RCNYILWX

The EPO did flip negative in the latter part of January and that ridge spike at the end of the month into early February dislodged the PV lobe that got trapped under the NAO block. The SSW weakened the PV enough to prolong and strengthen the -AO/-NAO. The -NAO also played a big role in making the 2 events in the last week of January what they were vs much warmer/farther northwest outcomes.

Snowing at a good clip under this lead band. If there wasn't a gap behind this, this earlier start than it was looking like yesterday might have been a reason for optimism. Sent from my SM-G965U using Tapatalk

The 18z NAMs indicate 2"+ amounts still possible in the CWA, but that's looking to be optimistic at this point. Would really have to rip under that next round out west of the MS River. I guess we'll see.

This was a thread in response to Makary's original WSJ op-ed: https://mobile.twitter.com/EricTopol/status/1362513761383321602 Sent from my SM-G965U using Tapatalk

Still looks like there's support for heavy rates. The unknown is if we end up with 10:1 ratios or even a bit higher or decently under 10:1. The Kuchera snow maps are actually lower in this case than 10:1 because of marginal lower level temperatures. However, some of the Cobb outputs have greater than 10:1 for a time due to good lift aligned with the DGZ. 1-3" is a good call with potential for a swath of 3-4" where the favorable ingredients come together for a 2-4 hour window.

There's some shades of February 4th here. Not gonna lock in rates that heavy yet, but duration should be better. Definitely ingredients for heavy snow with very steep mid-upper lapse rates, strong forcing for ascent (and very strong omega well enough aligned with DGZ), and solid moisture.

Wintry appeal at its finest with dendrites drifting down and sun glinting off them. Pure fluff with an inch here. Second photo is the top of the recycling bin. Stuff is so airy you can blow it off. The goods. I took a slow-mo but file size is too big to post unfortunately. Sent from my SM-G965U using Tapatalk

If the trackers are burnt out, then you can only imagine how it is for the meteorologists lol. For me personally this has been the busiest/most taxing stretch of winter weather in my career. Obviously 2013-14 was sustained relentless, but back then I was still newer (and younger ha) and only would work occasional midnight shifts. Now I have two kids and worked mids during the busiest stretch overlapping the end of January storm with lots of extra hours and in general have worked lots of extra hours on other shifts too. Good for the wallet but not good for the sleep. I wouldn't have it any other way though because what more could a snow lover ask for, and it's been fun tracking with everyone. Sent from my SM-G965U using Tapatalk

00z Euro op and UKMET were kind of disjointed and thus more paltry, but EPS was more similar to previous Euro runs. Trend is for more of a positively tilted short-wave scooting along. What I like in this setup is that it looks to be yet another one with steep to very steep mid-upper lapse rates. Also, guidance is showing a respectable PWAT plume. So, could be a relatively short duration but decent thump of warm advection snow. At this time, advisory type amounts are probably the ceiling.

Friday night could be off to the races too in favored spots if skies are clear enough. Sent from my SM-G965U using Tapatalk

La Nina episodes or Nina like patterns with a -PNA paired with some variant of high latitude blocking (-NAO, -AO, -EPO or all 3) have seemed to coincide with memorable stretches of winter weather and/or memorable events. 2011 is a good example of that with a historic snowy phase in the east through January with the -NAO/-AO, then of course GHD I came with a strong -EPO/-PNA couplet after that prolonged NAO/AO block finally eroded. 2018's record stretch of consecutive days of measurable snow in Chicago (that might be broken later today) on Feb 3-11 occurred during a -EPO/-PNA. Then in 2019, despite that year being a weak Nino, had a very Nina like February due to MJO forcing. That month had an amplified RNA pattern with a consistent strong -EPO that allowed Wisconsin, Iowa, and Minnesota to cash in in record fashion and the multiple freezing rain events in the LOT CWA and nearby. Our stretch this year will have occurred with a predominantly -NAO/-AO and -PNA, along with a -EPO in the mean height anomaly, which was very conducive not only for the remarkable snowy stretch for much of the area but also the prolonged cold snap this month once the PV lobe got trapped under the block. Fun stuff. Sent from my SM-G965U using Tapatalk

Definitely, could always use more solid reports down there, and the best part about CoCoRaHS is there's no set reporting requirements like the COOPs. The Kankakee COOP seems to be so infrequent in their reporting now compared to how it was when I got here. Sent from my SM-G965U using Tapatalk

I did call in your report once I saw it when I got home this morning, wish I had seen it earlier and got the LSR sent. Apologies it wasn't used for the map. And we only have one other snow report listed in the text listing for the county, so yours could've been added to that. Have you considered joining CoCoRaHS? Those almost always get incorporated into our post event reporting. Sent from my SM-G965U using Tapatalk

Unfortunate that ORD just missed being consistently under the goods by no more than a couple miles off to their east. The 6.7" total seems a little low and @Chicago Storm thinks there's probably a missing 1-1.5" to their total. Once we get CoCoRaHS reports in the morning, especially the ones closest to ORD's longitude, we'll have a better gauge on how realistic the amount is there. They may be able to get to 8"+ by 12z. Considering MDW 3SW coming in with 15.9" and 10.5" between 6pm and midnight, it was a so near yet so far situation for ORD coming in with another double digit event. It's the nature of LES though and this goes down as the 3rd 6"+ event in well under 1 month, which is extremely impressive. Plus the 20" snow depth, which was last reached in February 2011. What a stretch. Even though I was optimistic for a good stretch back when posting about it earlier in January, didn't think it would be THIS good lol. Sent from my SM-G965U using Tapatalk

Getting the goods here with enhancement from the LE band bisecting Schaumburg. Definitely 1/4SM or less, pouring snow. Sent from my SM-G965U using Tapatalk

For reference, here's the liquid equivalent for the 21z RAP. Even if you assume lower than Kuchera ratios, that's still a lot of snow to come.

Is DRSN supposed to be in a different portion of the METAR? I've seen it put there in the MDW METARs this winter. Sent from my SM-G965U using Tapatalk

Yep, SNINC means a depth increase. It means at least a half inch and no more than 1.4" in that hour to get the rounded up or down depth increase of 1". Sent from my SM-G965U using Tapatalk

Confident in saying it'll snow more than 1-2" there. Your area should be good for at least the range in the WWA. Consider it a win vs forecasts from a lot of the models a few days ago. Sent from my SM-G965U using Tapatalk

Steady -SN now, flake size not bad. We'll see if early arrival of synoptic snow means anything for totals. The NAMs keep snow going until 13-14z tomorrow, so for areas favored for lake enhancement, assuming they're right on end time, could boost totals an inch or two. Sent from my SM-G965U using Tapatalk

NAM is maybe a hair southeast, mainly a bit weaker, which resulted in less QPF and snow. Sent from my SM-G965U using Tapatalk

Getting -SN with decent flake size from what appears to be the far southwest fringe of the LES band here near the DuPage Will border, southeast Naperville. Sent from my SM-G965U using Tapatalk

The Kuchera ratio is a linear equation based off the maximum temperature from the surface to 500 mb. So necessarily when it's very cold, the ratios it gives are high with no regard for the snow growth processes (DGZ depth, lift through DGZ and whether it's we'll aligned with DGZ, and how well saturated the DGZ is). That's the flaw of the method, since there's plenty of occurrences of low ratio pixie dust type snow in very cold temps. The Cobb ratio is based off those snow growth processes. Edit:@madwx beat me to it

If anyone from the LOT CWA is interested, you can PM me your snow reports through the event. It would probably be easier to keep up that way. I know everyone on here is pretty diligent at measuring, so it would help to have some solid reports. Also, believe it or not we don't get a ton of reports from the city, so in particular for this event with the LES, it would be greatly appreciated. Sent from my SM-G965U using Tapatalk

My friend lives up in North Center/Roscoe Village area and he said already 2-3" down, I'm guessing which includes non LES into this morning. Sent from my SM-G965U using Tapatalk