MillvilleWx

Yup. I look at all the models like everyone here, but unless there’s some significant agreement within the ensembles and eventual hi-res, I will still go with the more trusted deterministic output than outliers. I haven’t wavered from my forecast for that very reason. Can’t be living and dying by every model run.

Reston is one of those tricky areas right in the dividing line of my typical main zones. I’d say 2-4” with upside potential 5” is probably a decent forecast for that area. There’s a little boom potential with this one for areas that stay all snow through the event, so it’ll be something to monitor.

I would say 10-20 miles outside beltways and 20-30 inside. Probably difference in areas >= 250’ ASL. I know I grew up in one of those areas that went from zero to 100 when it came to snowfall away from 95. Lived 8-10 miles west and went up over 280’ in that span. Crazy microclimates

No problem! I think that’s a result of the primary cyclogenesis with the low strengthening and creating a narrow channel of stronger 7H VV’s within the western flank of the circulation, proxy of 700mb low maturation. This is likely in combination with a strengthening CAA regime within the boundary layer allowing for maximum ascent between the 925-700mb layer. There tends to be a band that develops within that core during these types of regimes. Those are sneaky and can be a nice surprise for areas that miss out on the initial wave of snowfall. One of the reasons places like you mentioned into South Jersey can sneak into good snowfall totals.

Oh yeah. You’re in a solid spot. You should have average ratios up around 13:1 for the entire event with the final few hrs likely skewing closer to 15-16:1. Nice powder finish

@dailylurker That thump being advertised in AA County for the final 2-3 hrs looks incredibly legit for us lowlanders. That could be a solid punch before it all ends. Pretty consistent indication among guidance. Probably a shot at puking fatties within that window.

My forecast still looks to stay the same. NW of I-95: 3-6” w/ up to 8” max Along & SE if I-95: 2-5” w/ up to 6” max Area south if I-66 in NoVa and SMD: 1-3” w/ potentially up to 4” if everything breaks right Best areas for max potential: Parrs Ridge crew from NW MoCo up through Western HoCo and Carroll. This extends eastward into northern Baltimore Co over into northern Harford. This includes places like Parkton-Jarretsville-Norrisville. I like our border friends in PA for this one too. NW of Philly into the Lehigh Valley will probably see 4-8” w/ max of 10” possible. Unlikey to change my thoughts as things get locked in. Hoping for a surprise overperformer. It’s gonna snow

@DarkSharkWXhas the trends within the height field going back past few days. You can see the eastern seaboard see slightly better heights near our latitude as we get closer in time. I don’t think we’ll totally get there, but the door I think is open for some light QPF to make its way here for mid-week. The Eastern Shore will probably want to keep very close attention to this as they probably have the best shot as something more appreciable.

Got that look of deep winter for several days post snowfall. Outside some minor sublimation, this snow is not going to go anywhere.

ECMWF and GFS are now fairly close in QPF distribution and orientation. Only difference is GFS is a bit wetter, so it helps with higher totals. This is the range where these two models tend to lock in. Unless they take major steps in another direction with the overall Synoptics, I think we’ll start seeing a more definitive picture for what will transpire on Sunday. Good run and much closer to my thoughts. One note for the lowlands crew, this 00z suite has tended better for areas north of Charles County. AA county will be right on that edge for the good stuff me thinks. Some of the guidance is beginning to note some tertiary banding across the county with some locally higher QPF output. Something to keep an eye on.

Just catching up to what has transpired model wise today. It was a semi-lost day for me as I’ve been having some jaw issues from God knows what over the past several weeks. Went to orthodontist and they ruled out TMJ, so it’s off to the Dentist I go for whatever time they can take me next week. Been a long day of dealing with a flare up. Ugh Anywho, looking at guidance and there’s still two distinct camps for this one; a stronger surface reflection that delays the CAA regime and causes a sharp southern edge in the QPF distribution which negative feedbacks to lower snow totals until well NW of the fall line. The second option is the stronger Arctic boundary with less amplification of the surface reflection allowing for CAA regime to take shape with improving PBL as we step through the afternoon, a testament to the magnitude of the airmass that’s going to be making waves in these parts. The consensus I’m seeing is the over amplified cluster is losing steam with the GEM suite being the primary drivers for this scenario. The EC/GFS/NAMNest/GEFS/ECENS/EC AIGS ML output are in convergence mode with now only minor deviations in the thermal alignment/positioning, as well as the total QPF being depicted. Considering some solid 85H FGEN progs being depicted within the latest NWP iterations, it’s likely there will be some good mesoscale banding structures that will transpire during the height of the storm, and that will coincide with the bleeding arctic airmass leading to slight improvement of SLR’s (Snow-liquid ratios) even as we step into the afternoon. This is not a classic setup, but there have been multiple cases over the past 20-25 years of these types of events with good wave timing to take advantage of the advection paradigm while we get the better forcing intersecting at the same juncture. My initial forecast has been for 3-6” w/ locally up to 8” for places along and NW of I-95 with a southern inflection around I-66. 2-5” forecast for southeast of there, including the DC metro with a max of 6” plausible within any areas that get multiple banding structures over the course of the event. I feel this is a good storm for places NW of the fall line with higher ratios between 10-12:1 to start ending closer to 14-16:1 at the very end of the storm with some locally higher SLR’s within those climo favored areas along Parrs Ridge from NW MoCo up through Mt Airy into Carroll County. This is the type of wave that tends to get these areas pretty well, so unless we see a significant deviation in surface low placement within the 15-21z window on Sunday, I think my initial thoughts will remain steadfast with potentially some minor adjustments pending QPF output as models fine tune as we move closer. Looks like a beautiful snow day incoming with playoff football to make it feel even more like deep winter. I’ll try to chime in again as we get closer. Hopefully my mouth pain can be solved by next week. I’m tired of this -ish. Have a great night

Majority of the ECENS has members in the primary cluster that according to cluster analysis contribute to 41% of the total ensemble suite (ECENS/GEFS/GEPS). Surprisingly, the ECENS is strictly in just two camps; the primary camp with a decent hit and then another with very little. GEFS is sort of similar, although much of the GEFS has something appreciable with only 6% of the members showing very little. GEPS is distributed a bit better than the other two, but still showing 45-50% within the primary camp and 20-25% in the more amped scenario. I think we are approaching a decent consensus at 2 day leads. If the 12z doesn't sway too hard, we should start getting a clearing picture.

It's the range map. Typically the ranges are the 1st and 3rd quartile (25th and 75th percentile). I would say 3-6" w/ local to 8" as a good call for a lot of the sub. Likely more 2-5" along and southeast of I-95, but we will see how it shakes out as we get close.

Great write-up as always! Looks like we are seeing the proverbial “goal posts” among the deterministic and can assess the finer details likely either this afternoon, or by tonight. Ensemble spread is muted compared to yesterday. Looks like a beautiful day of snow and football this Sunday. Couldn’t be more stoked for that. I’ll try my best to follow what you volleyball set to me today

Ooooo. Baccarat! I see you too are a man of culture.

Season Total: 11.6”

True dusting in Edgewater area. Was still flurrying as I went to and from the store. Beautiful out

I keep an eye on it now along with the rest of the suite of models. Been pleasantly surprised at how it’s been performing.

Me and the Met on the QPF desk had lots of conversation while doing the forecast today. We both were taking note over the past several days of the AIFS remaining steadfast. I felt it was necessary to add to the disco as AI has been around for a while now and we have verification scores, and we have enough data to see trends over the past 1-1.5 years. It’s been a great tool to see where things could trend. When the AIFS is locked in, it has been really helpful. It was really good during Hurricane season and so far it’s been decent within mid-latitude evolution. Still not perfect by any means, but it’s very useful in the right scenario. This seems like it has some merit. I will say that the AI isn’t going to replicate banding structures very well and the QPF output is smoothed compared to dynamical output. That said, I believe it has the right idea and some minor shifts could still occur, but I think we have the main synoptic evolution down. Just down to finer details and thermal profiles.

You’re welcome

Light snow in Edgewater area. Man, what an awesome winter this has been for the lowlands and surrounds. Let’s keep this rolling thru Sunday, shall we?

First step is typically calibration, but sometimes it can just be in a bad spot for sunshine when it's directly on it. It's tough to really find a sweet spot for a weather station unless you have a huge yard or open field where it's at its best. I'd calibrate first, then try shifting if it still has that issue.

Your lips to God's ears....and hopefully my backyard

I'm telling you guys, when the AI is this locked in, everyone should take note. It's not a true dynamical model that can sway with regular perturbations like a ECMWF/GFS/(Insert Model here), it's basically a really well programmed analog with a historical dataset that it references on each run. When it looks like a duck and quacks like a duck....