MillvilleWx

The boundary layer was considerably cooler this run compared to the last set. 850mb temps were 1-3C colder at onset which is huge. That was a really nice run. Borderline WSW for the NW folks and a solid WWA for DC proper. Good run

This is a heads up to all that the ZR accumulation maps are just model interpreted rain soundings falling into sub-freezing surface layer. The total ice is another physical paradigm that has a lot of other factors at play. This event is certainly looking frozen for a lot in the forum, but mainly a quick snow to sleet/zr as the lower boundary layer warms quickly with the wave pressing northeast. However, the antecedent airmass ahead and in place during the event will be enough to create some issues, especially with a lot of the precip occurring after prime heating. Low dew points in the region should provide sufficient wet bulb to ~29/30 for areas to the NW of the fall line, which could lead to prolonged icing concerns for the evening. Hourly precip is light for the most part as well, so this should allow for a better accretion environment IF the GFS were to oblige verbatim. Looking at a sample sounding on Monday evening, check out KFDK where the precip algorithm is basically on the border of snow/sleet with ice further to the south and east. This is such a razor thin margin for what type of precip will be dominant during the beginning of greater mid-level ascent. In fact, it's even more of a snow signature for areas north of I-70 which is a benchmark for these types of borderline events. This has Winter Weather Advisory written all over it with an outside shot at WSW for areas north of the interstate and out by I-81. Lift is there. The cold is there for once. It's a matter of boundary layer warmth off the southerly low level flow between 7H and the surface.

One of the key differences with regards to ptype at the beginning of the event is the regional dewpoints which would allow for sufficient wet bulb with sub-0C within the boundary layer. Taking a look at the GFS and ECMWF differences, you can see a drier layer present aloft which would allow for enough of a wet bulb to begin as snow through areas north of Rt 50. ECMWF GFS Notice the contrast in lower dews to the north on the Euro compared to the GFS. This little tidbit may be the difference between a longer frozen event compared to a hit and run. This is a classic north of I-70 remaining frozen longer with more impacts for the evening rush since majority of precip is after 21z. Something to monitor. As far as the UL pattern goes, there isn't much of a difference between the 12/18z runs to the 00z, so the main characteristics of ascent are unchanged with focus mainly on surface and lower boundary layer.

Recovering from a back injury, so I have not followed anything in 2 weeks. I'll try to look at things in the coming days and give my 2 cents. On mid shifts until next Thursday AM. Hope all is well

Congrats to all the Buffalo fans in here. Crazy game .

Idk what kind of luck I'm having right now, but models trending more bullish here for snow. 5H track is close to perfect for Midland, but looks like best ascent is just off to the north. I'm probably going to do an early morning snow chase on Sunday and will return in time for the Ravens game. I really hope you guys can score soon. I'm just happy we're getting precip here.

Probably pretty rare in a Nina since you need that subtropical connection, but the wave amplitude so far has been anomalously in favor of digging s/w with lower lat push compared to normal. Hopefully it can keep the same pattern with more established cold. There were a fair amount of SWFE events in the front 6 years of the 2010's, but they've hit a snag recently. Probably just reverting to averages. Hopefully y'all can cash on one later this month or February.

My favorite part about SWFE events is the ferocity of the thump with a more organized system. No waste on virga, hot and heavy starts, massive aggregates, and typically pastes everything into a wintry scene. I know that you probably really enjoy those living well west of the fall line. Some of the best 12"+ storms are like that in your hood.

I would think so, but of course, there's no guarantee. As @WinterWxLuvr alluded to above, it should increase the threat for winter wx overall, but anything that cuts would still likely be a messy scenario with overrunning, then a flip due to WAA torching the boundary layer. I think the setup lays the grounds for easier ways to score. Significant snow is all prudent to the setup. If we lose amplification of the NHemi pattern and we shift to a zonal regime, anything of significance will be put on the back burner.

The middle to late month time frame is beginning to show a consistent look of either PV lobes dropping into the Great Lakes area, or just a dominant cross-polar flow regime with the 5H bridging nestled over western US/Canada by Day 10+. This is not the typical pattern to score big potential unless we get some kind of phasing to occur in the southern US, but this will be a door opening to high ratio fluff from progressive clippers that dive through the northern plains and head eastward. Snow pack will be increasing to the north and west, leading to less chances of modifying airmasses by the time it reaches Mid Atlantic longitude. This will also lay the grounds for a further south baroclinic alignment which could be fruitful for later in winter. Not a slam dunk obviously, but better than where it currently stands.

My optometrist would be proud

This is awful to hear Rich. Hopefully you can recover quickly and get back on the right track. Caffeine is nasty when it's coming off high doses over time. Thoughts are with you man.

Here's the final result to the evolution posted above. It's just a bit cold......

The GFS is the only model that goes out into the period where any arctic outbreak would occur for east of the Mississippi, so this is only basing off deterministic. That said, the large scale cold push into the Lower 48 is initiated with weak ridge-bridging over western Canada that brings the first round of significantly colder temps with lower heights over the eastern CONUS. There's a slight reshuffle between hrs 300-324, then a more significant bridging occurs towards the end of the run, leading to a more significant blast of arctic air with origins over Siberia as Cross-Polar flow occurs. There's sub 500dm heights on the deterministic over western Ontario into Manitoba at that point, so that's the real surge and matches well with HM's Jan 20-25th peak of when the cold floods the eastern US.

Come back as C6H12O6 and really make this place lively

We need a new Long Range Mid Atlantic Sub Bingo Card @NorthArlington101

The @psuhoffman window is poking its head out now. Obviously some things are likely to change with the overall pattern (+/-) strength of the blocking over top, teleconnection bases, etc. One thing you want to see is established cold over the northern plains working east with time. The cold stretch being advertised is fairly robust beyond 1/16. This is obviously an important element to getting any fruitful winter precip for the area. This is all stemming from a very favorable upper air pattern over the west, bridging into Canada. And then it gets even better..... If you don't fancy this look, Idk what to tell you

Not for snow reasons, but I'm looking forward to moving back north at some point in my career. I was really thinking about doing Florida or SE US offices, but I'm just too much of a lover of synoptics and snow to not move back north. Plus, the education systems in the south are.....pretty abysmal, so I want my kids having a great education and to be closer to family and friends. Growing up in the northeast US then moving to Texas was a culture shock. The people are nice overall, but the environment, weather, and way of life are not for my wife and I. I'm gunning for Sterling/State College/Boston for my forever offices.

We had a crazy gradient in our CWA too. It went from dry to completely parched the further west you went

I think it has something to do with the energy at hand. A northern stream system that has significant wave amplitude will begin with more energy and the colder air involved might add to the baroclinicity factor, especially once near the coast. That's just my proxy on that. I'll see if I can find any articles that pertain to the theory.

There was supposed to be precip but it was pretty dry sadly. Nothing really came to fruition until it was above freezing for much of the region. Sorry for the late response! Just worked day 6 of 10. Oyyy

HREF guidance at 00z pegs a corridor of light ZR accumulations across areas west of US15 out to the 81 corridor. There's a secondary bit along Pars Ridge in Carroll and the PA Line from Thurmont/Emmitsburg to northern Harford County. It's minor at 0.01-0.1" of ZR with temps between 29-32F for 3-6 hrs. It might make for tricky travel in the early morning before surface sufficiently rebounds above freezing between 14-17z everywhere. The further NE you are, the longer the sub-freezing temps will hold in this setup. Could be rough from PSU-Mappy-Jarretsville tomorrow morning.

Was thinking the same thing when I was mulling over guidance. That sucker will give us some serious wind for the Panhandle. Have the blocking a bit weaker to the north and someone could get lucky across VA. Smokey mountains would get popped pretty good on that presentation.

I remember this run! This one is up there with the 65" NAM run before the 2013 New England Blizzard lol The crazy part is the map is actually good outlining the hardest hit areas. Was just a touch rambunctious on the total snowfall lol

Sir. I'm gonna have to ask you politely to NEVER post this storm in here ever again. Sincerely, A Scarred Meteorologist and Mid Atlantic Snow Lover