Big Snowstorm Unlikely for the East Coast Friday-Saturday

[donsutherland1]

At this time, the setup appears completely different from those which have typically provided big snows to the major cities of the East Coast in early to mid-December.

Based on the latest run of the ECMWF, the presence of a strong ridge that will likely be heading northeastward from a position to the south-southeast of Cape Cod could do two things:

<img src="http://www5.wright-weather.com/bb/attachment.php?s=&postid=132477">

1) Tend to keep the storm track farther to the west
2) Bring in warmer air from off the Atlantic Ocean

At this time, a track that is somewhat inland, perhaps across the Appalachians appears to be more likely than an offshore coastal track. Greater intensification (something that cannot definitively be resolved at this time, though the Canadian Model seems to be much overdoing the possible storm's deepening would also contribute to warming of the lower atmosphere well inland if the ECMWF depiction proves accurate).

This setup is wholly different from that of the 1960 December blizzard which buried parts of the Mid-Atlantic and Northeast under more than a foot of snow.

<img src="http://www5.wright-weather.com/bb/attachment.php?s=&postid=132481">

If one also examines the past few days' movement of weather systems, the ECMWF idea of the ridge getting out in front of the possible storm looks to be reasonable.

<img src="http://www5.wright-weather.com/bb/attachment.php?s=&postid=132483">

<b>Note: </b> Greens, yellows, oranges, and reds=higher pressures; blues and purples=lower pressures.

Consequently, if the big cities are to receive a major snowfall this winter, this coming storm is not likely to be that storm.

[Stormsfury]

Cold air damming is about the only thing that looks like it's a go right now ... the details of everything else right now look like a Picasso painting ... very sketchy.

Variables include .. the tropical disturbance in the Caribbean, the disturbance dropping into the US and what it does in the confluent zone across the east ... among other things.

SF

[NEwxgirl]

like it's a go right now ... the details of everything else right now look like a Picasso painting ... very sketchy.

Variables include .. the tropical disturbance in the Caribbean, the disturbance dropping into the US and what it does in the confluent zone across the east ... among other things.

SF

I agree, SF. But I don't think this will be anything more than a major rain event for the big cities as it stands right now with maybe a bit of snow at the beginning and the end of the event. Its inland sections such as MDT, ABE, MPO, AVP, and BGM which have the best shot at a significnat snow event.

Last nights canadian run was questionable, I really don't buy it, but it does have some support from other models. This afternoons 12z GFS was in line with it, and so is the newest run of the navy NOGAPS.

500mb heights and vorticity>>>

https://www.fnmoc.navy.mil/CGI/PUBLIC/w ... 00&tau=120

the Nogaps builds a strong western ridge and digs the polar jet shortwave into the lakes as the sub-tropical branch energy comes out ahead of it allowing the two to phase. we also notice a 50/50 low (trough centered near newfoundland) would prevent an inland track. so we can assume that once phasing occurs the low closes off and surface low pressure should develop in the inverted trough along the east coast. The GFS no surprizingly has no signs of the sub-tropical brnahc shortwave.

Surface precipitation>>>

https://www.fnmoc.navy.mil/CGI/PUBLIC/w ... rp&tau=120

the tropical disturbance (at least through 120 hours) doesen't interact with the mid-latitude phasing in any way, remaining down in the central Caribbean. at least according to the nogaps.

850mb temperatures>>>
https://www.fnmoc.navy.mil/CGI/PUBLIC/w ... 50&tau=120

Critcal thickness>>>

https://www.fnmoc.navy.mil/CGI/PUBLIC/w ... hk&tau=120

The GFS digs the polar branch shortwave into the eastern lakes but has no signs of sub-tropical branch energy like the nogaps did at 120 hours.

500mb heights/vorticity 120-156 hours>>>

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_120l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_126l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_132l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_138l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_144l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_150l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_156l.gif

the system eventually cuts off from the main flow as the polr get lifts up and leaves the low pressure center behind. but we still notice low pressure of there to the east of newfoundland which would not let the system move northward or go out to sea very quickly at all.

lastly, this could be a very slow moving system considering that its going to try to cutoff, we have the low east of newfuondland, and the closest shortwave energy is back to the west of california. the height ruises to the north over quebec should keep surface high pressure in place across northern new england and that is the reason why the GFS and other models will not see the cold air damming until at least 84 hours before the event.

the ocean influence though should change the big cities to rain or mixed precipitation during the period of heaviest precipitation.

so you guys, i dont think its a big problem for the big cities, but inland areas of eastern pennsylvania. and yes this includes you too Colin, hehe, such as the lower susquehanna valley, poconos, lehigh valley, and far southeast new york, it is something that needs to be watchd very closely.

Sea-level pressure and 6 hour precipitation 120-150 hours>>>

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_120l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_126l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_132l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_138l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_144l.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 6_150l.gif

60-hour precipitation ending 0z december 7>>>

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_156l.gif

it's obviously overdone, but just something to remind us that winter's here, lol.

[NEwxgirl]

And Don, just becasue the pattern doesent look similar to other major east coast snowstorms doesent mean that an event of that magnitude can't occur (that's what was said about presidents day initially). I mean that's not my forecast (for a major snowstorm in the big cities) and it isn't yours either, but i have little confidence in anything other than a coastal low.

[Colin]

Cold air damming is about the only thing that looks

like it's a go right now ... the details of everything else right now look like a Picasso painting ... very sketchy.

Variables include .. the tropical disturbance in the Caribbean, the disturbance dropping into the US and what it does in the confluent zone across the east ... among other things.

SF

Its inland sections such as MDT, ABE, MPO, AVP, and BGM which have the best shot at a significnat snow event.

WOOOOO!!!!!

[NEwxgirl]

Thats right colin, there should be just enough cold air in place that what falls at Allentown should be mostly snow.

and for the rest of you guys, the ensembels are taking the NAO strongly negative by the middle of the month>>>

http://www.cpc.ncep.noaa.gov/products/p ... _ensm.html

And the PNA is showing signs of going back to positive>>>

http://www.cpc.ncep.noaa.gov/products/p ... _ensm.html

oh and our water temperature profiles>>>

https://www.fnmoc.navy.mil/products/OTI ... nomaly.gif

Very warm SSTA are increasing in coverage across the western pacific, cooling is taking place near the southeast coast of Russia, and to the north of hawaii.

but we still have a long way to go before we get to something like we saw last january>>>

https://www.fnmoc.navy.mil/products/OTI ... nomaly.gif

remember though with all that warm water between the dateline and 150E, it can enhance convection and support more frequent pulsing in the MJO (more frequent than the 30-60 day cycles). but also can lead to a very cold january in the central and eastern part of the country. (see our winter outlook).

[meso_jr]

If the trough keeps the storm either on or slightly west of the Apps, doesnt that mean the the Ohio Valley could get its first significant storm? I live in Dayton, but my parents live near Wheeling, WV near the Upper Panhandle. Pittsburgh isnt saying anything about this storm, but typically they are conservative. If the snow doesnt fall on the East Coast, than where will it fall- besides NY/PA?

Just another weenie,

Jay

[NEwxgirl]

I dont think it will track up along or west of the mountains. It's most likely a coastal storm. you could see some snow as the initial piece of energy transfers to the coast. the trough to the east near newfoundland and very sharp wavelengths should prevent an inland track.

[Colin]

At this particular time, how much snow do you think will fall? (Wide Range allowed )

[NEwxgirl]

At this particular time, how much snow do you think will fall? (Wide Range allowed )

No specific numbers (though I do have my ideas, *hehe*), we'll just say significant accumulations are possible across eastern pennsylvania far northwest new jersey and southeast new york.

[donsutherland1]

Erica,

I probably should have written somewhat more clearly. I believe that the storm will probably track close to the Coast or somewhat inland--my initial idea is somewhere within 50-100 miles of the ECMWF track.

Given its performance, the ECMWF is usually a starting point for me:

<img src="http://wwwt.emc.ncep.noaa.gov/gmb/STATS/html/graphics/acz5.gif">

Taking into consideration the GFS' bias also suggests "reasonableness" with regard to this initial idea--which is subject to change.

I mentioned a possible track along the Appalachians, because I see it as within the realm of possibility and used the word "perhaps." Such a track is considerably less probable than the one closer to the Coast. I'm sorry about the confusion.

As for the 2003 President's Day Storm, you make an excellent point. It certainly was one of the less common situations, though the High was generally to the storm's north even when the storm was situated off the Delmarva. In addition, throughout the storm, far more cold air with lower temperatures--at least than what is suggested by the guidance at this point in time--was present across eastern Canada, upstate New York and northern New England.

Overall, my general idea is that the big cities--DCA to BOS--are likely avoid a major snowstorm. Well inland, better prospects for snow--yes, Colin that means you--exist but amounts will depend on the track and strength of the storm.

A changeover is possible even there, but it's too soon to try to get into details (at least for me). I believe that the general idea of no major snowstorm for DCA to BOS looks reasonably good. Needless to say, this does not mean that there is not frozen precipitation at least for a time in at least some of those cities.

[donsutherland1]

SF,

I agree with you that many of the details concerning the possible storm, even whether it will be a major system or a more minor disturbance, remain to be resolved. The consistency of the model runs, a number of which show a strong storm under 990 mb suggests that there is a possibility of a fairly significant storm. Whether this proves to the case remains to be seen. Let's see how it holds together and then develops on the way east over the next couple of days.

[RNS]

A changeover is possible even there, but it's too soon to try to get into details (at least for me). I believe that the general idea of no major snowstorm for DCA to BOS looks reasonably good. Needless to say, this does not mean that there is not frozen precipitation at least for a time in at least some of those cities.

its possible that there could be a breif changeover even well inland... but soundings would primarly support snowfall through most of the event once 50 miles inland from the major cities. I don't want to get hooked up in all these specifics yet until at least tuesday when the models have a chance to get a better handle on it. In a way it short of looks like the February 2001 Nor'easter.

[RNS]

that system produced heavy amounts of snowfall well inland from the coast...check out the totals graphic from WFOPHI...

[RNS]

So all in all i think she has a darn good handle on the event. we/ll have to see what the EC has to say tonight

[donsutherland1]

RNS,

The soundings look good and I agree that Erica appears to have a good handle on the system. I also agree that in a few days, it will be a good time to begin trying to hone in on the details of the storm.

The comparison with the February 5, 2001 nor'easter is an interesting one.

<img src="http://wintercenter.homestead.com/files/5feb2001-2.jpg"><br>February 5-6, 2001 nor'easter (Westchester County, New York)

[RNS]

I noticed that WFOPHI in their afternoon update were dismissing the system as rain based on guidance when the know forewell that the GFS does a pathetic job with CAD in the medium range.

If i was the forecaster i would have gone with mixed precipitation in all zones NW of PHL and rain south. the system has enough cold air to work with that inland sections especially the lehigh valley and poconos would see an all snow event...continue the trend for OKX/s NW zones.

[Guest]

So you guys are saying natta for Central/Eastern OH from this? Or should i say very little?

[RNS]

the GFS 18z run is garbage...it completely misses the cold air feedback east of the mountsins courtesy of the high pressure center that builds up in the confluent flow to the northeast. as long as that high is up there the system will be forced to jump to the coast. and with the 50/50 low to the east the high is going to be in no hurry to get out of the way

[RNS]

right now i like the 12z NOGAPS solution the best. the 18z GFS is doing the same thing that it did on last nights 0z run...deepens and closes the H5 low too far to the west given the 50/50 low which would force it to dig more before turning east. look at the flow to the northeast on the back side of the 50/50 low its from the northwest...the system would not be able to deepn until MUCH later