Hoosier Posted June 22, 2015 Share Posted June 22, 2015 I probably shouldn't have started the 11/17 discussion, as it can be argued in many directions. You can see in the mesoscale discussions that day (and obs) that winds were locally backed to SSE across eastern Illinois and Indiana in the afternoon. Haha, it's alright. Tomorrow certainly has its share of questions. Depending how the MCS evolves, could have local backing of the surface winds in time for the next round. Just have to watch things closely. Link to comment Share on other sites More sharing options...
Quincy Posted June 22, 2015 Share Posted June 22, 2015 Haha, it's alright. Tomorrow certainly has its share of questions. Depending how the MCS evolves, could have local backing of the surface winds in time for the next round. Just have to watch things closely. It really comes back to the MCS evolution and subsequent air-mass recovery/wind fields. I won't run a play-by-play of the HRRR, but it's certainly making this a tough call - if one had to make a forecast right now. Impending SPC update should be very interesting to see which way they lean. Link to comment Share on other sites More sharing options...
homedis Posted June 22, 2015 Share Posted June 22, 2015 But even if the MCS comes, the atmosphere WILL recover as long as it ends around 1 pm Link to comment Share on other sites More sharing options...
jojo762 Posted June 22, 2015 Share Posted June 22, 2015 The hodographs look lovely at 18z, but they become less impressive/classic looking, although still favorable for tornadoes, by 21z and especially 00z. Maybe just splitting hairs here. The morning/initial MCS may very well throw more of a wrench in this setup than veering/backing winds. Not sure about that really.. In 00Z NAM soundings across N IL/S WI the hodographs improve from 18z to 21z to 00z... Link to comment Share on other sites More sharing options...
RCNYILWX Posted June 22, 2015 Share Posted June 22, 2015 Since 11/17 came up, here is the special 16z ILX sounding from that day. That setup wasn't necessarily a jaw dropper in terms of directional shear Untitled.png As for tomorrow, low level flow does tend to veer with time but as has been pointed out, the mid level flow is more W/WNW. We'll see how it shakes out. Speed shear was through the roof, which this event will have. The veered flow doesn't have to be a deal breaker also because of the reason you mentioned. And if the cap can be broken before 00z over northern IL, winds will be less veered at that point. Typically cold fronts oriented in the way tomorrow's will be are not the best to get discrete development, but the deep layer shear vector tomorrow will be northwest/WNW, so still oriented sufficiently orthogonal to the southwest to northeast boundary. Link to comment Share on other sites More sharing options...
Powerball Posted June 22, 2015 Share Posted June 22, 2015 But even if the MCS comes, the atmosphere WILL recover as long as it ends around 1 pm Someone posted an image above that shows the airmass never does recover for much of the risk area on the HRRR, FWIW. Link to comment Share on other sites More sharing options...
Quincy Posted June 22, 2015 Share Posted June 22, 2015 Someone posted an image above that shows the airmass never does recover for much of the risk area on the HRRR, FWIW. FWIW, 04z HRRR shows 0 instability, as in 0 J/kg SBCAPE, over portions of eastern Iowa and northeastern Illinois at 2 p.m. CDT. Link to comment Share on other sites More sharing options...
jojo762 Posted June 22, 2015 Share Posted June 22, 2015 FWIW the 04Z HRRR looks a bit less intense/ organized with the MCS--at least at 10Z--imo compared to the five previous model runs... And looking at the current radar observations can't say I disagree much. Link to comment Share on other sites More sharing options...
homedis Posted June 22, 2015 Share Posted June 22, 2015 Someone posted an image above that shows the airmass never does recover for much of the risk area on the HRRR, FWIW.True, although realistically does that seem very probable? The MCS is going to be moving at a VERY fast pace and wont have the precip shield advertized by the HRRR. These two things will allow the whole MCS system to move out of the area to allow for rapid destabilization, which the only reason I could see this not happening is because of backbuilding (not very probable) Link to comment Share on other sites More sharing options...
Powerball Posted June 22, 2015 Share Posted June 22, 2015 FWIW, 04z HRRR shows 0 instability, as in 0 J/kg SBCAPE, over portions of eastern Iowa and northeastern Illinois at 2 p.m. CDT. The latest RAP is practically the complete opposite though. Link to comment Share on other sites More sharing options...
Powerball Posted June 22, 2015 Share Posted June 22, 2015 True, although realistically does that seem very probable? The MCS is going to be moving at a VERY fast pace and wont have the precip shield advertized by the HRRR. These two things will allow the whole MCS system to move out of the area to allow for rapid destabilization, which the only reason I could see this not happening is because of backbuilding (not very probable) It's a possibility and something that has happened before in past events. But granted, the synoptic setup this time is more unusual. Link to comment Share on other sites More sharing options...
homedis Posted June 22, 2015 Share Posted June 22, 2015 FWIW, 04z HRRR shows 0 instability, as in 0 J/kg SBCAPE, over portions of eastern Iowa and northeastern Illinois at 2 p.m. CDT.Im honestly not buying into that... something must be off with the HRRR imo Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 22, 2015 Share Posted June 22, 2015 The 0z NSSL WRF is an ominous scenario for in and around the Rochelle area.. Link to comment Share on other sites More sharing options...
homedis Posted June 22, 2015 Share Posted June 22, 2015 It's a possibility and something that has happened before. But granted, the synoptic setup this time is more unusual. Oh yes, I'm not saying it isnt probable USUALLY, but this setup is not your normal setup Link to comment Share on other sites More sharing options...
Harry Perry Posted June 22, 2015 Share Posted June 22, 2015 I can see the SPC sticking with enhanced purely on the pretty large discrepancies among short range guidance. Link to comment Share on other sites More sharing options...
Powerball Posted June 22, 2015 Share Posted June 22, 2015 I can see the SPC sticking with enhanced purely on the pretty large discrepancies among short range guidance. That wouldn't surprise me, though I can definitely see them perhaps dialing things back for the northern edge of the risk area. Link to comment Share on other sites More sharing options...
homedis Posted June 22, 2015 Share Posted June 22, 2015 I can see the SPC sticking with enhanced purely on the pretty large discrepancies among short range guidance.I can see that but most models still point to an ominous setup tomorrow Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted June 22, 2015 Share Posted June 22, 2015 The latest RAP is practically the complete opposite though. RAP doesn't seem to be handling the MCS very well at all. It only brushes south Wisconsin... leaving N IL and MI untouched; it's an outlier Link to comment Share on other sites More sharing options...
jojo762 Posted June 22, 2015 Share Posted June 22, 2015 So much uncertainty and model disagreement about the MCS and what will happen in the afternoon lol SPC will almost guaranteed stick with a continuation of the ENH and maybe even the same outlook they had at 1730Z as far as delineation of the categories. Link to comment Share on other sites More sharing options...
Powerball Posted June 22, 2015 Share Posted June 22, 2015 RAP doesn't seem to be handling the MCS very well at all. It only brushes south Wisconsin... leaving N IL and MI untouched; it's an outlier The NAM / GGEM / RGEM show similar solutions though, so it's not a total outlier. Link to comment Share on other sites More sharing options...
andyhb Posted June 22, 2015 Share Posted June 22, 2015 So, so much conjecture in this thread right now. Link to comment Share on other sites More sharing options...
Hoosier Posted June 22, 2015 Share Posted June 22, 2015 Someone posted an image above that shows the airmass never does recover for much of the risk area on the HRRR, FWIW. The HRRR doesn't go past 15 hours as far as I know, so it's hard to know how much recovery would take place later in the afternoon and into the evening. Link to comment Share on other sites More sharing options...
homedis Posted June 22, 2015 Share Posted June 22, 2015 Well this would be a giant buzzkill: https://twitter.com/stormchaserQ/status/612842934740725760 ^^^^^ this post created complete havoc hahhaah Link to comment Share on other sites More sharing options...
Harry Perry Posted June 22, 2015 Share Posted June 22, 2015 So, so much conjecture in this thread right now. Lol was just thinking the same. Link to comment Share on other sites More sharing options...
Powerball Posted June 22, 2015 Share Posted June 22, 2015 The HRRR doesn't go past 15 hours as far as I know, so it's hard to know how much recovery would take place later in the afternoon and into the evening. Good catch. My mistake. I guess it was another hi-res model. Link to comment Share on other sites More sharing options...
homedis Posted June 22, 2015 Share Posted June 22, 2015 The HRRR doesn't go past 15 hours as far as I know, so it's hard to know how much recovery would take place later in the afternoon and into the evening.Yeah that's what I was thinking. We dont know what happens AFTER the MCS... which is what we need to know to decide Link to comment Share on other sites More sharing options...
geddyweather Posted June 22, 2015 Share Posted June 22, 2015 I can see the SPC sticking with enhanced purely on the pretty large discrepancies among short range guidance. I agree, it has gotten messy yet again. Curious to see how they'll handle it this time. Still sounds like it'll be a bigger day for most of the sub-forum, but short range impediments are throwing some curves as we approach the new D1 Link to comment Share on other sites More sharing options...
JacobChgo19 Posted June 22, 2015 Share Posted June 22, 2015 Storms firing on Iowa border right now... Link to comment Share on other sites More sharing options...
Kaner88 Posted June 22, 2015 Share Posted June 22, 2015 It's like analyzing models & discussions ahead of a winter storm, the only differences being that it's 75 degrees instead of 25 degrees outside, and we're hoping for tornadoes to drop (in open fields, of course) instead of snowflakes. Adds to the fun, I suppose. Link to comment Share on other sites More sharing options...
Hoosier Posted June 22, 2015 Share Posted June 22, 2015 Im honestly not buying into that... something must be off with the HRRR imo The MCS is still in the area at the time, so lack of surface based instability makes sense in the context of that particular model. Link to comment Share on other sites More sharing options...
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