Superstorm93 Posted June 13, 2014 Share Posted June 13, 2014 Wouldn't be shocked to hear reports of chasers with busted windows/windshields tomorrow Link to comment Share on other sites More sharing options...
Thunder Road Posted June 13, 2014 Share Posted June 13, 2014 literally? I wasn't aware that there was an actual diameter threshold for giant hail. Lol. Only seen that mentioned by the SPC a few times... Yup. I have a paper in front of me by a few forecasters at Valley, Pleasant Hill, and Topeka, and they defined "giant hail" as > 102 mm (4") in diameter. Link to comment Share on other sites More sharing options...
thewxmann Posted June 13, 2014 Share Posted June 13, 2014 The mid level height rises the GFS is showing on Monday probably wouldn't be good for initiation especially within that really impressive environment in IA. Ridiculous-parameter cap busts are infamous in IA... Saturday's probably our best bet at this point. Link to comment Share on other sites More sharing options...
andyhb Posted June 13, 2014 Author Share Posted June 13, 2014 12z Euro is indicating a good amount of surface backing taking place in E NE by 00z Sun. We saw this last year how the NAM failed to capture localized backing of the low level winds and OK ended up paying dearly for it. Also, the 700 mb weakness is not overwhelming on most of the 12z GFS soundings I've pulled. There is a bit of a deceleration, but it's not what I would look for in terms of a crippling weakness in the setup (unlike, say, 4/3). Man, if that second trough could eject properly ( ), there is some incredible instability available, but that probably won't happen judging by the strength of the eastern ridging. What's interesting about the 12z GFS on Monday is that it is showing a very favorable parameter space spreading north into MN as well rather than keeping it in cap bust happy IA. Link to comment Share on other sites More sharing options...
Chinook Posted June 13, 2014 Share Posted June 13, 2014 So what do you guys think for tomorrow (Saturday) - many discrete supercells, mainly a large squall line, or capping dominates? Link to comment Share on other sites More sharing options...
andyhb Posted June 13, 2014 Author Share Posted June 13, 2014 So what do you guys think for tomorrow (Saturday) - many discrete supercells, mainly a large squall line, or capping dominates? Initiation in NE appears likely, storm mode will depend on the evolution of the wind fields, which is still uncertain. Also, there are currently mid 40s dewpoints over the primary threat area, we are going to need some strong moisture advection, otherwise LCL heights are potentially problematic for tornadogenesis. Local WFOs seem quite bearish on tornado potential (understandably so). Link to comment Share on other sites More sharing options...
Thunder Road Posted June 13, 2014 Share Posted June 13, 2014 12z NMM and ARW both have several hours of discrete convection in eastern NE...but both hold off initiation until around 0z. Could end up being a race against darkness. Link to comment Share on other sites More sharing options...
Ian Posted June 13, 2014 Share Posted June 13, 2014 Initiation in NE appears likely, storm mode will depend on the evolution of the wind fields, which is still uncertain. Also, there are currently mid 40s dewpoints over the primary threat area, we are going to need some strong moisture advection, otherwise LCL heights are potentially problematic for tornadogenesis. Local WFOs seem quite bearish on tornado potential (understandably so). Models have backed off on moisture a bit lately it seems which shouldn't be too shocking this year. It'll be another crowded chase day at least. Link to comment Share on other sites More sharing options...
andyhb Posted June 13, 2014 Author Share Posted June 13, 2014 12z NMM and ARW both have several hours of discrete convection in eastern NE...but both hold off initiation until around 0z. Could end up being a race against darkness. After dark tornado event in the vicinity of several highly populated areas? Sounds like a big problem. Link to comment Share on other sites More sharing options...
Chinook Posted June 13, 2014 Share Posted June 13, 2014 the 12z NAM has a big cap for Lincoln NE area at 21z tomorrow. The 18z NAM takes it all away-- several degrees C difference at 800mb on those two soundings (same forecast hour, same place) Link to comment Share on other sites More sharing options...
andyhb Posted June 13, 2014 Author Share Posted June 13, 2014 the 12z NAM has a big cap for Lincoln NE area at 21z tomorrow. The 18z NAM takes it all away-- several degrees C difference at 800mb on those two soundings (same forecast hour, same place) I can already tell the 18z NAM is having problems based on what happens in the 700 mb VV fields in OK at 24 hrs out, whatever it is developing there suddenly rockets north into eastern NE/western IA by 21z. Link to comment Share on other sites More sharing options...
andyhb Posted June 13, 2014 Author Share Posted June 13, 2014 On a sidenote, pretty sure chasers would be hacking off limbs for what the 18z GFS shows at 144-150 hrs. A rather low amplitude wave with a 70 kt 500 mb jet max plowing into the southern Plains in June is not something you see on a regular basis. Link to comment Share on other sites More sharing options...
Ground Scouring Posted June 14, 2014 Share Posted June 14, 2014 On a sidenote, pretty sure chasers would be hacking off limbs for what the 18z GFS shows at 144-150 hrs. A rather low amplitude wave with a 70 kt 500 mb jet max plowing into the southern Plains in June is not something you see on a regular basis. The 12Z ECMWF has actually trended a bit toward the 18Z GFS in terms of ejection. Of course the cap will still be a huge problem as projected. Link to comment Share on other sites More sharing options...
andyhb Posted June 14, 2014 Author Share Posted June 14, 2014 The 12Z ECMWF has actually trended a bit toward the 18Z GFS in terms of ejection. Of course the cap will still be a huge problem as projected. Well yes if the Euro is hanging the trough/ULL up in the west for too long, then suddenly impressive potential comes on the table. Link to comment Share on other sites More sharing options...
tornadotony Posted June 14, 2014 Share Posted June 14, 2014 The NAM kisses LCL questions goodbye for tomorrow, and given the LLJ developing and the humidity reservoir across the srn plains, I buy it. Link to comment Share on other sites More sharing options...
Thunder Road Posted June 14, 2014 Share Posted June 14, 2014 If you're looking at the hi-res guidance, between a late initiation and the tendency to line out instantly, you have reason to be nervous about tomorrow. My thinking, though, is that the storm mode at least is being driven by the NAM not backing surface winds as much as the GFS/EC. And really, with pressure falls to the west, can you really maintain a 190 surface wind? The NMM and ARW, at least, use a WRF core, so they may be taking that veered out surface wind as input and hence the linear storm mode. Link to comment Share on other sites More sharing options...
brettjrob Posted June 14, 2014 Share Posted June 14, 2014 Between the H7 weakness/kink, concerns that the ongoing TX MCS could have at least a minor impact on moisture return, and the fact that we're seriously dealing with a banana low and crashing cold front on June 14, there's a lot not to like. I'm not dismissing tomorrow's potential, but it's a pathetic setup for this time of year in a few respects, with several plausible modes of failure. I can only hope against hope that this becomes bump-troll fodder in about 18 hours. And FWIW, the 00z NSSL WRF essentially shows nothing interesting through 02z. Link to comment Share on other sites More sharing options...
tornadotony Posted June 14, 2014 Share Posted June 14, 2014 Between the H7 weakness/kink, concerns that the ongoing TX MCS could have at least a minor impact on moisture return, and the fact that we're seriously dealing with a banana low and crashing cold front on June 14, there's a lot not to like. I'm not dismissing tomorrow's potential, but it's a pathetic setup for this time of year in a few respects, with several plausible modes of failure. I can only hope against hope that this becomes bump-troll fodder in about 18 hours. And FWIW, the 00z NSSL WRF essentially shows nothing interesting through 02z. Both the SPC and NSSL WRFs have off-the-charts updraft helicity with a discrete cell coming out of NE CO near the NE/KS border tomorrow afternoon/evening. That area is N of the sfc low, but within a tongue of moisture that the models wrap N of the low. That could be an intriguing target, and may honestly be the best tornadic target tomorrow. Link to comment Share on other sites More sharing options...
Quincy Posted June 14, 2014 Share Posted June 14, 2014 FWIW 00z NAM fire nest blows up a vigorous supercell in east-central NE around 22z and aside from a tail end Charlie just before sunset closer to the KS border, the forecast reflectivity implies line segments dominate and quickly merge into a strong line as the storms approach the IA border through the evening. Link to comment Share on other sites More sharing options...
andyhb Posted June 14, 2014 Author Share Posted June 14, 2014 In another note, if we get discrete storms firing in the projected environment on Monday, things could go south real quick. There appears to be a low amplitude s/w trough passing through the region on both the Euro and GFS, which would likely provide adequate forcing for ascent given less than crippling cap/700 mb temperatures (actually quite weak by June standards and with that much instability ready to fire). Link to comment Share on other sites More sharing options...
Jonbo Posted June 14, 2014 Share Posted June 14, 2014 Looks like they've expanded the mod risk a bit east due to wind. Also discussion of a potential derecho event. Link to comment Share on other sites More sharing options...
Jim Marusak Posted June 14, 2014 Share Posted June 14, 2014 looking a bit further ahead here, I am seeing a bit of a troubling trend up here in MN for especially Tuesday and Wednesday. looking at the bufkit plots for the twin cities, RWF, and elsewhere as well as the synoptic setup, if the models are even close to realistic on the convection into the Tuesday and Wednesday (and we all know the conjecture on that), somewhere between t+72 and T+84 from this morning's 12Z runs, the lapse rates from 800hPa up to 300hPa go from say 6-6.5 c/km to jumping up almost instantly between t+78 and T+84 to near 8c/kg, taking MU-CAPES from 1500 to near 4000 (GFS last night was hinting as much as 6000 for Wednesday up here) and taking a staunch lid of 150-200j/kg and absolutely collapsing it. That type of scenario, if it came close to becoming fruition, would mean as my shift ends at my current job at Andersen WIndows in Cottage Grove at 3pm, I might be more than tempted to go storm-chase mode right out of work. But that type of jump ahead of a short wave is the type of stuff disasters are made of, imho. honestly, I'm not a total believer of that scenario yet, but if the models remain more consistent about it like it's looking like they might, that is quite a nasty setup and I may just have to be prepared about the possibility in the metro. your thoughts?? am I seeing things, getting too weenie-ish here, or is there something to it like my eyes are seeing? Link to comment Share on other sites More sharing options...
Jayhawkers Posted June 14, 2014 Share Posted June 14, 2014 The RAP is such a horrible model... Literally doesn't develop anywhere close to the amount of instability that will be available across KS/NE only shows >2000J/KG SBCAPE across KS and AOA 2000 across NE when there is already CAPE values of 2000 at 10 in the morning. And that's just CAPE, I'm sure it has a variety of things wrong with it elsewhere. Link to comment Share on other sites More sharing options...
jcwxguy Posted June 14, 2014 Share Posted June 14, 2014 maybe its just me, but it seems like the models have the storms going more north then before. Also looks the the HRRR has a nice cell near G.I. around 8pm (and more storms north of there as well). Almost looks like what we had for our severe weather episode a few weeks ago) Link to comment Share on other sites More sharing options...
nwburbschaser Posted June 14, 2014 Share Posted June 14, 2014 In another note, if we get discrete storms firing in the projected environment on Monday, things could go south real quick. There appears to be a low amplitude s/w trough passing through the region on both the Euro and GFS, which would likely provide adequate forcing for ascent given less than crippling cap/700 mb temperatures (actually quite weak by June standards and with that much instability ready to fire). 12z GFS does seem to have a precip signal in a rather good environment on Monday. Unless I am looking past something, it seems like there is a good chance for some tornadoes in E NE and parts of IA. Link to comment Share on other sites More sharing options...
Quincy Posted June 14, 2014 Share Posted June 14, 2014 maybe its just me, but it seems like the models have the storms going more north then before. Also looks the the HRRR has a nice cell near G.I. around 8pm (and more storms north of there as well). Almost looks like what we had for our severe weather episode a few weeks ago)I do think this can very loosely be compared to June 3. Tornado potential not fully met (assumed) and damaging winds/large hail end up being the bigger story. I'm not really comparing the synoptic setup, but more so the threats. We'll see if storms can stay discrete longer. That last setup was kind of sloppy for the most part. (not forgetting that monster cell that the HRRR nailed as it got going early and then the diamond in the rough cell that fired up well west of the main action) This also happens to be in roughly the same area as 6/3. Link to comment Share on other sites More sharing options...
Thunder Road Posted June 14, 2014 Share Posted June 14, 2014 The hi-res guidance (NMM, ARW, SPC WRF and HRRR) has allcome around to showing some discrete development near the triple point. But man, some of them initiate waaay back west. I'm feeling better now than when I left this morning. Headed for Grand Island now, then probably south a bit. Link to comment Share on other sites More sharing options...
Chinook Posted June 14, 2014 Share Posted June 14, 2014 The HRRR shows several storms firing at 22z in NE Colorado. This area will have about 1500 J/kg and high effective shear. Effective helicity may also be high in NE Colorado. Link to comment Share on other sites More sharing options...
Quincy Posted June 14, 2014 Share Posted June 14, 2014 My only concern about further west is that there's a boundary/front that's already east of North Platte. Winds have shifted to NW west of Broken Bow along with lowering dew-points. I'd have to imagine the best tornado potential is across eastern NE where low level winds are still backed. We'll see how it evolves. Link to comment Share on other sites More sharing options...
andyhb Posted June 14, 2014 Author Share Posted June 14, 2014 Also, there are currently mid 40s dewpoints over the primary threat area, we are going to need some strong moisture advection, otherwise LCL heights are potentially problematic for tornadogenesis. This is looking like a check for now, upper 60s sfc Tds have spread across KS and are nosing into NE thanks to strong southerly surface winds in the 20-25 kt range. Link to comment Share on other sites More sharing options...
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