DEC 18th-20th 2023--Wet, White, Wind?

Since we are inside 4-5days lets start a thread for this threat and keep the LR for the time frame after.  

rb924119 wrote:I know, I know, 84-hR NAM, and it’s never smart to extrapolate, butttttttttttt it looked pretty darn enticing me lol maybe good mojo for 12z suite??

In the other thread Ive stated how I think this threat will go. Now I am going to allow my bias to creep in a little and say....Lets reel in some white for some of us!!!

Thanks for starting this, Scott! It looks like the NAM might actually be giving us the good mojo - ICON (FWIW) is much improved, and looking at the RGEM, I think the GEM may do something slightly stoopid haha we will see!

rb924119 wrote:Thanks for starting this, Scott! It looks like the NAM might actually be giving us the good mojo - ICON (FWIW) is much improved, and looking at the RGEM, I think the GEM may do something slightly stoopid haha we will see!

GFS looking lovely thus far too

You can see the potential on 12Z GFS. The timing is everything here. How much energy is left to capture off the coast, how fast can the occlusion occur. The block probably holds the key to a lot of this...

heehaw453 wrote:You can see the potential on 12Z GFS. The timing is everything here. How much energy is left to capture off the coast, how fast can the occlusion occur. The block probably holds the key to a lot of this...

I see two ways for this to work on the GFS verbatim.  If the second piece can dig into the back side of the southern piece crawling up the coast we inject the cold air, N piece needs to be a bit faster for that to happen.  OR If the N piece slows down and we get a little more space between the two we could raise heights out ahead and the N piece closes off and tilts neg and voila.  GFS seemed in between the two solns

An closed off ULL like this is never to be underestimated. I've seen too many times where surface maps take a longer time to catch up with the H5. If there was some mid-level energy close enough it would damange.

Nobody look at the 12z UKMET

Kind of an IMBY request, but could you guys please periodically mention the geographic extent of any good news updates for Sunday/Monday. Am I right that the Philly-NYC corridor and the Jersey coast have a very small but growing chance to cash in? Or are we only in the queue for snowy possibilities after this storm?

rb924119 wrote:Nobody look at the 12z UKMET

SENJsnowman wrote:Kind of an IMBY request, but could you guys please periodically mention the geographic extent of any good news updates for Sunday/Monday. Am I right that the Philly-NYC corridor and the Jersey coast have a very small but growing chance to cash in? Or are we only in the queue for snowy possibilities after this storm?

Confirm both of your questions: Philly-NYC corridor and Jersey have an increasing chance of seeing snow during our storm(s) of interest, and yes, snow chances should steadily increase after our storm(s) of interest.

Negatively tilted closed off ULL that's all i need to see.

Sorry 12Z UKMET even better

I just don't see any plummeting temps in that range at all. I say rain with maybe a mood flake or two Tuesday.

12z Euro just shifted the surface low from Jamestown, NY to off the Jersey coast lol four days out and we are still seeing shifts of 300 miles haha the bigger story, though, is what it did at H5. Verbatim, this run is not all that far off from a Christmas miracle, in my opinion.

rb924119 wrote:

SENJsnowman wrote:Kind of an IMBY request, but could you guys please periodically mention the geographic extent of any good news updates for Sunday/Monday. Am I right that the Philly-NYC corridor and the Jersey coast have a very small but growing chance to cash in? Or are we only in the queue for snowy possibilities after this storm?

Confirm both of your questions: Philly-NYC corridor and Jersey have an increasing chance of seeing snow during our storm(s) of interest, and yes, snow chances should steadily increase after our storm(s) of interest.

Very well then! It is now time to keep expectations in check, trust the process and TRACK!!

In general here is how I see it.  As prt of the discussion in the other thread it was my contention that the Polar Jet was too strong and the preverbial "door to the cold air" would stay shut.  This first image shows the two main short waves (s/w) that I prev outlined that are both of Pacific origin, aka warm source regions.



When they phase this gives rise to our main system for the 18th which is all warm and gives rise to this on the surface.  Warm and rain up into Canada



However; what is becoming quite clear is that a third s/w that originated behind the closed door of the cold air opens the door to the closed air for a period of time.  This allows some cold air to filter into the Ohio and Tenn valley's, all the while the ridging that is developing in the N Atlantic, ie the pseudo -NAO Ray has been harping about, slows down the flow enough such that the s/w from the N rounds the base of the trough and consolidates into a closed cut off ULL.  But here is the thing.  The door to the cold air is only open for a limited time; at least as we are currently seeing in the modeling verbatim.  If this holds true in order for this to work for anyone the strength of the ULL will need to generate its own cold air as you can see by the last image below the door to the cold air is closes again as the ULL reaches us. So at this point notice the blue circle over NJ and W LI. This is the system generating its own cold air.





Now there is for sure more time to see how this evolves further.  How long can that door stay open?  IF or when it shuts, is there enough cold air in the system to matter?  While I am still in the camp of this still not working out for most, it def got ALOT more interesting for many; enough to pay attention to for sure...

WE TRACK!!  

EXCELLENT analysis Doc, and clear as crystal, and sets the stage for what we must be looking for.Lot's of fun with this system and hoping we can all get a little snow OTG from it.

https://www.youtube.com/watch?v=rKLCEzF1XGo

I'm going to play devils advocate to sroc. Once it closes off it has all the cold air it needs from the polar jet. I would argue the ridge bridge keeps the storm consolidated, allows it to close off and will aid in slowing it down. I think if you didn't have that ridge bridge this has no chance for much impact to us. I'm still skeptical it will, but there is a path.

docstox12 wrote:EXCELLENT analysis Doc, and clear as crystal, and sets the stage for what we must be looking for.Lot's of fun with this system and hoping we can all get a little snow OTG from it.

https://www.youtube.com/watch?v=rKLCEzF1XGo

Agreed - that was extremely informative and clear to understand for those (like me) that usually don't understand and simply look for the final outcome.

Weather app now showing snow showers Tuesday night  with 1-3 inches expected. It's never been reliable and precipitation probability is 50% so I take with a grain of salt, but it's interesting it's even mentioning anything now several days after our experts began to sniff it out.

WTS even if it happens one snowfall does not mean winter exists, but it would be a good start for those trying to prove it still does.

Ok, NAM looks like it wants to take my ideas to the limit. It holds the southern stream back so long that it actually looks like it would give the northern stream system time to phase in BEFORE the southern stream reaches our latitude, or at least as the southern stream would arrive. First model to actually show this, but the GEM was close the other day. It’s nice to see, even if it is the 18z NAM at hour 84 aha

However, I can’t say that its depiction doesn’t make sense with the pattern. It’s eastern track of the initial southern stream system relative to other guidance matches the location and orientation of the ridge axis, the slow propagation fits the ideas discussed, and the behavior of the northern stream would also seemingly fit. Gotta see how this all evolves.

CPcantmeasuresnow wrote:Weather app now showing snow showers Tuesday night  with 1-3 inches expected. It's never been reliable and precipitation probability is 50% so I take with a grain of salt, but it's interesting it's even mentioning anything now several days after our experts began to sniff it out.

WTS even if it happens one snowfall does not mean winter exists, but it would be a good start for those trying to prove it still does.

You should move up here, CP, we still have a snowpack of 4” up here since it snowed earlier in the week aha winter mode has been fully engaged lol

rb924119 wrote:Ok, NAM looks like it wants to take my ideas to the limit. It holds the southern stream back so long that it actually looks like it would give the northern stream system time to phase in BEFORE the southern stream reaches our latitude, or at least as the southern stream would arrive. First model to actually show this, but the GEM was close the other day. It’s nice to see, even if it is the 18z NAM at hour 84 aha

Hey Ray, What result would that yield inland and to the coast?

aiannone wrote:

rb924119 wrote:Ok, NAM looks like it wants to take my ideas to the limit. It holds the southern stream back so long that it actually looks like it would give the northern stream system time to phase in BEFORE the southern stream reaches our latitude, or at least as the southern stream would arrive. First model to actually show this, but the GEM was close the other day. It’s nice to see, even if it is the 18z NAM at hour 84 aha

Hey Ray, What result would that yield inland and to the coast?

Certainly an increased likelihood of seeing at least some snow, for everybody.