Re: November 2023 Observations and Discussion

by **rb924119** Sun Nov 26, 2023 7:46 am

sroc4 wrote:
rb924119 wrote:
sroc4 wrote:
heehaw453 wrote:
rb924119 wrote:The threat for the 27th is alive and well folks. Don’t be surprised if the models start picking up on the white, as opposed to wet threat, especially for anybody north and west if I-287, in the coming days. I fully expect a colder/more consolidated trend with this one as we get closer. Whether or not it will be enough to get everybody in the game, I’m not sure. But I think some of us will definitely see an accumulating snow out of it.
The 500mb does suggest the storm should amp up and move slowly once doing so, but my thought is it does so a bit too far north for most folks around here. I just think there's not much cold air to work with at the onset and this will deepen as it gets past our latitude advecting the cold air behind it. Maybe elevated areas get something? But I think for most folks a cold rain incoming...

Beat me to it Haw. Just not seeing enough at 500 to warrant overt optimism for much of our coverage area with this one. There is too much disorganized lead vorticity for an initial wave of cold novermver rain and like mentioned the northern energy drops in too late. Northern NE may see a doozy and I guess perhaps there is still a little time for some of the higher elevations to get in on some flakes but overall it appears a cold Novermer rain is on the way.

Don’t get me wrong, fellas, I’m not saying everybody is gonna get snow, but I think those of us north and west of 287 (maybe I-80) have a legitimate shot at seeing some accumulation out of this. I wanted to make a video to explain, but I don’t think that I’ll have the time, so I’ll try to succinctly explain lol

Firstly, the overall pattern in the Northern Hemisphere strongly supports this trending colder, as we have the following factors favoring it:

-pseudo -NAO and 50/50 couplet
-70/70 ridge
-negative EPO
-positive PNA

We also have favorable tropics:

-negative SOI
-MJO phase

The ENSO state is neutral, in my opinion, as regions 1.2 and 3.4 are essential equally warm (anomaly-wise), however, we do have the anomalous warmth in the Gulf and Atlantic. The AO is essentially neutral, again, my opinion, and the WPO is positive. So, the warmth in the Gulf and Atlantic, and the positive WPO are not enough to resist the push from the trough coming into the eastern CONUS, in my opinion, which is why I like a colder trend here. This would thereby also support a faster and stronger northern stream system and earlier interaction with the lead wave, i.e. earlier injection of fresh cold air, into the lead system.

Additionally, I do not agree that the secondary low will be as late to bloom as guidance is suggesting when I look at the details. If you look at the following starting on Sunday, you’ll note the overlap in support for not only development of the secondary near the Delmarva, but also what should be an enhanced precip shield ahead of the front:

-lower level warm advection
-vorticity advection from both the relatively weaker lead wave plus the increasing advection from the northern stream energy AND general forcing for ascent downstream of the main trough axis
-decent jet support from the left exit region

Where is there support for the primary to remain the primary so long? From what I can tell, it’s occluded, as it’s already well removed from the jet. Based on this analysis, warm air transport ahead of the front should be less efficient, as the developing circulation from the secondary will work to retard it, drawing in cooler air from New England and the high pressure that should be able to exert a bit more influence than modeled thanks to the pseudo-NAO and 50/50 couplet. Temperatures near and above 850mb should remain sub-freezing, so that’s not the concern. As for the lower levels, 925-850mb, which is where the only warmth is for the areas I mentioned, if you’re drawing in cooler air from the northeast at the lower levels thanks to the sooner developing secondary low, then efficiently lifting that air thanks to the dynamics in play, it won’t take much to cool the column JUST ENOUGH to support snow. This time of year, you can snow in marginal air masses, and I think we will in the areas north and west of I-287/I-80. I haven’t really considered amounts, as my battle here is more with the white versus wet argument, but maybe I could expand on that later if time permits.

Again, this is just my opinion, but I wanted to at least explain where my head is at. It may be crazy, but it’s what I think, so, we’ll see haha

Morning Ray. Love the discussion. First I def did not state that your claim was that everyone was going to see snow. I simply stated that my optimism for most on the board to see snow was low. Regarding the area I bolded AND underlined in your comments I simply cannot argue any of it. Its pretty objective and in general all of those things favor cold and snow chances into the general region. However; I am going to have to respectfully disagree with your comments that are plain bolded above. This part of course is more subjective.

Id first like to address your second point first, and comment on the question "Where is there support for the primary to remain the primary so long?". Watching the 500mb vort charts over the past several days bot GFS and Euro, Ill use euro today for illustration, it appears that there isnt necessarily a "primary" and then a "secondary" in the traditional sense. It appears early on we get a primary to develop amidst the sea of vorticity in the northern branches as well as its own "primary" develop just off Cape Hatt associated with the lead energy in the STJ. The 500mb vort maps support this.

However as move further in time while it does appear we get some interaction, we never really consolidate into a main vort max at the base of a phased trough. Based on the 500mb vort maps vorticity advection alone still seems to support two separate LP centers in the locations that they are.

Now to me probably the single most important aspect of this is the point you made about the jet streak. Referring to the plain underlined comment above I believe the jet streak actually supports enhanced warm air advection well into the area. Traditionally for those who may not follow when you have a jet streak (Jet Streak Defined) in the upper levels of the atmosphere, below on the surface in the right rear quadrant of the jet streak (JS) and the left front quadrant of the JS the development/enhancement of low pressure/rising air is favored or enhanced. The mechanism for this is for another discussion. Keeping this in mind lets look at the 300mb maps and notice our jet streak is not the traditional one to our NE putting us in the R rear quadrant, but rather the JS is associated with he southern stream flow.

Given the position of the JS enhanced rising motion; therefore, LP is favored over the areas circled. Zoomed in below you can see this enhanced rising air in the L front Quad of the JS AND WAA from the LP over the GL region you get a broad area of precipitation in between both surface LP as a result.

Below is the surface pressure anomaly maps showing the favored LP blue over most of NE.

Next important fact here is pay particular attention to where the HP to our NE is positioned by Hr 54. Pretty much over the 50/50 region out over the Atlantic off the E Canadian coast. This needs to be 750-800miles further west and perhaps a tad further south as well if is to help. Instead the result is a position that hurts.

So now there are two extremely important factors that enhance warm air advection well into the area flooding the mid levels with above freezing temps.

Lets start looking at the images below. First image hr 54 has the LP off the Delmarva. Second; however, hr 60 has the LP centered just S of Cape Cod and getting stronger. Normally a strengthening LP that has moved east of Long Island would be drawing in cold air on the backside, but that doesn't seem to be happening here. Why?

Reason is because of the mechanisms I stated below. You absolutely need HP to our N. As stated it is not. The position of the HP is such that the developing LP is drawing in warm air over the open Atlantic rather than cold air from NE. Second, because there is an equally strong LP well to the NW over the GL and the JS enhances rising air to our N and NW this creates a wind vector to the N and NW AWAY from our coastal LP. So instead of the coastal low drawing in the cold air on the back side, that air is being "stolen" by the GL LP. so the dominating wind vectors for our surface coastal LP are from the E, SE, S, and WSW, all warm source regions. Below is 850mb and 925mb temp maps and you can clearly see the freezing line is way far NW, when again normally a LP sitting south of cape cod the mid levels would be crashing and that just isn't happening due to the mechanisms outlined above.

Unfort this is how I see it, so while I still wont rule out some flakes in the higher elevations, the expectation has to remain fairly low for most on the this board for this one IMHO.

Good rebuttal, buddy, but I want to counter you on something that I maybe didn’t do a good enough job of highlighting in my original post. I agree with you that this setup isn’t ideal - the Great Lakes/southern Canada low is always a wrench in the proverbial monkey, and the high is definitely further east than any of us would like to see it. However, the point that I want to make, and I guess I glossed over it the first time is with respect to the formation of the secondary coastal low. Firstly, I contend that it should develop more quickly than what guidance is suggesting, and yes, that’s purely subjective. However, let’s assume that hypothesis turns out to be correct for the sake of my argument. As it strengthens, it’s going to change the low-level flow. Not necessarily at 850mb, but at the surface. You’ll end up with an expanding cyclonic circulation as it continues to move northeastward such that the lowest level winds, say, surface to 950mb, will back and begin to shift easterly, northeasterly, northerly, and even north-northwesterly, AGAINST the backdrop of the overall southerly/southwesterly flow aloft. Where’s my support?

Take a look at the following normalized anomaly map valid for this evening:

November 2023 Observations and Discussion - Page 6 Img_1911

Obviously, you can see the higher pressure generally in and east of eastern New England, denoted by the red shading, and the lower pressures in our area denoted by the blue shading. The darker the colors, the stronger the anomaly. Keep in mind this is not based on my idea of an earlier/faster secondary coastal development, but you can see that the secondary is already MORE anomalous than the Great Lakes/southern Canada low, as depicted by the darker blue shading. Also note the “wedge” of relatively less negative anomalies cutting through central New England and into central PA. This is key. This depicts a zone of lower-level divergence, as some air is being drawn northward toward the Great Lakes/southern Canada low, and some is being drawn southward toward the strengthening secondary low off the coast think of tue pressure gradient force, which acts perpendicularly to pressure contours). Obviously, the coastal plain, I-95 Corridor, etc. are generally too warm for this to matter, but for areas further north and west, especially with elevation, such as the Poconos, Catskills, even into the Mid-Hudson Valley, this is hugely important. Why?

In those areas, based on guidance verbatim, the warmest layer above the surface is only getting to about 1-1.5°C, and that’s from just above the surface to about 850mb. But what happens if you start advecting even slightly cooler air from central New England southward into those areas, and THEN you force it to lift thanks to the dynamics already discussed (warm advection, vorticity advection, jet dynamics)? Additionally, I think there will be pretty substantial lift with this - I don’t think it’s going to be showers, rather, I think this will be a blossoming Nor’easter, so we should see a pretty well defined system and frontal structure, further aiding in enhancing the lift……..you lift marginally cool (1-1.5°C) air even half a kilometer at wetbulb rates, and it still cools 3°C, which gets you sufficiently below freezing, number 1, and number 2, into a zone of prime dendritic growth.

This is why for the areas north and west of I-80/I-287 I am not sold on a wet outcome. I think the models are too slow with the secondary coastal development, and I don’t think they are handling the results of that properly in a marginal airmass. Clearly I’m on an island here, so the bust potential is real, but if nothing else, it’s a good discussion haha

by **sroc4** Sun Nov 26, 2023 8:04 am

Off to my sons soccer game so I can’t write a details response but reading through Ray it’s as if I had a wet bulb, I mean light bulb, go off in my head. Lol. Dynamic cooling is certainly an important factor that has not really entered into my thought process yet and going back to your original write up you did in fact mention it. I guess I must of glossed over it as I was formulating my thoughts for my response.

That said looking at the 925 & 850 wind maps the wind barbs it still seems like there are problems. I’ll try and look at a few things that I previously hadn’t later today.

by **rb924119** Sun Nov 26, 2023 8:26 am

sroc4 wrote:Off to my sons soccer game so I can’t write a details response but reading through Ray it’s as if I had a wet bulb, I mean light bulb, go off in my head. Lol. Dynamic cooling is certainly an important factor that has not really entered into my thought process yet and going back to your original write up you did in fact mention it. I guess I must of glossed over it as I was formulating my thoughts for my response.

That said looking at the 925 & 850 wind maps the wind barbs it still seems like there are problems. I’ll try and look at a few things that I previously hadn’t later today.

All good, brother, go enjoy the game, and I’ll look forward to reading your follow-up later! The board isn’t going anywhere……unless Frank has other plans that none of us know about lol besides, I’ll be processing firewood all day, so I won’t be around until later anyway haha

As a follow-up to my recent post, as an example (and not direct led specifically at you, but for the board in general), take a look at the latest SPC mesoscale surface analysis - note there are already winds from the easterly through the north-northwesterly sector of directions extending all the way into NJ, Delaware, Maryland and Virginia, with a well-defined circulation. As my old professor says, it’s that “dammed cold air” - this is a pretty classic cold air damming signature right now. But the stronger and faster this low can develop, the more pronounced that cold air damming (cold advection sourced in New England) will be as the storm approaches our latitude. Just gotta keep an eye on this thing as the day wears on.

November 2023 Observations and Discussion - Page 6 Img_1912

by **dkodgis** Sun Nov 26, 2023 8:33 am

Out of the blue, but I have been known to miss things, a now 80% chance or rain around sunset. I didn’t see that one coming

by **rb924119** Sun Nov 26, 2023 8:35 am

Latest SREFS are a blow torch, so I don’t expect the NAM to be much different lol. As I said, I’m way out on a limb with this with ZERO model support, but the only way to know if a hypothesis is correct or not is to test it, right? Haha

by **Frank_Wx** Sun Nov 26, 2023 8:54 am

The upper energy associated with tonight’s storm is pretty scattered and elongated ahead of the trough. It would’ve been quite tough for that secondary to pull itself together in time. I was actually more interested in the backside energy that swings through on Tuesday.

November 2023 Observations and Discussion - Page 6 Img_6612

But trough is too positive and there’s no phasing.

by **sroc4** Sun Nov 26, 2023 1:36 pm

rb924119 wrote:
sroc4 wrote:Off to my sons soccer game so I can’t write a details response but reading through Ray it’s as if I had a wet bulb, I mean light bulb, go off in my head. Lol. Dynamic cooling is certainly an important factor that has not really entered into my thought process yet and going back to your original write up you did in fact mention it. I guess I must of glossed over it as I was formulating my thoughts for my response.

That said looking at the 925 & 850 wind maps the wind barbs it still seems like there are problems. I’ll try and look at a few things that I previously hadn’t later today.

All good, brother, go enjoy the game, and I’ll look forward to reading your follow-up later! The board isn’t going anywhere……unless Frank has other plans that none of us know about lol besides, I’ll be processing firewood all day, so I won’t be around until later anyway haha

As a follow-up to my recent post, as an example (and not direct led specifically at you, but for the board in general), take a look at the latest SPC mesoscale surface analysis - note there are already winds from the easterly through the north-northwesterly sector of directions extending all the way into NJ, Delaware, Maryland and Virginia, with a well-defined circulation. As my old professor says, it’s that “dammed cold air” - this is a pretty classic cold air damming signature right now. But the stronger and faster this low can develop, the more pronounced that cold air damming (cold advection sourced in New England) will be as the storm approaches our latitude. Just gotta keep an eye on this thing as the day wears on.

So after looking at a few things in the modeling and current meso analysis I just cant get on board with it Ray. Right now current position of the low off the coast and western GL is right on track with the maps I posted yesterday. Maps were valid for 18z Sunday which equates to 1pm. Again right on track except maybe a tad weaker than euro had it(coastal low) modeled at this time. Again there are two primary lows here. This is not a transfer of a cutting primary to the coast. This is a primary low into the GL secondary to the digging mean trough, and a primary weak low on the coast associated with the the lead somewhat disorganized southern stream vorticity/energy.

November 2023 Observations and Discussion - Page 6 Ecmwf133

November 2023 Observations and Discussion - Page 6 Ecmwf132

CURRENT MESO ANALYSIS:

November 2023 Observations and Discussion - Page 6 Meso_s11

Looking at the surface map above this simply is not a cold air damning(CAD) signature. The HP is just not in an appropriate spot for CAD. And as stated in the prev discussion the GL Low is drawing the surface wind away from the coast to the coastal lows NE. The position of the HP and the coastal surface low are pumping air into NE off the Atlantic. This time of year with SST's still warm, so unless the HP is centered to the N; no further east than say 70 longitude it will not have much trouble scouring out cold air.

Especially when you have an 850mb and 925mb set up that looks like the current meso analysis like below. There is no way the mid levels dont warm up with this set up.

November 2023 Observations and Discussion - Page 6 Meso_910

November 2023 Observations and Discussion - Page 6 Meso_810

by **sroc4** Sun Nov 26, 2023 1:51 pm

Here is the surface wind map and LP via the HRRR valid 5am tom am. Again normally a LP in this position would have NW, NNW, and N winds on the back side. As you can see this just isnt the case. See prev discussions as to why.

November 2023 Observations and Discussion - Page 6 Hrrr10

And after evaluating dew point maps you just cant find a dew point below freezing south of the Canadian boarder or perhaps northern most NE throughout the entire run. Going to be near impossible to cool the column with DP's this high

November 2023 Observations and Discussion - Page 6 1701079200-AWMhRDrYtOE

November 2023 Observations and Discussion - Page 6 1701079200-AWMhRDrYtOE

November 2023 Observations and Discussion - Page 6 1701079200-Q5zHRTZE2Gk

November 2023 Observations and Discussion - Page 6 1701079200-d41LlweijJ8

by **1190ftalt** Sun Nov 26, 2023 3:23 pm

Just started raining with a little hail 39 degrees .

by **amugs** Sun Nov 26, 2023 4:16 pm

HRRR very bullish on snow squalls in the NYC metro area on Tuesday. pic.twitter.com/K6aF8fe2J5
— IsaacWxObserver (@IsaacWxObserver) November 26, 2023

Some snow squalls Tuesday afternoonish?

by **Frank_Wx** Sun Nov 26, 2023 4:40 pm

amugs wrote:
HRRR very bullish on snow squalls in the NYC metro area on Tuesday. pic.twitter.com/K6aF8fe2J5
— IsaacWxObserver (@IsaacWxObserver) November 26, 2023

Some snow squalls Tuesday afternoonish?

This feels right. The trough swinging through has loads of PvA.

by **rb924119** Mon Nov 27, 2023 9:34 am

Scott, good try brother, but I’ll take the “W” on this one. Turned to heavy snow here about 1am and it never looked back. Woke up to this:

November 2023 Observations and Discussion - Page 6 Img_1512

November 2023 Observations and Discussion - Page 6 Img_1510

November 2023 Observations and Discussion - Page 6 Img_1511

About 5” of the white stuff, tough to tell because of the quick compaction and relative warmth of the ground yet.

Nah, I can’t lie, I’m totally kidding haha these are pictures from an event last year haha you were right, although I’m not sure we torched as bad as what could have been. I think we only made it to like 2°C aloft from what I can tell. There wasn’t enough to really get our coastal cranking in time to change the wind field enough to make the difference. As always, though, it was just nice to actually talk weather for a change, and for the first of what I think will be many opportunities to do so. Hopefully lol and, hopefully you got a laugh out of it like I did haha

by **sroc4** Mon Nov 27, 2023 2:01 pm

rb924119 wrote:Scott, good try brother, but I’ll take the “W” on this one. Turned to heavy snow here about 1am and it never looked back. Woke up to this:

About 5” of the white stuff, tough to tell because of the quick compaction and relative warmth of the ground yet.

Nah, I can’t lie, I’m totally kidding haha these are pictures from an event last year haha you were right, although I’m not sure we torched as bad as what could have been. I think we only made it to like 2°C aloft from what I can tell. There wasn’t enough to really get our coastal cranking in time to change the wind field enough to make the difference. As always, though, it was just nice to actually talk weather for a change, and for the first of what I think will be many opportunities to do so. Hopefully lol and, hopefully you got a laugh out of it like I did haha

You SOB. You got me. My knee jerk response to reading that first sentence and seeing the pics was to immediately look at your location. LBI NJ....I was like "NO FREAKING WAY!?!?" LOL Then I saw the Greentown Pa and I was like "wait a minute...where the heck is that and what's its elevation?"

It was def nice to have some discussion about the short term rather than trying to predict the long term, and I definitely did get a good laugh at this post and my reaction to the post. lol

by **phil155** Mon Nov 27, 2023 4:17 pm

Frank_Wx wrote:
amugs wrote:
HRRR very bullish on snow squalls in the NYC metro area on Tuesday. pic.twitter.com/K6aF8fe2J5
— IsaacWxObserver (@IsaacWxObserver) November 26, 2023

Some snow squalls Tuesday afternoonish?

This feels right. The trough swinging through has loads of PvA.

Interested to see if this plays out, I know nothing is likely to stick unless we get a very heavy squall but mood flakes will be nice

by **aiannone** Mon Nov 27, 2023 8:45 pm

One can only hope. Mood flakes possible tmw

November 2023 Observations and Discussion - Page 6 Img_6510

by **heehaw453** Tue Nov 28, 2023 8:26 am

Flakes came through my area. Most of the activity was well to my south though. A coating though is appreciated in November.

by **amugs** Tue Nov 28, 2023 12:07 pm

Can these small snow showers hold together?? Looks convective enough we'll see what it produces Morris County reporting snow flakes.

November 2023 Observations and Discussion - Page 6 Inxr1Knyca_h

November 2023 Observations and Discussion - Page 6 Inxr1Knyca_h

by **frank 638** Tue Nov 28, 2023 12:16 pm

amugs wrote:Can these small snow showers hold together?? Looks convective enough we'll see what it produces Morris County reporting snow flakes.

I hope so. At one point it was getting very dark now the sun’s coming out but today it has that January feeling no snowflakes yet.

by Snowprincess0204 Tue Nov 28, 2023 12:37 pm

Flurries in Union township, Union county

by **amugs** Tue Nov 28, 2023 12:42 pm

by **amugs** Tue Nov 28, 2023 1:51 pm

Just had some flurries here at work in Allendale for about 5 minutes at about 1:15PM!!

by **phil155** Tue Nov 28, 2023 1:53 pm

nada here in edison thus far

by **frank 638** Tue Nov 28, 2023 2:07 pm

Just had a couple snowflakes

.

by **aiannone** Tue Nov 28, 2023 2:27 pm

Had a nice quick squall come through

November 2023 Observations and Discussion - Page 6 Img_6512

by **docstox12** Tue Nov 28, 2023 2:45 pm

32 degrees partly cloudy and windy.Popcorn snow showers all around.Have not seen any here yet.

by **frank 638** Tue Nov 28, 2023 2:47 pm

Snowing pretty good now and it’s very windy out

by **brownie** Tue Nov 28, 2023 3:08 pm

Snow squall here right now!

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