MESO: Mesoscale Discussion 0549

ACUS11 KWNS 240008
SWOMCD
SPC MCD 240008
ILZ000-240145-

MESOSCALE DISCUSSION 0549
NWS STORM PREDICTION CENTER NORMAN OK
0708 PM CDT THU APR 23 2009

AREAS AFFECTED...WEST CENTRAL IL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 240008Z - 240145Z

ISOLATED STRONG WIND GUSTS AND HAIL WILL BE POSSIBLE WITH THE
STRONGER STORMS THAT DEVELOP AND MOVE ENEWD ACROSS WEST CENTRAL IL
DURING THE EARLY EVENING.

AT 00Z...REGIONAL RADARS INDICATED SEVERAL CLUSTERS OF TSTMS
EXTENDING FROM HENDERSON/NRN HANCOCK COUNTIES IL TO STARK AND PEORIA
COUNTIES IL. STRONGEST LOW LEVEL CONVERGENCE PER OBJECTIVE ANALYSIS
WAS LOCATED ALONG THE WEST CENTRAL IL BORDER REGION WITH NERN MO
WHERE A SURFACE ANALYSIS INDICATED AN APPARENT MESO-LOW IN THIS
REGION...WHILE A BOUNDARY EXTENDED SEWD INTO FAR SRN IL. LOW LEVEL
CONVERGENCE ACROSS FAR NERN MO/WEST CENTRAL IL COUPLED WITH FORCING
FOR ASCENT CONFINED TO COMPACT MID LEVEL MCV IS RESULTING IN
STRONGEST TSTM INTENSITY WITH NEWEST ACTIVITY THAT DEVELOPS OVER FAR
WEST CENTRAL IL. LOW LEVEL MOISTURE/WAA MAXIMIZED ALONG THE NOSE OF
A 40-45 KT SSWLY LLJ IS FEEDING THE ACTIVITY FROM THE SW WHERE THE
AIR MASS IS MODERATELY UNSTABLE. THESE STORMS ARE LIKELY ELEVATED
GIVEN PRESENCE OF STRONG INHIBITION PER OBJECTIVE ANALYSES.

TSTMS THAT CONTINUE TO DEVELOP ALONG THE WRN PERIPHERY OF THIS
SYSTEM SHOULD BE THE STRONGEST GIVEN PROXIMITY TO GREATER
INSTABILITY FEED. EFFECTIVE BULK SHEAR OF 50-65 KT WILL SUPPORT
STORM ORGANIZATION. STEEP MID LEVEL LAPSE RATES /7-7.5 C/KM/ SHOULD
SUPPORT ISOLATED HAIL WITH THE STRONGER ACTIVITY...WITH LOCALIZED
STRONGER WIND GUSTS...GIVEN LINEAR STRUCTURE TO TSTM CLUSTERS. A
WEAKENING TREND WILL OCCUR AS STORMS MOVE FARTHER ENEWD INTO NORTH
CENTRAL IL WHERE SURFACE BASED INHIBITION IS GREATER AND INSTABILITY
WEAKER.

..PETERS.. 04/24/2009

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

ATTN...WFO...ILX...DVN...

LAT...LON 40619110 40949081 41099012 40998974 40488982 40319025
40379079 40469103 40619110

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