Storm Chance 12/30/12

[RowanBrandon]

I figured we should start a thread for this possibility about 150 hours away. Smarter people than I, discuss.

[Thunder Road]

I've never taken a formal Synoptics class but here's my thoughts:

First, I want to point out the 18z GFS ens mean, because it certainly is intriguing:

You have a decent signal for a coastal storm given you're 6 days out, and with 850 mb temps closer to -3 or -4 C, we're probably not as likely to have temperature issues this time around.

But love is fleeting. Take a look at the 0z ens mean (Note: this is 6 hours later than the above image):

The signal is not nearly as robust.

The 18z individual members are pretty nice though. By my count, 9/12 members produce accumulating snowfall in Philadelphia (as judged by a period of at least 0.10" of liquid and 850 mb temperatures < 0 C), although they come in different evolutions.

What I did notice from the individual members though is that...

1) The "primary" is not nearly as strong as it will be with Wednesday's storm. The deepest primary is, I think, ~991 mb, but every other solution has it at or above 1000 mb.

2) There actually are several goldilocks solutions. I remember commenting that with the Wednesday storm that the ens mean looked nice, but that was because the individual solutions were either wrapped up and rainy or suppressed and dry, and not because there was a consensus of a coastal track. In other words, there were no "just right" solutions. That is not the case this time.

So what changed to cause the 0z solution to be, well, not as nice?

Below is the 18z 500 mb height anomaly from the ens mean:

Now, here's the 0z. (Again, note the slight timing difference.)

The biggest change from the first to the second is that the E-Pac ridge is significantly more amplified. But notice that what that also does is cause that area of lower heights in the SW US (actually a cut-off Low on the Op) to deepen a bit more. That, combined with ridging over eastern Canada being slightly stronger and pushing just a tad more south, causes our potential storm to not quite deepen enough for a big hit (although we do still get maybe an inch or two of snow on the 0z).

The 0z individual members will be interesting to see when they come in, but overall, I think the pattern favors an out-to-sea track of our potential storm over a Lakes Cutter due to the orientation of our blocking and the trouble we will (potentially) have getting our eastern US trough to amplify. Therefore, I don't think we have to worry about an inland rainy storm, but I do think a wide-right miss is at least a possibility. But with cold air (somewhat) in place following Wednesday's storm, and with said storm becoming a 50/50 Low, I'm cautiously more optimistic with this storm than I was (except for a brief period Friday) with Wednesday's storm.

[NaoPos]

Euro has a nice great for 95 NW peeps...

Go Giants! Go Cowboys!

[phlwx]

12/30 storm on 0z Euro is snow generally above the Fall line.

[Thunder Road]

fwiw, the 0z UKMET would probably be a nice hit:

The Canadian only gets down to 1005 mb, and it looks more like a southern slider than any kind of amplified system. Of course, the GGEM hasn't been performing all that well so far, so let's see if it was even worth mentioning.

[phlwx]

helluva thump for SNE. Precip just starting to crank up as the low passes us. N/W of 95 around here get a few inches but not as good as CT.

[Thunder Road]

FIM is similar to the GFS. 1000 mb Low inside the benchmark. Roughly 0.30-0.40" for Philly, all or most frozen.

[Thunder Road]

5/12 members of the 0z GEFS (not including the Op this time) produce accumulating snowfall in Philly. As expected, the solutions have a generally "flatter" look to them than they did at 18z.

[NaoPos]

0z euro ens says threat is legit:

What can go wrong between now and then...

[famartin]

0z euro ens says threat is legit:

What can go wrong between now and then...

Just about everything that went wrong for the system on Wednesday

Except, of course, that the Ray curse will have been transferred back to Elko

[NaoPos]

Just about everything that went wrong for the system on Wednesday

Except, of course, that the Ray curse will have been transferred back to Elko

Hahaha. Touché !

One thing that I like this far out is a little bit more colder air available to our NW:

Next 2 storms are baby steps in getting some type of baroclinic zone to set up between inland and the coast.

[Voyager]

0z euro ens says threat is legit:

What can go wrong between now and then...

Just about everything that went wrong for the system on Wednesday

Except, of course, that the Ray curse will have been transferred back to Elko

I'll believe it when I see it. For the past few years the "next storm" is the big threat and our best chance, only to be a non-issue once it arrives.

[Heisy]

I don't like how there is an inverted trough towards the lakes. We need some kind of HP to pinch down in between it. EURO ens look better than OP, but that is to be expected. We'll see what happens.

[chubbs]

Agree this is a little better threat with cold air more available. A couple of things have me worried: 1) There is not a strong HP to the N to hold in the cold air, 2) Non-Euro models appear to be trending warmer leading up to storm, and 3) the trough is broad so in many model runs the coastal is late to develop. We have a shot but as usual need things to break right.

[chubbs]

I'll believe it when I see it. For the past few years the "next storm" is the big threat and our best chance, only to be a non-issue once it arrives.

Only a fraction of the threats deliver in this area. Our good winters have a lot more threats. Still many don't pan out.

[Storm At Sea]

1) Check the Kocin snowstorm book. There are many instances in which the high pressure center is NOT over the NE, but instead, is located over the Midwest. There's certainly a high pressure influence on all of the models.

2) This is the trend thus far this season. The GFS will likely continue to correct NW with time, but it is still far enough SE.

Agree this is a little better threat with cold air more available. A couple of things have me worried: 1) There is not a strong HP to the N to hold in the cold air, 2) Non-Euro models appear to be trending warmer leading up to storm, and 3) the trough is broad so in many model runs the coastal is late to develop. We have a shot but as usual need things to break right.

[Parsley]

I'll believe it when I see it. For the past few years the "next storm" is the big threat and our best chance, only to be a non-issue once it arrives.

I hear ya man. I'm on that boat.

[chubbs]

1) Check the Kocin snowstorm book. There are many instances in which the high pressure center is NOT over the NE, but instead, is located over the Midwest. There's certainly a high pressure influence on all of the models.

2) This is the trend thus far this season. The GFS will likely continue to correct NW with time, but it is still far enough SE.

Not saying it wont happen and agree with 1+2. Those are just the things that have me worried

[thedude11]

GFS still coming in, but drives the storm off the Carolinas and off to the NE, giving what would appear to be an all-snow event for most, with the majority of the precipitation for areas closer to the coast... The good thing is that there is a big area of HP to our north keeping the cold air locked in. This storm definitely has potential, without a doubt.

[Harbourton]

My worry is that the upcoming pattern change may be faster than forecasted and bump this storm OTS.

[chubbs]

GFS still coming in, but drives the storm off the Carolinas and off to the NE, giving what would appear to be an all-snow event for most, with the majority of the precipitation for areas closer to the coast... The good thing is that there is a big area of HP to our north keeping the cold air locked in. This storm definitely has potential, without a doubt.

Agree. Some room for a stronger storm closer to the coast to stay snow

[RowanBrandon]

Jackpot!

[NaoPos]

132, 1004mb off the NC coast. plenty cold throughout the area..light snoe (.1-.25") falling entire EPA-SEPA to coast back to state college)

[NaoPos]

138 nice HIT! 992 inside the BM. .5: south jersey, 850s cold enough, 32 line runs right parallel of 95 in jersey. .25-.5" for se pa up to pocnos...

[Thunder Road]

Euro is a solid 4-8" for the I-95 corridor, maybe more in SNJ

[famartin]

Euro is a solid 4-8" for the I-95 corridor, maybe more in SNJ

All because I'll be gone by then...

[RowanBrandon]

Of course it's going to snow that weekend, because I won't be here to enjoy it.

[NaoPos]

All because I'll be gone by then...

Between today, Thursday, and then Saturday and what you've missed back in Elko, I feel for ya. At least you weren't here last winter!!

[wolfie09]

Euro for knel (lakehurst)

SAT 18Z 29-DEC   1.6    -0.9    1017	  63	  91    0.00	 552	 538   
SUN 00Z 30-DEC   0.8    -3.7    1012	  93	  99    0.10	 548	 539   
SUN 06Z 30-DEC   1.5    -1.5    1001	  99	 100    0.52	 539	 539   
SUN 12Z 30-DEC  -0.1    -5.5    1000	  86	  92    0.33	 529	 529

[jwilson]

Still too soon to buy in. I would actually prefer this to be suppressed down to Bermuda right now, as it is presently at the prime location, I imagine this comes inland. It looks like both the NAO and AO may be positive around the time of this system, as well.