Alert archive / Illinois / Mesoscale Discussions in 2012
Mesoscale Discussion 1753
The Storm Prediction Center issued this mesoscale discussion at Aug 13, 2012, 3:15 PM CDT for 7 states. It was in force for 30 min.
The area
The outline as issued.
The facts
- Issued
- Aug 13, 2012, 3:15 PM CDT (20:15 UTC)
- Expired
- Aug 13, 2012, 3:45 PM CDT
- In force
- 30 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 95%
All 93 counties
Arkansas County, AR, Ashley County, AR, Bradley County, AR, Chicot County, AR, Crittenden County, AR, Cross County, AR, Desha County, AR, Drew County, AR, Lee County, AR, Lincoln County, AR, Mississippi County, AR, Monroe County, AR, Phillips County, AR, Poinsett County, AR, St. Francis County, AR, Alexander County, IL, Edwards County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jefferson County, IL, Johnson County, IL, Massac County, IL, Perry County, IL, Pope County, IL, Pulaski County, IL, Saline County, IL, Union County, IL, Wabash County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Gibson County, IN, Pike County, IN, Posey County, IN, Vanderburgh County, IN, Ballard County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Crittenden County, KY, Fulton County, KY, Graves County, KY, Henderson County, KY, Hickman County, KY, Livingston County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, Union County, KY, Webster County, KY, Cape Girardeau County, MO, Dunklin County, MO, Mississippi County, MO, New Madrid County, MO, Pemiscot County, MO, Scott County, MO, Stoddard County, MO, Benton County, MS, Bolivar County, MS, Carroll County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Humphreys County, MS, Lafayette County, MS, Leflore County, MS, Marshall County, MS, Panola County, MS, Quitman County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tunica County, MS, Washington County, MS, Yalobusha County, MS, Carroll County, TN, Crockett County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Haywood County, TN, Henry County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN
The radar
The Memphis radar (KNQA), 59 km from the middle of the area, began a volume at 20:16 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Little Rock, AR (KBYH), launched 12:00Z, 8.3 hours before the alert went out and 116 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
- 1586 J/kg
- Mixed-layer CIN
- -113 J/kg
- Mixed-layer LCL
- 909 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 163 m²/s²
- 0-3 km storm-relative helicity
- 211 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 8.0
The text
As transmitted, in the capitals the NWS used until 2016.
376
ACUS11 KWNS 132015
SWOMCD
SPC MCD 132015
INZ000-KYZ000-TNZ000-ILZ000-MSZ000-MOZ000-ARZ000-132045-
MESOSCALE DISCUSSION 1753
NWS STORM PREDICTION CENTER NORMAN OK
0315 PM CDT MON AUG 13 2012
AREAS AFFECTED...FAR SERN MO/SRN IL/FAR SWRN IND/WRN KY/WRN TN/ERN
AR/NWRN MS
CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY
VALID 132015Z - 132045Z
PROBABILITY OF WATCH ISSUANCE...95 PERCENT
SUMMARY...A SVR TSTM WATCH IS LIKELY FOR PARTS OF THE MID MS VALLEY
SWD TO THE MID SOUTH /ERN AR INTO NWRN MS/. TSTMS WILL CONTINUE TO
DEVELOP ALONG A COLD FRONT IN FAR SWRN IL AND ADJACENT SERN MO SWWD
INTO PARTS OF ERN AR THIS AFTERNOON. STRONGER ACTIVITY WILL BE
CAPABLE OF PRODUCING AT LEAST ISOLATED STRONG WIND GUSTS AND HAIL.
DISCUSSION...AT 20Z...VISIBLE SATELLITE IMAGERY AND TRENDS IN
SURFACE OBSERVATIONS INDICATED A COLD FRONT TRAILING SSWWD FROM AN
AREA OF LOW PRESSURE IN SRN IL THROUGH SERN MO TO NERN-EAST CENTRAL
AR TO SWRN AR. HEATING IN THE WAKE OF MORNING CONVECTION/CLOUDINESS
HAS ALLOWED THE AIR MASS TO BECOME STRONGLY UNSTABLE WITH MLCAPE
RANGING FROM 1000 J/KG OVER SRN IL TO 3000 J/KG OVER SERN AR.
DESPITE THE WEAKER CAPE WITH NWD EXTENT...THE PRESENCE OF STRONGER
FORCING AND SHEAR ACROSS SERN MO/SRN IL ARE EXPECTED TO COMPENSATE
AND SUPPORT STORM ORGANIZATION AS CONVECTIVE INITIATION OCCURS.
MEANWHILE...FARTHER S...THE BULK SHEAR IS WEAKER /LESS THAN 30
KT/...BUT GREATER INSTABILITY WILL PROVE SUFFICIENT IN PROMOTING
ROBUST UPDRAFTS WITH THE AVAILABLE SHEAR RESULTING IN MULTICELL
STORMS. OBJECTIVE ANALYSES SUGGESTED SURFACE BASED INHIBITION HAS
ALL BUT ERODED ACROSS THE DISCUSSION AREA AND ALONG THE COLD FRONT
WITH TSTM DEVELOPMENT ALREADY UNDERWAY IN ARKANSAS/POINSETT COUNTIES
AR.
..PETERS/CARBIN.. 08/13/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...OHX...IND...PAH...MEG...JAN...LSX...LZK...SHV...
LAT...LON 38478916 38588752 38498718 35918838 33248979 33039096
33079150 33319248 34019208 35019118 35999051 36499025
38138958 38478916SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 12, 10:26 PM CDT | Mesoscale Discussion | SPC | Crawford, Franklin, Howard, Little River, Logan, Montgomery and 5 more | 94 min |
| Aug 12, 10:49 PM CDT | Severe Thunderstorm Watch | SPC | Benton, Boone, Carroll, Conway, Crawford, Franklin and 16 more | 5 hr |
| Aug 13, 1:45 AM CDT | Mesoscale Discussion | SPC | Arkansas, Baxter, Benton, Boone, Carroll, Cleburne and 36 more | 2 hr |
| Aug 13, 7:48 AM CDT | Mesoscale Discussion | SPC | Ashley, Bradley, Chicot, Cleveland, Desha, Drew | 87 min |
| Aug 13, 3:32 PM CDT | Severe Thunderstorm Watch | SPC | Arkansas, Chicot, Crittenden, Cross, Desha, Drew and 7 more | 7 hr |
| Aug 13, 12:38 PM CDT | Severe Thunderstorm Watch | SPC | Wayne | 4 hr |
| Aug 13, 5:14 PM CDT | Mesoscale Discussion | SPC | Alcorn, Attala, Benton, Calhoun, Carroll, Chickasaw and 20 more | 91 min |
| Aug 13, 12:21 PM CDT | Mesoscale Discussion | SPC | Franklin, Grundy, Lincoln, Moore | 24 min |
| Aug 13, 3:49 PM CDT | Mesoscale Discussion | SPC | Bledsoe, Bradley, Hamilton, Marion, Meigs, Rhea and 1 more | 56 min |
Nearby
Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Mississippi, 2012Mesoscale Discussions in Arkansas, 2012Every mesoscale discussion 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.