A-L-E-K Posted January 4, 2014 Share Posted January 4, 2014 Hey you guys think someone will get....THUNDERSNOW?! STL to CMI looks most likely Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 4, 2014 Share Posted January 4, 2014 anyone seen cyclone...trends are good for his back yard Link to comment Share on other sites More sharing options...
McDude Posted January 4, 2014 Share Posted January 4, 2014 STL to CMI looks most likely Nothing from this current banding in northern Illinois? Seems like the type of rapid growth that would produce it. Link to comment Share on other sites More sharing options...
csnavywx Posted January 4, 2014 Share Posted January 4, 2014 Cross-posting a post I did from our STL forums: I'm done dissecting the 12Z NAM BUFKIT profile and perusing the other models to ensure consistency.The first panel here is BUFKIT output for late tomorrow morning on the NAM. On the right is the forecast skew-T and omega profile (increments of 5 microbar/sec) and on the left is RH with theta-e (equivalent potential temperature) superimposed so we can diagnose saturated theta-e (generally RH >80%). Note that the theta-e surfaces in the green go vertical for quite some time tomorrow morning. This indicates weak to moist neutral vertical stability. The omega profile certainly shows strong upward vertical motion.Note the nearly unidirectional, decently sheared flow in the mid-levels. So, we do have a case for possible CSI. I don't have access to absolute angular momentum plots that I can use to compare to the saturated theta-e surfaces, but I can still use absolute vorticity charts to give me a good idea. I would need an area of weak absolute vorticity to line up with the conditions outlined above. So, do I have it? Yep:12Z Sunday18Z SundayThese two panels clearly show an area of weak absolute vorticity moving over the area between 12Z and 18Z Sunday. This is backed up by quite a few other model runs as well. So, it appears I have all of the necessary conditions in place. But, let's do a sanity check and make sure this matches up with what's going on upstairs at 300mb and 500mb:300mb winds - 15Z Sunday500mb winds - 15Z SundayCheck and check. We seem to be parked underneath the entrance region of an slightly anti-cyclonically curved jet at 300mb and the exit region of a strengthening cyclonically curved mid-and-upper level jet streak (centered over OK/AR at this time). Great jet coupling going on, so I know the lower-level depiction of strong UVV is probably spot on. The entrance region of an anti-cylonically curved jet also lets me know that CSI is possible.All-in-all, this seems to be a great candidate for CSI-enhanced banding. With the inrush of very cold air at the low levels after 12Z (to the point of developing a second ice crystal growth zone in the low levels after 15Z), we will see snow ratios skyrocket after this time, probably peaking towards the end of the maximum forcing.The interesting thing is, even though a dry slot cuts in after 18-21Z above 600mb, mid to low level temps become perfect for dendrites, allowing us to hold on to a light fluffy snow well into the afternoon. Link to comment Share on other sites More sharing options...
Chicago Storm Posted January 4, 2014 Author Share Posted January 4, 2014 correct main system still looks to miss all but the far SE CWA We're in the game for a moderate hit from the main system. Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 4, 2014 Share Posted January 4, 2014 NAM/GFS currently too far south with the fgen band. Link to comment Share on other sites More sharing options...
csnavywx Posted January 4, 2014 Share Posted January 4, 2014 STL to CMI looks most likely Essentially this. CSI looks more prevalent on the STL side. Strictly speaking, you need about 5 m/s of upward motion to get lightning, CSI generally doesn't get quite that strong, though in this case it's very borderline between CSI (slantwise) and upright, so you may end up seeing a few strikes. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 4, 2014 Share Posted January 4, 2014 We're in the game for a moderate hit from the main system. Agreed. Link to comment Share on other sites More sharing options...
Chicago WX Posted January 4, 2014 Share Posted January 4, 2014 4km NAM 2m temps at 0z Monday. What a squeeze. http://www.meteo.psu.edu/~fxg1/NAMSFC4_12z/temp36.html Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 4, 2014 Share Posted January 4, 2014 4km NAM 2m temps at 0z Monday. What a squeeze. temp36.gif you'll be fine Link to comment Share on other sites More sharing options...
Hoosier Posted January 4, 2014 Share Posted January 4, 2014 anyone seen cyclone...trends are good for his back yard He bailed last night. Link to comment Share on other sites More sharing options...
Chicago WX Posted January 4, 2014 Share Posted January 4, 2014 you'll be fine Haha, that wasn't a "OMG rain" post...just was digging the temp crash. Link to comment Share on other sites More sharing options...
Hoosier Posted January 4, 2014 Share Posted January 4, 2014 Posted a little about this last night but the rapid, extreme temperature drop (temps well below zero) behind this thing is quite something. I've been looking through the records and I've only found a couple similar events around here over the past 100+ years and they were like 100 years ago. A snow of this magnitude with an immediate temperature drop of this magnitude may be a once or twice in a lifetime thing around here. Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 4, 2014 Share Posted January 4, 2014 Haha, that wasn't a "OMG rain" post...just was digging the temp crash. all those writing is on the wall posts earlier had me fooled enjoy your big dog. game time in a couple. hope we finally beat down psu. Link to comment Share on other sites More sharing options...
TugHillMatt Posted January 4, 2014 Share Posted January 4, 2014 Posted a little about this last night but the rapid, extreme temperature drop (temps well below zero) behind this thing is quite something. I've been looking through the records and I've only found a couple similar events around here over the past 100+ years and they were like 100 years ago. A snow of this magnitude with an immediate temperature drop of this magnitude may be a once or twice in a lifetime thing around here. There is going to be some MAJOR drifting with this. Link to comment Share on other sites More sharing options...
A-L-E-K Posted January 4, 2014 Share Posted January 4, 2014 kevlon is getting trained with SN/+SN Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 4, 2014 Share Posted January 4, 2014 Geos will start off 18" ahead of the rest of everyone Link to comment Share on other sites More sharing options...
hoosierwx Posted January 4, 2014 Share Posted January 4, 2014 Posted a little about this last night but the rapid, extreme temperature drop (temps well below zero) behind this thing is quite something. I've been looking through the records and I've only found a couple similar events around here over the past 100+ years and they were like 100 years ago. A snow of this magnitude with an immediate temperature drop of this magnitude may be a once or twice in a lifetime thing around here. Was it 94 when we got the 15" or so of snow and temps dropped into the -30's? Don't know if you guys had the same. Link to comment Share on other sites More sharing options...
Chicago WX Posted January 4, 2014 Share Posted January 4, 2014 all those writing is on the wall posts earlier had me fooled enjoy your big dog. game time in a couple. hope we finally beat down psu. I'm not 100% confident mind you, but I like it right now. I'm sleep deprived...pre-storm jitters in anticipation I guess. If I say something crazy, just ignore me. Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted January 4, 2014 Share Posted January 4, 2014 Generally agree with this. Trace for me! Take it or leave it. I'm done with Winter. I can't believe The Weather Network is still showing the Storm Watch segment on TV calling for 4-8" in the GTA. There is no way that happens. Link to comment Share on other sites More sharing options...
ILSNOW Posted January 4, 2014 Share Posted January 4, 2014 kevlon is getting trained with SN/+SN started as sleet and just changed to snow Link to comment Share on other sites More sharing options...
Chicago WX Posted January 4, 2014 Share Posted January 4, 2014 Geos will start off 18" ahead of the rest of everyone Geos will have 3 feet OTG after this one. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 4, 2014 Share Posted January 4, 2014 16z RAP seems to have a good handle looking at radar. Things really take off later this afternoon Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted January 4, 2014 Share Posted January 4, 2014 http://www.theweathernetwork.com/news/articles/ontario-prepares-for-its-first-winter-storm-of-2014/18890/ Link to comment Share on other sites More sharing options...
Hoosier Posted January 4, 2014 Share Posted January 4, 2014 Was it 94 when we got the 15" or so of snow and temps dropped into the -30's? Don't know if you guys had the same. We didn't get big snows with that here. Besides, the temp drop took longer/was not as extreme. We are talking about going from heavy snow to perhaps 15 below zero or colder in a matter of several hours. Link to comment Share on other sites More sharing options...
Chicago Storm Posted January 4, 2014 Author Share Posted January 4, 2014 NAM/GFS currently too far south with the fgen band. HRRR is handling things well. The first wave stays along/north of a DKB-PWK line. Second wave is farther south across the heart of the area, and develops after 1PM and lasts into tonight. Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted January 4, 2014 Share Posted January 4, 2014 Was it 94 when we got the 15" or so of snow and temps dropped into the -30's? Don't know if you guys had the same. January 16-19, 1994. Link to comment Share on other sites More sharing options...
Geos Posted January 4, 2014 Share Posted January 4, 2014 Geos will start off 18" ahead of the rest of everyone Lol. Snowing solid moderate here with 1/2 diameter flakes. Link to comment Share on other sites More sharing options...
hoosierwx Posted January 4, 2014 Share Posted January 4, 2014 We didn't get big snows with that here. Besides, the temp drop took longer/was not as extreme. We are talking about going from heavy snow to perhaps 15 below zero or colder in a matter of several hours. I was just thinking it may have taken a day or two for the cold to settle in. Long time ago. Link to comment Share on other sites More sharing options...
Gilbertfly Posted January 4, 2014 Share Posted January 4, 2014 Little sidebar note...the near freezing temps combined with wind friction has created a thin layer of crust to the 9-12" snowpack IMBY....on one hand this helps to keep the previous fallen fluff from blowing too much...but on the other hand will aid in any new fluff to blow and drift even easier as friction will be greatly depleted by the new smoother surfaces... FWIW Link to comment Share on other sites More sharing options...
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