RCNYILWX

At least there's something interesting meteorologically until we might see chances increase of finally getting more of the metro a solid event. Sent from my SM-G965U using Tapatalk

If only we could be as creative in our AFDs like back in the day when Gino had a Facebook group dedicated to his AFDs haha. My main source of optimism right now is that it looks like we're unlikely to melt the glacier much before the hopeful arrival of a better pattern, so until that time, at least it's better than no snow OTG on these cloudy/foggy days and the kids can get out and sled every day. I spent hours doing that with my kids over the holiday weekend [emoji4]

I attached the ensemble mean (EPS first 2 and GEFS next 2 images) 200 mb isotachs (wind speeds) to illustrate. If you go from current to out around day 10 or so, the pattern blocks off the northern stream/Polar Jet and is very southern stream dominant, hence the overall zzzz look. The pattern on the attached images is quite different from that, with the northern Pacific/polar jet coming ashore and coupling with the enhanced southern stream forced underneath the block. The -NAO is quite evident in the anti-cyclonic curvature of the height lines up to the vicinity of Greenland. Anyway, I'd envision Pacific hybrid type systems and clippers in the above pattern depending on point of entry short-wave impulses. If the -PNA trend the EPS and GEFS are showing out at the end of their respective runs is legit, then you can get a west southwest to east northeast tracking Colorado low that would eventually see the primary running into the block and a secondary probably redevelop underneath. Could also see that with more vigorous Pac hybrid systems tracking from west northwest to east southeast. I might get attacked by Angrysummons for this, but if I'm not mistaken both 2009-10 and 2010-11, the most recent examples of prolonged sustained -AO/-NAO blocks during the heart of met winter also were accompanied by periods of neutral to negative PNA. Not bringing these up as a promise of what we'll get, but as a way to demonstrate that the east coast weenies getting excited about the upcoming pattern doesn't have to automatically mean we'll get screwed out in the central and western subforum. I certainly can't guarantee some systems not getting suppressed and favoring southern parts of sub and points south and then the east coast, but as modeled and if we can get them into non-fantasy time-range, the ensemble means look solid for a good chunk of the sub to cash in potentially. You don't see it by looking solely at the 500 mb anomalies, but there is a suppressed WAR progged off the east coast, so that's not a northwest flow CAD hell look to me once out to mid month. Finally, if we go back to the last strong -NAO during the cold season, March-April 2018, that period had some more than solid winter systems that benefitted portions of the sub. Would like to see any long range experts or enthusiasts chime in with feedback on my thoughts. Don't want to get hopes up too much quite yet when there's a lot of time to go.

This stagnant/blocky pattern we're in with extensive snow/glacier cover is why I'm at times loathe to advertise those warm color AN probs CPC graphics this time of year. With no synoptic system to shake things up with a warm sector to melt some of the snow/ice, can easily lean colder highs and milder lows than much of the guidance is showing. These patterns give the MOS fits because the 850/925 mb temps would favor generally AN temps... if we had no snow cover and sun. Because of the warmer mins, we'll average above normal for average temps during this stretch, but I don't think anyone but Beavis would confuse this with warm. After current round of fog and hoar frost and spotty low level snow showers improves behind the cold front tonight, looking at another good setup for these conditions to return Tuesday evening into Wednesday, which might not really clear out until Saturday given little change in the pattern.

Revisiting what I posted earlier today, no changes in overall thinking based off most recent ensemble runs. End of 12z EPS quite promising in showing a slightly -PNA developing as the western NOAM ridge retrogrades off the west coast, which the GEFS continues to point toward as well. We can only hope this look gets to within 10 days because I could see it offering multiple chances to more than localized portions of the sub given the -AO/-NAO favored to lock in. Prior to that, definitely a stagnant zzzz look. There's a chance some southern stream energy can break through later Sunday into Monday to bring a light snow threat for some areas. Ensembles showing low to medium chances of light measurable QPF during that time and the 12z GGEM did show a weak wave as well. Definitely not seeing anything supporting even widespread advisory type snows while we're in this blocky STJ dominated pattern, barring sizable changes in the medium range.

It doesn't look great through mid month but it also doesn't look like a torch because of the strong west based -NAO. Without it, it would be a full on torch. Pacific jet will remain active during this time with a tendency for systems to come underneath, though you can't rule out individual waves edging a bit north. One thing to keep in mind about the upcoming pattern is it should help keep a lot of the snow/glacier cover in place if you're into that. Mid month and beyond should have colder air involved as the EPO trends neutral to slightly negative (the ens means h5 looks more negative than the charts) and PNA also trends neutral to possibly slightly negative while maintaining -AO/-NAO. The pattern hasn't really gotten pushed back, week 1 into week 2 never looked great. I wouldn't rule out some snow for parts of the sub, but better chances should arrive toward and beyond 1/15 barring big changes from what we're seeing later in the ensemble runs. If we can get the slightly negative PNA the GEFS is advertising toward end of run, that would only help but even the EPS has the ridge axis far west enough that it doesn't scream CAD necessarily. Sent from my SM-G965U using Tapatalk

Congrats @A-L-E-K Sent from my SM-G965U using Tapatalk

As others have mentioned in January thread, tonight looks good for a solid fairly short- lived burst of snow. Nice mid-level lapse rate (>7C/km) plume advecting northward over the mini trowal across northeast and central IL and northwest Indiana. One of these similar setups last winter produced a localized swath of 3-4". I think 1-2" amounts will be common for all but the northern tier, with spots of 2-3". Can't rule out a very localized 3"+ given the nature of these potent little waves with good lapse rates.

Enjoy your 1-3"

Borderline moderate snow here in southeast Naperville, really wet stuff, but will be a nice topper to the glacier. Sent from my SM-G965U using Tapatalk

There was an AWOS in Lake in the Hills that has since gone defunct. I'm not sure the process in getting an AWOS to an airport but it sure would be nice to have one in McHenry. As far as ASOS goes, I think it depends on the size of the airport to get one put in. Sent from my SM-G965U using Tapatalk

Yeah clearly something wrong with RFD. I think we're going to have the electronics technicians go up there to check it out. Sent from my SM-G965U using Tapatalk

If the ECMWF weeklies are on the right track, you can toss that CFS January prog as far as you can throw it. Here's a loop of the weeklies put together by a frequent poster on the New England sub: Because there were very valid fears about a warm outcome this winter and we see already how mild December was, the increasingly likely development of major high latitude blocking in the Arctic and Atlantic can only be a good thing. We take and hope more of the subforum can benefit this month and likely beyond. Can probably also include this in the medium-long range thread. PS: Happy New Year to all! Here's to a snowy next couple months and eventually better things to come in 2021 than what 2020 gave us.

Just a note about RFD, we strongly suspect it's been running warm the past few weeks. Sent from my SM-G965U using Tapatalk

I think it's definitely plausible north except probably right near the lake, even south can't rule it out. Question there is does the latent heat release from the warmer rain drops eventually win out for southern areas. Recalling the 2019 ice storm, the expected warming above freezing didn't happen during the steady precip because winds stayed northeast the whole time and the surface wet bulb zero line struggled to advance northward. That'll be the key to watch tomorrow is the surface wet bulb zero line.

I think that it looks like mostly snow and maybe some sleet up there and I guess that's why no advisory, though since there will be some travel impacts, thought they might have erred on the side of caution. Sent from my SM-G965U using Tapatalk

If the 21z RAP is right, the only areas getting above freezing through the event are basically southeast of I-55 and along the Lake Michigan shore. I noticed that in our AFD, mentioned all areas along and south of I-88 warming to above freezing. I think that's probably too optimistic except along the Lake Michigan shore and a bit inland of there, and obviously if something like the RAP is right, ice accumulations could end up higher than forecast. [mention=14]Hoosier[/mention] made a good point earlier about accretion rates potentially being higher farther north where the warm nose is not as warm. That's something to watch and another reason to be concerned about some locations overperforming ice wise. Another thing we'll have to watch observation wise is how cold the low level cold wedge remains. The December 28 2015 event that's been discussed verified colder at that level than model forecasts, and if something like that happens tomorrow, also could have a zone that stays sleet for a while until flipping back to snow. Finally, was a bit surprised my office and DVN didn't extend the advisories to the northern tier counties staying snow, since it seems they have solid potential to come in at near typical advisory criteria for snow anyway. Will be an interesting event to watch unfold.

This might be worst/best case scenario, but was thinking that even for the areas that get more snow and sleet plus some ice, going to be very dense, high water content stuff, so the impacts would be more than those snow amounts would typically entail, along the lines of your thinking.

Would recommend looking at the 00z HREF page tonight for freezing rain tomorrow night into Friday. They recently added 3 hr and 24 hr FRAM mean ice accumulation to the winter parameters. FRAM (freezing rain accumulation model) is what we use in the NWS for ice accums and it's much more sophisticated than the QPF to ice accums that's available on COD, Pivotal Wx, WeatherBell, etc. Here's a link to a pdf about the FRAM if you're interested in learning more: https://www.google.com/url?sa=t&source=web&rct=j&url=https://vlab.ncep.noaa.gov/documents/10157/137122/FRAM_VLAB_Presentation.pdf/50ff7877-c52d-80f4-1413-b294db7710e9&ved=2ahUKEwjUmoSJ8_btAhV6B50JHVLaDZYQFjAAegQIBBAC&usg=AOvVaw2fMu-m4aPPk_bnXxwA6ivl&cshid=1609372449468 Sent from my SM-G965U using Tapatalk

I had sold on sustained sleet with this, but what you had shows how convection can modify the thermal profiles and keep sleet going and even the mixed large flakes when otherwise you'd probably be freezing rain quicker. Fascinating stuff. Sent from my SM-G965U using Tapatalk

Depending on what rates are like, non-zero chance it could go back over much later/pre-dawn hours, as the guidance is showing some modest cooling aloft ahead of the frontal zone. Sent from my SM-G965U using Tapatalk

KFFL in southwest DVN CWA getting close already with scattered 3600' clouds and broken at 4700'. OTM broken clouds at 4600'. Not seeing any red flags yet that the antecedent dry air is going to be more prohibitive than expected. Sent from my SM-G965U using Tapatalk

Link to a loop of the ECMWF weeklies run last night for the 00z/28 cycle: https://33andrain.s3.amazonaws.com/monthly_2020_12/ecmwf-weeklies-avg-nhemi-z500_anom_7day-1609113600-1609718400-1613088000-20.gif.64969e182ab9478fa5381e7fe5f284d5.gif Not sure if it'll work. Tried to post the .gif but file size is too big. In sum, the ++EPO Pac puke dominated start to January goes over to an Atlantic and Arctic blocking dominated pattern. The latter portions of recent ensemble runs also going to that sort of look. Been a lot of discussion on SSW likelihood into January. Certainly don't want to hype it like it often gets, but long range experts are saying there's good precursors going on near Siberia to favor the occurrence. If so, the tendency for -AO/-NAO that's been there could further deepen and point toward a colder outcome than expected from mid January or thereabouts and probably into Feb. If a major anomalous blocking episode develops, they tend to stick around for quite a while. For most recent met winters that had deep Arctic and Atlantic blocking in the heart of the winter, have to go all the way back to 2009-10 and 2010-11. The 09-10 block lasted all the way through Feb and into March, but the 10-11 block collapsed in early Feb (and probably helped those of us who cashed in on GHD I). After a mild start to January, things "could* turn more interesting if we get cooperation from the Pacific. We'll see how things play out as we get closer to that period. Sent from my SM-G965U using Tapatalk

00Z ECMWF looks more concerning for a longer duration of ice on Friday north of I-80 and away from the lake. Dew points at 12z in the lower to mid 20s and still upper 20s to around 30 at 18z. Because of a weaker surface low and it tracking northeast from STL instead of more due north, winds become progressively more northerly. Also at 12z the surface ridging across the western lakes trended stronger at 1028 mb. I still wonder if 925 mb ends up being colder because of the surface pattern favoring it, but if not, that run definitely ups the ante for icing concerns. Crazy thing is part of the event is still out to and beyond the end of the NAM range, so there's still plenty of time for changes. The 00z EPS has a pretty large west to east spread of individual member sfc low positions, with relative clustering on the more west and more easterly camps. Sent from my SM-G965U using Tapatalk

Based on this, any snow accumulated after 06z south of the 850 mb zero line probably sleet to freezing rain in reality. Sent from my SM-G965U using Tapatalk