OHweather Posted June 22, 2015 Share Posted June 22, 2015 4K NAM is questionable as well with its moisture forecast... across WI and IL it has DP's from the lower 50's across NC/C WI to mid 60's south of there at 12Z. Then at 15Z it shoots DP's to the upper 60's lower 70's across NC/C WI all with some convection over N IL/IA at the time, a significant increase by about 8-10 degrees in 3 hours... Thats either erroneous, or some pretty intense WAA.I'd have to look at soundings to know for sure, however it's possible that's a result of the nocturnal low level inversion mixing out and allowing higher dew points from just above the ground to mix down in the morning. Link to comment Share on other sites More sharing options...
Powerball Posted June 22, 2015 Share Posted June 22, 2015 Looks like the 03z RAP at 21z tomorrow tries to initiate some action along the warm front also... (of course, it's assuming widespread highs near 90*F). Link to comment Share on other sites More sharing options...
jojo762 Posted June 22, 2015 Share Posted June 22, 2015 Um, are you not seeing the strength of the low level winds tomorrow? Moisture surges like that are very common in these types of events. I've noticed it, reference a few of my other posts that talk about the WAA and LLVL winds. It was just an observation off of one model that everyone has been salivating over for obvious reasons.. Link to comment Share on other sites More sharing options...
Harry Perry Posted June 22, 2015 Share Posted June 22, 2015 The old lady and I are supposed to be taking the camper to cedar point tomorrow... To be honest, not sure if that's going to happen anymore. Link to comment Share on other sites More sharing options...
jojo762 Posted June 22, 2015 Share Posted June 22, 2015 Anyways... Some SPC thoughts about tonight... MESOSCALE DISCUSSION 1111NWS STORM PREDICTION CENTER NORMAN OK1125 PM CDT SUN JUN 21 2015AREAS AFFECTED...DAKOTAS...WCNTRL MNCONCERNING...SEVERE THUNDERSTORM WATCH 327...VALID 220425Z - 220600ZTHE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 327CONTINUES.SUMMARY...LARGE HAIL AND DAMAGING WINDS ARE POSSIBLE WITH CONVECTIONACROSS WW327 TONIGHT.DISCUSSION...UPWARD EVOLVING MCS IS PROGRESSING STEADILY ACROSS ERNND AIDED IN PART BY DEEPENING/STRENGTHENING MID-LEVEL FLOW AHEAD OFSHORT-WAVE TROUGH. STRONGEST SURGE WITHIN THE MCS IS ALONG THE SRNFLANK WHERE AN ARC-SHAPED LINE IS PROPAGATING SEWD AT ROUGHLY 40KTINTO MCPHERSON COUNTY SD. DAMAGING WINDS APPEAR LIKELY ALONGLEADING EDGE OF THIS SURGE. FARTHER NORTH...AN MCV APPEARS TO BEFORMING NEAR LAMOURE COUNTY ND AND FURTHER EXPANSION OF THIS COMPLEXOF STORMS IS POSSIBLE AS IT MOVES TOWARD WCNTRL MN BY 07Z.UPSTREAM...A SW-NE BAND OF TSTMS IS ORGANIZING ALONG WIND SHIFT FROMSWRN ND INTO EXTREME NERN WY. THIS ACTIVITY SHOULD PROGRESS EWDACROSS SRN PORTIONS OF WW327 WITH A THREAT FOR LARGE HAIL ANDDAMAGING WINDS...DARROW.. 06/22/2015 Link to comment Share on other sites More sharing options...
Harry Perry Posted June 22, 2015 Share Posted June 22, 2015 Also, any thoughts on what happens when those nice big cells jump over 40° water (check mid lake buoy temps - 40-47°)? I know APX mentioned 1998 in the analogs, but does anyone have a place or record of what water temps were that summer? Link to comment Share on other sites More sharing options...
andyhb Posted June 22, 2015 Share Posted June 22, 2015 Well this would be a giant buzzkill: https://twitter.com/stormchaserQ/status/612842934740725760 Link to comment Share on other sites More sharing options...
Chicago Storm Posted June 22, 2015 Share Posted June 22, 2015 The HRRR pretty much jives with what my thoughts have been. The MCS is the main show for many areas. It will likely still be severe for areas it impacts in the morning/early afternoon, with greater potential in MI/N. IN/N. OH with re-strengthening and/or further development in the afternoon. This would put additional development along the cold front (north of I-80) in question, in regards to coverage and strength. One potential area to watch in this scenario would be along the OFB in the afternoon, where-ever it may setup in IA/IL...Most likely near I-80. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted June 22, 2015 Share Posted June 22, 2015 Well this would be a giant buzzkill: https://twitter.com/stormchaserQ/status/612842934740725760 Yeah but the MCS is exiting WI at 1PM... so they'd be in the clear after that. This solution could certainly throw a wrench in destabilization though. But this solution would also send an MCS down my way with rather large instability ahead of it... so... http://i.imgur.com/wuxBROd.gif Link to comment Share on other sites More sharing options...
Powerball Posted June 22, 2015 Share Posted June 22, 2015 00z NMM and ARW still insist on tracking tonight's MCS through N. IL and S. WI, like the HRRR. EDIT: Tons of cloud debris ahead of it too. Link to comment Share on other sites More sharing options...
homedis Posted June 22, 2015 Share Posted June 22, 2015 Yeah but the MCS is exiting WI at 1PM... so they'd be in the clear after that. This solution could certainly throw a wrench in destabilization though. But this solution would also send an MCS down my way with rather large instability ahead of it... so... http://i.imgur.com/wuxBROd.gif Yeah the instability would occur immediately after whenever it says the MCS will hit, which in that case would be around noon Link to comment Share on other sites More sharing options...
Stebo Posted June 22, 2015 Author Share Posted June 22, 2015 Yeah but the MCS is exiting WI at 1PM... so they'd be in the clear after that. This solution could certainly throw a wrench in destabilization though. But this solution would also send an MCS down my way with rather large instability ahead of it... so... http://i.imgur.com/wuxBROd.gif HRRR is over the top with the huge rain mass surrounding the MCS. Even if it were right about the MCS idea with it forward propagating, there won't be some massive rain shield with it like that is showing. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted June 22, 2015 Share Posted June 22, 2015 god model is interesting. MCS forces the boundary south along with the biggest threat int he evening but really pops off some big time storms to the SW of here. Link to comment Share on other sites More sharing options...
Quincy Posted June 22, 2015 Share Posted June 22, 2015 Well this would be a giant buzzkill: https://twitter.com/stormchaserQ/status/612842934740725760 The thing is, strong instability is still present across much of Iowa, but it's unclear if the MCS continues to back-build or not. Out of all the scenarios possible, I'm not sure a back-building MCS was one of them. That could get very messy as the cold front approaches, but who knows if it's right or not. I wouldn't be surprised if SPC keeps ENH, but could see a MDT justified too, just for the wind fields alone. It won't take much instability to go nuts. (The Rochelle environment was around 1000-1200 MLCAPE, for what it's worth) Link to comment Share on other sites More sharing options...
Chicago Storm Posted June 22, 2015 Share Posted June 22, 2015 HRRR is over the top with the huge rain mass surrounding the MCS. Even if it were right about the MCS idea with it forward propagating, there won't be some massive rain shield with it like that is showing. That's because it's a composite sim radar reflectivity image. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted June 22, 2015 Share Posted June 22, 2015 HRRR is over the top with the huge rain mass surrounding the MCS. Even if it were right about the MCS idea with it forward propagating, there won't be some massive rain shield with it like that is showing. Yeah, that looks weird. There's no reason for it to weaken either, is there? It's moving into a largely unstable atmosphere... dunno why it would weaken. Link to comment Share on other sites More sharing options...
Powerball Posted June 22, 2015 Share Posted June 22, 2015 Yeah, that looks weird. There's no reason for it to weaken either, is there? It's moving into a largely unstable atmosphere... dunno why it would weaken. Unstable yes, but also an increasingly capped atmosphere displaced from the better synoptic forcing (assuming it tracks into your backyard). Though obviously if a cold pool develops, anything can happen. Link to comment Share on other sites More sharing options...
OHweather Posted June 22, 2015 Share Posted June 22, 2015 Yeah, that looks weird. There's no reason for it to weaken either, is there? It's moving into a largely unstable atmosphere... dunno why it would weaken. Although I think Chicago Storm's idea of potential restrengthening farther east across parts of MI/N IN/N OH is definitely on the table, the MCS will start to outrun the better low level winds as it gets that far east. If it can develop a good MCV by tomorrow afternoon that may locally enhance the low level winds enough to keep it going. A lack of instability shouldn't be an issue ahead of the MCS if it forward propagates. Link to comment Share on other sites More sharing options...
Harry Perry Posted June 22, 2015 Share Posted June 22, 2015 00z NMM and ARW still insist on tracking tonight's MCS through N. IL and S. WI, like the HRRR. EDIT: Tons of cloud debris ahead of it too. Hey, we know all about debris clouds. Link to comment Share on other sites More sharing options...
Powerball Posted June 22, 2015 Share Posted June 22, 2015 Hey, we know all about debris clouds. They both actually aren't AS bad as feared Although the MCS itself diminishes, the MCV from it acts as a trigger for single cell t'storms (wouldn't call them supercells) along the warm front. Link to comment Share on other sites More sharing options...
Quincy Posted June 22, 2015 Share Posted June 22, 2015 I'm still leaning on the side of caution with red flags showing up. I know the wind fields and SLP deepening are unseasonable, but we've seen MCSs cause plenty of choas this season. Even with all that aside, I can't help feel the veering of winds (even if it's just SSW) in the mid to late afternoon will hold this back from being a greater tornado threat. Just my $0.02. This is no 11/17, but that setup featured a lot of S winds, but the model projections are largely SSW by prime time. Link to comment Share on other sites More sharing options...
Powerball Posted June 22, 2015 Share Posted June 22, 2015 Somehow, it all still worked out on the NMM and ARW (despite the midday MCS from the Plains). Link to comment Share on other sites More sharing options...
Stebo Posted June 22, 2015 Author Share Posted June 22, 2015 I'm still leaning on the side of caution with red flags showing up. I know the wind fields and SLP deepening are unseasonable, but we've seen MCSs cause plenty of choas this season. Even with all that aside, I can't help feel the veering of winds (even if it's just SSW) in the mid to late afternoon will hold this back from being a greater tornado threat. Just my $0.02. This is no 11/17, but that setup featured a lot of S winds, but the model projections are largely SSW by prime time. How many events this season had a kinematic setup like this? As for the surface winds, 11/17 also didn't have mid level winds that veered to WNW like this event does, plus the comparisons don't make sense as they are 2 completely different times of the year. Link to comment Share on other sites More sharing options...
ClicheVortex2014 Posted June 22, 2015 Share Posted June 22, 2015 Unstable yes, but also an increasingly capped atmosphere displaced from the better synoptic forcing (assuming it tracks into your backyard). Though obviously if a cold pool develops, anything can happen. Although I think Chicago Storm's idea of potential restrengthening farther east across parts of MI/N IN/N OH is definitely on the table, the MCS will start to outrun the better low level winds as it gets that far east. If it can develop a good MCV by tomorrow afternoon that may locally enhance the low level winds enough to keep it going. A lack of instability shouldn't be an issue ahead of the MCS if it forward propagates. Off topic: Oh sweet, I'm hoping to be at OU next semester as a Meteorology major! On topic: I wasn't expecting anything for Monday... so an MCS would be a bonus. We need the rain. Strong winds would be excellent. Link to comment Share on other sites More sharing options...
Quincy Posted June 22, 2015 Share Posted June 22, 2015 The 4km NAM has really struggled with convection lately via the simulated radar product. On Sunday, the 18z run failed to show anything in Missouri, despite 20z severe convection (a long string of convection in general) with large to very large hail. Link to comment Share on other sites More sharing options...
Quincy Posted June 22, 2015 Share Posted June 22, 2015 How many events this season had a kinematic setup like this? As for the surface winds, 11/17 also didn't have mid level winds that veered to WNW like this event does, plus the comparisons don't make sense as they are 2 completely different times of the year. I said this isn't 11/17, it was the first event that came to mind that (recently) had strong wind fields and didn't have widespread backing in terms of SErly winds. Confusing point I guess, since I was trying to infer that 11/17 didn't have the best directional shear, yet still produced numerous significant and long-track tornadoes. We've seen wind fields help out before. I just see mixed signals for this event, even if many of the parameters and the synoptic setup appear great on paper. Link to comment Share on other sites More sharing options...
jojo762 Posted June 22, 2015 Share Posted June 22, 2015 I'm still leaning on the side of caution with red flags showing up. I know the wind fields and SLP deepening are unseasonable, but we've seen MCSs cause plenty of choas this season. Even with all that aside, I can't help feel the veering of winds (even if it's just SSW) in the mid to late afternoon will hold this back from being a greater tornado threat. Just my $0.02. This is no 11/17, but that setup featured a lot of S winds, but the model projections are largely SSW by prime time. If this was over the central/southern plains this would make more sense to me since you usually need more backed flow for a substantive tornado threat, however other regions of the country are quite diferent... Anywyas when you look at the wind profile on forecast soundings from most models they still show substantial veering with height (much like Stebo stated) and curved elongated hodographs. You don't always need backed SFC flow to see a big tornado threat, what matters more is the amount of directional and speed shear in the profile imo.. Link to comment Share on other sites More sharing options...
Hoosier 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 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. Link to comment Share on other sites More sharing options...
Quincy Posted June 22, 2015 Share Posted June 22, 2015 If this was over the central/southern plains this would make more sense to me since you usually need more backed flow for a substantive tornado threat, however other regions of the country are quite diferent... Anywyas when you look at the wind profile on forecast soundings from most models they still show substantial veering with height (much like Stebo stated) and curved elongated hodographs. You don't always need backed SFC flow to see a big tornado threat, what matters more is the amount of directional and speed shear in the profile imo.. 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. Link to comment Share on other sites More sharing options...
Quincy 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. 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. Link to comment Share on other sites More sharing options...
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