Thundersnow12 Posted June 29, 2014 Author Share Posted June 29, 2014 New day 2 ..CENTRAL PLAINS/MIDDLE MISSISSIPPI VALLEY EAST TO GREAT LAKES REGION... AS NOTED IN THE PREVIOUS OUTLOOK...BOTH DETERMINISTIC AND ENSEMBLE GUIDANCE CONTINUES TO PROVIDE A STRONG SIGNAL FOR DEVELOPMENT OF A MESOSCALE CONVECTIVE SYSTEM WITH SWATHS OF DAMAGING WINDS MONDAY ACROSS THE MID-MISSISSIPPI VALLEY REGION...AND PROGRESSING EASTWARD INTO THE PORTIONS OF THE GREAT LAKES/UPPER MISSISSIPPI VALLEY MONDAY NIGHT. THE INFLUENCE OF OVERNIGHT CONVECTION LATE SUNDAY/EARLY MONDAY IS ONE COMPLICATING FACTOR...BUT HIGHER SEVERE PROBABILITIES MAY BE WARRANTED IN SUBSEQUENT OUTLOOKS ACROSS THIS REGION AS MESOSCALE DETAILS BECOME MORE CLEAR. TSTMS MAY BE ON-GOING MONDAY MORNING ACROSS EASTERN NEBRASKA/WESTERN IOWA ASSOCIATED WITH WARM ADVECTION TO THE NORTH OF THE FRONTAL BOUNDARY. AS HEIGHT FALLS ASSOCIATED WITH THE AMPLIFICATION OF THE UPPER FLOW OVERSPREAD THE AREA...ADDITIONAL TSTM DEVELOPMENT IS LIKELY BY AROUND MIDDAY AS THE FRONTAL BOUNDARY BEGINS TO MOVE EASTWARD ACROSS THE AREA. STRONG DEEP-LAYER SHEAR IN THE PRESENCE OF MODERATE/STRONG MLCAPE WILL SUPPORT SUPERCELLS AS THE INITIAL STORM MODE WITH A RISK OF LARGE HAIL...POSSIBLY SIGNIFICANT...DAMAGING WINDS AND A FEW TORNADOES. UPSCALE GROWTH IS LIKELY TO OCCUR WITHIN A FEW HOURS OF INITIATION...AND AN EASTWARD-MOVING CONVECTIVE COMPLEX WITH POTENTIALLY WIDESPREAD DAMAGING WINDS SHOULD MOVE ACROSS PORTIONS OF CENTRAL/SOUTHERN IOWA...NORTHERN MISSOURI AND INTO NORTHERN ILLINOIS/SOUTHERN WISCONSIN BY EVENING. Link to comment Share on other sites More sharing options...
Stebo Posted June 29, 2014 Share Posted June 29, 2014 Good to see they added MI as well with a mention of multicell/supercell though I think they are light on the MLCAPE, I am thinking more in the 2500 J/kg MLCAPE where as they are going 1500 J/kg MLCAPE. With the higher CAPE that I expect and the strong shear in place I would lean more supercell vs multicell. Link to comment Share on other sites More sharing options...
The_Doctor Posted June 29, 2014 Share Posted June 29, 2014 Not sure what I'd do if I lived in the blue lol Link to comment Share on other sites More sharing options...
RCNYILWX Posted June 29, 2014 Share Posted June 29, 2014 Are you tempting fate like you did with the no hail over 1" call a few weeks back? Storm mode remained discrete much longer than SPC expected on 6/12/13, as one example. Link to comment Share on other sites More sharing options...
Hoosier Posted June 29, 2014 Share Posted June 29, 2014 Good to see they added MI as well with a mention of multicell/supercell though I think they are light on the MLCAPE, I am thinking more in the 2500 J/kg MLCAPE where as they are going 1500 J/kg MLCAPE. With the higher CAPE that I expect and the strong shear in place I would lean more supercell vs multicell. Disco mentioned 1500-2500 ... ADDITIONALLY...OTHER SVR TSTMS WILL BE POSSIBLE ALONG AND IN ADVANCE OF THE FRONTAL BOUNDARY EXTENDING NORTHEAST ACROSS CENTRAL AND NORTHERN WISCONSIN/LOWER MICHIGAN MONDAY AS MLCAPE OF 1500 TO 2500 J/KG DEVELOPS IN THE PRESENCE OF 35 TO 45 KTS OF DEEP SHEAR. Link to comment Share on other sites More sharing options...
Hoosier Posted June 29, 2014 Share Posted June 29, 2014 Storm mode remained discrete much longer than SPC expected on 6/12/13, as one example. 6/5/2010 is another one. There's a lot of examples over the years but storm mode is one of the tougher aspects to nail down. Link to comment Share on other sites More sharing options...
Powerball Posted June 29, 2014 Share Posted June 29, 2014 Not sure what I'd do if I lived in the blue lol this would suck.gif I thought it was cute when I first saw it. They might as well just fill in that small gap, for aesthetic purposes is nothing else... Link to comment Share on other sites More sharing options...
Stebo Posted June 29, 2014 Share Posted June 29, 2014 Disco mentioned 1500-2500 ... ADDITIONALLY...OTHER SVR TSTMS WILL BE POSSIBLE ALONG AND IN ADVANCE OF THE FRONTAL BOUNDARY EXTENDING NORTHEAST ACROSS CENTRAL AND NORTHERN WISCONSIN/LOWER MICHIGAN MONDAY AS MLCAPE OF 1500 TO 2500 J/KG DEVELOPS IN THE PRESENCE OF 35 TO 45 KTS OF DEEP SHEAR. I guess I read it fast, that said I am leaning higher vs lower on that one anyways. Link to comment Share on other sites More sharing options...
Powerball Posted June 29, 2014 Share Posted June 29, 2014 Good to see they added MI as well with a mention of multicell/supercell though I think they are light on the MLCAPE, I am thinking more in the 2500 J/kg MLCAPE where as they are going 1500 J/kg MLCAPE. With the higher CAPE that I expect and the strong shear in place I would lean more supercell vs multicell. The 12z GGEM shows an interesting solution. I'm not sure if you took a peek at it. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 29, 2014 Author Share Posted June 29, 2014 Everything is really there tomorrow for a localized tornado event across eastern IA/northwest IL if I had to pick a spot if storms remain discrete longer than currently thought. Link to comment Share on other sites More sharing options...
chase_stormz Posted June 29, 2014 Share Posted June 29, 2014 Everything is really there tomorrow for a localized tornado event across eastern IA/northwest IL if I had to pick a spot if storms remain discrete longer than currently thought. It sure does have a 6/5/10 feeling to it doesn't it Link to comment Share on other sites More sharing options...
A-L-E-K Posted June 29, 2014 Share Posted June 29, 2014 6/5/2010 is another one. There's a lot of examples over the years but storm mode is one of the tougher aspects to nail down. yeah, i'm not making a rock solid call here or anything but given initiation in central/eastern IA, I have a hard time imagining things not congealing long before it makes it into LOT's CWA. Eastern IA and NW IL are another story. I do like a severe MCS pushing into the city during the evening. Link to comment Share on other sites More sharing options...
Stebo Posted June 29, 2014 Share Posted June 29, 2014 The 12z GGEM shows an interesting solution. I'm not sure if you took a peek at it. Yeah I saw it, if the line were to form a strong cold pool, the ggem solution would be reasonable. Link to comment Share on other sites More sharing options...
Hoosier Posted June 29, 2014 Share Posted June 29, 2014 yeah, i'm not making a rock solid call here or anything but given initiation in central/eastern IA, I have a hard time imagining things not congealing long before it makes it into LOT's CWA. Eastern IA and NW IL are another story. I do like a severe MCS pushing into the city during the evening. I'd lean toward congealing as well but I think the embedded supercell tornado threat is higher than what you were suggesting. The CAPE/shear parameters remain very favorable for tornadoes well into the evening so I'd have to think the threat won't just shut off so quickly. Link to comment Share on other sites More sharing options...
A-L-E-K Posted June 29, 2014 Share Posted June 29, 2014 I'd lean toward congealing as well but I think the embedded supercell tornado threat is higher than what you were suggesting. The CAPE/shear parameters remain very favorable for tornadoes well into the evening so I'd have to think the threat won't just shut off so quickly. fair Link to comment Share on other sites More sharing options...
A-L-E-K Posted June 29, 2014 Share Posted June 29, 2014 noice Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 29, 2014 Author Share Posted June 29, 2014 I'd lean toward congealing as well but I think the embedded supercell tornado threat is higher than what you were suggesting. The CAPE/shear parameters remain very favorable for tornadoes well into the evening so I'd have to think the threat won't just shut off so quickly. Yes they do, I believe the LOT CWA had like 5 tornadoes with the 8/4/08 derecho. Link to comment Share on other sites More sharing options...
Gilbertfly Posted June 29, 2014 Share Posted June 29, 2014 Yes they do, I believe the LOT CWA had like 5 tornadoes with the 8/4/08 derecho. yes....one of which was three blocks from my home if I am remembering correctly Link to comment Share on other sites More sharing options...
RCNYILWX Posted June 29, 2014 Share Posted June 29, 2014 6/5/2010 is another one. There's a lot of examples over the years but storm mode is one of the tougher aspects to nail down. Yep, that's an excellent example. Agree with your thoughts that even if initial discrete development becomes linear that the threat for embedded supercell/mesovortex tornadoes is higher than usual given the progged low level shear profile. Link to comment Share on other sites More sharing options...
Geos Posted June 29, 2014 Share Posted June 29, 2014 4km NAM at 21z - 3z tomorrow. Link to comment Share on other sites More sharing options...
RCNYILWX Posted June 29, 2014 Share Posted June 29, 2014 Yes they do, I believe the LOT CWA had like 5 tornadoes with the 8/4/08 derecho. Even a bit more recently, the QLCS on 6/20/11 had an EF-1 tornado in Downers Grove. Link to comment Share on other sites More sharing options...
Hoosier Posted June 29, 2014 Share Posted June 29, 2014 Yes they do, I believe the LOT CWA had like 5 tornadoes with the 8/4/08 derecho. Yeah, including an EF2 well after things had gone linear. Everything is a learning experience and tomorrow will be no different. You have potential linear mode while parameters are very favorable for tornadoes. It'll be interesting to see what "wins out" so to speak. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 29, 2014 Author Share Posted June 29, 2014 Progged environment over western Chicago metro at 0z. Sounding is for ARR and supercell composite at 0z. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 29, 2014 Author Share Posted June 29, 2014 Even a bit more recently, the QLCS on 6/20/11 had an EF-1 tornado in Downers Grove. I remember that day well even though I was in Orlando. Was following on here a lot and had tons of people texted me when Gino issued the warning. Link to comment Share on other sites More sharing options...
tornadotony Posted June 29, 2014 Share Posted June 29, 2014 I'm having a real hard time thinking linear mode quickly tomorrow. Yes the LLJ will be strong, but so will veering with height. And if the NAM wind fields in the upper levels are more correct than the GFS, the ventilation aloft will be much higher than anyone really has expected. This smells like a typical trap toward linear thinking and we've seen events in the past where the low-mid level flow has not really supported linear organization but yet everyone bit on the NAM/GFS QPF output and even some of the mid-range high-res runs and we all got burned. I've seen 6/12/13 and 6/5/10 listed in this thread and those are fantastic examples. I mean, maybe it goes linear fast, but boy oh boy I wouldn't put any money on it. And if things don't go linear fast, it's very, very clear that one or more violent tornadoes is not only possible but really likely. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 29, 2014 Author Share Posted June 29, 2014 I'm having a real hard time thinking linear mode quickly tomorrow. Yes the LLJ will be strong, but so will veering with height. And if the NAM wind fields in the upper levels are more correct than the GFS, the ventilation aloft will be much higher than anyone really has expected. This smells like a typical trap toward linear thinking and we've seen events in the past where the low-mid level flow has not really supported linear organization but yet everyone bit on the NAM/GFS QPF output and even some of the mid-range high-res runs and we all got burned. I've seen 6/12/13 and 6/5/10 listed in this thread and those are fantastic examples. I mean, maybe it goes linear fast, but boy oh boy I wouldn't put any money on it. And if things don't go linear fast, it's very, very clear that one or more violent tornadoes is not only possible but really likely. Couldn't have said it any better. Well done. Leaning towards Clinton to Cedar Rapids as a starting point. Don't want to get too far west at first and let something develop and come to you. Link to comment Share on other sites More sharing options...
tornadotony Posted June 29, 2014 Share Posted June 29, 2014 Couldn't have said it any better. Well done. Leaning towards Clinton to Cedar Rapids as a starting point. Don't want to get too far west at first and let something develop and come to you. I might take a gamble and stay just E of the river. Should still be plenty of daylight when storms get there and crossing back and forth with a monster at my back is not something I fancy. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 29, 2014 Author Share Posted June 29, 2014 I might take a gamble and stay just E of the river. Should still be plenty of daylight when storms get there and crossing back and forth with a monster at my back is not something I fancy. Exactly. I was thinking Clinton yesterday for that reason but also don't want to miss the more discrete stuff to the west if it does congeal like some models say by the time it reaches IA. Link to comment Share on other sites More sharing options...
Central Illinois Posted June 29, 2014 Share Posted June 29, 2014 ILX thinking (4000 cape values and 35 -45 kt shear values) severe weather will Impact most of Central IL before losing steam in SE IL Link to comment Share on other sites More sharing options...
Hoosier Posted June 29, 2014 Share Posted June 29, 2014 Is it me or is the 18z NAM coming in more unstable? Link to comment Share on other sites More sharing options...
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