wxsniss

Great stuff. Your posts read like a thriller that educates. What I'm looking for in next 72 hours to optimize that handoff from isoentropic to cyclogenic-CCB mechanisms: beyond just looking for an 850/925 low closing as far southwest as we can get it and maintaining easterly inflow lasting to 0z-6z Tuesday, I'm thinking earlier arrival of the energy rounding the trough and better tilt of the trough will help. At the moment, 0z ICON last night was the best depiction of getting this done I could find, with widespread 20"+ possible in eastern SNE. It's backed off a bit since but there are still hints on all guidance. Fwiw, 18z NAM at 6z Monday looks alot like 0z ICON... ie., potential to get very interesting Monday.

12z AIFS crushes and continues to hint at lingering coastal through Monday evening

An example of what I and others posted earlier... 0z ICON last night showed this as well (but backed off at 12z today). This is from 12z UK, keeps low level easterly flow into 0z-6z Tuesday... this is what we'd need to get us closer to 20": (EDIT: this is 850, 0z Tuesday, from 12z UK run Jan 22):

Without digging deeper for a better example, 0z ICON last night had the closest depiction of this we have a closed low 925-850 just southeast-east with easterly flow well into 0z-6z Tuesday Not totally outlandish either for these lower levels... Higher up 850-700 probably not happening fast enough

Agree, one of the more suspenseful remaining aspects of this imo if we're looking for the more "exotic" "nirvana" solutions of SWFE + CCB to get us to 20" and over I think ICON has had some of the better depictions of this, by virtue of faster infusion of energy and tilting of the trough

Agree Jerry I think 10-16" is a lock for most of SNE... but a few model runs flirting with better coastal development and capture... that would get us to 20" and more 13z Jan 22 NBM output...

Agree, exactly why in the cold vs. qpf debate about what's more important for a snowy winter, I always go with cold, even if it risks cold dry runs. The historic ones are often preceded by an anomalous cold dome... 2-14F, –2-27 Jan 21,22, 2005 3-19F Jan 6, 1996

12z ICON is great, but did back off a bit on the coastal development and capture... you can see at H5 the energy is slower to infuse and tilt the trough compared to the 0z ICON Just something to watch if we're looking for the more "exotic" "nirvana" solutions of SWFE on steroids + CCB to get us above 20"

NESIS 4-5 likely... these geographically massive ones you can see a mile away https://www.ncei.noaa.gov/access/monitoring/rsi/nesis

Very similar to 12z run at H5 and surface Doesn't quite develop and capture coastal like 0z ICON, but still would deliver 10-20" all of SNE assuming better than 10:1

Yeah EC AIFS followed same pattern as GFS... 0z and 12z similar, 18z outlier 0z and 12z better phase, coastal redevelopment, big hit SNE especially east

I like the comparisons, was lucky to experience both In terms of phase interactions, 0z GFS resembles 12z GFS as well as 0z ICON (ie., 18z GFS disconnect was hopefully an anomaly)

12z CMC and UK also had hints of more potent backend vorticity rounding the trough which would improve coastal development Just catching up... been a while since we've been staring at a region-wide foot+ with lots of buffer. Quick look, key variables determining 12"+ vs. 20"+ in SNE include • proficiency of coastal development, and how well it can vertically stack and better develop a comma head • ratios: 12-15:1? • CF enhancement for eastern areas? Thanks @MegaMike for that link earlier... here's an NBM product I haven't seen before, run 13z Jan 21:

0z EPS jumped ~150 north compared to 12z EPS mean QPF now 0.7-1" all of SNE

Agree I've been browsing through NARR there are H5 similarities to Jan 1994 and Feb 2013... it's nice to be in a favorable setup for a change... in the what's-more-important cold vs. qpf debate for optimizing chances, we're rolling with cold for a few weeks and I think we do well