showmethesnow

I didn't think the issue would be the temps. Looking at the dry lower levels I had a feeling that we would see a better response then what we were seeing on some of the model output. My question was the amount of precip. WxWSAF brought this up with the soundings a couple of times and I had to agree with him. The look just didn't fit with the qpf the models were throwing out. I will be curious what the actual precip totals were post frontal (especially during and after the flip to frozen). Would be shocked if they came close to verifying and am actually expecting they were closer to 50% of what was advertised. eta: Now my thoughts are in relation to what we are seeing west of the Bay. The models may very well verify down in your neck of the woods (eastern shore). I really wasn't focused down that way so I am not sure. After all this is a MBY sport. after all.

Any measurable is a win in my book. But with what some of the better models were throwing out even up to game time it was pretty much a fail. Not going to go back and check but it seemed that once the NAM's got into their range they did a decent job on this especially the 3K. I have thought about this before but I have to wonder if the models don't handle the typography well in our region in these type of events. In particular the down sloping off the mountains to our west that dry the lower levels.

Winter of 19-20 Running snow totals. ******************************************** Dec 4 (Early morning hours): 1/2" Dec 11 (Early morning post frontal snows) .6 " ******************************************** Total for season: 1.1"

Looking at radar looks as if I am pretty much done with any snow excepting a stray flake or two. Looks rough for anyone west of the bay for that matter. Going to go with .6 inches on elevated surfaces and the grass as my final measurement.

Very light snow at this time with temps of 31. Eyeballing maybe a half inch (grass and elevated surfaces).

They are?

If 10% of these modeled frontal passage snows (outside of 24-48 hrs) verified I would be shocked. We get teased with them several times a year and yet I can't even remember when the last one came close to verifying. For the most part I stayed out of the disco thread for this very reason. Why spoil the fun of the newbies and weenies. Let them learn the hard way like I did.

Probably the biggest reason we are seeing a more favorable trough setup is because of the higher heights showing above it through southern Canada on this latest run. Below is the run over run change from yesterdays 12Z. This helps to create better dig as well as a better turning of the trough axis. The changes with the lower pressures reflect the response we see from the trough from those higher heights.

That's what they made alcohol for.

Euro upped the ante for the day 7 period. Kuchera actually shows greater totals for the cities and north I just couldn't get the whole time frame for the whole region using it. Believe it or not though, If this idea of closing off the 500's with the trailing trough is legit there is even more potential upside with the snow map above especially for those in the southern and eastern portions of our region. As it is the blowup we see on the snow from the previous run is directly related to how the trough is handled. We are seeing the trough axis having a more neutral look compared to the somewhat sheared look previously. We are also seeing a quicker closing of the 500's as well. These things are enabling a better feed of moisture into our region. Right now the trough is lagging behind somewhat from the lower pressures we are seeing first in the south and then off the east coast. But if we can see the separation between the two lessened by 1/2 to a day as well as possibly a quicker closing of the trough we probably would see a much more vigorous system or even possibly a 1, 2 punch. ****Actually saw encouraging signs across the board (GFS, GEFS, Euro, EPS) But we are talking seven days away, so...***

One thing that makes this a possible accumulating snow vs. a white rain scenario is what we are seeing in the lower levels. Below are the soundings for central Carroll county about 6 hours before we should see a flip. If you note the lower levels are torching. But this is 6 hours later just shortly before we would expect the flip to begin. Notice that the lower levels have cooled significantly. What we are seeing here is a dry air intrusion into the lower levels centered roughly on the 850 mb. What this is doing is dropping the dews (green line) below freezing for all but the surface. So what we have is good lift (far left diagram) in the moister air (700 mb and above) creating precip that is in turn falling through the drier air below and rapidly cooling it. Now checking soundings around the DC/Balt corridor all show a similar signature of a lower level dry air intrusion. ***Now I don't have the soundings for the Euro but looking over the different maps suggests to me that it also sees this lower level dry air intrusion.*** So what does the above mean? It means that the difference between white rain and accumulating snow will be highly dependent on rates. Well DUH, right? We will need the rates to cool what is significant warming from 800 mbs and down, especially at 950 mbs to the surface. Don't get the rates and we never see the cooling needed at the very lowest levels of the atmosphere to get anything more then white rain. This could once again be a case where those that get into the heavier banding shown on the precip maps above score a few inches and yet those just north or south get a mulch covering or just white rain. Considering that this will be highly rate dependent the potential for bust, one way or the other is high as well for any particular locale. Especially when you note the difference between the Euro and the GFS from my previous post on precip totals as well as banding.

You may be wondering why we are seeing such a difference on the precip post frontal between the Euro and the GFS. Has to deal with the shortwave we see riding through the south. Below we have the Euro's depiction and it is a very weak feature. But notice on the GFS it has a somewhat stronger shortwave. So what that is doing is providing some push back to the cold air (which we don't have on the Euro) in the mid and upper levels so we are seeing a better moisture feed over top the colder air. So basically it is raising heights somewhat in front of the shortwave in it's natural tendency to try to force ridging. You can see the impact this has when looking at the Precipitable water maps. Note with the Euros weaker shortwave we are seeing a pretty much straight line. But note the slight bowing of that precipitable. we see on the GFS. This is due to the stronger shortwave providing more push back to the colder air.

One of the major reasons we are seeing such a difference between the Euro and the GFS. This is total precip after we are starting to see a flip in the far NW burbs on the GFS. Euro is also lagging a couple of hours behind the GFS on the flip as well.

06Z has the same general distribution with snowfall (Kuchera) as we saw on the overnight run though totals are slightly less. Generally a 2-6" event through the DC/Balt corridor with the higher amounts N/W of the cities.

No snow? Looks like you would be in the 1-2 inch region. Which brings us to this comment. Couldn't wait a full 3 days before you put the lie to this statement.

It has been backing off for quite awhile now on its eastward progression. This is the last 10 runs of the GFS. Notice we also aren't seeing as much dig from the cold as the coldest anomalies have been moving northward. One thing to note is that we are seeing a more west to east alignment to the cold vs. north/south as mentioned by PSU. This is more conducive for post frontal precip. The one thing we should probably expect is that any possible snow will move northward with the boundary as well but of course timing of energy running along the front will play into that as well. . GEFS has actually sped up the eastward progression of the cold from just a few runs ago but the dig is far less. So more of a west/East vs. North/south alignment as well.

Nothing is settled when it comes to possible post frontal precip and/or type. The arctic push southward continues to ease run over run and we see the short wave responding. Seeing a much stronger shortwave pulling out of the SW then just a few runs ago as to where we are seeing the GFS closing it off for a time in the deep south. Getting close as to where that feature may come more into play other then just throwing some extra moisture northward post frontal. The 06Z GFS actually has a low come up the coast to OBX as to where it suggests the possibility of an ice storm as CAD would more then likely be stronger then currently depicted on the run. Euro has also been easing the NS flow and so we are seeing some gymnastics with the shortwave as well though not to the degree as the GFS. With the fact that we are seeing this shortwave continual to strengthen and is now achieving a neg tilt in the deep south before being washed out, the GFS is pretty much telling us that this possibly could become a player (not so much as of yet with the Euro). Especially if there is any potential PAC/NS energy that can dig behind it that the models aren't currently picking up on. As far as anything beyond the above period? I have no clue. The above shortwave could possibly play a part in scrambling things up for starters and beyond that it is a very active pattern with many moving parts. NS will play a big part as far as timing and dig depth/location of energy we see flowing through it. One thing I will say, if we continue to see improvements with the height builds in the Eastern and/or Central NOA domain through the extended, as WxUSAF has alluded to the possibility of, then it could get very interesting, very quickly.

This coming from someone who normally has winter canceled by now.

The latest EPS is more in line with the overnight GEFS. Not as aggressive pushing southward with the initial cold dump reserving more energy for an eastward push. Thus we are seeing a better breakdown of the higher heights (WAR) moving forward through the extended. Somewhat subtle differences from the overnight ESP run when looking at the 7 day mean at the end of the extended (pretty close to the overnight GEFS look) but they mean the difference between a Meh look and a Hmmmm.... look.

Winter of 19-20 Running snow totals. ******************************************** Dec 4 (Early morning hours): 1/2" ******************************************** Total for season: 1/2"

Some comparing the 7 day mean (DAY 8-15) on the GEFS and the EPS might not see that much of a difference. After all both feature -EPO, +PNA, WAR (western Atlantic ridging), eastern trough/western ridge with just some minor differences. But the slight differences here are key when it comes to what we see with the WAR as well as the EPO to a smaller degree. But look at what we actually see as far as temps. Striking differences. These looks are the differences between transient cold shots and probably cutters to our west (eps) or sustained deeper cold with transient shots of warmth with systems having a good shot of riding under us and to our east. There are several things in play here and it begins with what we see occur with cold shot that enters the central US at roughly day 6. What we are seeing is the EPS is expending most of its energy in driving southward and very little to the east. So we are seeing the cold push deep into the south and yet it quickly withdraws northward giving us a somewhat glancing blow and doing little to break down the higher heights to the NE (WAR). But we aren't seeing that with the GEFS. What we are seeing there is the energy is moving only so far south before it begins pushing eastward. With the smoothing the means provide it isn't really discernible but I do believe that what we are seeing is GEFS keying on splitting the energy dropping down in the NS. First piece drives only so far southward initially and then as it is retreating back northward it is creating a weakness to the NE as it helps break down those higher heights. The secondary push of the NS is taking advantage of this and moving eastward into that weakness and helps to further breakdown those higher heights to the NE (WAR). This breaking down of the higher heights has ramifications moving forward. What we see a few days down the road is that we have another push southward of the NS. Though the timing is off a little between both models if you look at where the mean trough reaches neutral you see a notable difference. Note the EPS is driving the trough deep into the south and it is reaching a neutral state in E Texas. The GEFS on the other hand isn't driving as far southward and is reaching a neutral state over the Mississippi (actually a favored spot to see snow through our region). The differences here are the result of the initial cold push and its effects on the WAR (look at the differences in strength and placement) as well as the greater weaknesses created in the south by the EPS' deeper plunge initially. ***Now I noted above that the EPO played a role here as well but didn't discuss it. What we are seeing here is interplay between it and the WAR through this period. The weaker and further displaced east we see the WAR the more likelihood we see a stronger EPO (and N based +PNA as well). The stronger these features the better the ability to deliver cold air in these pushes south by the NS. At this point IMO everything rides on what we see with the initial plunge of cold. See a EPS type evolution with that feature and I think we struggle to score snow. GEFS solution on the other hand and I believe are chances increase quite a bit and we see a decent stretch of cold. ***NOTE: If the GEFS' evolution is right with the initial push with the cold it might be worth keeping an eye on energy running up that boundary as it moves through our region (Would all depend on timing as far as possible snows). EPS, not so much.

There is just no way that this from wxbell can be the mean or median for snowfall. (note the circled area is mostly from the system that passed in overnight). Not when I see this. I would say that the top map may be the Control run of the GEFS but even that doesn't make sense. At this point I think something is just wrong with their coding. Besides that, there are quite a few good hits in the mix. For those that keep track we are seeing the hits centered roughly on day 8, day 10-11, day 15-16.

So which won out. Work? Or snow?

@C.A.P.E.Happy belated B-Day, you Grinch. Peeing all over the fantasy snow. My kind of guy.