MillvilleWx

Banana

I haven't examined the Pittsburgh area too much, but you guys will be well away from any warm boundary layer advection outside a slight climb as the SLP gets into PA. I think WSW criteria snowfall is certainly at play for you guys. I really like the Laurels for this one. This is a great storm for places like JST/Altoona area. I think you guys will get some love out that way.

If y'all have any questions to the map, tag me and I'll try to answer them. I'll have a longer write up later today after work on my thoughts. I'll likely post in the MA thread, but I'll copy the post here for all to read. Thanks for the feedback guys

First Call Map I'll have more on my current thoughts later today when I get a chance. I also want to see any shifts in the ULL track and timing of vertical stack with the SLP. Some changes may occur in the next 24-36 hrs for my forecast, but zones should stay relatively the same.

Still haven’t looked at a dang thing, but I too am interested in the Nest, starting tomorrow. Nest did amazing with March 2017. This is a good setup for it. .

Just a heads up for everyone in here; I am going to be busier than a one armed coat hanger today at work so I will not have any time to look at a single model run for the 12z suite until perhaps very late in the afternoon. Might be more likely after I get off work. Too much going on. Storm wise: My thoughts have not changed on expected impacts. There will be a strong nose of warm air nestled between 850-700mb as the LLJ on the eastern side of the cyclone will be robust, approaching 2-3 StDev above normal for climo, which is impressive to say the least. I mentioned this before but the u-vector component with the wind is going to be off the charts. This is both good and bad. The good is the advection of moisture is going to be stout to the point that people are continuingly underestimating what kind of front end thump we are looking at. The 850-700mb frontogen pattern expected is bananas. 1-2"/hr snowfall rates will be COMMON with this storm on the front end. Add in the orographic ascent typical for the area and things will come in like a wall of white. WAA snows wait for no man. Despite the drier antecedent airmass in place, things will moisten up rapidly. I wouldn't even worry about that part. The bad part of the stronger u-vector component will be the mix line racing in tandem with the precip field. Things will changeover likely a little faster than what you would want, but I do feel the globals are overestimating the scouring of the SURFACE cold a bit too much. Piedmont areas, especially anywhere above 500' AGL may struggle to warm much above freezing with freezing conditions remaining out near I-81, west of the BR. This is textbook for a storm like this. What to look for: When does the storm stack? Is there an adjustment on the strength and longitudinal shift of the mean trough/ULL that develops over the Deep South? Where is the SLP located when the turn north occurs? Are there any significant trends with regards to thermals as the system arrives? What is the DEPTH of the warm nose being advected into the region? Is there a change in the speed of the N/S vort that is supposed to phase into the disturbance? These are the questions to make a checklist for. Today should shed more light on the prospects, but I feel the NAM Nest range is when things will have a better indication on the finer details, so don't worry about banding prospects until we get closer to game time. That's all I have for now. Enjoy the tracking today y'all! Hopefully there's a little bit of a SE trend to get more love to the sub

That was a solid adjustment from the GFS after gleaning over it. Ignore the developed ptype algorithm maps for the time being. Soundings tell the story and climo wise we're beginning to see how this would usually shape up. The wall of snow is still well within reason. I-81 corridor still favored, but the metros will not get shutout. I love the cold antecedent airmass leading in too. I have no changes to what I've made previously.

That is amazing. I was 5 years old for those storms and my first weather memory is actually from the Blizzard of 96. Absolutely incredible scene in my neighborhood with piles only beaten by 2003 and 2010. I wish I was older so I can have a fonder appreciation for that storm, but now I live through the meteorology. Glad you got to experience and remember it all!

Truth. I just see the make up with the strength of the LLJ and 700mb moisture flux can kind of combat the inevitable flip and keep the storm within reason for the DC metro area. A 3-6"/4-8" with more north and west is what I'm projecting right now, which is what happened in 1996. Evo is sort of similar, and it has higher grades for the 500 and 850mb height pattern which are good levels to look at with CIPS when it comes to similarities. Final forecast won't be out till Sunday with a first guess on Saturday. Still too much to parse to make a distinct call atm. One things for sure, it's not going to be lacking moisture. Have a theta-E advection regime most would enjoy during severe season. Talk about your influx of mid and boundary layer moisture.

I...... Jk. I think your area will be right on the tightrope. If the GFS was right, you'd flip to sleet. Euro would be a high chance of staying all snow. I think your area could do very well with this system as well.

@mappy When I saw that map posted without a legend, you were the first person I thought of. I had a feeling you were ready to lose your mind with that one haha

Those of you in the LSV should get a good whack from this system. Areas like Franklin/Adams/York counties should clean up along the southern tier before any flip occurs. I think a spot like @Cashtown_Coopshould get hammered along with those along I-81 up to Harrisburg. I'll poke in over the next succession of days. Look forward to living vicariously

Wrong storm. That was the Blizzard of 1996 which was its predecessor. This was afterwards. They got 6-10" at Dulles from this one according to the snow data

January 12th, 1996 showing up high on the list of analogs for this storm now. I've seen it on the CIPS list for the past few days. Has a pretty decent look for areas north and west of the fall line. Almost in line with my current thinking. Not as dynamic with the 5H pattern, but similar positions of the mean tough and 850mb flow pattern expected. Interesting

That front end thump on both the GFS and Euro are something else. This is giving me very 2/2014 vibes right now. That precip will come in like a wall. With the mid-level ascent depicted, 1-2"/hr wouldn't just be a possibility, it would be a certainty. Would certainly be fun to watch come down in the first part of the storm.

There's a bit of a trowal signature on the Euro when looking at the 850-700mb frontogen pattern. I would say right now it's just barely in MD and more into PA, but watch for that backend stuff. That will not be something resolved game time.

Current National Blend of Models 50th percentile for the region through 00z Tuesday next week. This displays a pretty idea of what the current thinking should be given everything we've seen so far. Meso-banding and other parts will of course change localized amounts, but this is solid for a smoothed mean.

Parsing through some of the details, this run is very similar to the current NBM result from this AM, and it also jives with the CIPS run from last night in terms of impacts and evolution of the precip field. There's differences in the strength of the low compared to a blended mean and analog pattern, which lends credence to a pretty sizeable thump off a significant 700mb frontogen depiction, then a flip to sleet/rain for areas east of Rt 15. I-81 corridor is going to be close, but some sleet likely gets west of the BR, but could easily change back to snow on the back end of system. It's overall not a terrible run for west of the bay and certainly better than last nights 06z run.

00z runs last night shed a bit more light on what to expect for certain areas, but there's still some question marks to be answered in the overall evolution. Looking at the GFS and ECMWF, there's a distinct period at the end of the storm that bares watching for trends that could save some areas that experience a quicker changeover during the storms height. As of now, the GFS does not have as pronounced a comma head to the precip and any that does develop is off to the NW into PA and perhaps towards the Alleghany front. The ECMWF otoh has a pretty significant back play of the deformation zone that sweeps back east as the low occludes to the north and drifts NE. This is a period where snow can pile up quickly due to increased forcing on the backside of the low within the deformation zone. The DZ often has the best ratios for snowfall due to the prevailing dynamics at play with a robust mid-level frontogen signature and funneling CCB classic with a prevailing SLP in the development stage. This is partly why the snowfall is pretty solid on the ECMWF despite the proposed changeover. Two factors here are important for this to occur: 1) The SLP has to be away from the BR as backside flow from the W/NW would induce down-sloping off the Apps and create a cull in the precip on the underside of the low. A low further east towards the bay has more room to alleviate those concerns, which we have seen in the past. 2) The low needs to continue on a development phase into at least SoPA for this to become a possibility. An occlusion early would incur a persistent warm fetch off strong SE flow. This is less likely to occur as model guidance has now, but something to monitor. A passage of the ULL to the south is what we want. A passage overhead may provide a period of ascent locally under the attendant ULL, allowing for a switch from liquid/IP to snow before the snow shuts completely off. The path of least resistance to scoring would be for the low to pass to the south. Any pass south of Rt 50 would likely yield a fruit of at least 2 hrs of solid snowfall as heights crash and we get a top-down shift in the ptype. Think what happened in 1/26/11...This storm will have a similar ULL strength, so the prospects are there, but the evo right now as progged is off. ULL's are tricky. They can change their paths on a moments notice depending on a multitude of variables, but most notably the proxy of other s/w features that could aid/hinder the height pattern near and downstream of the prevailing longwave trough. Moral to the story, there is a lot we still don't know, some we have a general consensus on, and some mesoscale details that will be fine tuned in the future. NAM 3km will actually be VERY useful this storm. It did a great job on the transition zone in a myriad of events with the most notable being March 2017. Remember, with the HP to the NE, the u-vector component of the wind field will be very robust, so the intrusion of warm air could be tough to overcome, especially east of the fall line. As for areas that can hold off the climo factor of screaming easterlies, that is our I-81 gang. That's why I would wager, for the time being, they will be the benefactors for snow, but high impacts along the transition zone to the fall line are still likely. Temperatures will struggle at the surface for elevations above 500'. Same song and dance, so keep the faith and know a meteorological marvel will probably unfold before our eyes on Sun-Mon. As a meteorologist with absolutely no skin in this game, I will be watching satellite and wishing I was back home. Synoptic meteorology has a special place in my heart.

Guys, it's a deterministic at Day 6. Yes, as it shows, it would be an I-81 special and people east of Rt 15 would get a driving sleet/rain before changing back. There's too many variables on the table to decipher before pegging any particular solution. There could even be a piece that's not even modeled that could throw another variable into the mix. Welcome to the world of chaos with a dynamic fluid that is the atmosphere.

The dress looks nice so far

For the most part, yup. The GFS and CMC both had a bizarre back end of the storm with it petering to nothing almost. There is no way that happens with a bomb like this. That comma head would be a thing of beauty, which is exactly what the Euro depicted. I still think we are far from being able to parse the nitty gritty on the setup, but the trends are favorable for a sizeable system.....for now. Hopefully it can stay locked in. It's going to be a wild ride until Friday me thinks.

This does have a lot of similarities, although the kicker here is it's showing a more powerful setup. These models are gonna underestimate the 500mb prowess up until game time. Euro I think has the closest idea to what I would expect with that evo

I was there for that and remember it well. An incredible storm in so many ways. The thundersnow occurred when we were all hanging out sledding that evening. Crazy Very much the 500mb evolution for that one. Super dynamic ULL, which for the time being this storm also has. There's a pretty good chance of thundersnow somewhere in the sub-forum and NC/VA if this holds. That was on one of the lists outside the top 10, but it was there!

Sooooooo. The 12z CIPS analogs are out...... The top two analogs with regards to the 500mb height pattern at 132 hrs out are: 1/26/2011 2/13/2014 Lead up at 120 hrs out number one analog...... 2/10/1983 This doesn't mean we can expect those exact results, but it does show what type of pattern and setup we are heading into these next 5-7 days. Remarkable swing these last 18 hrs.