Keith Reedy keithreedy@xxxxxxxxxxxx Begin forwarded message: > From: National Weather Service <nws.noaa@xxxxxxxxxxxxxxxxxxxxxxx> > Subject: NOAA's National Weather Service SPC Mesoscale Discussion Update > Date: September 21, 2012 2:42:57 PM EDT > To: keithreedy@xxxxxxxxxxxx > Reply-To: National Weather Service <nws.noaa@xxxxxxxxxxxxxxxxxxxxxxx> > > You are subscribed to SPC Mesoscale Discussion for NOAA's National Weather > Service. > > > SPC MD 1978 > 09/21/2012 02:37 PM EDT > > MD 1978 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR CNTRL IL...WCNTRL > IND > > > MESOSCALE DISCUSSION 1978 > NWS STORM PREDICTION CENTER NORMAN OK > 0136 PM CDT FRI SEP 21 2012 > > AREAS AFFECTED...CNTRL IL...WCNTRL IND > > CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE > > VALID 211836Z - 212000Z > > PROBABILITY OF WATCH ISSUANCE...60 PERCENT > > SUMMARY...AN ISOLATED SEVERE THREAT IS EXPECTED TO DEVELOP ACROSS > CNTRL IL INTO WRN IND THIS AFTERNOON. ISOLATED LARGE HAIL AND WIND > DAMAGE WILL INITIALLY BE THE MAIN THREAT. AN ISOLATED TORNADO THREAT > COULD ALSO DEVELOP LATER THIS AFTERNOON. WW ISSUANCE MAY BECOME > NECESSARY ACROSS THE REGION ONCE THE SCENARIO BEGINS TO UNFOLD. > > DISCUSSION...THUNDERSTORMS ARE CURRENTLY INITIATING AND INCREASING > IN INTENSITY JUST TO THE EAST OF A DEEPENING SFC LOW CENTERED OVER > NE MO. THE STORMS ARE LOCATED ON THE NERN EDGE OF INSTABILITY AND ON > THE NOSE OF A MID-LEVEL JET MOVING INTO THE REGION FROM THE WEST > NORTHWEST. THE STRONG MID-LEVEL FLOW ASSOCIATED WITH THE JET IS > CREATING FAVORABLE SHEAR PROFILES FOR SEVERE STORMS IN SPITE OF THE > WEAK INSTABILITY IN PLACE. THE WSR-88D VWP AT SPRINGFIELD IL > CURRENTLY SHOWS ABOUT 65 KT OF 0-6 KM SHEAR WITH SUBSTANTIAL VEERING > WITH HEIGHT FROM 2 TO 3 KM. THIS COULD SUPPORT A SUPERCELL THREAT AS > LOW-LEVEL MOISTURE ADVECTS NWD INTO THE MCD AREA AND INSTABILITY > INCREASES. 500 MB TEMPS OF -15 C TO -19C WILL BE SUPPORTIVE OF > ISOLATED LARGE HAIL WITH THE MORE INTENSE CORES. IN > ADDITION...LOW-LEVEL LAPSE RATES HAVE STEEPENED SOME ACROSS ECNTRL > IL INTO WRN IND AS SHOWN ON MESOSANALYSIS WITH 0-3 KM LAPSE RATES > NOW AROUND 7.0 C/KM. THIS ALONG WITH THE STRONG WIND FIELDS AT > LOW-LEVELS MAY SUPPORT AN ISOLATED WIND DAMAGE AS CELLS MATURE LATE > THIS AFTERNOON. AN ISOLATED TORNADO THREAT COULD ALSO DEVELOP > ESPECIALLY IF THE CELLS CAN ROTATE AND PERSIST. > > ..BROYLES/MEAD.. 09/21/2012 > > ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... > > ATTN...WFO...IWX...IND...PAH...LOT...ILX...LSX...DVN... > > LAT...LON 40548702 41378876 41728987 41669052 41169094 40539089 > 39348998 38558854 38778681 40548702 > > Read more > > > > > To change your subscriptions or preferences log in to your Subscriber > Preferences Page with your e-mail address. > > Delete profile > > For questions or problems with the subscription service, please contact > support@xxxxxxxxxxxxxxxx > > This service is provided by NOAA's National Weather Service. > > > > GovDelivery, Inc. (800-439-1420) sending to keithreedy@xxxxxxxxxxxx on behalf > of the National Weather Service · 1325 East West Highway · Silver Spring, MD > 20910