January 2nd-3rd Potential Snowstorm

Like I discussed in my latest blog, early January offers a lot of potential in terms of possible snowstorms. The pattern is changing to one we have not seen so far this year, and that is a +PNA/-AO pattern with a semi negative NAO.

A piece of energy ejecting out of Canada has an opportunity to phase with another piece of energy in the southeast. If the two come together, it could produce a big storm.



The euro 500 mb map above shows a nice ridge in the west (+PNA) which helps the northern stream energy dig into the trough.

The problem is, there is a kicker to its north that is flattening the ridge as you can see below also from the EURO.



If the ridge flattens, both pieces of energy will not phase and we may just see some high ratio snowfall from the northern stream energy. We want the ridge axis to stay as far west as possible (not toward the Midwest like euro shows).



Above you see the euro is close to a big storm, but kicks the southern steam energy ahead of the northern stream energy. There is also a strong confluence to our north thanks to the polar vortex which prevents snow from getting to a certain latitude.



GFS looks drastically different. THe confluence to the north is not as strong a coastal does develop. If the phase was 6 hours sooner, it would be a big storm.

So...

1. Need the PNA ridge to stay amplified, not flatten out
2. Need the PNA ridge to stay west, not shift east into the Midwest
3. Need the confluence to our north to remain weak to allow moisture to get to our latitude
4. Need a phase with both polar and sub tropical jets, or else this would be a weak snow event (fine with me)

This time frame is not the only one to watch either. The 5th-10th offers more potential as well.

Frank, what are your thoughts on the 0Z EURO ensembles?



The mean shows a low pressure system off the coast but doesn't look that impressive.  

Meanwhile, the snow totals for the 51 members of the ensemble are looking more impressive.  On the right hand side of the image below, I put a green dot next to the members that give Central Park, NY at least 6 inches of snow and a red dot next to those with less than 6 inches:



19 of the members show at least 6 inches of snow (assuming of course the 10:1 ratio verifies).  Meanwhile, the Ensemble mean has over 5 inches of snow on this run.  Should be an interesting next few days to track this system...

Alex,

Looks good to me but I would prefer a GFS solution at this point and that dam PNA spike better not flatten out or move past Idaho!!

If I recall correctly this has a similar NEMO set up from 2-8-13??

Watch how this board explodes over the next couple of days  

Euro ensembles actually look like the latest 12z GFS. GFS just showed a nice 3-6 inch snowfall for the area. It's all northern stream energy driven. The STJ is almost non existent this run.

Well, NW areas are going to see some high ratio snowfall if the system works out. The 12z GFS has most places in low to mid 20s except for southern NJ coast. 850s are pretty much around -5 except for coastal areas again, as they are closer to -2. So even if we see limited precip around .3-.5, we can still see some pretty good accumulations. Still a lot to work out, but the cold air is in place with this. Check that off the list.

Cold air is there for everyone. The Canadian just came in and shows a major storm on the east coast. Wow

Models are beginning to bark louder now for January 2nd-3rd storm. As long as the PNA ridge remains amplified and does not flatten from the kicker to its north, that should allow the northern stream energy to dive in on the backside of the trough. The question now becomes...will there be STJ interaction? The GFS was a nice high ratio snowfall, but it was all northern stream driven with a piece of the PV attempting to dive into the conus. Strictly northern stream phasing really turns this into a thread the needle type of situation. However, if the STJ was there, a classic phase between the two jets could yield a very big storm. The euro still has this idea going. Also, the orientation of the ridge in the west would be better if it was a more north-south flow because that would allow vorticity to consolidate feasibly into the base of the trough and potentially get it to negatively tilt. A lot to watch, but I love the trends regardless. This threat is real.

Euro is a MECS for the area


http://usa-wx.com/uploads/monthly_12_2013/post-40-0-20731100-1388255196.jpg

Euro is 6 hours too late of a complete phase from showing a Godzilla

Wow, there is certainly a lot to iron out, Euro and CMC appear to agree fairly close on the amount of snow. 12z GFS shows much weaker but still some snow. Looks like if as it stands now could see up to or over 10 inches for my area. That would be nice but not gonna be a fun drive during the work day but hey i'll take it. Watching for something bigger, something tells me this may be your so called Godzilla, just a gut opinion though.

From Upton:
12Z MODELS ARE COMING INTO BETTER AGREEMENT REGARDING THE POTENTIAL
OF A COASTAL STORM AFFECTING US THURSDAY INTO FRIDAY. ALTHOUGH FULL
PHASING OF NORTHERN AND SOUTHERN STREAMS ARE STILL FORECAST TO OCCUR
TO OUR EAST...A SHARPENING LONGWAVE TROUGH STARTS TO BECOME
NEGATIVELY TILTED AS ITS AXIS IS NEAR US. THIS WILL HELP STRENGTHEN
LOW PRESSURE EMERGING OFF THE MID-ATLANTIC COAST SOMETIME LATE
THURSDAY/THURSDAY NIGHT. MODELS HAVE THE CENTER OF THIS STORM
EVENTUALLY PASSING NEAR THE 40N/70W BENCHMARK LATE THURSDAY NIGHT
BEFORE HEADING FARTHER NE ON FRIDAY. WITH HIGH PRESSURE OVER THE
VICINITY OF NORTHERN NEW ENGLAND...ANTECEDENT COLD AIR WOULD HAVE
ANY PRECIP BEGIN AS SNOW...AND DEPENDING ON THE EVENTUAL TRACK OF
THE STORM...THIS HAS THE POTENTIAL TO BE AN ALL-SNOW EVENT. BEST
CHANCES FOR ANY MIXING AS USUAL WILL BE OVER SE SECTIONS OF THE CWA.
NOT ENOUGH CONFIDENCE AT THIS TIME IN THE TIMING/TRACK/STRENGTH OF
THE STORM FOR A MENTION IN THE HWO. WOULD FIRST LIKE TO SEE SOME
RUN-TO-RUN CONSISTENCY FOR EACH MODEL AS WELL AS CONSISTENCY AMONG
THE DIFFERENT MODELS. ADDING TO THE UNCERTAINTY IS THAT BOTH THE 12Z
ENSEMBLE MEAN FOR THE ECMWF...AND NOT SURPRISINGLY FOR THE GFS...ARE
FARTHER SOUTHEAST WITH THE TRACK OF THE STORM. HIGH PRESSURE WOULD
THEN BUILD BEHIND THE DEPARTING STORM FRIDAY NIGHT AND SATURDAY WITH
DRY WEATHER AND BELOW-NORMAL TEMPERATURES.

Hey Upton - wouldn't we all like to see model run consistency?!
BTW aren't we going to have below normal temps after this Nor'easter Sunday??

18z GFS is a bit less amplified and much weaker than the 12z Euro( un-similar evolution of the system, later phase etc) and the 12z GFS. A less amplified pattern out west allows for a further east track of the low and less amplification of the trough in the east. The system as shown is a Long lasting light snow event over 24 hours and still drops plow able snowfall. Another possible solution by the GFS lol....waiting on ensembles...
One more thing,
We have to remember that the pieces of this system are not onshore yet, and that models will have closer solutions(hopefully) once we can get better sampling.
18 GFS snow map

HOLY SNIKES!!!

This go be a big one, just have to wait and see. Bit I just have a feeling that phasing may happen and in time to give us a good dumping of snow.

You can tell from the above image just how much the EURO gets the STJ involved in this storm. It's important because we do not have to rely on much phasing from the PV and the trough goes positively tilted.



Tonight's 00z GFS still looks pretty much like previous runs. No STJ interaction, kicker in the Pac NW causing the ridge to roll over and pretty much force an overrunning event with the northern stream energy.

Eventually, something's gotta give.

Clearly I can't sleep...

00z NAVGEM...

Thanks Frank Looking Good so far   

Still lots of model disagreement. We have a long way to go. I like to look at the ensembles at this time. Here are euro ensembles

Sorry frank so what does that map above showing for us here?

Ill tell you from a really zoomed out view of this the only thing that seems to be consistent is the inconsistency from run to run from individual models, and different solns between models. The theme so far this year has been for the models underplay just how strong the energy involving the STJ is in the long and medium range. As Ace said above that the pieces of the puzzle will be coming ashore with better sampling over the next 2-3 days and a soln will/should finally take shape. What I see so far, as has also been the theme so far this season, will be the failure of the timing of the pieces so no full phase in time and we will be left with like Frank said an over running event. IF it plays out similar to prev events the southern stream energy shows up much stronger than was modeled as it taps into the Gulf moisture, and heads towards the coast. As a result of being a bit stronger than modeled it ends up west of the BM hugging the coast causing the I-95 coastal plain to battle with the slop due to the E-SE flow off the Atlantic. However, this time the NAO is modeled to be slight neg right around the time our pieces should come together around the east coast, so the southern energy could be slowed just enough this time around to catch at least a glimps of the phase and all its glory. A SECS (significant east coast storm) or a MECS (Major East Coast Storm) is still not out of the question. It should all become more clear in the next few days.

I still feel like with the established pattern this year the track ends up inside the BM and the coastal plain battles the R/S regardless.

I thought at around this time along the coast the cold air will be established and when I say established really cold not marginal. So in that case it wouldn't matter it would be snow IMO

sroc4 wrote:I still feel like with the established pattern this year the track ends up inside the BM and the coastal plain battles the R/S regardless.

I agree wholeheartedly.

Some winters the timing between the cold air and the storms is just perfect every time, 93-94, 95-96, 09-10, 10-11.
others are awful and the timing is never right 97-98, 01-02, 11-12.

So far this winter cant seem to decide one way or the other. Looking ahead I don't see this changing.