MESO: Mesoscale Discussion 1250

ACUS11 KWNS 221841
SWOMCD
SPC MCD 221841
ILZ000-MOZ000-IAZ000-221945-

MESOSCALE DISCUSSION 1250
NWS STORM PREDICTION CENTER NORMAN OK
0141 PM CDT FRI JUN 22 2007

AREAS AFFECTED...CNTRL/ERN IA...NERN AND N CNTRL MO...EXTREME W
CNTRL IL

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON

VALID 221841Z - 221945Z

ENVIRONMENTAL CONDITIONS HAVE BECOME FAVORABLE FOR SEVERE STORMS AND
A WATCH ISSUANCE WILL BE COORDINATED BETWEEN THE SPC AND THE
AFFECTED LOCAL NATIONAL WEATHER SERVICE OFFICES SHORTLY.

LOW LEVEL OUTFLOW BOUNDARY FROM EARLIER CONVECTION IS EVIDENT IN
VISIBLE SATELLITE IMAGERY FROM DALLAS CNTY IA SWD TO DECATUR CNTY IA
THEN SEWD INTO SULLIVAN CNTY MO CONTINUING TOWARD STL.
THUNDERSTORMS ARE BEGINNING TO INCREASE ALONG THE BNDRY FROM S CNTRL
IA INTO EXTREME N CNTRL.

CLEARING SKIES IN THE WAKE OF THE EARLIER MCS HAVE RESULTED IN
STRONG DIURNAL HEATING ACROSS SRN IA WITH TEMPERATURES RANGING FROM
THE MID 80S OVER SWRN IA TO THE LOW 80S IN SERN IA. DEW POINTS IN
THE UPPER 60S COUPLED WITH MODERATELY STEEP LAPSE RATES ARE
CONTRIBUTING TO UNSTABLE ENVIRONMENT WITH MLCAPE OF 1500-2000 J/KG.
WESTERLY MID LEVEL WINDS HAVE BEEN ENHANCED BY THE EARLIER MCS WITH
SLA PROFILER SHOWING 40-45 KT AROUND 5 KM AGL AND 40 KT OF DEEP
LAYER SHEAR IN THE LOWEST 6 KM. AS HEATING/DESTABILIZATION CONTINUE
THUNDERSTORMS ARE LIKELY TO FURTHER INTENSIFY THIS AFTERNOON...WITH
LARGE HAIL AND OCCASIONAL STRONG WIND GUSTS THE PRIMARY THREATS.

.WEISS.. 06/22/2007

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

ATTN...WFO...ILX...LSX...DVN...DMX...EAX...

39499273 39689341 40989410 42149420 42589394 42619276
42319144 41299086 39619029 39449085 39449202

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