Hoosier Posted December 16, 2016 Author Share Posted December 16, 2016 The way the bottom falls out temperature wise right afterwards sort of reminds me of what happened in early January 2014. You aren't talking a couple days later... it's almost an immediate plunge off the cliff. Link to comment Share on other sites More sharing options...
RCNYILWX Posted December 16, 2016 Share Posted December 16, 2016 I keep thinking this thread is really picking up, but it's just Chicago Storm double posting. Sitting quietly observing this one, I really think this will surprise the Chicago Metro north of 88. QPF and evolution just seems off on the models and is starting to catch up. Time will tell.My gut feeling is that too. I think the WAA snow could perform pretty well and the 00z runs have better backed that potential after also trending more robust with the earlier runs today. Also, as I mentioned in the AFD, and others have, the surface low track is quite favorable for significant accumulations in parts of northern IL. There's been a few runs that depict that conceptual model well, such as recent runs of the GEM, so perhaps the globals are getting the track part right, but missing on other aspects. I was very close to issuing a Winter storm Watch for the northern tier of counties, but instead of a another confusing headline situation, decided on the advisory. If Euro trends better tonight, I'll feel pretty confident that we'll need to upgrade to a warning at least along the WI border and possibly down to the I-88 corridor counties. Link to comment Share on other sites More sharing options...
Minnesota Meso Posted December 16, 2016 Share Posted December 16, 2016 Upper level divergence over SW MN with a strong h85 low over Sioux Falls, looking like this could be an over achieve here in the MSP metro. Calling for 9-14, with a band of 14-18 from Mankato to just north of Rochester MN. I there is a error in this call, it may be that I'm a little low on the high side for the Metro, especially the southern metro. Link to comment Share on other sites More sharing options...
Chinook Posted December 16, 2016 Share Posted December 16, 2016 Apparently the NAM thinks there will be (nearly) a 4-precipitation-type point on the map in OH. This is the NAM valid 06z Saturday. I'm not sure if the NAM will be correct regarding the extent of freezing rain and sleet. I will be near that area on the map next week. Link to comment Share on other sites More sharing options...
cyclone77 Posted December 16, 2016 Share Posted December 16, 2016 New Ukie has a decent deformation band from central KS up through east IA/northern IL similar to it's 12z run. Gonna up my first call for here/QC from 0.5-2, up to 2-4" now that the models look a little wetter with the deform/frontogenesis precip. WAA wing still looks like a brief burst of snow before lifting northeast with 1" or so maybe. Probably several hours of freezing drizzle tomorrow night, and perhaps some very light freezing rain for a time. To me the most entertaining part of this storm is the extreme cold following, along with the insane temp gradients from the surface on up. Very impressive. Link to comment Share on other sites More sharing options...
Stebo Posted December 16, 2016 Share Posted December 16, 2016 Looks like the Euro ticked a bit cooler this run locally, never gets above freezing here now. Link to comment Share on other sites More sharing options...
nwohweather Posted December 16, 2016 Share Posted December 16, 2016 2 hours ago, Stebo said: Looks like the Euro ticked a bit cooler this run locally, never gets above freezing here now. Noticed that too. Heck the NAM doesn't go above 35 in Toledo on Saturday. Very weird storm to say the least, 4-6" locally followed by freezing rain and sleet, followed by rain, followed by snow to finish and a return to frigid temps Link to comment Share on other sites More sharing options...
Baum Posted December 16, 2016 Share Posted December 16, 2016 Here is a decent graphic for Chicago area depicting differences in total from GFS and Euro: Link to comment Share on other sites More sharing options...
DAFF Posted December 16, 2016 Share Posted December 16, 2016 Trends are looking to be cooler and backside low has more moisture in the cold sector wrt NAM/GFS. Gem still shows rain for SE Michigan and the backside precip field is dryer and much like the previous runs of the GFS. Waiting for the next run of the HRRR Link to comment Share on other sites More sharing options...
smoof Posted December 16, 2016 Share Posted December 16, 2016 6z NAM is nice and juicy here riding the 10" kuchera ratio line on it and around 11" on GFS still. Link to comment Share on other sites More sharing options...
weatherbo Posted December 16, 2016 Share Posted December 16, 2016 Hoping to see 12-15" here with some enhancement. Link to comment Share on other sites More sharing options...
smoof Posted December 16, 2016 Share Posted December 16, 2016 Hmmm nice coating of pixie dust on the car already, models were showing this to be just virga until this afternoon here. Link to comment Share on other sites More sharing options...
Harry Perry Posted December 16, 2016 Share Posted December 16, 2016 This is such an odd system. Link to comment Share on other sites More sharing options...
cyclone77 Posted December 16, 2016 Share Posted December 16, 2016 Models had slowly been trending a bit wetter through last night, and then all the new 12z, and high-res are like nope. Still gonna ride my 2-4" call and hope the 18z/high-res trend back the other way. Also hoping that last-gasp deform band overachieves tomorrow afternoon lol. Been a fun week of tracking this thing at least. Link to comment Share on other sites More sharing options...
Chicago Storm Posted December 16, 2016 Share Posted December 16, 2016 Models had slowly been trending a bit wetter through last night, and then all the new 12z, and high-res are like nope. Still gonna ride my 2-4" call and hope the 18z/high-res trend back the other way. Also hoping that last-gasp deform band overachieves tomorrow afternoon lol. Been a fun week of tracking this thing at least.Indeed. 12z NAM/RGEM/GGEM all came in drier across MN/IA/WI/IL. Further east not so much. Link to comment Share on other sites More sharing options...
Chicago Storm Posted December 16, 2016 Share Posted December 16, 2016 Models had slowly been trending a bit wetter through last night, and then all the new 12z, and high-res are like nope. Still gonna ride my 2-4" call and hope the 18z/high-res trend back the other way. Also hoping that last-gasp deform band overachieves tomorrow afternoon lol. Been a fun week of tracking this thing at least.Indeed. 12z NAM/RGEM/GGEM all came in drier across MN/IA/WI/IL. Further east not so much. Link to comment Share on other sites More sharing options...
Hoosier Posted December 16, 2016 Author Share Posted December 16, 2016 Track wise, looks like a south tick and cooler in bulk of 12z runs. Link to comment Share on other sites More sharing options...
Stebo Posted December 16, 2016 Share Posted December 16, 2016 3 minutes ago, Hoosier said: Track wise, looks like a south tick and cooler in bulk of 12z runs. Sounds like the last storm, seems like that is the new normal adjusting south and east last minute. Link to comment Share on other sites More sharing options...
n1vek Posted December 16, 2016 Share Posted December 16, 2016 19 minutes ago, Stebo said: Sounds like the last storm, seems like that is the new normal adjusting south and east last minute. My point-and-click for Royal Oak has jumped up to 6" for tonight. I wonder if the advisory will need updating. Hopefully the colder trend continues through the nowcast window. Building a nice snowpack here for mid-Dec. Link to comment Share on other sites More sharing options...
Luftfeuchtigkeit Posted December 16, 2016 Share Posted December 16, 2016 There are some stronger radar returns starting to pop up already in far northeastern Iowa that aren't indicated in the short term and high-res guidance. Hopefully this is a sign that these models that have been coming in drier are under-forecasting QPF. Link to comment Share on other sites More sharing options...
ConvectiveIA Posted December 16, 2016 Share Posted December 16, 2016 Eeeeeeew. 12z NAM has dessicated Iowa, leaving Dsm with next to no snow at all now Link to comment Share on other sites More sharing options...
Hoosier Posted December 16, 2016 Author Share Posted December 16, 2016 Well, I guess I'll go with 3-5" total here, with some light icing. After being too low 2 weekends ago and being too high last weekend, hopefully this one works out. Or if it doesn't, it's because it overperforms. Link to comment Share on other sites More sharing options...
hlcater Posted December 16, 2016 Share Posted December 16, 2016 37 minutes ago, Stebo said: Sounds like the last storm, seems like that is the new normal adjusting south and east last minute. Out here, IA/NE it has been north at the last minute, can't speak for areas to the east though. Link to comment Share on other sites More sharing options...
Stebo Posted December 16, 2016 Share Posted December 16, 2016 I think locally 5-8" is good probably on the lower end down by work but on the higher end out this way and to the north. Link to comment Share on other sites More sharing options...
Hoosier Posted December 16, 2016 Author Share Posted December 16, 2016 Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 1139 AM CST Fri Dec 16 2016 .UPDATE... 1139 AM CST No changes to going headlines and forecast thinking at this time. Recent AMDAR sounding out of MDW shows low level dry air centered at 900 mb, and another somewhat dry layer above 700 mb. As south- southwest warm air advection and f-gen at 850 mb continues to ramp up in advance of a mid-level shortwave lifting northeast, plus ascent from that wave, watching the top down saturation process occur in the airport obs and on radar, and now at the surface with light snow beginning in the Rockford area. Expect bands west-northwest to east-southeast bands of snow similar to current one over northern CWA to fill in through the afternoon, particularly northeast half of the CWA. Straight QPF output from the most recent high- res guidance could be concerning, but forecast soundings suggest we don`t have any issues saturating, and support for a 5-7 hour period where occasional moderate snow rates are possible. The 12z sounding from SGF (Springfield MO), which is a good proxy for air mass being advected northward into the cold air, had a PWAT value of 0.6" and mean mixing ratio of 3 g/kg. So the pieces are still in place with good forcing for ascent and good moisture in a snow situation to produce accumulating snow during the commute. The message continues that snow will easily accumulate on all roads, likely to result in significant impacts to the commute. Have not made any changes to snow amounts through the evening, with expectation of 1 to 5 inches, highest near the Wisconsin border. Will address concerns in next discussion update with likely lulls in the precipitation later this evening through Saturday morning where freezing drizzle could become an issue even north of I-80. Finally, based off assessment of new guidance, concern has increased for icing in southeast CWA not currently in headlines. Trend has been for a slightly farther south low pressure track overall, which will tend to keep boundary layer temperatures colder through Saturday morning. Warm nose aloft will result in full melting of hydrometeors, so freezing rain/drizzle will become likely overnight. Then on Saturday morning, even if temperatures creep slightly above freezing, very cold road and ground temperatures could mean that there will still be freezing on roads. So am expecting to issue a Winter Weather Advisory for the southeast CWA counties not in a headline with the afternoon forecast package. Castro Link to comment Share on other sites More sharing options...
SchaumburgStormer Posted December 16, 2016 Share Posted December 16, 2016 Flurries falling imby. Link to comment Share on other sites More sharing options...
CoachLB Posted December 16, 2016 Share Posted December 16, 2016 Are we going to have any sampling for 18z. Link to comment Share on other sites More sharing options...
Hoosier Posted December 16, 2016 Author Share Posted December 16, 2016 1 minute ago, CoachLB said: Are we going to have any sampling for 18z. Typically there's not any new upper air soundings that get into the models other than the 00z/12z cycles. Link to comment Share on other sites More sharing options...
Hoosier Posted December 16, 2016 Author Share Posted December 16, 2016 Some of the models are hinting at some showery/convective elements in the freezing rain zone later. That would be of some concern for more rapid ice buildup, at least on a localized basis. Link to comment Share on other sites More sharing options...
CoalCityWxMan Posted December 16, 2016 Share Posted December 16, 2016 5 minutes ago, Hoosier said: Some of the models are hinting at some showery/convective elements in the freezing rain zone later. That would be of some concern for more rapid ice buildup, at least on a localized basis. It shows some banding of snow/freezing rain right along the changeover zone south of I-80 overnight. Looks rather localized but could setup some heavy snow/ice where it does like you pointed out Link to comment Share on other sites More sharing options...
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