December 2017 Mid-Long Range Disco

[showmethesnow]

11 hours ago, cae said:

Thanks.  I'd love to see regional verification scores, but as far as I know they don't exist (at least publicly).  The best I've found so far for our region is the North American verification score.  It doesn't perfectly reflect what's going on around here, but it's better than I would have guessed.  I think that's because a models tend to get things wrong in our region when they get the broader pattern wrong across North America.

During the summer I would think the verification scores are a fairly accurate reflection for our region as well. I am not so sure when it comes to the winter (late fall, early spring as well), at least at times. As we all know, what is paramount with most on these boards is snow so what we are concerned with is how do the models verify for short periods of time within our region. Considering the east coast (coastal waters) is quite often a volatile region , where the difference between storm, weak storm, no storm is often a fine a line to draw, one actually wants to know how the models verify within that specific small period of time within a fairly small scope of area. This is where I think the disconnect between verification and the handling of an actual storm comes into play quite often. So while a model may be aces across the board (N Hemi) with the macro features and verify high I think often enough they fail with the micro features in our small corner of the world (all of which is lost in the wash) to warrant some skepticism. I myself will put some weight into the verification scores but I think I place more weight on watching the actual model runs for those specific periods of time to form my own conclusions. It's a continual learning process as quite often a model may handle one setup extremely well and yet fail miserably in another setup. This is part of what makes tracking fun for me. The uncertainty and trying to guess where a model is headed.

[BristowWx]

6z wants to keep it chilly and perhaps icy for Xmas.  The happy side of the boundary.

[showmethesnow]

Though yesterdays runs were somewhat unimpressive, overnight runs were a little better, I don't know if I would get discouraged. We are definitely in the game as far as the models are concerned throughout the next 15/16 days as it looks to be active with nothing that suggests a shut out pattern in my mind. Just a broad brush and ignoring what we are seeing with the different indices and what is occurring over top with the blocking, the worst I see is some brief warm ups and what looks to be an attempt to plant a trough in the southwest in the extended which consequently pops SE ridging. I would not be surprised to see these warm periods muted/shortened over the coming days (actually favor this) as well as see the southwest trough be damped down somewhat,  so transient in nature it is hardly worth mentioning or actually shifted eastward towards the central US (slightly favor a shifting eastward setting up a mean trough in the central US). Changes with the SW trough would impact what we see as far as the SE ridging. And even if we do see a strong SW trough planted there for a period of time it can still work for us if we see the pv located farther south helping to suppress the SE ridging and consequently the storm track and temps.

All in all, though everything looks somewhat unimpressive/discouraging at this time I actually think we are sitting fairly well for the next two weeks if what the models are currently showing are somewhat accurate. Now this doesn't mean we will score anything, it just means that I feel the odds are much higher then we would typically see at this time of year.

[showmethesnow]

Thought I would revisit a post I made on Sunday. In that post I mentioned the possibility that we may see a deeper/sharper trough dropping into the central portion of the country Sunday depending on what the pv moving into Alaska did. Argued that with a quicker, stronger, distinct pv it offered an opportunity for our region (early next week) as it squeezed the flow between it and the low rotating through the 50/50 region. Well we have seen 2 of the 3 things occur with the pv rotating in (Stronger, distinct) and look at the changes we have seen through the CONUS. A better response from the ridging in the PAC NW as it is now running over top of the trough forcing it farther southward and making it sharper. This in turn is creating ridging between the trough and the exiting low off the east coast. At this point though we see the trough being forced into SW corner of the US where it gets partially hung up and only the northern portion moves eastward. Not a great overall look for our chances. But if we can get that 3rd thing from the pv, quicker, I think we may have a shot though it would probably entail the cold chasing the warm through our region. If I am playing this through my mind correctly, a quicker pv would force the digging trough farther eastward which would probably mean that the whole trough would swing eastward instead of the southern portion getting bogged down in the southwest. That would change the dynamics fairly significantly.

Now I am not throwing this out here to suggest we are going to see a Snowstorm early next week, in fact I think the odds are somewhat long at this time to be honest. I am throwing this out here to show you what type of impact just seemingly small changes to a key feature can mean downstream and why models can seemingly make huge changes over a few runs.

eta: Failed to mention a farther south track was preferable with that pv as well. We have not seen that either but in fact that would maybe compensate for a slower pv as that would also probably result in a farther east dig by the trough. 

 

 

 

 

[CAPE]

39 minutes ago, losetoa6 said:

Looks like a storm parade on the 6z....plenty to track thru Christmas . Cold near by or on us 

Has it all too- snow, ice, rain.

[MillvilleWx]

GEFS overnight was not bad at all if you are looking for storminess in the LR. Christmas time frame was especially more active with total precip going over 1" in a 6 day span beginning at D9 through D15. Yes, it's way out there, but it seems like we might be seeing multiple waves of low pressure ride a baroclinic zone setup from Texas to the Mid Atlantic. Temp anomalies were below normal at both surface and 850mb around Christmas time, moving forward which is good, because that means we are on the correct side of the baroclinic setup. MSLP anomaly was insistent on strong HP diving out of Canada and pushing cold air eastward. If we can get a solid surface ridge to push east and keep the baroclinic zone south of here, it opens the door for waves of LP to move up from the south and push into the colder air. Now, transition type storms could also occur in these setups as well, so it might not be all snow, but frozen precip is at play if you take the run at face value. I just want to see a storm signal on the models at this point. There will be a relaxation period for a time prior to Christmas, but pattern looks to reload somewhat heading into the end of the month. Remember, temp anomalies do not have to be significant in order to get frozen precip anymore. We are heading toward our peak climo for cold with end of December through January the coldest time frames on average. My biggest concern at this point in the LR is the WAR which could fight back and keep us riding the borderline more often than not. We'll cross that bridge when we get to it. 

[Superstorm]

Nice write-ups in this forum. Best of the bunch.


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[showmethesnow]

20 minutes ago, MillvilleWx said:

GEFS overnight was not bad at all if you are looking for storminess in the LR. Christmas time frame was especially more active with total precip going over 1" in a 6 day span beginning at D9 through D15. Yes, it's way out there, but it seems like we might be seeing multiple waves of low pressure ride a baroclinic zone setup from Texas to the Mid Atlantic. Temp anomalies were below normal at both surface and 850mb around Christmas time, moving forward which is good, because that means we are on the correct side of the baroclinic setup. MSLP anomaly was insistent on strong HP diving out of Canada and pushing cold air eastward. If we can get a solid surface ridge to push east and keep the baroclinic zone south of here, it opens the door for waves of LP to move up from the south and push into the colder air. Now, transition type storms could also occur in these setups as well, so it might not be all snow, but frozen precip is at play if you take the run at face value. I just want to see a storm signal on the models at this point. There will be a relaxation period for a time prior to Christmas, but pattern looks to reload somewhat heading into the end of the month. Remember, temp anomalies do not have to be significant in order to get frozen precip anymore. We are heading toward our peak climo for cold with end of December through January the coldest time frames on average. My biggest concern at this point in the LR is the WAR which could fight back and keep us riding the borderline more often than not. We'll cross that bridge when we get to it. 

Kind of conflicted on what I want to see happen over the coming holidays in regards to where we see the possible baroclinic set up through our region. On one hand I will be visiting my Father-in-law for 5 days through Christmas which is located just an hour east of Pittsburgh. On the other hand the DC/Balt corridor is and always has been my Home Team when it comes to snow. Now it is possible that we see the zone setup where both places are in play, but I don't think it is probable. So that begs the question. Do I want to see that zone set up just north of the DC/Balt region where I can score at my father-in-laws? Or do I want to see my Home Team cash in on the goods while I am away? I guess that answer is probably better left unsaid. Otherwise I might be run out of the Mid-Atlantic forum. 

[psuhoffman]

We have seen this kind of pattern work enough times that I'm not going to freak out about every bad run until we're into the short term. The epo looks consistent. The guidance is trending stronger with the mjo into our colder phases so as much as we sometimes joke about those things it does favor a colder look. I remember late last winter when we finally got a favorable string mjo wave we ended up getting a legit cold period in march. Obviously that was too little too late but it did come. 

This is going to depend entirely on where the boundary sets up. Too far NW and we rain. Too far south and we're cold and dry. The models have us close enough to that boundary to keep me interested and hopeful heading into late December. 

[Superstorm]

We have seen this kind of pattern work enough times that I'm not going to freak out about every bad run until we're into the short term. The epo looks consistent. The guidance is trending stronger with the mjo into our colder phases so as much as we sometimes joke about those things it does favor a colder look. I remember late last winter when we finally got a favorable string mjo wave we ended up getting a legit cold period in march. Obviously that was too little too late but it did come. 

This is going to depend entirely on where the boundary sets up. Too far NW and we rain. Too far south and we're cold and dry. The models have us close enough to that boundary to keep me interested and hopeful heading into late December. 

Id rather be right along the boundary. You will have wins and losses.


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[aldie 22]

I'm all in with boundary straddling....better than needing a telescope to see it in the distance. We need a sweet sleet storm this year

[pasnownut]

6 minutes ago, leesburg 04 said:

I'm all in with boundary straddling....better than needing a telescope to see it in the distance. We need a sweet sleet storm this year

I'm a fan of long duration overrunning events.  Steady stream of light precip is great.  

would like to see that happen this season.

Nut

[showmethesnow]

1 minute ago, pasnownut said:

I'm a fan of long duration overrunning events.  Steady stream of light precip is great.  

would like to see that happen this season.

Nut

Think I myself would prefer a steady stream of heavy snow. But I guess we all have our preferences.

[WxUSAF]

Big differences here but an interesting forecast challenge. More of these than not would put us in the game.

 

[pasnownut]

1 hour ago, showmethesnow said:

Think I myself would prefer a steady stream of heavy snow. But I guess we all have our preferences.

Well of course I would also, but with overrunning it is typically not in the cards. A long duration 3-6” is attainable....and I’m a realist at heart. Keeps me away from the ledge.   

If you can make it happen, I/we are all in.

Nut

[Bob Chill]

55 minutes ago, WxUSAF said:

Big differences here but an interesting forecast challenge. More of these than not would put us in the game.

 

It's going to be close. The good thing is the pattern "should" progress regardless of whether the front makes it through or not on the holiday. GEFS has trended towards slightly favoring us being on the good side. Only 12 days to go!  lol

[AfewUniversesBelowNormal]

This is like, really good

[AfewUniversesBelowNormal]

I think we are seeing signs at 500mb of the 10mb Stratospheric warming happening, began 4 days ago.

[AfewUniversesBelowNormal]

This is awesome

Enjoy a nice period of snow and cold. 

[usedtobe]

36 minutes ago, Bob Chill said:

It's going to be close. The good thing is the pattern "should" progress regardless of whether the front makes it through or not on the holiday. GEFS has trended towards slightly favoring us being on the good side. Only 12 days to go!  lol

My guess is probability of snow is lower than normal to around the 23rd or so and then rises to normal for Christmas since we don't know which of the members are right and there will be lots of cold air in the conus, if you extend it past Christmas than I think the probability is a little above normal.  OF course at those time ranges,  the models, even the ensemble have problems. 

[yoda]

3 minutes ago, StormchaserChuck said:

This is awesome

Enjoy a nice period of snow and cold. 

Yes... the RAIN it shows is a nice period of it

[Bob Chill]

22 minutes ago, usedtobe said:

My guess is probability of snow is lower than normal to around the 23rd or so and then rises to normal for Christmas since we don't know which of the members are right and there will be lots of cold air in the conus, if you extend it past Christmas than I think the probability is a little above normal.  OF course at those time ranges,  the models, even the ensemble have problems. 

Agreed, it all depends on how you look at it. It's "likely" that we return to a seasonal or below normal temp pattern sometime around the holidays. I can live with being on the wrong side on Christmas knowing that winter will be returning. 12z gfs says it happens before and then a miracle running the boundary afterwards. I'll hug that general idea for now. lol

[yoda]

12z GFS looks decent after the front passes through Dec 23... some snow on Christmas Eve, and even a coastal shows up late on Christmas Day and brings some cheer

[Bob Chill]

1 minute ago, yoda said:

12z GFS looks decent after the front passes through Dec 23... some snow on Christmas Eve, and even a coastal shows up late on Christmas Day and brings some cheer

I'm hugging the CMC through d10 and then the gfs beyond. Boom. 

[yoda]

LOL 12z GFS teases us with a likely snowstorm as the run ends... massive arctic blast in the Plains is coming as well

[RedSky]

12z GFS might be the best run ever yes please.

 

[psuhoffman]

10 minutes ago, RedSky said:

12z GFS might be the best run ever yes please.

 

I dunno...this was a pretty good run too

[yoda]

12 minutes ago, yoda said:

LOL 12z GFS teases us with a likely snowstorm as the run ends... massive arctic blast in the Plains is coming as well

 

 

[Thanatos_I_Am]

1 minute ago, psuhoffman said:

I dunno...this was a pretty good run too

Heh.. this one wasn't too shabby either. 

[mitchnick]

and not a peep out of JI???

it's almost like, he just likes to whine!   lol