tornadotony Posted July 13, 2015 Share Posted July 13, 2015 Extended 10% TOR/hatched probs farther north though... Definitely a much-needed step in the right direction. Link to comment Share on other sites More sharing options...
cyclone77 Posted July 13, 2015 Share Posted July 13, 2015 ..SUMMARY MULTIPLE ROUNDS OF SEVERE THUNDERSTORMS CAPABLE OF DAMAGING WINDS...TORNADOES AND LARGE HAIL ARE LIKELY TODAY AND TONIGHT ACROSS MUCH OF THE MIDWEST...BUT ESPECIALLY ACROSS PORTIONS OF ILLINOIS...INDIANA...AND KENTUCKY. ..IND/OH/KY/TN A LARGE BOWING MCS IS TRACKING SOUTH-SOUTHEASTWARD ACROSS CENTRAL IND. THIS SYSTEM WILL PROGRESS INTO CENTRAL KY AND EVENTUALLY INTO MIDDLE/EASTERN TN. A VERY MOIST/UNSTABLE AIR MASS IS PRESENT AHEAD OF THE STORMS...ALONG WITH INCREASING WINDS ALOFT. PRESENT CONDITIONS SUGGEST STORMS MAY INTENSIFY INTO A LONG-LIVED AND DAMAGING BOW ECHO WITH THE RISK OF WIDESPREAD DAMAGING WINDS /DERECHO/. HAVE ADJUSTED THE MDT RISK TO INCLUDE MUCH OF CENTRAL KY AHEAD OF THIS ACTIVITY. ..WI/IA/IL AND WESTERN IND/KY THE OUTFLOW BOUNDARY FROM THE AFOREMENTIONED MCS CURRENTLY EXTENDS ACROSS CENTRAL IL INTO EASTERN IA. VISIBLE SATELLITE IMAGERY SHOWS STRONG HEATING IS COMMENCING OVER NORTHERN IL AND SOUTHERN WI ON THE COOL SIDE OF THE BOUNDARY. SURFACE WINDS HAVE ALREADY SHOWN SOME SIGN OF VEERING BACK TO SOUTHWESTERLY IN THIS REGION...SUGGESTING THAT A MOIST AND EXTREMELY UNSTABLE AIR MASS WILL RE-DEVELOP. MOST 12Z MODELS DID NOT INITIALIZE THE LOCATION OF THE OUTFLOW BOUNDARY...LENDING UNCERTAINTY TO PLACEMENT OF CONVECTIVE INITIATION LATER TODAY. CURRENT THINKING IS THAT RAPID CONVECTIVE DEVELOPMENT WILL OCCUR BY MID/LATE AFTERNOON OVER SOUTHERN WI/NORTHERN IL. RARE COMBINATIONS OF EXTREME INSTABILITY AND FAVORABLE VERTICAL SHEAR SUGGEST A RISK OF INTENSE SUPERCELLS CAPABLE OF VERY LARGE HAIL AND A FEW TORNADOES. THIS ACTIVITY WILL LIKELY CONGEAL INTO ANOTHER FAST-MOVING BOW ECHO THIS EVENING AND TRACK ACROSS PARTS OF IL/IND. ..HART/MOSIER.. 07/13/2015 Looks about how I was thinking. They properly returned the enhanced into Chicago, and also upped tor probs there as well. Link to comment Share on other sites More sharing options...
MattPetrulli Posted July 13, 2015 Share Posted July 13, 2015 They really should of upgraded to a 15% Link to comment Share on other sites More sharing options...
jojo762 Posted July 13, 2015 Share Posted July 13, 2015 HRRR is doing terrible with current MCS, and shows meh redevelopment later. Disregard it and don't even look at it. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted July 13, 2015 Share Posted July 13, 2015 IWX Update: UPDATE ISSUED AT 1131 AM EDT MON JUL 13 2015 GROWING CONCERN FOR SIGNIFICANT SEVERE WEATHER THIS AFTERNOON...MAINLY SOUTH OF US 30. TEMPERATURES HAVE ALREADY JUMPED INTO THE UPPER 70S ACROSS NORTHERN ILLINOIS IN THE WAKE OF MORNING CONVECTION. EXPECT TEMPERATURES TO RISE QUICKLY IN OUR AREA BY EARLY AFTERNOON. FULL SUN FOR SEVERAL HOURS AND EFFICIENT EVAPOTRANSPORATION SHOULD RESULT IN MODERATE TO EXTREME DESTABILIZATION ALONG AND WEST OF A MICHIGAN CITY TO FORT WAYNE LINE. LAST FEW RUNS OF THE HRRR HAVE SUPPORTED THIS THINKING WITH STORMS DEVELOPING ALONG THIS FRONT BY LATE AFTERNOON. IF STORMS DEVELOP IN THAT ENVIRONMENT...SUPERCELLS WILL BE THE PRIMARY STORM MODE WITH 0-6 KM SHEAR IN EXCESS OF 50 KNOTS...STEEP MID LEVEL LAPSE RATES...AND SIGNIFICANT TURNING OF THE WINDS WITH HEIGHT. TORNADOES WILL ALSO BE POSSIBLE IN THIS SCENARIO GIVEN SOUTHERLY SURFACE WINDS AND AN INCREASINGLY STRONG LOW LEVEL JET FROM THE WEST. MAY NEED TO ADD SEVERE WORDING TO THE GRIDS WITHIN THE NEXT FEW HOURS IF DESTABILIZATION BEGINS AS EXPECTED. Link to comment Share on other sites More sharing options...
jojo762 Posted July 13, 2015 Share Posted July 13, 2015 They really should of upgraded to a 15% Best guess is that could happen at 20Z if it becomes evident that the tornado/supercell threat is realized, lots of uncertainty right now due to the models being a mess. A 10% chance for seeing a tornado within 25 miles of any point is still pretty high when you think about it... Link to comment Share on other sites More sharing options...
Central Illinois Posted July 13, 2015 Share Posted July 13, 2015 I wouldn't shift the axis northeast at all. I think the 1300z outlook corridor of higher probs is pretty good, but they should have kept enhanced area further northeast including Chicago. You nailed that outlook! Looks like what you said Sent from my iPhone 6 using Tapatalk Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted July 13, 2015 Share Posted July 13, 2015 IWX Update: UPDATE ISSUED AT 1131 AM EDT MON JUL 13 2015 GROWING CONCERN FOR SIGNIFICANT SEVERE WEATHER THIS AFTERNOON...MAINLY SOUTH OF US 30. TEMPERATURES HAVE ALREADY JUMPED INTO THE UPPER 70S ACROSS NORTHERN ILLINOIS IN THE WAKE OF MORNING CONVECTION. EXPECT TEMPERATURES TO RISE QUICKLY IN OUR AREA BY EARLY AFTERNOON. FULL SUN FOR SEVERAL HOURS AND EFFICIENT EVAPOTRANSPORATION SHOULD RESULT IN MODERATE TO EXTREME DESTABILIZATION ALONG AND WEST OF A MICHIGAN CITY TO FORT WAYNE LINE. LAST FEW RUNS OF THE HRRR HAVE SUPPORTED THIS THINKING WITH STORMS DEVELOPING ALONG THIS FRONT BY LATE AFTERNOON. IF STORMS DEVELOP IN THAT ENVIRONMENT...SUPERCELLS WILL BE THE PRIMARY STORM MODE WITH 0-6 KM SHEAR IN EXCESS OF 50 KNOTS...STEEP MID LEVEL LAPSE RATES...AND SIGNIFICANT TURNING OF THE WINDS WITH HEIGHT. TORNADOES WILL ALSO BE POSSIBLE IN THIS SCENARIO GIVEN SOUTHERLY SURFACE WINDS AND AN INCREASINGLY STRONG LOW LEVEL JET FROM THE WEST. MAY NEED TO ADD SEVERE WORDING TO THE GRIDS WITHIN THE NEXT FEW HOURS IF DESTABILIZATION BEGINS AS EXPECTED. WOW that really makes me feel good that they're saying that in N Indiana. Maybe there's hope that the moderate and enhanced will come even further north and east later. Link to comment Share on other sites More sharing options...
sokolow Posted July 13, 2015 Share Posted July 13, 2015 Saw a fairly decent light show over downtown while SB on 90/94 this AM, including a fairly impressive run of what looked to be strikes on the masts of the Sears and rump towers Link to comment Share on other sites More sharing options...
DaveNay Posted July 13, 2015 Share Posted July 13, 2015 These pictures were from around 6:20am today south of DeKalb. SchaumburgStormer's house is about 1/2 mile from where these were taken. Looking north.....it was actually MUCH darker than this picture shows. Looking east... Link to comment Share on other sites More sharing options...
JacobChgo19 Posted July 13, 2015 Share Posted July 13, 2015 I am starting to loose confidence of anything "major" in the western Burbs, around where I am located. (I55/I294 interchange, give er take a mile or two.).. The previous outbreak that tore up Coal City set itself up with a major enviorment, similar to this, and it veered around the city. Unless 20Z brings some changes, I will not be too surprised if we just get some minor wind and rain. On another note, it's very humid and warm, and everything is rebounding quickly, faster than any other setup this summer. Probably attributed to the quick departure of the MCS. My biggest concern is the "hype" being regarded as false, and everybody turns a blind eye to the weather, as Chicagoins normally do, and then having something major come tearing through, be it supercells or a linear type setup. I will continue watching somewhat closey, but I am going to start heading the way of "I'll believe it when I see it". Link to comment Share on other sites More sharing options...
Quincy Posted July 13, 2015 Share Posted July 13, 2015 From an awareness point, I can see the argument about higher probabilities in Chicago. Analytically, I would think the greatest tornado threat lies along the instability gradient from Quad Cities area to NW IL. As mentioned, mesoanalysis currently shows 60-70kts of bulk shear along this gradient. Can't say I disagree much with the SPC graphics, although the wording seems fairly meh given the parameters. Link to comment Share on other sites More sharing options...
MattPetrulli Posted July 13, 2015 Share Posted July 13, 2015 From an awareness point, I can see the argument about higher probabilities in Chicago. Analytically, I would think the greatest tornado threat lies along the instability gradient from Quad Cities area to NW IL. As mentioned, mesoanalysis currently shows 60-70kts of bulk shear along this gradient. Can't say I disagree much with the SPC graphics, although the wording seems fairly meh given the parameters. I agree Link to comment Share on other sites More sharing options...
csnavywx Posted July 13, 2015 Share Posted July 13, 2015 Better height falls start coming in around/after 18Z, so I would expect initiation to take place shortly after that (prob. 20Z or so), in conjunction with areas reaching convT. Link to comment Share on other sites More sharing options...
tornadotony Posted July 13, 2015 Share Posted July 13, 2015 From an awareness point, I can see the argument about higher probabilities in Chicago. Analytically, I would think the greatest tornado threat lies along the instability gradient from Quad Cities area to NW IL. As mentioned, mesoanalysis currently shows 60-70kts of bulk shear along this gradient. Can't say I disagree much with the SPC graphics, although the wording seems fairly meh given the parameters. But you're acting as if that instability gradient is fixed and won't move. If it's already over the QC/NW IL and the area to the east is clearing and destabilizing, what do you think is going to happen? It might not make it to Chicago, but it sure as hell is probably going to get closer. Link to comment Share on other sites More sharing options...
Stebo Posted July 13, 2015 Share Posted July 13, 2015 Since I have been sleeping, I didn't get a chance to comment on this but I agree wholeheartedly with the others that the MDT shouldn't have been removed especially down to a slight and they are already correcting back. I would expect more correction back toward their original outlook as well now that it is more obvious that the morning convection isn't going to have the effect they thought it would have at 1300z. Link to comment Share on other sites More sharing options...
jojo762 Posted July 13, 2015 Share Posted July 13, 2015 Recent vis sat imagery appears to show the western portion of the OFB in E IA is beginning the processes of retreating slowly E/NE. Somewhat of an increase in cloud cover though along this portion... isolated elevated small shower activity in N IL/S WI... Link to comment Share on other sites More sharing options...
radionicist Posted July 13, 2015 Share Posted July 13, 2015 WOW that really makes me feel good that they're saying that in N Indiana. Maybe there's hope that the moderate and enhanced will come even further north and east later. We've had over a foot of rain in the last six weeks. My hope is that this system stays the hell out of NW Ohio. Link to comment Share on other sites More sharing options...
Stebo Posted July 13, 2015 Share Posted July 13, 2015 But you're acting as if that instability gradient is fixed and won't move. If it's already over the QC/NW IL and the area to the east is clearing and destabilizing, what do you think is going to happen? It might not make it to Chicago, but it sure as hell is probably going to get closer. Yeah, the warm front will move more northeast from the current location, that OFB has washed out on radar and satellite so the doors are wide open. Link to comment Share on other sites More sharing options...
Wmsptwx Posted July 13, 2015 Share Posted July 13, 2015 SPC write up was less enthusiastic than the previous. Link to comment Share on other sites More sharing options...
MattPetrulli Posted July 13, 2015 Share Posted July 13, 2015 Latest surface observations in IN are showing some decent clearing from away from the MCS in North central IN. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted July 13, 2015 Share Posted July 13, 2015 The skies are clearing so fast behind this MCS. Wish I could post a loop of this. http://www.ssec.wisc.edu/data/wisc/index.php?n=8 Link to comment Share on other sites More sharing options...
tornadotony Posted July 13, 2015 Share Posted July 13, 2015 81/73 at VYS on the latest ob. Link to comment Share on other sites More sharing options...
extremewx52 Posted July 13, 2015 Share Posted July 13, 2015 Yeah, the warm front will move more northeast from the current location, that OFB has washed out on radar and satellite so the doors are wide open. But you're acting as if that instability gradient is fixed and won't move. If it's already over the QC/NW IL and the area to the east is clearing and destabilizing, what do you think is going to happen? It might not make it to Chicago, but it sure as hell is probably going to get closer. Exactly. This is where the RAP has the instability gradient by this evening. Might be a bit overdone with the eastward extent...but still. Link to comment Share on other sites More sharing options...
Quincy Posted July 13, 2015 Share Posted July 13, 2015 But you're acting as if that instability gradient is fixed and won't move. If it's already over the QC/NW IL and the area to the east is clearing and destabilizing, what do you think is going to happen? It might not make it to Chicago, but it sure as hell is probably going to get closer.Maybe splitting hairs. I suppose timing of initiation is going to be a factor too. Earlier firing might favor more of a QC area, while later could bring initiation cautiously close to Chicago. Satellite imagery shows the boundary nearly stationary, but there is time for NE movement. The most impressive obs are down near PIA, while SQI has veered to the SW. Not an easy call. It's going to be close, particularly on the SW side of Chicago. Link to comment Share on other sites More sharing options...
Harry Perry Posted July 13, 2015 Share Posted July 13, 2015 Unreal... Clouds mixing out fast (east) with clear blue skies nearly overhead. I don't think I've seen the sky that blue in a long time. Filtered sun with a temp of 74° already. Almost curious as to what could happen in these parts later on now as well as south of here. Link to comment Share on other sites More sharing options...
Stebo Posted July 13, 2015 Share Posted July 13, 2015 Exactly. This is where the HRRR has the instability gradient by this evening. Capture.JPG Yeah a great collocation of the best shear along the boundary and the best instability right over Chicago metro area. Link to comment Share on other sites More sharing options...
extremewx52 Posted July 13, 2015 Share Posted July 13, 2015 Outflow boundary basically stalled right over KILX radar. Now rapidly mixing northward the last few scans. Link to comment Share on other sites More sharing options...
The_Doctor Posted July 13, 2015 Share Posted July 13, 2015 Had some weak gusts and a really ragged shelf cloud roll through a couple minutes ago. There was a bit of thunder before the gust front went through but since then there really hasn't been any lightning/thunder. Link to comment Share on other sites More sharing options...
tornadotony Posted July 13, 2015 Share Posted July 13, 2015 Maybe splitting hairs. I suppose timing of initiation is going to be a factor too. Earlier firing might favor more of a QC area, while later could bring initiation cautiously close to Chicago. Satellite imagery shows the boundary nearly stationary, but there is time for NE movement. The most impressive obs are down near PIA, while SQI has veered to the SW. Not an easy call. It's going to be close, particularly on the SW side of Chicago. But you need SW flow in that area to recover. And if you look at velocity from DVN, you can see that even with SW sfc flow, there's over 90° of turning in the low-mid levels! Link to comment Share on other sites More sharing options...
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