MESO: Mesoscale Discussion 1530

ACUS11 KWNS 262123
SWOMCD
SPC MCD 262123
ILZ000-WIZ000-262330-

MESOSCALE DISCUSSION 1530
NWS STORM PREDICTION CENTER NORMAN OK
0423 PM CDT FRI JUL 26 2013

AREAS AFFECTED...PORTIONS OF WRN/NRN IL AND FAR SRN WI

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 262123Z - 262330Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...A FEW STORMS MAY PRODUCE STRONG TO MARGINALLY SVR WIND
GUSTS DURING THE NEXT FEW HOURS. WHILE CONVECTIVE TRENDS WILL BE
MONITORED...THE ISSUANCE OF A WW IS CURRENTLY UNLIKELY.

DISCUSSION...THUNDERSTORMS CONTINUE TO BE MAINTAINED ALONG AND
IMMEDIATELY AHEAD OF A COLD FRONT THAT ARCS FROM S-CNTRL WI INTO
NWRN IL AND NERN MO. THE AIR MASS AHEAD OF THIS FRONT IS ONLY
MARGINALLY UNSTABLE OWING TO RELATIVELY COOL SFC TEMPERATURES
ASSOCIATED WITH WIDESPREAD CLOUD COVERAGE/EARLIER PRECIPITATION.
HOWEVER...LOT VWP DATA INDICATE AROUND 25-30 KT OF UNIDIRECTIONAL
FLOW THROUGH THE CLOUD LAYER BELOW 5 KM AGL. AND...WITH AT LEAST
MODEST DEEP SHEAR ACCOMPANYING THE ENHANCED MID-LEVEL FLOW...ALONG
WITH AT LEAST SOME INSTABILITY BEING MAINTAINED IN ASSOCIATION WITH
DCVA ATTENDANT TO A MID-LEVEL SHORTWAVE IMPULSE CROSSING THE
REGION...ORGANIZED CONVECTIVE CLUSTERS INCLUDING MULTICELLS MAY
ENSUE. A FEW INSTANCES OF MARGINALLY SVR WIND GUSTS CANNOT BE RULED
OUT. HOWEVER...THE SPATIOTEMPORAL EXTENT OF SUCH POTENTIAL WILL BE
LIMITED...AS STORMS LIKELY OUTRUN ANY SUBSTANTIVE PRE-FRONTAL
INSTABILITY IN THE NEXT FEW HOURS AS THEY ADVANCE INTO ERN IL WHERE
CLOUDS ARE MORE WIDESPREAD/OPAQUE. IN THE MEANTIME...INSTABILITY IS
EXPECTED TO BE TOO LIMITED FOR A MORE SUBSTANTIAL SVR THREAT TO
EVOLVE.

..COHEN/BROYLES.. 07/26/2013

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

ATTN...WFO...LOT...ILX...MKX...LSX...DVN...

LAT...LON 42298964 43018877 43048803 42568790 41528840 40248959
39689061 40179132 41279037 42298964

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