Potential Coastal Storm This Weekend

[USCG RS]

always a voice of reason -- good to see ya on here... I see my post a few back wasnt heeded by anyone oh well, part of the comedy is watching people in here argue about semantics 5 days out

Thank you kindly, it is nice to see you as well. Yes, there storms bring out a plethora of emotions in people, but that's half the fun of it.

United States Coast Guard Rescue Swimmer

[IsentropicLift]

Surface and mid-level winds turn due northerly...no temperature issues here. This is what a deep cyclone can do; the ageostrophic component gets stronger and any initial SW flow rapidly turns towards a colder flow. 

Exactly, that's why in my opinion precip type issues should be the least of everyones worries.

 

If this comes NW it will not bring the rain with it. That's a common misconception.

 

[WintersGrasp]

As this is the first run that actually hits our area, I wouldn't worry so much about how much precip the model shows falling over any area. Taken as is, yes, there is the difference between 2-3" of snow in northern NJ and 10-12" of snow in southern NJ. It has clearly made HUGE changes since yesterday and now has the potential to be a very significant storm. We all know the solution will change. It is 4 days away. Trending north with every run, next run could have it hammering us with 20" of snow. It could also be kicked more out to see and graze us with barely an inch. Most important thing to remember at this point is that this is our best chance of this winter season so far. One day out from a simple clipper and we still can't figure out if it will give us an inch or more.....so, many, many more model runs to go.

[Neblizzard]

As this is the first run that actually hits our area, I wouldn't worry so much about how much precip the model shows falling over any area. Taken as is, yes, there is the difference between 3-4" of snow in northern NJ and 10-12" of snow in southern NJ. It has clearly made HUGE changes since yesterday and now has the potential to be a very significant storm. We all know the solution will change. It is 4 days away. Trending north with every run, next run could have it hammering us with 20" of snow. It could also be kicked more out to see and graze us with barely an inch. Most important thing to remember at this point is that this is our best chance of this winter season so far. One day out from a simple clipper and we still can't figure out if it will give us an inch or more.....so, many, many more model runs to go.

You have a -EPO and +PNA. It's doable but things still have to go right. Next weeks pattern really looks promising but I don't wanna get ahead of myself.

[Monmouth_County_Jacpot]

I know this isn't the tread for this question forgive me but was there a storm behind this one??

[Stormlover74]

As this is the first run that actually hits our area, I wouldn't worry so much about how much precip the model shows falling over any area. Taken as is, yes, there is the difference between 2-3" of snow in northern NJ and 10-12" of snow in southern NJ. It has clearly made HUGE changes since yesterday and now has the potential to be a very significant storm. We all know the solution will change. It is 4 days away. Trending north with every run, next run could have it hammering us with 20" of snow. It could also be kicked more out to see and graze us with barely an inch. Most important thing to remember at this point is that this is our best chance of this winter season so far. One day out from a simple clipper and we still can't figure out if it will give us an inch or more.....so, many, many more model runs to go.

Exactly. I believe this is the first time since Thanksgiving that the GFS and Euro both had something inside 5 days (that wasn't a clipper)

[Isotherm]

It's much tougher to get great thread the needle scenarios to work out here at the coast when the AO is in such

a positive state since so much often goes wrong. 

 

 

The AO is not positive in the days preceding this storm. The next few days will feature a slightly negative AO, and there will also be east based blocking w/ higher heights pushing SW into northern Greenland. If you note prior synoptic patterns to storm set-ups, east based blocking was often a feature. An example: The AO and NAO index were both slightly positive during the Feb 2003 snowstorm, however, an east based block was present, keeping the upstream flow conducive for a colder storm solution. The east based blocking aids in maintaining the SE Canadian vortex upstream.

 

 

 

[donsutherland1]

Several quick thoughts...

 

1. The potential storm is something to be watched.

2. One should pay more attention to the development of the system and its track than the specific qpf numbers right now.

 

Nevertheless, if one is watching the qpf, the figures have trended up in recent runs of the GFS. Two examples:

 

Islip:

1/19 18z: None

1/20 0z: None

1/20 6z: 0.21"

1/20 12z: 0.79"

 

New York City:

1/19 18z: None

1/20 0z: None

1/20 6z: 0.12"

1/20 12z: 0.40"

[SnowGoose69]

That is the GFS which is usually too cold and far east at these ranges. 

Lets see what the Euro looks like at 12z and the next few critical runs.

 

I see nothing that can bring this thing any closer that tucked into the coast, and even then it would probably snow heavily eventually, there is enough confluence up north as this crosses the SE and that system across Canada that its going to be off the coast.

[IsentropicLift]

City is almost 0.75 more east

NO

 

Barely 0.50", and actually going off of DonS's numbers, 0.40" since the 0.50" includes tommorrow.

 

[SnoSki14]

I see nothing that can bring this thing any closer that tucked into the coast, and even then it would probably snow heavily eventually, there is enough confluence up north as this crosses the SE and that system across Canada that its going to be off the coast.

It looks like it also has a kicker that'll help tug it a bit further east. 

[Neblizzard]

The AO is not positive in the days preceding this storm. The next few days will feature a slightly negative AO, and there will also be east based blocking w/ higher heights pushing SW into northern Greenland. If you note prior synoptic patterns to storm set-ups, east based blocking was often a feature. An example: The AO and NAO index were both slightly positive during the Feb 2003 snowstorm, however, an east based block was present, keeping the upstream flow conducive for a colder storm solution. The east based blocking aids in maintaining the SE Canadian vortex upstream.

You can see the vortex east of NF on these maps. Although temporary that acts as your 50/50 low.

[wolfsheepsheadbay]

Don't be surprised if the Euro is even more tucked in and a tick warmer than 0z if the GFS is this amped now. 

Good. That will mean more snow, because in the setup as modeled, there won't be rain during the most meaningful precip even out by you. Cheer up Bluewave.

[Brian5671]

The AO will not be negative long enough to negate the SE Ridge playing a role for coastal sections. Interior

sections always have more leeway in marginal set ups like this one. 

Good point on the ridge.  We saw that screw us last Monday 1/12/15

[donsutherland1]

A quick note on the forecast teleconnections:

 

The potential storm is forecast to occur when the AO is positive and the PNA is positive (according to the GFS ensembles). Such a set up has seen numerous 4"-8" snowstorms in the NYC area during the second half of January. In fact, an AO+/PNA+ accounts for 46% of such storms since 1950.

 

If one is looking for a bigger storm, all snowstorms that brought more than 8" to NYC during the second half of January commenced during an AO-/PNA+ set up.

[WintersGrasp]

A quick note on the forecast teleconnections:

The potential storm is forecast to occur when the AO is positive and the PNA is positive (according to the GFS ensembles). Such a set up has seen numerous 4"-8" snowstorms in the NYC area during the second half of January. In fact, an AO+/PNA+ accounts for 46% of such storms since 1950.

If one is looking for a bigger storm, all snowstorms that brought more than 8" to NYC during the second half of January commenced during an AO-/PNA+ set up.

Thanks Don. By the looks of it, 4-8" is a real possibility. It's a good thing we have you as the calm voice of reason here when a situation goes awry. Very informative, straight to the point, and never condescending.

[USCG RS]

The rest of the 12z model suite doens't look good. Both Nogaps and Ukmet are out to sea.

Euro will be the Grand finale. Let's see what the Euro shows, as always brother.

United States Coast Guard Rescue Swimmer

[PB GFI]

Good point on the ridge.  We saw that screw us last Monday 1/12/15

 

You may rain for a bit and maybe you should expect it  .That way when it pops up on the models you don`t go all bat %^& crazy and throw one of your tantrums . 

 

But you me BW will flip back to snow and probably heavy . You will not be screwed 

[wolfsheepsheadbay]

No.

Yes actually. Navgem is a miss now and the Ukmet was never a hit. That being said, the Navgem has done this before. Just need to see what Dr. No does here.

[Superstorm93]

The trailing vort is really holding this system back. Still looks entirely possible that this gets kicked out to sea just like the earlier runs were showing. 

 

[USCG RS]

You may rain for a bit and maybe you should expect it .That way when it pops up on the models you don`t go all bat %^& crazy and throw one of your tantrums .

But you me BW will flip back to snow and probably heavy . You will not be screwed

As has been said many times over the years, 'you have to smell the rain to get the most and heaviest snow.'

United States Coast Guard Rescue Swimmer

[Ralph Wiggum]

Yes actually. Navgem is a miss now and the Ukmet was never a hit. That being said, the Navgem has done this before. Just need to see what Dr. No does here.

I was implying no as a negative towards the subject of his post.

[BoulderWX]

The trailing vort is really holding this system back. Still looks entirely possible that this gets kicked out to sea just like the earlier runs were showing. 

 

a very real possibility... would say its 50/50 at this point - should have a better idea once we get some sampling.. 

[SnoSki14]

Eventually is the operative word which implies that P-types will be a coastal issue  before any potential change back to snow with a far enough west track. If the track ends up further east, than the bulk of precip misses us anyway.

Seems though that models are leaning farther east at the moment. You said a SE ridge is still in play so does that mean you favor a west track. 

[PB GFI]

As has been said many times. Over the years, 'you have to smell the rain to get the most and heaviest snow.'

United States Coast Guard Rescue Swimmer

 

Agree . If I expect the worse case ( rain at the onset being worst case ) then if it rallies to a colder solution great . 

But I do no think this fits the profile of 33 and an extended  cold rain .

 

There is mid level warmth in almost every great storm . We live and die here by close shaves . 

[Animal]

I was implying no as a negative towards the subject of his post.

 

Always a problem if the nogaps is out  to sea & you need/want/hope for a coastal storm.

[Weathergun]

The AO will not be negative long enough to negate the SE Ridge playing a role for coastal sections. Interior

sections always have more leeway in marginal set ups like this one. 

 

How do you know for sure this will happen? Don S stats make this less revelant, anyway.

[Superstorm93]

GFS Ensemble mean gives the area pretty much no precip with a track that's largely OTS (with the exception of SNJ) 

[IsentropicLift]

GFS Ensemble mean gives the area pretty much no precip with a track that's largely OTS (with the exception of SNJ) 

They are still running two sets of GFS ensembles. The newer GEFS mean run off of what was the PGFS is stronger and closer to the coast.

[Brian5671]

You may rain for a bit and maybe you should expect it  .That way when it pops up on the models you don`t go all bat %^& crazy and throw one of your tantrums . 

 

But you me BW will flip back to snow and probably heavy . You will not be screwed 

  haha.  Usually around here, we tend not to have snow, rain back to snow...those forecasts often stay all snow (2/9/13) being the recent example.  But I get your point that all of us could be dangerously close to the rain/snow line as your hero JB notes in his recent post.