MillvilleWx

Your area is always tricky due to your proxy and unfavorable endeavor with a screaming SE wind upstairs. You know your climo though and are reasonable with expectations. I would think Advisory level snowfall is well within cards and maybe even near low end warning. The coastal, if it materializes will be a bugaboo for a while as you roast in the boundary layer. You would need an arctic feed to keep you all frozen. You can catch the backside pivot as the 7H and 85H low cut underneath and cold air crashes back in. Tough call, but hopefully you can get some white for your hood. I love seeing pictures of your home with snow

There is considerable divergence in the 5H pattern post 00z Sun on the GFS compared to other globals and even the NAM. The GFS remains in fairly decent envelope of 5H progression with a strong, negatively tilted trough centered over E KS and W MO by the Saturday night time frame. For whatever reason, the GFS then opens the wave and the energy becomes diffuse for a 24-36 hr period before reorganizing as it pivots southeastward after reaching a latitude of southern MI. No other global has this, even it's GFSv16 brother. The rest of guidance is in close proxy to each other in terms of 5H low positioning, surface reflection, and overall handling of the precip field as it exits east of the Mississippi. The GFS could very well score a coup or the other guidance can start to gradually move towards a GFS-like scenario. Another option is a meet in the middle marker with regards to the 5H progression and we see another plethora of options in terms of potential outcomes downstream. This is a pretty delicate setup for the east coast where small ticks in strength or low placements will mean the difference between a small event or significant outcome. Don't be surprised if we see 20 different variations of an outcome by Sunday with a blend of a few that handle the UL pattern the best.

WPC weights their progs for forecasts based on the short term and utilizes so much incoming data to base what their preferences are for a time period. My buddy works at WPC and said it's a lot to take in, but it's like riding a bike once you do it so many times. They are not in the GFS camp at this time due to progressive bias and currently not in sync with what's currently occurring in the CONUS. It can certainly shift in the short term and has happened on occasion. For this system in NC, the GFS handled it much better and the other models played catchup. In fact, EPS was actually signaling the deterministic was out to lunch prior to the cave, so for whatever reason, the Euro just couldn't get a firm handle until close in. Right now, Euro is doing a better job at handling the AR off the PAC with favorable 5H positioning and other synoptic features. We'll see what happens with a new data ingest at 12z as this will bring us inside 72 hrs, a period when some will need to start addressing watches for the Midwest.

I'll take this 5H forecast in Days 3-7 all the time https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif Surface is pretty decent as well... Close up of Days 4 and 5.... D4 D5

Possibly, but the air that corrupts the boundary layer is straight off the Atlantic, so typically that air comes in like a banshee. It's why we can get blasted and why we changeover. Blessing/curse type deal.

There wasn't too much to hate for from the EPS. I loved the strong signal for a moderate WAA piece for Sunday. It's a setup where 0.5" precip can yield WSW criteria snowfall with the temps depicted. I'll be banging that drum until it happens.

Pass the coffee

I could see that. It was legit splitting hairs on who gets bombed on that run. I was digesting the 7H low progression and it was legit 25 miles north from the sweet spot. I'm just glad the Euro hung on to nice transfer and vort passage compared to the GFS which has been sloppy. I know people in here are worried about things trending too far north, and it's justified, BUT if you follow weather around here, these Miller B/Hybrid setups are NEVER easy. You have to walk the tight rope. The cool part is, when they happen, they are magic.

The mid-level dynamics need to a be a bit further south in order to cash with the coastal. 850-700mb is the area you watch for low passage as this is where the best lift for dendritic growth occurs and you see better banding structures.

ALWAYS the concern with these setups. It's a tight rope walk for the area. Euro/CMC/Para GFS are all good for the WAA piece. CMC is like the dividing line between the Euro and GFS. IF I was to bet where the best snow will occur, I predict Rt30 to the PA Turnpike with 50 miles either side being well within the clear for a MECS. Need a little more of a southward trend for DC/NoVA. Miller B life

Correct. 7H over CHO up to Fredericksburg is the ticket

This! These are rare to see, but there's two ways to actually score here. There's an easy way to score a nice low-end WSW criteria snowfall with the WAA piece ahead of the surface low into the OH Valley. The antecedent airmass ahead is ripe for the picking and is something everyone should be rooting for. I know you know how Miller B's work around back home. It'll be a tight rope walk as usual, but the prize could be epic. The key is keep the primary from going too far north if you ONLY want the coastal. Need the confluence to the NE to hold it's ground and the surface low to not tuck back over land like the Euro. That caused some boundary layer issues for about 6-12 hrs east of the fall line.

I would say this is the most valid concern for the whole event. Miller B's/Hybrids are ALWAYS a tight rope balance for the Mid Atlantic.

THAT was one hell of a run for much of the sub-forum. Despite the bit of mixing during part of the coastal for the cities, everyone is puking dendrites at some point during the height of the coastal. US15 to I81 from Winchester to Harrisburg could be the deformation zone on this run verbatim. The whole area gets walloped in all. 1'+ for a ton of the sub. Even with the slightly farther north track of the surface low into southern Ohio, the goods are still delivered. I liked seeing a consistent hold of the ULL as it crosses into the Ohio Valley as well, strengthening again as it moves east. The 7H low cuts right over the Potomac. Just a slightly further south depiction, and it's blockbuster for basically everyone. A great run

You think that's disturbing? Try spending tens of thousands of dollars, taking copious math courses, drowning yourself in coffee/tears/booze, and then subjecting yourself to no sleep for the rest of your life so you can see how water condenses and air moves.

Well that was one hell of a GFS extended run. @HighStakes nailed it on the head. Plenty of waves to contend with too and baroclinic zone pressed to the south, which prevents the cutter potential. Hell, even a marginal low track can bring winter that those kind of temp anomalies. Hopefully the trend for that time frame continues. That's historically the meat and potatoes for snow events back home.

Pretty much. And it's certainly a cause for concern for anyone in the Mid Atlantic in general. Hopefully the Euro stays the ground because I sure like what the CMC/Euro combo is doing.

I haven't peeked at it yet, but I certainly will now that you mention it. We've got our own fun wind bags incoming for this weekend and pretty much half of next week, so I've been mulling over the data there. Could have a 3 day High Wind Warning for Guadalupe Pass out here next week. Good times! lol

I agree.... so $100 on the GFS?

I muted Ji a long time ago, and I still don't think it was enough. He might be the one of the worst posters I've ever come across on any forum, and I'm on Twitter...

So.....we're putting $50 on the GFS, right?

I just logged on and took a brief look at the 00z runs tonight. One of the best details I'm seeing is in regard to the first 6 hrs of the event with the WAA piece. The airmass ahead of the precip is ripe for a better snow consistency as boundary layer temps are pretty cold. The 850-700mb Frontogen on the CMC/Euro is pretty respectable, so the crystal structure would start out as more dendritic, then shift as the 850mb WAA noses in, and we proceed to larger aggregates with more rime exteriors. You don't need hefty precip in order to have some respectable totals for the area. The CMC is a beautiful compromise for WSW criteria snowfall. Of course, a 12z Euro presentation would be epic for a multitude of reasons, but the potential for a formidable event has increased in my eyes, just off the initial slug that presents itself on Sunday and Sunday night.

I just woke up briefly. One more night of mids, so I’ll be on the model watch night shift. I must say, to see CIPS coming in that bullish, I’d be beyond ecstatic for all the sub-forum. Traditional caveats aside for these storms, it’s hard to hate the coastal low placement and strength. We don’t have potential for anomalous u-wind vectors to transport warm Atlantic air into a decaying boundary layer. We don’t have HP moving East into Nova Scotia as the low reaches MD/VA latitude. We don’t have a screwball low to the north that causes temp issues later on and instigates a drier NW flow on the western front to cut into precip expansion. If the GFS comes on board tonight, I’d say start prepping the shovels, grab the beer, and get ready for fun. I’ll have more to talk about tonight. But first, back to your regularly scheduled zombie. .