discussion | SPC | Massac | 91 min |
| Apr 28, 6:28 PM CDT | Mesoscale Discussion | SPC | Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more | 3 hr |
| Apr 28, 5:48 PM CDT | Mesoscale Discussion | SPC | Bartholomew, Boone, Brown, Clark, Clay, Daviess and 35 more | 117 min |
| Apr 28, 2:33 PM CDT | Mesoscale Discussion | SPC | Adair, Allen, Anderson, Barren, Bourbon, Boyle and 44 more | 87 min |
Nearby
Mesoscale Discussions in Illinois, 2017Mesoscale Discussions in Indiana, 2017Mesoscale Discussions in Missouri, 2017Every mesoscale discussion in 2017
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.