Re: Long Range Thread 17.0

[Guest]

I am actually (sorry to all who want this) rooting for nothing or little on I-95 from sat till sunday night, anytime before or after that game on, but I am not letting a snowstorm hinder my weekend plans, way too important, the wife and I get but one or two chances a year to get a overnight sitter.  I am hoping this is mainly on the latter part of 9th and into 10th, 10th be great no school : )

Every time there is snow forecast or snow actually falling you complain. Either about driving or being in a snow hole or about someone getting more or about the urban heat island. Just move to Mt Washington where there’s 60 mph winds every day

[jmanley32]

I am actually (sorry to all who want this) rooting for nothing or little on I-95 from sat till sunday night, anytime before or after that game on, but I am not letting a snowstorm hinder my weekend plans, way too important, the wife and I get but one or two chances a year to get a overnight sitter.  I am hoping this is mainly on the latter part of 9th and into 10th, 10th be great no school : )

Every time there is snow forecast or snow actually falling you complain. Either about driving or being in a snow hole or about someone getting more or about the urban heat island. Just move to Mt Washington where there’s 60 mph winds every day

No not true did you see me complain on the 15th LOL, that was awesome, my resolution for this year was to not get upset when I get stuck with squat but this particular event could not fall on a worse date.  And it is about the travel, if we are getting 6-12 as Euro shows that not exactly something I should be driving 120 miles in don't ya think? Always best to stay off the roads.  On the contrary I do want to see a snowstorm for sure but its just a connundrum that either way I lose, storm its go be a pain getting there, no storm I do not get a storm LOL.  The lives we live. And no I do not want to live on Mt. Washington, those winds would get annoying quick, the whole ex citement of it for me is its uncommon, if it was everyday and as cold as it is up there I would hate it.

[Frank_Wx]

We still have some work to do with the PAC. Not sure anything will materialize on the 10th, but it is close enough where it should be watched. It's not like the pieces are missing. They're all there. If changes in the PAC occur, namely with the axis of the western ridge being pulled west, then it is game on. However, most guidance shows the axis of this ridge over Montana not Idaho.

[Guest]

We still have some work to do with the PAC. Not sure anything will materialize on the 10th, but it is close enough where it should be watched. It's not like the pieces are missing. They're all there. If changes in the PAC occur, namely with the axis of the western ridge being pulled west, then it is game on. However, most guidance shows the axis of this ridge over Montana not Idaho.

Book a trip for yourself and we will get buried

[Frank_Wx]

We still have some work to do with the PAC. Not sure anything will materialize on the 10th, but it is close enough where it should be watched. It's not like the pieces are missing. They're all there. If changes in the PAC occur, namely with the axis of the western ridge being pulled west, then it is game on. However, most guidance shows the axis of this ridge over Montana not Idaho.

Book a trip for yourself and we will get buried

I'll be in Barcelona for 1 week in February. That should cement at least a Godzilla

[SnowForest]

Hey everyone, check out the latest CMC:



That's a lot of snow for Virginia and Maryland, but NJ still gets at least 7 inches.

[skinsfan1177]

I'm not a fan of the CMC seems to always show what the snow weenies want. The Euro looked alot better and had a phase. My concern was the lack of cold air on the euro

[algae888]

We are very close for this to be a major East Coast storm for our area too many short waves for the models to figure out which is going to impact the low over the southeast also that shortwave coming out of Eastern Canada on the GFS has to be resolved to how strong will not be and how far south would it come and where would the Confluence set up fun times ahead tracking this one

[skinsfan1177]

Also it looks to be delayed until the 10th

[sroc4]

Still high volatility in sorting out the various pieces of energy regarding both potency and timing in both the N branch AND southern branch. Temper expectations, be patient as its still early Dec, and hopefully we can pull this off.  As of this writing all solns are still on the table, and the window on no one soln has began to close yet.  Much of this energy is still in poorly sampled regions and need to still move into poorly sampled regions over the next 24-48hrs(ie: much of the N energy is in the N PAC and still needs to visit the arctic circle before diving into Canada).  Euro took a step in the right direction overnight.  That said one model run does not make a trend.  Repeat: Give it another 24-48hrs before we start to close windows and possibly open new ones; for better or worse.  

GFS:


EURO:

[sroc4]

Looks like we are all on the same page.

[Guest]

Ok crew. I’ll start paying attention Wednesday lunchtime
Until then I’ll check in for occasional updates

[bobjohnsonforthehall]

The systems have been so strung out lately. Can this one buck the trend? I agree looks like Wednesday until we have any real idea. Perhaps even Thursday.

[skinsfan1177]

The issue is their is to much confluence in Maine not allowing the storm to come north

[Frank_Wx]

Here is a look at the 12z EURO valid December 9th.



I have a couple of issues with this look. For starters, the flow over the Northeast is too fast. The trough over Maine promotes confluent winds over New England. This will prevent heights from rising along the east coast. Secondly, the PNA ridge remains displaced too far east and is not very parallel to the canadian energy. It is slanted. The southern piece of energy, or Gulf energy, is EXTREMELY impressive. To the point that if a phase actually happened it would not doubt be a Godzilla storm. But if the 2 main issues I pointed out do not get resolved then we'll end up with dry/cold conditions.

[sroc4]

Here is a look at the 12z EURO valid December 9th.



I have a couple of issues with this look. For starters, the flow over the Northeast is too fast. The trough over Maine promotes confluent winds over New England. This will prevent heights from rising along the east coast. Secondly, the PNA ridge remains displaced too far east and is not very parallel to the canadian energy. It is slanted. The southern piece of energy, or Gulf energy, is EXTREMELY impressive. To the point that if a phase actually happened it would not doubt be a Godzilla storm. But if the 2 main issues I pointed out do not get resolved then we'll end up with dry/cold conditions.

The Pacific is a mess too with all sorts of energy crashing the NA Wcoast at various times ultimately affecting the PNA ridge as you mention. Night and day differences; however, between the evolution between Euro and GFS which makes me ponder the question which model is less wrong with the evolution? As mentioned earlier this am the real soln wont reveal itself for a few days.

[skinsfan1177]

Another thing to note is the features that are being discussed can change its 6 days away

[rb924119]

A more complete writeup will be forthcoming, but my initial fears about suppression remain in tact for this system, and I’m holdng my course for now. My consideration for a northward trend mentioned a couple days ago is off the table at present.

[Frank_Wx]

Another thing to note is the features that are being discussed can change its 6 days away

For sure!

[rb924119]

As a preface, I normally like to do videos for situations such as this, where I go through my analysis and explain my reasoning. However, I have been getting the sense lately that written posts may be a more preferred method of providing my thoughts; mainly for two reasons: 1. Links provided amongst an ongoing conversation on a forum are easily missed, and 2.  Our discussions are almost exclusively text-based anyway.

That said, let’s get started.

Initially, and many days ago, I offered my opinion that this system (7th-10th December period) would remain too suppressed for our northern posters to really capitalize, and that the southern and central Mid-Atlantic was the region that I was favoring for a sizeable event. Without rehashing everything here, my analysis at the time had led me to believe that there would be nothing stopping the cold and associated northern stream flow from pressing southward. Every available teleconnection was progged to be supportive of this (-A.O./N.A.O., 50N/50E low, +P.N.A., -E.P.O./W.P.O., 70N/70E ridge, and highly anomalous Canadian snow/cold feedback, which has already been seen several times this season already) with only limited resistance (MJO Phase 3, but likely decaying amplitude based on my own subjective analysis, recent Niño 1.2 spike, and warm coastal waters around the U.S. aiding latent heat release from convection associated with the system itself).  The S.O.I. was not considered due to a lack of any substantial coherent and prolonged signal. Recent model data, however, has changed remarkably with respect to the above. Aside from the 70N/70E ridging, 50N/50E low, and Canadian snow/cold feedback, we have lost the favorability of the other Northern Hemispheric teleconnections. During the period in question, we will be losing the –N.A.O. and +P.N.A., accompanied by the presence of positive phases of the A.O., E.P.O., and W.P.O. We did, however, end up gaining the favorability of the M.J.O., which is now likely to be solidly into Phase 2 during the target period, and not Phase 3.

Upon seeing the transition in the modeling when it first occurred a couple of days ago, I posted about considering “jumping ship” on my idea of suppression, as in conventional setups, the recent trend of the Northern Hemisphere prognostications coupled with the state of the tropics (with consideration of the modeling/subjective analysis of the MJO, and localized diabatic effects in and around the system itself) would certainly favor a northward correction of our feature of interest in later runs according to the algorithm I use for forecasting. Although considered, I was not yet ready to walk the plank and wanted to analyze a bit more. After doing so, I remain with my initial thinking that this system will remain largely suppressed, although I do feel that we will see a bit of a northward adjustment such that the target area outlined above ends up being close to reality (Mason-Dixon line would be about the northern extent of most of the precipitation). My reasoning, however, is different than before.

Using the above discussion of where modeling is now as a starting point, and as already stated, I would expect a large northward connection in most “ordinary circumstances” (can I even use that phrase when discussing the weather? lol) where we have the presence of an established western Atlantic ridge and we have see how much it can be resisted. This time, though, we do not have that thanks to the pattern that will be preceding the period in question: It will essentially be nonexistent and displaced 500+ miles to the southeast of Bermuda. Given the pattern, we should still see ridging emerge either over or near eastern North America, but from where? This is where it gets interesting.

The P.N.A. ridge will actually be the source for the emergence of ridging where we would look for it, as the wave train the Northern Hemisphere has now become progressive. As the southern stream trough traverses the country, it will prevent the base of the P.N.A. ridge from collapsing as they travel eastward in tandem, but the top of the ridge will fold over (wave break) on the heels of the southern stream energy. Although current guidance suggests that it will not become latitudinally stacked with southern stream energy, it will work to prolong the presence of northwesterly steering flow across the northern Mid-Atlantic and Northeast (also known as confluence in this case) while it propagates eastward essentially along the U.S.-Canadian Border to the northwest of the southern stream. This persistence of the northwesterly steering flow will very likely prevent the type of height rises ahead of the southern stream and along the East Coast that we need to see significant precipitation make it into the northern Mid-Atlantic and New England.

As for any phasing, while I was initially very bullish on this early on due to my initial analysis, I am no longer, as in my opinion, the factors already discussed do not support any northern stream involvement of significance. Therefore, I believe for our intents and purposes, this will be an entirely southern stream-driven system.

Are there any corrections that I expect to see in future guidance? Yes, BUT unfortunately, my opinion is that none of them will be positive. Based on the analysis provided heretofore, the largest correction I expect to see is that the top-half of the P.N.A. ridge actually breaks earlier and begins its transition eastward sooner. I also think that it will end up stronger than currently modeled. Both of the above would lend credence to the idea of an occluding and slow-moving feature once along the Eastern Seaboard, yet also (obviously) support my idea of a suppressed storm.

All of this said, I DO NOT KNOW ANYTHING DEFINITIVELY, and this all a highly subjective analysis. I do, however, firmly believe it will have merit, but then again, I believed in my forecast of the last snowstorm too Hopefully this made sense and you guys enjoyed the read! If you have any questions or would like to discuss further, I am all ears!

[skinsfan1177]

Its crazy look at the difference in the 12z to 18z gfs. Huge difference. This isn't over and no solution is etched in stone. The confluence over Maine could be over modeled and if so we will see a shift north imo

[algae888]

RB one aspect that the models could be under playing is the strength of the subtropical jet this year with the El Nino and the strength of the shortwave that will be entering Southern California in about 72 hours if that shortwave is stronger it could gain latitude and raise Heights out ahead of it as it moves across the Southern Tier of the u.s. then if the Confluence to the north is weaker than modeled our area comes into play with a significant snow storm still a lot to be determined and I agree with a lot of what you said suppression Stills looks more likely than not let's see how this all plays out

[algae888]

By the way both GFS Suites made a significant jump North at 18z

[algae888]

Gefs are also further north the 2-inch line gets to Trenton a few nice hits in there 6 inch line gets to DC I believe the 12z had no snow for either area

[algae888]

I'm hearing the Euro weeklies are looking fantastic starting right around Christmas right through January very Nino like pattern. negative e p o positive p n a negative Nao many sleepless nights ahead if they are correct

[rb924119]

I'm hearing the Euro weeklies are looking fantastic starting right around Christmas right through January very Nino like pattern. negative e p o positive p n a negative Nao many sleepless nights ahead if they are correct

I can confirm. The weeklies are a blend of ‘77-‘78 temps with ‘93-‘94/‘95-‘96 snowfall POTENTIAL. Legitimately am speechless. They went right to their seasonals. Incredible signal from them.

[rb924119]

RB one aspect that the models could be under playing is the strength of the subtropical jet this year with the El Nino and the strength of the shortwave that will be entering Southern California in about 72 hours if that shortwave is stronger it could gain latitude and raise Heights out ahead of it as it moves across the Southern Tier of the u.s. then if the Confluence to the north is weaker than modeled our area comes into play with a significant snow storm still a lot to be determined and I agree with a lot of what you said suppression Stills looks more likely than not let's see how this all plays out

You certainly have a very valid points, and are things that I have considered in the above discussion. However, as you said, an under/over-estimation could lead to large errors in either direction. One thing that really concerns me, though, is just how far south the southern stream enters the CONUS. Using the general rule that storms exit the CONUS at roughly the same latitude that they enter, that doesn’t leave us much room unless we see very potent northern stream interaction, and I don’t foresee that happening. That said, I also don’t think the southern stream energy will be strong enough to sufficiently alter the steering flow to its northeast more than the collapsing PNA ridge and gain *enough* latitude to get us all in the ballgame.

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