Mesoscale Discussion 1847

Issued

Aug 31, 2012, 6:01 PM CDT (23:01 UTC)

Expired

Aug 31, 2012, 7:30 PM CDT

In force

89 min

Issued by

the Storm Prediction Center

The St Louis radar (KLSX), 102 km from the middle of the area, began a volume at 23:00 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.

036 
ACUS11 KWNS 312302
SWOMCD
SPC MCD 312301
ILZ000-KYZ000-TNZ000-MOZ000-ARZ000-010030-

MESOSCALE DISCUSSION 1847
NWS STORM PREDICTION CENTER NORMAN OK
0601 PM CDT FRI AUG 31 2012

AREAS AFFECTED...NE AR...ERN MO...IL...WRN KY AND WRN TN

CONCERNING...TORNADO WATCH 600...601...

VALID 312301Z - 010030Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 600...601...CONTINUES.

SUMMARY...A TORNADO THREAT WILL LIKELY CONTINUE ACROSS ERN MO AND
SCNTRL IL THIS EVENING. ISOLATED WIND DAMAGE WILL ALSO BE POSSIBLE
WITH THE MORE ORGANIZED LINE SEGMENTS.

DISCUSSION...SEVERAL LINES OF STRONG THUNDERSTORMS ARE ONGOING IN
THE MID MS VALLEY. THE FIRST LINE IS LOCATED JUST TO THE SOUTH OF
SPRINGFIELD IL ALONG AN AXIS OF MODERATE INSTABILITY WHERE MLCAPE
VALUES ARE ESTIMATED IN THE 1000 TO 1500 J/KG RANGE. A SECOND LINE
EXTENDS SEWD FROM THE ST LOUIS AREA AND IS LOCATED ON THE WRN EDGE
OF MODERATE INSTABILITY. THE SECOND LINE IN FAR ERN MO NEAR THE MS
RIVER IS ALSO LOCATED NEAR THE ERN EDGE OF A 40 TO 55 KT LOW-LEVEL
JET WHICH IS HELPING TO CREATE SHEAR PROFILES FAVORABLE FOR
TORNADOES. THE WSR-88D VWP AT ST LOUIS CURRENTLY SHOWS 0-1 KM SHEAR
AROUND 30 KT WITH STRONGLY BACKED FLOW AT THE SFC. THIS WIND SHEAR
ENVIRONMENT SHOULD CONTINUE TO SUPPORT ROTATING STORMS WITH TORNADO
POTENTIAL. THE GREATEST TORNADO THREAT OVER THE NEXT FEW HOURS
SHOULD EXIST IN SRN IL AS THE LINE MOVES INTO A MORE UNSTABLE
AIRMASS TO THE EAST WHERE THE COMBINATION OF SHEAR AND INSTABILITY
APPEAR TO BE MAXIMIZED.

..BROYLES.. 08/31/2012

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

ATTN...WFO...PAH...LOT...ILX...MEG...LSX...LZK...SGF...

LAT...LON   35459006 35469098 35869101 35919136 36279127 36329127
            36509144 36509110 36819111 36839122 37069120 37089100
            37529128 37629113 37699116 37739132 37809130 37799145
            38129148 38189161 39129161 39149143 39429146 39579120
            39779143 39769094 40279090 40259048 40179042 40169023
            40438989 40428975 40358973 40318851 40408844 40398796
            38868792 38878820 38628823 38598874 37378874 37358895
            36628880 36418883 36398893 36268895 36198913 35938924
            35868938 35578952 35618983 35459006

Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Missouri, 2012Mesoscale Discussions in Arkansas, 2012Every mesoscale discussion in 2012

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.