AREAS AFFECTED...SERN MO...SWRN KY...SWRN IND...SRN/WRN IL
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 300008Z - 300215Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...A LINE OF TSTMS IS EXPECTED TO CONTINUE PROGRESSING
EWD...GRADUALLY INCREASING IN STRENGTH AS IT ENCOUNTERS A MORE
FAVORABLE ENVIRONMENT. PRIMARY THREAT IS DAMAGING WIND GUSTS BUT THE
STRENGTH OF THE SHEAR SUGGESTS A FEW BRIEF TORNADOES ARE POSSIBLE.
DISCUSSION...A WEAKLY FORCED LINE OF TSTMS CONTINUES TO MOVE EWD
FROM WRN IL AND SERN MO INTO CNTRL/SRN IL. SURFACE ANALYSIS SHOWS
THIS LINE OF STORMS IS WELL AHEAD OF THE COLD FRONT...WHICH IS
EXTENDS ACROSS NWRN IL SWWD ACROSS CNTRL MO AND INTO NERN AR.
DEWPOINTS OVER THE REGION ARE IN THE MID 50S WITH SURFACE
TEMPERATURES IN THE LOW 60S ACROSS W-CNTRL IL AND ERN IND AND IN THE
UPPER 60S ACROSS SERN MO...SRN IL...AND SWRN KY. DESPITE THESE
UNSEASONABLY WARM AND MOIST CONDITIONS...A WARM LAYER BETWEEN 850
AND 700 MB IS KEEPING THE OVERALL INSTABILITY VERY LOW /MLCAPE LESS
THAN 100 J PER KG/. AS A RESULT THIS ACTIVITY IS EXPECTED TO
GRADUALLY MOVE EWD WHILE MAINTAINING AT LEAST THE SAME INTENSITY AS
CURRENTLY OBSERVED. THE LOSS OF DIURNAL HEATING IS EXPECTED TO HAVE
LITTLE INFLUENCE AS STRENGTHENING LLJ COUNTERS ANY TEMPERATURE
DECREASE WITH WAA AND INCREASING LOW-LEVEL MOISTURE. GIVEN THE
CURRENT OBSERVED RADAR TRENDS AND FORECAST...ISOLATED GUSTY WINDS
ARE POSSIBLE AS THE LINE MERGES WITH CELLS DEVELOPING IN THE WAA
AHEAD OF IT. COVERAGE OF SVR WINDS IS UNCERTAIN AND A WW IS NOT
ANTICIPATED ACROSS NRN/CNTRL IL.
HOWEVER...STRENGTHENING CONVECTION ALONG OR JUST AHEAD OF THE FRONT
ACROSS NRN AR AND S-CNTRL MO IS EXPECTED TO MOVE EWD/NEWD INTO SWRN
MO...SRN IL...AND SWRN KY. THIS IS THE AREA WHERE SVR TSTMS ARE
EXPECTED TO DEVELOP DURING THE NEXT FEW HOURS. THE LLJ IS EXPECTED
TO STRENGTHEN...REACHING 70 KT AT 850 MB. 00Z LZK SOUNDING CONFIRMS
THIS WITH 70 KT REPORTED AT 850 MB AND 700 MB. RECENT RADAR TRENDS
HAVE SHOWN A STRENGTHENING TREND WITH THE DEVELOPMENT ACROSS SWRN
IL. A WW WILL LIKELY BE NEEDED AS STORMS MOVE INTO THIS AREA FROM
THE SW.
..MOSIER/HART.. 01/30/2013
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LMK...IND...PAH...LOT...ILX...MEG...LSX...
LAT...LON 39078959 39808913 40448859 40808803 40508710 39918669
38868682 37208711 36738788 36518897 36579047 36689093
37109078 37949022 39078959
