Thundersnow12 Posted May 17, 2013 Share Posted May 17, 2013 The 12z ncep 4km WRF has CI a bit earlier tomorrow than previous runs. Blows up a supercell near Greensburg then tracks ENE. The environment in south central KS near/after 0z tomorrow is going to be very interesting with the strong LLJ. Link to comment Share on other sites More sharing options...
OKpowdah Posted May 17, 2013 Share Posted May 17, 2013 putting aside all other details, it's nice to finally have a severe threat with multiple days of antecedent moisture. Walked outside last night around 2am and there were areas of thick fog. Still low clouds and drizzle this afternoon. These are the kind of classic conditions I like to see leading into the threat Link to comment Share on other sites More sharing options...
brettjrob Posted May 17, 2013 Share Posted May 17, 2013 12z runs have really beefed up the upper flow for tomorrow, which was the primary expected weakness of the setup. Areas near and just N of the sfc low look rather fantastic on some progs... I completely agree with the placement of the MDT. Link to comment Share on other sites More sharing options...
Ed Lizard Posted May 17, 2013 Share Posted May 17, 2013 Just a quick look at lunch, I still suspect that while they'll be a big tornado or two, hopefully in open country, the bigger threat, not so much for death, but number of people affected and damage, is hail. Very fat mid level CAPE on soundings with decent shear across the region, and I don't see TTs 60 or above very often, Link to comment Share on other sites More sharing options...
Jim Marusak Posted May 17, 2013 Share Posted May 17, 2013 12z runs have really beefed up the upper flow for tomorrow, which was the primary expected weakness of the setup. Areas near and just N of the sfc low look rather fantastic on some progs... I completely agree with the placement of the MDT. mine, or SPC's? either way, tomorrow is looking better for chasers than it has been most of the year so far. Link to comment Share on other sites More sharing options...
OKpowdah Posted May 17, 2013 Share Posted May 17, 2013 dew points up to the low 70's in southern OK now Link to comment Share on other sites More sharing options...
Ian Posted May 17, 2013 Share Posted May 17, 2013 We are off! Link to comment Share on other sites More sharing options...
brettjrob Posted May 17, 2013 Share Posted May 17, 2013 We are off! You seriously couldn't have picked a better day... well, maybe arriving this past Wed, but meh. I'm more and more impressed with tomorrow as I look at 12z runs. Striking similarities to 6/9/05 in several respects. If we get solid 35-40 kt midlevel flow over the dryline/triple point region tomorrow and still can't manage a few good tubes, this season really is hopeless. Link to comment Share on other sites More sharing options...
dljuly3 Posted May 17, 2013 Share Posted May 17, 2013 Hello 70 dew points! Also, Day 2 mod risk. Link to comment Share on other sites More sharing options...
Ian Posted May 17, 2013 Share Posted May 17, 2013 You seriously couldn't have picked a better day... well, maybe arriving this past Wed, but meh. I'm more and more impressed with tomorrow as I look at 12z runs. Striking similarities to 6/9/05 in several respects. If we get solid 35-40 kt midlevel flow over the dryline/triple point region tomorrow and still can't manage a few good tubes, this season really is hopeless.I'm psyched. We were due to run into a real setup.. Hopefully we don't cut it too close but should get in early afternoon. Link to comment Share on other sites More sharing options...
SmokeEater Posted May 17, 2013 Share Posted May 17, 2013 I guess the concerns about the models overdoing moisture isn't coming to pass. Dews already in the 70's in S OK, damn. Link to comment Share on other sites More sharing options...
Uncle Bobby Posted May 17, 2013 Share Posted May 17, 2013 This setup looks pretty sweet for tomorrow, per 12Z NAM. It is my nature and my obsession to find flaws in the parameters. I have a couple thoughts to share. For a MDT area target: With only moderate upper speeds the sfc L is going to be just a little shallower than I'd like to see. i.e. ~996mb. As such, sfc winds are progged at only around 15kts, and with a generally N'wd motion that is a potential problem. Unless I catch a right-mover, any supercell may have an inflow problem. Also, for anyone who may be chasing and hasn't chased in that area before, be aware that the Sandhills absolutely SUCK for chasing purposes. I will not go in there to chase. Period. Visibility is non-existent most of the time, and there is no road network per se. It's nice to live here! I am no more than 3 hours from the target as I type! P.S. and OT: I have to be in Columbus OH no later than next Friday for a wedding (the 26th). This trough will take me right there. It couldn't have worked out any better if I asked for it, LOL! Link to comment Share on other sites More sharing options...
andyhb Posted May 17, 2013 Share Posted May 17, 2013 12z runs have really beefed up the upper flow for tomorrow, which was the primary expected weakness of the setup. Areas near and just N of the sfc low look rather fantastic on some progs... I completely agree with the placement of the MDT. Someone is going to see some absolutely monster hail tomorrow. Link to comment Share on other sites More sharing options...
Ed Lizard Posted May 17, 2013 Share Posted May 17, 2013 We are off! I love giant hail videos you know, Ian. Don't assume you've failed if you get grapefruits but no tornadoes. I know models and targets will be adjusted, but both GFS and NAM soundings scream canteloupes for Tulsa Sunday. Look at that speed and directional shear across the fat part of the CAPE above about 750 mb! I have plans Sunday, but watching the YouTubes during lunch hour Monday, on the agenda. Link to comment Share on other sites More sharing options...
andyhb Posted May 17, 2013 Share Posted May 17, 2013 For a MDT area target: With only moderate upper speeds the sfc L is going to be just a little shallower than I'd like to see. i.e. ~996mb. As such, sfc winds are progged at only around 15kts, and with a generally N'wd motion that is a potential problem. Unless I catch a right-mover, any supercell may have an inflow problem. Also, for anyone who may be chasing and hasn't chased in that area before, be aware that the Sandhills absolutely SUCK for chasing purposes. I will not go in there to chase. Period. Visibility is non-existent most of the time, and there is no road network per se. Storm movement tomorrow, if this is what you are referring to, is not going to be to the NW (like, say, 5/22/08), and the sfc wind fields and SLP depth are plenty. Also, the primary threat area as of now looks to be generally south of the Sandhills, so I would hope nobody would get lost out there. Link to comment Share on other sites More sharing options...
David Reimer Posted May 17, 2013 Share Posted May 17, 2013 Myself and a few other chasers will be heading up to the Best Western in Greensburg tonight and plan to chase in that general area tomorrow. The 12Z NAM looks pretty sweet! Link to comment Share on other sites More sharing options...
OKpowdah Posted May 17, 2013 Share Posted May 17, 2013 12z NAM is looking pretty impressive for south-central KS tomorrow. Link to comment Share on other sites More sharing options...
KSWx Posted May 17, 2013 Share Posted May 17, 2013 Greg Forbes at TWC is calling for West and Central Iowa to have the highest chances for a tornado Sunday, anyone seeing anything that backs up his view? Link to comment Share on other sites More sharing options...
andyhb Posted May 17, 2013 Share Posted May 17, 2013 Mesoanalysis/current obs. now showing a 72 degree dewpoint at Enid, 73 at SNL, high 60s are basically to the KS/OK border. Link to comment Share on other sites More sharing options...
Ed Lizard Posted May 17, 2013 Share Posted May 17, 2013 12z NAM is looking pretty impressive for south-central KS tomorrow. namSGP_sfc_prec_039.gif Screen Shot 2013-05-17 at 1.43.58 PM.png Screen Shot 2013-05-17 at 1.45.14 PM.png Cloud bases look a smidge high for tornadoes at Medicine Lodge (As a rank amateur, I like my forecast soundings with numbers) at 7pm, but assuming low level flow picks up at dusk and cloud bases lower... BTW, I mentioned humungous hail on a storm chasing admins FB post early this morning, but SWODY2 mentions an algorithm. LIX/MSY used to discuss algorithms used for severe forecasting. It would probably involve importing data files, so not for someone like me, but a grad student in a met department at OU, would students have access to those kind of programs? Link to comment Share on other sites More sharing options...
Jim Marusak Posted May 17, 2013 Share Posted May 17, 2013 Greg Forbes at TWC is calling for West and Central Iowa to have the highest chances for a tornado Sunday, anyone seeing anything that backs up his view? Synoptically, I think I see what he is getting at. you have a double-barreled low moving up towards i-29 for sunday. If you believe the NAM, you'll have low#1 come up I-29 and make its way over towards northern MN in the morning and drag its front through with round one of storms. But as low #1 moves north and occludes in the afternoon, low #2 will come up from KS and NE, lifting the front back up as a warm front before all the pieces come together in the afternoon, turning the dynamics and the boundaries into a mesoscale jumble that will allow for anything with any decent clearing. As for the GFS look at it, low#1 heads northwards into MN in the morning, then into Northern Ontario in the afternoon, leaving a much different synoptic boundary. But low #2 develops in KS and NE in the morning, moving towards FSD late in the afternoon, bringing a second warm front through with that push of air. And with low#2, western and central IA as well as extreme southern MN and northern MO will be under the bigtime gun for the perfect dynamics for anything and everything. South of I-70, you're looking at a cold front that would start a pretty ugly squall-line late evening into the overnight once things unzip in IA. either way, the 2-low scenario is what I think will boost the tornado risk there compared to other areas, imho. Link to comment Share on other sites More sharing options...
AgeeWx Posted May 17, 2013 Share Posted May 17, 2013 Not necessarily in our region but there's a report of a tornado on the ground in Athens, AL right now. Link to comment Share on other sites More sharing options...
OKpowdah Posted May 17, 2013 Share Posted May 17, 2013 Cloud bases look a smidge high for tornadoes at Medicine Lodge (As a rank amateur, I like my forecast soundings with numbers) at 7pm, but assuming low level flow picks up at dusk and cloud bases lower... BTW, I mentioned humungous hail on a storm chasing admins FB post early this morning, but SWODY2 mentions an algorithm. LIX/MSY used to discuss algorithms used for severe forecasting. It would probably involve importing data files, so not for someone like me, but a grad student in a met department at OU, would students have access to those kind of programs? With a temp-dp spread no more than 10F degrees, LCLs (and cloud bases) should be just fine. I don't know about the specifics of the hail algorithm being used, but general predictive scheme probably includes CAPE, freezing level, and wet bulb zero level... involves mid level moisture. So high CAPE, low freezing level, and mid level dry air are three characteristics related to large hail ...but that's pretty general Link to comment Share on other sites More sharing options...
OKpowdah Posted May 17, 2013 Share Posted May 17, 2013 Not necessarily in our region but there's a report of a tornado on the ground in Athens, AL right now. TOR on the puniest cell ever Link to comment Share on other sites More sharing options...
Indystorm Posted May 17, 2013 Share Posted May 17, 2013 We are off! Best of luck to you...stay safe in the zoo, and give us timely reports! Link to comment Share on other sites More sharing options...
Chinook Posted May 17, 2013 Share Posted May 17, 2013 Greg Forbes at TWC is calling for West and Central Iowa to have the highest chances for a tornado Sunday, anyone seeing anything that backs up his view? Looks like southwest Iowa will be near a warm front on Sunday. Link to comment Share on other sites More sharing options...
AgeeWx Posted May 17, 2013 Share Posted May 17, 2013 TOR on the puniest cell ever I giggled when I saw it but there was definitely rotation with it for a scan or two. Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 17, 2013 Share Posted May 17, 2013 FWIW, the 12z 4KM NAM looks extremely impressive for tomorrow as well as Sunday. By late afternoon tomorrow (around 20z) it has supercells exploding in western Kansas and Nebraska and track NE. The updraft helicity on these cells look absolutely intense, probably the kind that put down quite a few tornadoes. And finally, by 21z Sunday it has supercells (with some extreme updrafts) in Missouri, with discrete cells firing in northern Oklahoma. Been going over the higher resolution models over the past hour and I think tomorrow might see a decent expansion of the MDT risk. Really liking how things look... Round 1- Saturday (UPDRAFT HELICITY) Round 2- Sunday (UPDRAFT HELICITY) Link to comment Share on other sites More sharing options...
andyhb Posted May 17, 2013 Share Posted May 17, 2013 Those UH signatures tomorrow are insane, and with the substantially low LCLs, well I think the rest can be filled in from there. Link to comment Share on other sites More sharing options...
Uncle Bobby Posted May 17, 2013 Share Posted May 17, 2013 Actually, I'm wondering why anyone has doubts about Iowa for Sunday. With 00Z Td's in the 70's and the left front exit region of the 500mb speed max, what is the problem? Link to comment Share on other sites More sharing options...
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