Hoosier Posted April 3, 2017 Share Posted April 3, 2017 Not sure this will end up being something significant/thread worthy, but there would appear to be increasing potential for a late season snow event mid to late week. Models are suggesting just enough cold air wrap-in/dynamic cooling for a band of wet snow developing on Wednesday. The devil is in the details of course, and small adjustments in the thermal profiles could have significant ramifications. One thing that looks likely is that the system will be fairly slow moving, so there will at least be the potential for some significant snow accumulations (especially by April standards) as long as the low levels are cold enough. Link to comment Share on other sites More sharing options...
Hoosier Posted April 3, 2017 Author Share Posted April 3, 2017 Even with a heavy/wet snow, you could actually argue a period of near blizzard conditions on the 00z NAM, especially closer to Lake Michigan. Link to comment Share on other sites More sharing options...
Stebo Posted April 3, 2017 Share Posted April 3, 2017 Ugh, I just hope it melts fast. Link to comment Share on other sites More sharing options...
Hoosier Posted April 3, 2017 Author Share Posted April 3, 2017 7 minutes ago, Stebo said: Ugh, I just hope it melts fast. You're in luck. Link to comment Share on other sites More sharing options...
Stebo Posted April 3, 2017 Share Posted April 3, 2017 Just now, Hoosier said: You're in luck. Well yeah it is April, but yawn. To be honest I think the thermodynamic profile still needs work before I buy into any appreciable accumulation. Link to comment Share on other sites More sharing options...
Hoosier Posted April 3, 2017 Author Share Posted April 3, 2017 4 minutes ago, Stebo said: Well yeah it is April, but yawn. To be honest I think the thermodynamic profile still needs work before I buy into any appreciable accumulation. As mentioned in the other thread, I'd like to see 925 mb temps a bit cooler than progged given the time of year. Perhaps it will turn out to be good enough with heavier precip rates (especially after dark). Link to comment Share on other sites More sharing options...
Stebo Posted April 3, 2017 Share Posted April 3, 2017 Just now, Hoosier said: As mentioned in the other thread, I'd like to see 925 mb temps a bit cooler than progged given the time of year. Perhaps it will turn out to be good enough with heavier precip rates (especially after dark). Yeah nighttime would help because otherwise I would think a mixed bag or cold rain for this one. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted April 3, 2017 Share Posted April 3, 2017 The 0Z GFS wants to go all out for the LES areas Link to comment Share on other sites More sharing options...
Hoosier Posted April 3, 2017 Author Share Posted April 3, 2017 There's going to be some serious waves on Lake Michigan, and maybe lakeshore flooding/erosion given the strong winds and duration as it looks now. Link to comment Share on other sites More sharing options...
hawkeye_wx Posted April 3, 2017 Share Posted April 3, 2017 The south trend on the models for the midweek system continues unabated. For a week this was going to be the big show for Iowa. Now the GFS and GEM are total whiffs south and the NAM is flirting with a whiff. This system is just coming in too quickly behind the first big system(which is more expansive than earlier expected), so south it goes. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 3, 2017 Share Posted April 3, 2017 GFS has been straight up awful in handling this system up to this point. Parts of Iowa have gone from a 3-5" rain event to literally not a drop of rain. The weakening trend (more towards the usually correct Euro) has continued. I don't even know why I even bother looking at the GFS beyond 84hrs. Link to comment Share on other sites More sharing options...
OHweather Posted April 3, 2017 Share Posted April 3, 2017 A storm that performed well that may be somewhat similar to this one is April 2-3, 2005...similar temp profiles (850mb temps only bottomed out at -4 to -6C with the coldest part of the storm) and similar intensity. That one closed off and deepened a little farther east than the models show with this one but ended up at a similar intensity and placement over the NE by the time it did deepen to what is shown here. With that storm it snowed and accumulated during the day in north-central OH with 850mb temps not even down to -5C. If this storm closes off and deepens farther west it may put the heaviest snow over lower MI as opposed to extreme NE OH and NE PA where the 2005 storm dropped a widespread 4-8" on north central and NE OH and locally 20-30" in the higher terrain in extreme NE OH and NW PA. This one may move a tad quicker so potential amounts may not be that mind boggling...but it shows that similar temp profiles to what is being modeled have produced nicely in the region before this time of year. We get decent sampling for the 12z runs which may help get some better model agreement...though convection in the warm sector will have impacts on the overal evolution of the storm and will be poorly modeled so this may be one where it's hard to pin down until the last minute. Link to comment Share on other sites More sharing options...
Hoosier Posted April 3, 2017 Author Share Posted April 3, 2017 Added complication in the LOT cwa could be figuring out how much impact that 40-50 mph winds blowing off a lake in the low 40s will have. By observing numerous past events, I have noticed that is about the threshold where some negative impacts can begin, especially in setups that are marginal to begin with. Winds do eventually turn more offshore from the Illinois side. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 3, 2017 Share Posted April 3, 2017 36 degrees and rain on Wednesday. Something we saw quite frequently the last 4 months. Link to comment Share on other sites More sharing options...
OHweather Posted April 3, 2017 Share Posted April 3, 2017 3 hours ago, Hoosier said: Added complication in the LOT cwa could be figuring out how much impact that 40-50 mph winds blowing off a lake in the low 40s will have. By observing numerous past events, I have noticed that is about the threshold where some negative impacts can begin, especially in setups that are marginal to begin with. Winds do eventually turn more offshore from the Illinois side. That'll be interesting to figure out if LOT ends up being in the potential swath of snow. On one hand, just from a couple of glances at the NAM it looks like there may be just enough instability over the lake for a little bit of enhancement...so you may add some precip downwind of the lake...but does that counteract at least a couple of degrees of warming? It may have to snow heavily for accums within 10-15 miles of the lake with how strong the winds are likely to be. It does look like the east/weaker trend from the last several runs of the non-Euro models has stopped this run, and the Euro and EPS may be a tick stronger/west as well...which would be good for those south/west of Michigan hoping to see an accumulating snow. Link to comment Share on other sites More sharing options...
Toronto4 Posted April 3, 2017 Share Posted April 3, 2017 18 minutes ago, OHweather said: That'll be interesting to figure out if LOT ends up being in the potential swath of snow. On one hand, just from a couple of glances at the NAM it looks like there may be just enough instability over the lake for a little bit of enhancement...so you may add some precip downwind of the lake...but does that counteract at least a couple of degrees of warming? It may have to snow heavily for accums within 10-15 miles of the lake with how strong the winds are likely to be. It does look like the east/weaker trend from the last several runs of the non-Euro models has stopped this run, and the Euro and EPS may be a tick stronger/west as well...which would be good for those south/west of Michigan hoping to see an accumulating snow. I just saw the latest 12z Euro and it looks like the primary low tracks into northern OH before transferring to a secondary low around eastern PA Thursday afternoon. That secondary low really intensifies into a 980mb low in central NY state Friday morning. The ECMWF snow maps (both operational and EPS) show accumulating snow in southern Ontario and parts of MI, OH and WNY. Link to comment Share on other sites More sharing options...
Hoosier Posted April 3, 2017 Author Share Posted April 3, 2017 25 minutes ago, OHweather said: That'll be interesting to figure out if LOT ends up being in the potential swath of snow. On one hand, just from a couple of glances at the NAM it looks like there may be just enough instability over the lake for a little bit of enhancement...so you may add some precip downwind of the lake...but does that counteract at least a couple of degrees of warming? It may have to snow heavily for accums within 10-15 miles of the lake with how strong the winds are likely to be. It does look like the east/weaker trend from the last several runs of the non-Euro models has stopped this run, and the Euro and EPS may be a tick stronger/west as well...which would be good for those south/west of Michigan hoping to see an accumulating snow. 850's eventually drop to around -6C or -7C, so delta T should be good enough for some enhancement. Winds may be shifting more toward favoring Indiana by then but we'll see. Whatever enhancement there is probably will be semi-disorganized or make it very far inland given the strength of the low level winds. Link to comment Share on other sites More sharing options...
Hoosier Posted April 3, 2017 Author Share Posted April 3, 2017 The 40-50 mph gusts that I mentioned earlier may even be conservative for areas near Lake Michigan. With that super long fetch and the progged wind fields/mixing, there may be a shot for some gusts near if not over 60 mph, particularly on Thursday. Link to comment Share on other sites More sharing options...
Snowstorms Posted April 3, 2017 Share Posted April 3, 2017 18z Nam has a heavy rain transitioning to heavy wet snow type of situation Thursday Night - Friday. Would be a messy outcome if it occurred. 18z Nam showing 6-8" + for the GTA. Euro also has 4-6" for the GTA. However, I'm still not sold out on this solution. Alot of variables at play and sometimes backend snow doesn't always pan out as modeled. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted April 3, 2017 Share Posted April 3, 2017 If this would happen I doubt most people would be expecting it. Link to comment Share on other sites More sharing options...
Jonger Posted April 3, 2017 Share Posted April 3, 2017 18 hours ago, Stebo said: Yeah nighttime would help because otherwise I would think a mixed bag or cold rain for this one. Looks more like a rain event for Detroit. Link to comment Share on other sites More sharing options...
Stebo Posted April 3, 2017 Share Posted April 3, 2017 Just now, Jonger said: Looks more like a rain event for Detroit. Yeah I think so, I would be surprised if it turns out more than that. Link to comment Share on other sites More sharing options...
Hoosier Posted April 3, 2017 Author Share Posted April 3, 2017 1 hour ago, HillsdaleMIWeather said: If this would happen I doubt most people would be expecting it. Significant differences between the NAM and GFS, with the NAM being much more favorable with dynamic cooling. This is especially evident in places like northern IL. And needless to say, we will have to be much more cautious than usual with these snow maps. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted April 3, 2017 Share Posted April 3, 2017 16 minutes ago, Hoosier said: Significant differences between the NAM and GFS, with the NAM being much more favorable with dynamic cooling. This is especially evident in places like northern IL. And needless to say, we will have to be much more cautious than usual with these snow maps. Agreed, there are so many moving parts to this system. Link to comment Share on other sites More sharing options...
CoachLB Posted April 4, 2017 Share Posted April 4, 2017 Well just seen the first snowfall maps pop up on social media. With the old this is not a forcast. But.. like our post and send us $$. Link to comment Share on other sites More sharing options...
Hoosier Posted April 4, 2017 Author Share Posted April 4, 2017 Another one to look at for some similarities may be the early April 1970 storm. That one had a more expansive snow band than what this one will have (extended back into the Plains) but there are similarities with the track/evolution/thermal profiles etc. Of course any slight differences can go a long way in changing the outcome. Impressively, Midway Airport (official Chicago observation site at the time) recorded 8.2" of snow (.96" liquid) on April 1 despite temps not dropping below 34. Link to comment Share on other sites More sharing options...
Hoosier Posted April 4, 2017 Author Share Posted April 4, 2017 Here's what LOT had to say about the wind potential on Lake Michigan. Depending on how it looks, I might head to the shore on Thursday if I have time. A more substantial storm system is expected to impact the Lake Wednesday through Friday. This storm system has a decent potential to produce a major northerly wind event over Lake Michigan, with Storm force winds above 50 KT. However, at the present, we have remained conservative on winds, only going to 45 KT. Given the good potential of this high impact event, we have decided to go with an early Gale watch, though admittedly a storm watch/warning may be needed if these higher end winds materialize. The Gale watch goes through late Wednesday into Friday. Waves on southern Lake Michigan with this type of wind event could easily exceed 16 FT, especially over southern portions of the lake by Thursday. KJB Link to comment Share on other sites More sharing options...
Hoosier Posted April 4, 2017 Author Share Posted April 4, 2017 I think areas near southern Lake Michigan may be susceptible to some tree damage from high winds. Obviously not really having the trees leafed out helps, but March was quite wet and will be adding more precip with this storm. Long duration of gusts potentially into the 50-60 mph range and wet soils could cause some problems. Any snow building up on the trees would add to it. Link to comment Share on other sites More sharing options...
smoof Posted April 4, 2017 Share Posted April 4, 2017 That 16" bullseye 25 miles SW of me on the 0z GFS with 50mph wind gusts is pretty sweet to look at, too bad this is going to come down to a nowcast situation with plenty of time for things to change yet. Link to comment Share on other sites More sharing options...
josh_4184 Posted April 4, 2017 Share Posted April 4, 2017 LOL at NAM, ready for spring........ Link to comment Share on other sites More sharing options...
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