JAN 4th Coastal

[Ralph Wiggum]

Phew, one the the tightest gradients I think I've seen. Atlantic City with over a foot+ and maybe a dusting for Northeast Maryland.
But we've seen it before, boxing day, Dec 2000. etc.
 

Jan 87?

[PhineasC]

Eh, six inches isn't enough to draw me back down to Millville this week. Need a foot+.

[csnavywx]

1 minute ago, WxUSAF said:

Models account for virga.  A bigger concern in my mind is for there to be more convection offshore which could rob the western edge of moisture. We’ve seen that happen before *cough*march2013*cough*

That's a concern of mine as well. There's certainly going to be a lot of convection.

[osfan24]

Welp, for better or worse, the NAM is going to keep me trudging forward with this one. Still have two days for trends our way. If the NAM is right, it would take very small changes over the next two days to turn this into a significant storm for us. Maybe we get a January 2000 surprise. Just wish it had some company at this point and wasn't on an island.

[Ralph Wiggum]

Models account for virga.  A bigger concern in my mind is for there to be more convection offshore which could rob the western edge of moisture. We’ve seen that happen before *cough*march2013*cough*

Do u think that the anomalous thermal gradient between BN airmass and AN sst's could yield convection nearer the coast? Looks like a real balancing act imo on whether the western convection or the easterm convection becomes more dominant which will have huge implications on precip shield. What r your thoughts?

[Cobalt]

1 minute ago, PhineasC said:

Eh, six inches isn't enough to draw me back down to Millville this week. Need a foot+.

Small potatoes, double or nothing. 2 feet.

[WxUSAF]

1 minute ago, Ralph Wiggum said:

3 minutes ago, WxUSAF said:

Models account for virga.  A bigger concern in my mind is for there to be more convection offshore which could rob the western edge of moisture. We’ve seen that happen before *cough*march2013*cough*

Do u think that the anomalous thermal gradient between BN airmass and AN sst's could yield convection nearer the coast? Looks like a real balancing act imo on whether the western convection or the easterm convection becomes more dominant which will have huge implications on precip shield. What r your thoughts?

Eh, that’s possible I suppose. Certainly a very strong thermal gradient near the coast in this situation. Generally, there are more things that could go wrong for us than right. But if the 3km NAM is right and a 950mb low crosses the benchmark while we eat cirrus (and the Deep South gets shellacked), that is gonna sting a bit.

[usedtobe]

3 minutes ago, WxUSAF said:

Models account for virga.  A bigger concern in my mind is for there to be more convection offshore which could rob the western edge of moisture. We’ve seen that happen before *cough*march2013*cough*

I'd feel better about he NAM if the closed off low wasn't so far east that we never get into any easterly component at that level.  Instead we have the southern end of thee northern stream trough approaching us during our "snowy" period.  Also, it's interesting to note that the 3 km doesn't have the 010" line anywhere near DC and has it south of me. 

[psuhoffman]

2 minutes ago, mappy said:

the northern s/w did better this NAM run. it was more south than east, allowing some movement with the southern s/w and its precip shield back west. 

This was the first "significant" improvement in that feature I've seen. The 3k especially is digging the northern steam vort into Indiana like I said I want to see to have a chance. It's still tight but it opens up enough space that I could at least see this possibly coming a bit west. I still doubt it and if it doesn't show on other guidance this morning it's just the nam being the nam but this was the first really good move in the piece I've been most down on. Still lots of other issues including how the two systems interact. For us to have a chance we need the northern stream trough to pull the low north not kick it east. Earlier runs suggested an almost inverted trough type interaction that drew precip well northward from the actual low. That idea seems dead now. 

1 minute ago, Mdecoy said:

Phew, one the the tightest gradients I think I've seen. Atlantic City with over a foot+ and maybe a dusting for Northeast Maryland.

But we've seen it before, boxing day, Dec 2000. etc.

 

I was living in south jersey about 18 miles southeast of Philly in 1989. I remember the forecast was 6-12" when I went to bed. Knew it was a bust when I woke up to sunshine. Ended up with some flurries.  Meanwhile places only 20 miles east of me had 10" and the immediate coastal towns had 20". 

[Ralph Wiggum]

RGEM farther NW with surface features thru 36

[Ralph Wiggum]

Just keep hugging, just keep hugging....

[Cobalt]

Just now, Ralph Wiggum said:

Just keep hugging, just keep hugging....

The snow weenie tradition of hugging the model with the most snow. I like it

[psuhoffman]

8 minutes ago, WxUSAF said:

Eh, that’s possible I suppose. Certainly a very strong thermal gradient near the coast in this situation. Generally, there are more things that could go wrong for us than right. But if the 3km NAM is right and a 950mb low crosses the benchmark while we eat cirrus (and the Deep South gets shellacked), that is gonna sting a bit.

I wonder if the circulation from northern stream low is inhibiting the moisture transport into our area as the low passes our critical juncture off the VA capes. The 3k nam track is about as good as we can how to get given where this is starting. It's as good as many of  those global runs that gave us a snow a few days ago. It's not ideal but close enough to usually get something. Yet the ccb is incredibly contracted and disjointed at our latitude. You can see the banding trying to set up and that one weak band that gets into Frederick county is kind of where you would expect the back edge to be if the while system simply translated North. But it's doing that disjointed reorganization thing it was doing to Nee England the other day only it's at our latitude now. If that's real we're done.  That would mean no matter if we get another nudge west in the track qpf might not even respond if we're inside the sphere of influence of the northern stream flow and it's cutting off the moisture transport from the east. 

[Ralph Wiggum]

1 minute ago, Cobalt said:

The snow weenie tradition of hugging the model with the most snow. I like it

No no no silly.....hug the coast. Im spooning this model, not hugging it. Big difference :-)

[WxUSAF]

1 minute ago, psuhoffman said:

I wonder if the circulation from northern stream low is inhibiting the moisture transport into our area as the low passes our critical juncture off the VA capes. The 3k nam track is about as good as we can how to get given where this is starting. It's as good as many of  those global runs that gave us a snow a few days ago. It's not ideal but close enough to usually get something. Yet the ccb is incredibly contracted and disjointed at our latitude. You can see the banding trying to set up and that one weak band that gets into Frederick county is kind of where you would expect the back edge to be if the while system simply translated North. But it's doing that disjointed reorganization thing it was doing to Nee England the other day only it's at our latitude now. If that's real we're done.  That would mean no matter if we get another nudge west in the track qpf might not even respond if we're inside the sphere of influence of the northern stream flow and it's cutting off the moisture transport from the east. 

Yeah, that’s a great point and very possible. 3k gets good precip farther west in southern and central VA relative to 12k, but then 3k shuts it down up toward us. 

[psuhoffman]

2 minutes ago, WxUSAF said:

Yeah, that’s a great point and very possible. 3k gets good precip farther west in southern and central VA relative to 12k, but then 3k shuts it down up toward us. 

That was just my impression looking at h5 and then the surface. I guess the weenie playbook says assume the 3k is right with the storm track but wrong with the northern stream interaction. 

[Bob Chill]

If nothing else, the RGEM loop sure is nice to look at. 

[Cobalt]

1 minute ago, Bob Chill said:

If nothing else, the RGEM loop sure is nice to look at. 

Another storm with so much digital snow, and probably not much, if any snow to look at on the ground

[usedtobe]

9 minutes ago, psuhoffman said:

I wonder if the circulation from northern stream low is inhibiting the moisture transport into our area as the low passes our critical juncture off the VA capes. The 3k nam track is about as good as we can how to get given where this is starting. It's as good as many of  those global runs that gave us a snow a few days ago. It's not ideal but close enough to usually get something. Yet the ccb is incredibly contracted and disjointed at our latitude. You can see the banding trying to set up and that one weak band that gets into Frederick county is kind of where you would expect the back edge to be if the while system simply translated North. But it's doing that disjointed reorganization thing it was doing to Nee England the other day only it's at our latitude now. If that's real we're done.  That would mean no matter if we get another nudge west in the track qpf might not even respond if we're inside the sphere of influence of the northern stream flow and it's cutting off the moisture transport from the east. 

I think thee reason is that at 500h, the upper low with the southern stream is far enough off the coast that our winds at that level never have an easterly component and instead are southwesterly.  I think that helps keep the elevated frontogenesis well to our south and east. 

[WxUSAF]

4 minutes ago, Bob Chill said:

If nothing else, the RGEM loop sure is nice to look at. 

Boy isn’t it. Classic SECS/MECS. I’ll hug it, but I’m not holding my breath. Looking forward to the GFS run that barely scrapes OC.

[aldie 22]

certainly an interesting storm for sure, I suppose we have a general idea but there sure does seem to be some uncertainty left

[SnowGolfBro]

RGEM for the win!

[psuhoffman]

2 minutes ago, SnowGolfBro said:

RGEM for the win!

My weenie handbook says we get the 3k nam track with the rgem ccb distributions. 

[clskinsfan]

Interesting that the RGEM is still insistent on getting precip over most of NOVA. It just seems to have a much larger area of precip to the west than any other model. I have to hug it. It's the only one that gives me snow

[Bob Chill]

4 minutes ago, psuhoffman said:

My weenie handbook says we get the 3k nam track with the rgem ccb distributions. 

You forgot to add "until something better comes along"

[mitchnick]

Snow totals on Rgem are on the light side.

[mitchnick]

fwiw, GFS at 24 hrs. is deeper with the southern vort vs. last run

[psuhoffman]

4 minutes ago, clskinsfan said:

Interesting that the RGEM is still insistent on getting precip over most of NOVA. It just seems to have a much larger area of precip to the west than any other model. I have to hug it. It's the only one that gives me snow

I tried to see why but the rgem h5 graphics suck and only ones I can find are 36 and 48 hours. But it's obvious the rgem is having a different interaction between the northern stream and the storm. Where the nam seems to be inhibiting the ccb on the west side as the storm runs into this influence the rgem instead is almost creating an inverted trough type setup that draws moisture even further northwest towards to lakes low. This leads to the extreme solutions where the nam has a significantly more west track but east qpf field. Could be the h5 isn't cutting off as fast on the rgem and so the moisture is drawn up the east side of the northern stream trough. Once the system cuts off that's done. That's my guess because the rgem does do that only it's later and kind of screws NYC some instead of us. Perhaps it's simply cutting off later and so that problem isn't until north of us. Not sure the rgem doesn't have in between h5 plots that I can find to confirm that. 

[ryanconway63]

did the low jump way west on the gfs at hour 30?

 

[cae]

I'd love to hug the RGEM, but there are all sorts of red flags on that run.  It's the wettest model, near the end of its range, trended slightly drier, and was wetter than the high-res RGEM at 06z.  Aw heck, I'll hug it anyway.