RCNYILWX

From a pattern recognition/climo perspective, it's very difficult to get warning level snowfall into the heart of the Chicago metro with wraparound from a surface low that initially tracks so far NW. The various solutions that have shown a big hit demonstrate that those outcomes are certainly plausible. However, with needing to get the multiple moving parts right, there's plenty of failure modes (as shown by the solutions that keep the big snow out of the metro), and reason to be skeptical locally. Sent from my SM-S936U using Tapatalk

It's decidedly a myth that the models are a shit show. The truth is the opposite. If you're wanting truly stable solutions at this lead time for a rapid deepening cyclone, we don't live in that world yet. Sent from my SM-S936U using Tapatalk

I was today years old after surveying all day yesterday when finding out about this potential snowstorm/blizzard. March gone wild. Sent from my SM-S936U using Tapatalk

What's crazy is that we already had a 5" candidate that would also break the record and then got the 6" report. That's one of the most intense thunderstorms on record in IL. Twice setting new state hail records (likely) with a significant tornado just south of the giant hail. Plains type stuff. Definitely feel for everyone affected down there. Sent from my SM-S936U using Tapatalk

Yes, the current record is Minooka, IL on June 10, 2015 at 4.75". I actually happened to be the warning operator that day and took part in the committee with LOT, NCEI, MRCC, and the IL state climatologist to confirm the record. Sent from my SM-S936U using Tapatalk

Glad to hear you're okay! Current plan is for me to be on the survey team in southern Kankakee tomorrow. We'll have another team heading into Newton and Jasper. Hope everyone else from the area that posts on the board is alright and no friends or family were significantly affected.

Re. the Central Park ob and possibility of officially getting to 20+, hopefully OKX has an agreement with the CPK Conservancy folks who do the measuring to take a measurement once the snow fully comes to a stop. The 6 hour board clearing rule doesn't apply when the accumulating snow ends. For FAA contract observer sites, if the arrangement is the same there as it is out here, we call them for the final measurement when confident there's no more accumulation on the way. Sent from my SM-S936U using Tapatalk

As a meteorologist, pet peeve is spelling lightning as lightening, which is most commonly associated with late in pregnancy ha. Keep up the great updates otherwise! Sent from my SM-S936U using Tapatalk

That's radar ground clutter. You can better tell it's an artifact by flipping over to velocity. https://www.noaa.gov/jetstream/anomalous-propagation Sent from my SM-S936U using Tapatalk

That's Z time, for Zulu time, which is the same thing as Greenwich Mean Time (GMT). It's the time system used in meteorology and in aviation. 00z in EST(EDT) is 7pm (8pm), 06z is 1am (2am), 12z is 7am (8am), and 18z is 1pm (2pm). Sent from my SM-S936U using Tapatalk

No prob! I work and live in the Chicago area (NWS met at WFO Chicago/LOT) but I grew up in Queens in NYC and started my career at OKX. Wish I could be there to experience this one but happy to offer insight to any questions about the storm. Sent from my SM-S936U using Tapatalk

Very high moisture content/QPF going into the snow doesn't necessarily yield very heavy wet snow. While the surface temps started off mild and above freezing, the rest of the profile isn't marginally cold. To get the really gloppy heavy wet snow you need surface temps near to even above 32, and a deep isothermal layer near freezing above it, which creates snowfall aggregates (clumps of snowflakes, almost like mini snowballs). This will be a dense snow and tough to shovel but still prone to blowing and drifting. The snow will get fluffier with time as colder air moves in and exacerbate the blowing and drifting into tomorrow morning, as that snow will be easily transported atop the denser snow below it. Edit: The very well written OKX AFD mentions initial 10:1 ratios (about climo for your area) improving to 12-14:1 with time, which seems reasonable. You'll probably have an effective ratio higher than 14:1 wherever the f-gen death band sets up. The heavy wet snow you may have been anticipating generally entails ratios as low as 5-8:1.

A few important aspects to keep in mind: - There is no human intervention in that dataset. The underlying NWS NDFD forecast is applied to the WPC super ensemble data and does adjust the statistical spectrum a bit, but this is done automatically. - There may be time lagging affecting the low end members of the super ensemble, with various inputs possibly being earlier model cycles. - The above being said, given the extreme top end of the spectrum which we can see with the GFS (and many GEFS members) and NAM, those top end 90th percentile amounts are physically plausible, and again, automatically derived (with a ratio applied I believe). - There is certainly a good deal less spread now than earlier today, but you'll still have some ensemble members that have much lower QPF at this range (and some of these may be from earlier cycles, as noted above). For this reason, the 10th percentile low end amount undeniably seems ridiculous given the extreme top end amounts, but in this case, the 10th percentile is not completely unreasonable. As spread decreases, that will most certainly come up on subsequent runs. Sent from my SM-S936U using Tapatalk

Such textbook synoptics. The NAM and GFS progs are extreme, upper echelon - but think of it this way, 75% of that sort of outcome is still a crusher. Def wish my work schedule lined up in a way that I could have flown out to experience it. January 96 was a seminal event on my path towards becoming a NWS met. Ironically enough, during 2006 I was up skiing at Whiteface where we just had cirrus up there. And then in 2016 I had already been in the Chicago area for 5.5 years. Did get to experience the Feb 2010 craziness after missing the early month 'snowmageddon' and happened to be back in NYC during Nemo in 2013. Here's to an all timer for the area.

There's no such thing as a blizzard watch. Just a winter storm watch indicating the potential for blizzard conditions within the watch. Sent from my SM-S936U using Tapatalk