Shortwave still intact, Supercells possible
Posted by JAC on 6/8/2009, 1:24 pm
 MESOSCALE DISCUSSION 0987 NWS STORM PREDICTION CENTER NORMAN OK 1154 AM CDT MON JUN 08 2009 AREAS AFFECTED...NORTHERN/WEST CENTRAL IL INTO ADJACENT SOUTHERN WI/NORTHWEST INDIANA/EASTERN MO CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 081654Z - 081830Z SEVERE RISK MAY DEVELOP/INCREASE ACROSS NORTHERN/WEST CENTRAL IL AND ADJACENT PORTIONS OF SOUTHERN WI/NORTHWEST INDIANA/EASTERN MO THROUGH EARLY/MID AFTERNOON. WHEN INITIATION OF DEEP CONVECTION BECOMES APPARENT...A WATCH MAY BE NEEDED FOR PORTIONS OF THE REGION. WATER VAPOR IMAGERY FEATURES A NORTHEAST ADVANCING SHORTWAVE TROUGH OVER EASTERN IA AT MIDDAY...WITH ASSOCIATED MID LEVEL JET STREAK /50 KT AT 500 MB/ CROSSING THE MIDDLE MISSISSIPI VALLEY. ALTHOUGH THIS SHORTWAVE TROUGH WILL BEGIN TO SPREAD NORTHEASTWARD AWAY FROM THE REGION WITH POTENTIAL FOR LARGE SCALE HEIGHT RISES BY MID/LATE AFTERNOON...IT SEEMS PROBABLE THAT TSTMS WILL DEVELOP ALONG A SURFACE COLD FRONT/PREFRONTAL TROUGH ADVANCING INTO/ACROSS NORTHERN IL THIS AFTERNOON. WITH CLOUD COVER TENDING TO CLEAR ACROSS FAR EASTERN IA/NORTHERN IL AT MIDDAY...SOME SIGNS OF INCIPIENT DEEP CONVECTIVE DEVELOPMENT PER VISIBLE SATELLITE IMAGERY MAY ALREADY BE OCCURRING IN VICINITY OF THE COLD FRONT AND/OR SUBTLE PREFRONTAL TROUGH...AND OVERALL IT SEEMS PROBABLE THAT TSTMS SHOULD DEVELOP/INCREASE THROUGH EARLY/MID AFTERNOON. AS THE PREFRONTAL BOUNDARY LAYER CONTINUES TO HEAT/DESTABILIZE...AFOREMENTIONED MODERATELY STRONG MID LEVEL FLOW WOULD SUPPORT SUFFICIENT VERTICAL SHEAR FOR SOME SUPERCELLS AND WELL-ORGANIZED MULTICELLS. DAMAGING WINDS AND SEVERE HAIL SHOULD THE PRIMARY THREATS. WHILE AN ISOLATED TORNADO RISK CANNOT BE RULED OUT...WEAKENING/VEERING LOW LEVEL FLOW ACROSS THE WARM SECTOR SHOULD KEEP SUCH A THREAT LOW. THE TIMING/EXTENT OF THE SEVERE THREAT SEEMS A BIT MORE QUESTIONABLE WITH SOUTHWESTWARD EXTENT TO WEST CENTRAL IL/EASTERN MO...GIVEN EARLY DAY TSTMS/RESIDUAL CLOUD COVER...IN ADDITION TO BEING MORE REMOVED FROM THE INFLUENCE OF THE PARENT SHORTWAVE TROUGH. NEVERTHELESS...A SEVERE THREAT MAY INCREASE ACROSS THIS CORRIDOR LATER THIS AFTERNOON. ..GUYER.. 06/08/2009 |
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In this thread:
Possible Severe Weather for IL Monday - JAC, 6/5/2009, 1:48 pm
- Bigger squall-line heading toward Milwaukee - JAC, 6/8/2009, 3:36 pm
- Chicago could still be under-the-gun - JAC, 6/8/2009, 2:36 pm
- Re: Chicago could still be under-the-gun - JAC, 6/8/2009, 2:42 pm
- Looks like today is the big day before the shortwave deamplifies - JAC, 6/7/2009, 10:12 am
- Re: Possible Severe Weather for IL Monday - Cape_Fear_NC, 6/7/2009, 12:41 am
- Re: Possible Severe Weather for IL Monday - JAC, 6/7/2009, 8:59 am
- SREF throttles the shortwave back - JAC, 6/6/2009, 11:27 pm
- North IL / Chicago needs to pay attention - JAC, 6/5/2009, 1:57 pm
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