RCNYILWX

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More complete write-up in my AFD today, but a few points here: we think the Kuchera ratios are low-balling tomorrow. Kuchera is based off the max wet bulb T from sfc to 500 mb, and warmest temps will be at the sfc. The flaw in the method is that when the DGZ is deep like tomorrow but sfc temps not that cold, it doesn't adjust for favorably deep DGZ, it's strictly based off MaxT aloft. The Cobb method is preferred and averages 15:1, which is what WPC also preferred in their assessment, while the Kuchera is only 9 or 10:1. ECMWF and NAMs have been in good agreement on that corridor of up to or slightly over 0.2" LE, which should fluff up to spots of 3"+ when accounting for the ratio. Our graphic is using a little bit of creative license because in reality the highest total I forecast within the CWA is 2.8", but we went broad in public facing message because if that 0.2"+ LE does occur, then 3"+ amounts are pretty likely. Another wild card is lake enhancement, which actually looks fairly decent for once. We'll see shortly what 00z CAMs show but the 18z NAMs and 12z NMM showed a wind shift to north behind sfc trough passage, which really increases the convergence, plus thermos being solid enough. Above models got the lake enhancement onto IL side for a few hours and then settled into NW IN. Could be a nice bonus wherever that sets up.

I noticed that the 12z run had something wrong with the output, looked like the coding of the data they get caused QPF to come in at 10x higher. Sent from my SM-G965U using Tapatalk

I look at this season as somewhat similar to 2012-13 thus far. That winter was mild in December through mid Jan, but did have two much better events than anything in most of the sub this winter (MSN ~2 ft dump, and warning criteria event in IND CWA on 12/26. The Chicago metro simply had wretched luck that season. ORD went into Feb with I think under 3" and finished up at 30.1 or something. The north suburbs had a huge Feb 2013 and then we finally all scored a regional warning event on March 5th. Bad luck came back to bite us again with the miss south for the storm in mid to late March that gave SPI 18". If we maintain some semblance of blocking (and recall Feb-March 2013 had a legit -NAO) in Feb and the pattern otherwise goes more classic La Nina, could be a decent month. I think 25-30" is a reasonable call at this vantage point. For our winter outlook, we went near normal, and I'll stick with that for now. If the potential late next weekend into early the week after works out, that would really help get the seasonal total back in a respectable range. Sent from my SM-G965U using Tapatalk

Are you right in the town of McHenry? We can send your report as an LSR once you have your final measurement. Nice to have a mini event that performed exactly to expectations. Sent from my SM-G965U using Tapatalk

Well that's part of the equation, the not having cold air deal, which is certainly the case now, has good ens support in finally changing for the better. The 12z EPS seemed to trend stronger in spiking ridging to and north of AK next week and the GEFS has been favoring that consistently, so that should get cross polar flow going in concert with continued Arctic and Atlantic domain blocking, along with -PNA keeping a steady stream of shortwaves coming ashore. There's nothing like the black hole AK vortex +++EPO from 2011-12 in the offing and since the ensembles haven't trended away from a colder and active look as the period has gotten closer, not inclined to punt now. Sent from my SM-G965U using Tapatalk

It's the same thing every winter and considering how the models can't nail down events within 2 days, suggest not to get all worked up over operational runs beyond day 4-5. Looking at the ensembles, see no reason to back off from idea of getting into a favorable stretch for at least a solid event or two. Still would not rule out the Thursday-Friday overrunning setup from coming back into play. It hinges upon whether northern stream trough digs in too quick and confluence over the region shreds everything south, and I certainly wouldn't bank on the operational models having this nailed down 6 days out. Best signal in the ensembles is next weekend into early the following week, with a trough ejecting out of the southwest. This is the timeframe when the ensemble mean shows a biggest jump in snowfall, so a bunch of members are contributing to that. Obviously full spectrum of outcomes on the table including suppression, but on the other hand would still think the NAO helps prevent a full fledged warm cutter. Finally, the most recent ECMWF weeklies came in much less mild than the previous run due to a continuation of Arctic and Atlantic blocking. This winter has certainly been frustrating and I'm not really trying to be overly optimistic, just honest about predictability that far out. If and until the ensembles back off from their active look, I'd again recommend against using operational models to make definitive statements about nothing good happening 5-7+ days out. Sent from my SM-G965U using Tapatalk

Drove under one on the way to work, rippage with huge flakes. 1/2 mile or less visibility and instantly coated the road. Bodes well for the rest of the day. SPS going out now. Sent from my SM-G965U using Tapatalk

The operational ECMWF was the second strongest member of the 12z Euro suite. One other member down to 972 mb over northern Lake Michigan. Most were in the 1000s or 990s and farther east. That's probably a good indicator of the op solution being a lower probability scenario. Sent from my SM-G965U using Tapatalk

Tomorrow looks fun on the 00z HRRR. Been quite a while since we've had a solid convective snow shower setup. Sent from my SM-G965U using Tapatalk

The SQW has a wind component so I don't think we would be issuing one unless it's really ripping under a few of the snow showers tomorrow. That plus temps being near to slightly above 32F should mitigate road impacts some as well. That said, I think we could see 30-40 dbz popcorn tomorrow. If snow shower coverage is more widespread and we're getting higher end impacts, could envision a short fused WWA vs SQW. On order of likelihood of product issuance tomorrow, I'd go SPS, WWA and then very remote chance of SQW.

I'd lean miss south being more likely than a cutter/rainer like 12z Euro but I think we're right in the envelope for a decent event with the late next week potential. Conceptually it looks more conducive to an overrunning scenario with a weaker surface wave like the GFS and the GEM are showing. Really doubting a 979 mb low north of Detroit next Friday. Sent from my SM-G965U using Tapatalk

Yeah, things definitely went the other way for anything meaningful into this evening. All but the far NW burbs hard pressed to get any accums. As has already been discussed, tomorrow's snow showers could produce some nice bursts at times. Liking late tomorrow night into Sat AM for an inch or two on the backside of the upper low and Sunday currently looks favorable for up to a couple inches. Sent from my SM-G965U using Tapatalk

I'd be surprised with that depiction cutting that far north into the strong NAO block. At this distance would rather it shows a strong system and ptype issues rather than a miss south like the previous run. The huge swing between 00z and 12z also highlights the variance at that range anyway. Sent from my SM-G965U using Tapatalk

Since I was part of the forecast process (I issued LOT's watch for the event), GHD II is easily one of my favorites, favorable trends right up until the snow started falling. If we're going to break the schneid, the upcoming pattern is what you'd like to see. Sent from my SM-G965U using Tapatalk

The painful miss just east/southeast on 2/24/16 really seemed to set us on this bad luck streak that we've been on, minus some exceptions in the 2017-18 and 2018-19 cold seasons. I still feel optimistic about scoring during the upcoming pattern, but if we don't, then it's really just not our winter. Bad luck certainly happens, it doesn't make it easier to take for snow lovers though. Sent from my SM-G965U using Tapatalk

Yep, the way our Federalist system works is that the states have a lot of power and autonomy. So they were always going to have a large role in the vaccine rollout. That said, agree, the federal government could and should have done much much more to organize the effort among the states, this is literally the largest vaccination campaign in our history. In past crises, we didn't essentially tell the states, "good luck" . Also it's a failure of Congress to not provide much needed funds for vaccine distribution until the recently passed relief bill. The failures of the initial vaccine rollout are similar to the failure of the federal govt to help organize the testing regime after the CDC fiasco with the test kits back in February. Yet another example in which our outcomes have been worse than they could've been. Don't think there's any way we avoid a large number of deaths from this virus, but even 100-150k less when it's all said and done would've been that many lives saved and that many less families in anguish, not to mention less people having spent time alone in the hospital battling the virus, and less people with long term health impacts.

One thing I'm seeing as a possible missed opportunity with the vaccine rollout is that households aren't being vaccinated. We're hearing that doses have been sitting unused and the vials once open have a limited shelf life. If a health care worker also has a spouse and x # of kids, why not vaccinate them all? Another example is a household where one person is 75+ and their spouse is 70-74. Why would only vaccinate the 75+ year old and not both? If the goal is getting population immunity, shouldn't we be trying to get as many shots in arms as possible and banking on the supply being there for the 2nd dose? I think that's the philosophy being applied in the moves to alleviate the excess supply this week, I'm just wondering if we could be doing even more. Someone can correct me if I'm wrong on the speculation.

It's been bad, too often in recent years we've had a long dull stretch for most of December into January, and this season didn't have the benefit of cold and snow in November. It's easy to forget because the snow season ended up being so long, but 18-19 had a stretch every bit as long and boring as this winter, probably worse in a way. December 2018 had 1.4" of snow and was +5.5 at ORD and January 12-13 2019 was the first bonafide measurable snow since November 25-26 2018. We'll really need to make a run to bring up the ranking of this season and need the upcoming favorable looking stretch to deliver on its potential. The good news is that cold air supply will be there and there should be a steady stream of Pac shortwaves coming ashore, so if we have bad luck with one system, we should have more chances. I remember being optimistic about the 2nd half of January 2019 and the background pattern for Feb looked very good, the predominant storm track was just too far northwest. That's where the progged strong -NAO could really help us and points east this time.

Quite a read catching up on the posts today. I felt like if anything we had a slight favorable trend of getting anything interesting tomorrow. There's support there for rain changing to a fairly short thump of snow from large scale (mid-level height falls and positive vorticity advection from a vort lobe wrapping around the ULL) and mesoscale from steep lapse rates and 850-700 mb fgen. Limiting factor is residence time of heavier rates and antecedent mild temps. Don't have too much to add on Friday's snow shower potential other than that it's a pretty good synoptic setup for them and[mention=1610]purduewx80[/mention] posted a forecast sounding to highlight this. Finally, I like Sunday for a longer period of light to at times moderate snow with forcing rather modest but good DGZ depth and steep mid-upper lapse rates. None of this should add up to anything more than a few inches in the Chicago metro, but it's certainly a nice change from the long boring stretch. It's always good to keep expectations in check and appreciate the meteorology of some of these setups. I really do think our time is coming for something a lot more fun during the late month period and into February.

The key is getting extensive snow cover down across the region, that can help modulate a pattern with some milder risk. Re. your question, it's possible to be related to a smaller diurnal range. The 850 mb anomalies are probably more relevant, especially if we can get solid snow cover down. And those anomalies even in the milder stretch shown in first half of Feb are not that far above normal, so you can easily still snow in that, as[mention=55]Stebo[/mention] mentioned above. I tend to look at the 500 mb pattern before then 850 mb temperature anomalies and don't usually look at the 2m because if I'm not mistaken those are a lower skilled parameter in weekly and seasonal forecasts.

Except it likely isn't going to stay like it's been. The +EPO/+WPO looks like it's going to go opposite phase for a time and then eventually could go to a neutral or weakly +EPO and still solidly -WPO. Sent from my SM-G965U using Tapatalk

Gotta be careful just looking at the temperature anomalies on those weeklies. The mean 500 mb pattern and anomalies suggests that the western ridge will continue to retrograde to more of a Aleutian ridge common in La Nina but we should keep NAO blocking if the effects of the SSW make it to North America. A good poleward Aleutian ridge (-WPO) continues to provide cold air delivery into the northern CONUS, as opposed to a strong lobe of the polar vortex over the entire AK domain (like 2012) which torched the CONUS all winter. While a -WPO/-PNA pattern does introduce a warmer risk by themselves as southeast ridge is allowed to flex more, having the AO/NAO stay negative is key and could keep a wintrier pattern going instead of warmer cutters that only benefit MSP and points north/northwest. Sent from my SM-G965U using Tapatalk

Agree, wouldn't expect a full handle until Wednesday on the specifics. At least we've been looking at the 15th as approximate date of arrival of a better pattern and getting a snow threat in the region around that time is a decent sign. As we've been discussing on the med-long range thread, see no reason to diverge from the thinking that pattern will become more favorable for more frequent snow threats on the last 10 days of the month and into February Sent from my SM-G965U using Tapatalk

Had mentioned the improvements on the 12z EPS vs last night's EPS. This tweet has a good visualization of those favorable changes, with strong height increases near AK and near Greenland. Sent from my SM-G965U using Tapatalk