Back to Moderate Risk at 9:15 PM Weds.June 12th, 2013 at 12:36 pm by Bill Steffen under Bill's Blog, News, Weather
Back to a Moderate Risk as of 9:15 PM. Tornado Watch out for NE Iowa, NW Illinois, SW Wiscconsin. This is a PDS Tornado Watch – Particularly Dangerous Situation. Storms have started in NE Iowa. Next Watch east will be for SE WI, NE IL, SW MI and N. IN. Warm front and 70-degree dew points up to the Indiana border. Follow rapid satellite scans here. South of a line from Holland to Lansing looks to have very significant threat of wind damage. SPC says: “A SIGNIFICANT SEVERE WEATHER OUTBREAK APPEARS INCREASINGLY LIKELY ACROSS PORTIONS OF THE UPPER MIDWEST/LOWER GREAT LAKES FROM THIS AFTERNOON THROUGH THIS EVENING. INTENSE STORM DEVELOPMENT IN A VERY UNSTABLE AIRMASS…COINCIDENT WITH A COMPACT AND INTENSIFYING SURFACE LOW SHOULD RESULT IN NUMEROUS DAMAGING WIND EVENTS AS WELL AS SCATTERED…POSSIBLY STRONG TORNADOES…Potentially EXPLOSIVE Storm Development to occur….Potentially Strong Tornado Threat may be maximized…possible DERECHO…WRF-ARW SIMULATION TAKES THE APEX OF THE PROGRESSIVE MESOSCALE COMLEX FROM CHICAGO TO DETROIT IN UNDER 6 HOURS WITH A FORWARD SPEED IN EXCESS OF 50 MPH….SHEAR AND INSTABILITY WITHIN AND AHEAD OF THIS CONVECTION WILL REMAIN SUPPORTIVE OF BOTH HIGH WINDS, PROBABLY WELL IN EXCESS OF 70 MPH, AS WELL AS A FEW TORNADOES.” LINK TO DISCUSSION. Here’s specific probabilities of tornadoes, damaging winds and severe hail. This is the probability of a severe report within 25 miles of a point in that area. A 60% probability on wind damage is an extremely high probability for an SPC forecast.
From GRR NWS: “FLASH FLOOD WATCH BASED ON THE POTENTIAL FOR HEAVY RAIN WITH THE TROWAL FEATURE NORTH OF THE MAIN UPPER LEVEL WAVE AS IT COMES THROUGH TONIGHT. THE SPC SREF…THE 15Z HRRR AND THE 15Z ESRL RAP MODELS ALL SHOW 2 TO 3 INCHES OF RAIN TONIGHT JUST SOUTH OF INTERSTATE 96. GIVEN THE CONVECTIVE NATURE OF THE EVENT IT WOULD SEEM REASONABLE THAT FLASH FLOODING IS POSSIBLE IN THIS AREA.”
Tornado Watch likely for S. Michigan with the most likely time for storms in the 5 PM to 10 PM range. Eastern Iowa likely to see explosive thunderstorm development between 2:45 and 4 PM EDT. People are taking this seriously: “Magic Waters, the large water park in the Rockford, Illinois Area, will be closing at 1:30 CDT due to the threat of severe weather.
Check out Regional radar to see the rain across the Great Lakes. Here’s GRR radar, local lightning data, meso-discussions and current watches from SPC and a satellite loop. Here’s current Michigan temperatures, National lightning data and the latest discussion from GRR NWS. Here’s National Storm Reports for today and yesterday. Here’s a live pic. of the beach at Grand Haven, Here’s the latest Grand Rapids NWS discussion. Here’s radar from Chicago, Milwaukee, E IA and NW IL and N. Indiana.
Your friends in the high and moderate risk areas need to be aware of the potential for significant wind damage. Please forward the link to the blog and watch for updates on WOOD-TV. We may start streaming coverage later tonight online. In my view, the greatest threat remains in N. IL, N. IN with a significant threat along and south of I-94. See links in the threads below this one.