Jonbo Posted April 27, 2016 Share Posted April 27, 2016 Rotation has been really broad on the storm just SE of Council Bluffs but seems to be trying to tighten up a little. Maybe a spinup soon. Link to comment Share on other sites More sharing options...
KSWx Posted April 27, 2016 Share Posted April 27, 2016 Rotation has been really broad on the storm just SE of Council Bluffs but seems to be trying to tighten up a little. Maybe a spinup soon. Yeah, looks like they've added the "Tornado possible" hazard to the severe thunderstorm warning. Link to comment Share on other sites More sharing options...
Chicago Storm Posted April 27, 2016 Author Share Posted April 27, 2016 Next storm to watch is just east of Hopkins, MO...Along the IA/MO border. Link to comment Share on other sites More sharing options...
Jonbo Posted April 27, 2016 Share Posted April 27, 2016 Yeah, looks like they've added the "Tornado possible" hazard to the severe thunderstorm warning. That seems unusual to do but I could be wrong. I sincerely regret leaving Omaha/CB yesterday thinking today would not do much. Link to comment Share on other sites More sharing options...
codfishsnowman Posted April 27, 2016 Share Posted April 27, 2016 this reminds us of our forum in the winter with all this discussion over a really unexceptional event, it is like us having a fifty page thread for an advisory level snowfall which happens in a ratter winter the weather channel just makes this constant national news, seems like a retrospective on the super outbreak of 2011 would be more interesting Link to comment Share on other sites More sharing options...
KSWx Posted April 27, 2016 Share Posted April 27, 2016 this reminds us of our forum in the winter with all this discussion over a really unexceptional event, it is like us having a fifty page thread for an advisory level snowfall which happens in a ratter winter the weather channel just makes this constant national news, seems like a retrospective on the super outbreak of 2011 would be more interesting After the last couple Springs (and yesterday for that matter,) we take what we can get. Link to comment Share on other sites More sharing options...
MattPetrulli Posted April 27, 2016 Share Posted April 27, 2016 Friday looks interesting for the OKC metro area. Will be interesting to see if morning convection affects airmass, but could help tornado potential by possibly setting up a OFB over the area. 18z NAM continues to insist a threat of a strong tornado or 2 in Central OK. Another tough forecast. Sigh. Link to comment Share on other sites More sharing options...
Jonbo Posted April 27, 2016 Share Posted April 27, 2016 New rotation popped up north of Glenwood. Seems to be tightening up fairly quickly. edit: Practically gone. Seems the overall threat there is going down looking at velocity. Link to comment Share on other sites More sharing options...
wildwestpb Posted April 27, 2016 Share Posted April 27, 2016 Friday looks interesting for the OKC metro area. Will be interesting to see if morning convection affects airmass, but could help tornado potential by possibly setting up a OFB over the area. 18z NAM continues to insist a threat of a strong tornado or 2 in Central OK. Another tough forecast. Sigh. 18z GFS is coming in now. I am waiting for it to get to Sat 00z to see what it shows. So far none of the other models show anything like what the NAM is predicting. Edit: 18z GFS still not showing anything like the NAM is saying with the soundings. Link to comment Share on other sites More sharing options...
Chinook Posted April 27, 2016 Share Posted April 27, 2016 This just goes to show- you don't have to have that classic supercell shape to have a tornado. This is southwest Iowa. I get a little confused as to how squall line tornadoes develop (such as this) but I know it happens a lot. A lot of QLCS/squall line tornadoes are surveyed to be EF0 or EF1. Squall lines are pretty downdraft-oriented, but sometimes some weird things happen, particularly with stronger low-level shear or SRH. Link to comment Share on other sites More sharing options...
MattPetrulli Posted April 27, 2016 Share Posted April 27, 2016 This just goes to show- you don't have to have that classic supercell shape to have a tornado. This is southwest Iowa. I get a little confused as to how squall line tornadoes develop (such as this) but I know it happens a lot. A lot of QLCS/squall line tornadoes are surveyed to be EF0 or EF1. Squall lines are pretty downdraft-oriented, but sometimes some weird things happen, particularly with stronger low-level shear or SRH. Yeah saw a video on Twitter of that. It was kinda of a rainwrapped tornado, couldn't say it was large as I couldn't find the right edge, but a sizable tornado. Link to comment Share on other sites More sharing options...
SmokeEater Posted April 27, 2016 Share Posted April 27, 2016 I couldn't believe SPC went with the PDS Watch yesterday. The veer-back-veer wind profiles should have been a huge warning sign for storm mode. Corfidi...Did this guy make an account 7 hours ago just to bash Corfidi? Link to comment Share on other sites More sharing options...
capbreak Posted April 28, 2016 Share Posted April 28, 2016 That seems unusual to do but I could be wrong. I sincerely regret leaving Omaha/CB yesterday thinking today would not do much. I left Omaha this morning at 10am thinking today would not do much. Boy do I feel dumb. A friend of mine took a quick screen grab of the video he shot today of the Stanton, IA tornado. Grungy, but I'd take it over the grungier tornadoes I saw yesterday near Salina. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted April 28, 2016 Share Posted April 28, 2016 The 0Z NAM for Friday is still insane for part's of Oklahoma, the sounding at 0Z Saturday is so bad that the SARS cant even find analogs for it. Link to comment Share on other sites More sharing options...
jojo762 Posted April 28, 2016 Share Posted April 28, 2016 The 0Z NAM for Friday is still insane for part's of Oklahoma, the sounding at 0Z Saturday is so bad that the SARS cant even find analogs for it.GFS maybe starting to look a bit better. Still shows the large MCS across N TX which would limit LLVL flow as well as moisture quality. But it does show a bit less lingering convection across OK...Still is the NAM/4KNAM going insane vs. everything else not... For the most part at least. Link to comment Share on other sites More sharing options...
brettjrob Posted April 28, 2016 Share Posted April 28, 2016 I'm fairly pessimistic about the chances for anything "big" Friday. There are strong indications that a morning MCS will overturn most of the warm sector (at least in OK) and essentially ruin the environment for the rest of the day, similar to so many events in 2015. The NAM is less aggressive with morning convection than most of the other guidance, and yet even it fails to initiate on the dryline before 00z on tonight's run. If very strong dryline convergence is needed for initiation within a slowly-recovering environment post-MCS, then the lackluster surface low that's depicted (with a rapidly-advancing cold front pinching it off from the NW) is not what we want to see. Definitely too early to write it off, but as of now, odds favor us exiting this whole period of significant troughing/SW flow with relatively little to show for it on the Plains. Link to comment Share on other sites More sharing options...
Chicago Storm Posted April 28, 2016 Author Share Posted April 28, 2016 Didn't chase Tuesday, and not gonna chase Friday either. Early day convection and lingering effects will be too much of an issue most likely. Link to comment Share on other sites More sharing options...
jojo762 Posted April 28, 2016 Share Posted April 28, 2016 I'm fairly pessimistic about the chances for anything "big" Friday. There are strong indications that a morning MCS will overturn most of the warm sector (at least in OK) and essentially ruin the environment for the rest of the day, similar to so many events in 2015. The NAM is less aggressive with morning convection than most of the other guidance, and yet even it fails to initiate on the dryline before 00z on tonight's run. If very strong dryline convergence is needed for initiation within a slowly-recovering environment post-MCS, then the lackluster surface low that's depicted (with a rapidly-advancing cold front pinching it off from the NW) is not what we want to see. Definitely too early to write it off, but as of now, odds favor us exiting this whole period of significant troughing/SW flow with relatively little to show for it on the Plains. then eyes turn to something we could potentially see in early/mid-may... Going to be a solid week or so of almost nothing for the plains between Friday and whenever the next system comes. Link to comment Share on other sites More sharing options...
BuffaloWeather Posted April 28, 2016 Share Posted April 28, 2016 Today had 19 tornado reports, yesterday had 8...I don't think I'll ever understand tornadic outbreaks. Link to comment Share on other sites More sharing options...
andyhb Posted April 28, 2016 Share Posted April 28, 2016 Normally a relatively low amplitude (as opposed to Tuesday's) neg tilt shortwave with a 70-80 kt H5 jet plowing across the S Plains in late April = yikes. Synoptically in the mid/upper levels, this one looks pretty darn stout, it would be good if we had a stronger cap than advertised like what verified on Tuesday to perhaps keep some of that early junk to a minimum, although obviously I'm not too optimistic on that happening. One thing of note though, even with slight VBV, the forecast hodographs on both the GFS and NAM are much less messy overall in the lowest 6 km and also the cross-boundary shear supports propagation away from the dryline vs. along it. I also do like the relatively zonal flow aloft that might tend to shift the early stuff away from the region of backed low level flow south of the warm front. Link to comment Share on other sites More sharing options...
thewxmann Posted April 28, 2016 Share Posted April 28, 2016 I'm fairly pessimistic about the chances for anything "big" Friday. There are strong indications that a morning MCS will overturn most of the warm sector (at least in OK) and essentially ruin the environment for the rest of the day, similar to so many events in 2015. The NAM is less aggressive with morning convection than most of the other guidance, and yet even it fails to initiate on the dryline before 00z on tonight's run. If very strong dryline convergence is needed for initiation within a slowly-recovering environment post-MCS, then the lackluster surface low that's depicted (with a rapidly-advancing cold front pinching it off from the NW) is not what we want to see. Definitely too early to write it off, but as of now, odds favor us exiting this whole period of significant troughing/SW flow with relatively little to show for it on the Plains. Even the NAM verifies in the morning, that's enough convection to rob a warm sector. NAM just destabilizes unrealistically quickly, which was something we observed in 2015 as well. Link to comment Share on other sites More sharing options...
andyhb Posted April 28, 2016 Share Posted April 28, 2016 Even the NAM verifies in the morning, that's enough convection to rob a warm sector. NAM just destabilizes unrealistically quickly, which was something we observed in 2015 as well. Well last year was largely a function of rampant cold pool generation (especially the 5/7-9 event). If that early stuff on the NAM/whatever else is not overly organized, then you'd have a better shot at destabilizing in behind. Definitely think 2000-3000 CAPE is more realistic than 4k+ in the wake of that, but that would be enough with 60+ kt 0-6 km shear and strongly backed low level flow assuming initiation. I'd be foolish to ignore a favorable looking synoptic solution like this as opposed to Tuesday, which even on the synoptic level generally ended up downtrending with time (shorter wavelength, sharper, more meridional, etc). Link to comment Share on other sites More sharing options...
bjc3395 Posted April 28, 2016 Share Posted April 28, 2016 Normally a relatively low amplitude (as opposed to Tuesday's) neg tilt shortwave with a 70-80 kt H5 jet plowing across the S Plains in late April = yikes. Synoptically in the mid/upper levels, this one looks pretty darn stout, it would be good if we had a stronger cap than advertised like what verified on Tuesday to perhaps keep some of that early junk to a minimum, although obviously I'm not too optimistic on that happening. One thing of note though, even with slight VBV, the forecast hodographs on both the GFS and NAM are much less messy overall in the lowest 6 km and also the cross-boundary shear supports propagation away from the dryline vs. along it. I also do like the relatively zonal flow aloft that might tend to shift the early stuff away from the region of backed low level flow south of the warm front. Unfortunately it doesn't matter if the warm front can't quite advance northward enough such that favorable coupling of shear and instability are maximized. Worth following. This will likely be a tough forecast. Link to comment Share on other sites More sharing options...
andyhb Posted April 28, 2016 Share Posted April 28, 2016 Unfortunately it doesn't matter if the warm front can't quite advance northward enough such that favorable coupling of shear and instability are maximized. Worth following. This will likely be a tough forecast. Yeah, I can't say I'm expecting much (looks likely that at least one rogue ripple in the mid/upper flow will initiate a mess early on that could easily suffocate the whole warm sector). I'll be damned if it isn't a fairly impressive looking shortwave ejecting though. Link to comment Share on other sites More sharing options...
bjc3395 Posted April 28, 2016 Share Posted April 28, 2016 Yeah, I can't say I'm expecting much (looks likely that at least one rogue ripple in the mid/upper flow will initiate a mess early on that could easily suffocate the whole warm sector). I'll be damned if it isn't a fairly impressive looking shortwave ejecting though.it can't be ruled out. Central OK def should be paying attention because a nam verf would be pretty bad. At least potentially. Literally no cap is a big issue though. Any forcing and boom.. no bueno. Link to comment Share on other sites More sharing options...
nwburbschaser Posted April 28, 2016 Share Posted April 28, 2016 Yeah, I can't say I'm expecting much (looks likely that at least one rogue ripple in the mid/upper flow will initiate a mess early on that could easily suffocate the whole warm sector). I'll be damned if it isn't a fairly impressive looking shortwave ejecting though. I can't look past this yet. If I were a betting man I'd say this doesn't work out, but I'm not going to rule anything out because I really like the look of this depending on destabilization. Link to comment Share on other sites More sharing options...
andyhb Posted April 28, 2016 Share Posted April 28, 2016 it can't be ruled out. Central OK def should be paying attention because a nam verf would be pretty bad. At least potentially. Literally no cap is a big issue though. Any forcing and boom.. no bueno. Get an EML -> trough no bueno. Get a trough -> EML no bueno. Link to comment Share on other sites More sharing options...
bjc3395 Posted April 28, 2016 Share Posted April 28, 2016 It's an interesting forecast. Limited early morning convection could really set up something explosive. However.. limited cap also provides its own issues. One thing this has over may 16th is it seems like less of a meridional component to the mid and upper level flow, which would allow morning cloud cover to get out of the warm sector much quicker should convection be on the lesser side. Link to comment Share on other sites More sharing options...
brettjrob Posted April 28, 2016 Share Posted April 28, 2016 I see the likelihood of a high-end event Friday as really minimal, and not just conditional on minimizing morning crapvection. The fact that there's a rapidly-advancing cold front before late evening is an entire separate issue that could throw a total wrench in things. Firstly, it's very hard to find big dryline days when you have a swiftly-advancing cold front in play before dark. Tonight's 4 km NAM and NCEP WRFs are much more aggressive with the front than the coarse-grid models, bringing it into central OK by 00z Sat. With seasonably cold temperatures behind it, I'm inclined to think they're onto something. Even a compromise solution has the front somewhere around Shamrock to Woodward by 00z... you could still have a serious supercell threat in the warm sector, I suppose, but the window would be limited and it would need to be down the dryline from the triple point to avoid undercutting. Getting the dryline convergence needed for initiation after MCS stabilization and with the sfc low likely being banana-like is... well, a tall order is putting it nicely. Maybe Tuesday is biasing me on the bearish side a tad, but I just don't see it. Link to comment Share on other sites More sharing options...
andyhb Posted April 28, 2016 Share Posted April 28, 2016 I feel like your posts are getting more depressing with each passing year lol. Link to comment Share on other sites More sharing options...
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