12z Thu ECMWF Continues Midweek Threat

[Anonymous]

The new European continues to show the threat of a major storm moving across the eastern half of the nation in the early and mid part of next week. Although the 500mb maps are not quite as impressive as last night's run, the surface maps depict a strong area of low pressure moving from the GOM into the South and eventually winding up off the Carolina coast, and from there it heads northeast to a position well east of the Delmarva by Day 7 (next Thursday). Taken at face value, this presumably implies a nice hit for southern portions of the Mid-Atlantic... perhaps N/W NC, S VA, and the Delmarva. IF this storm can manage to come up the coast, it would be a Miller A system with no worries about redevelopment, something we haven't seen for a while. The cold air looks a little better on tonight's run, and as Stormsfury mentioned in another thread, the possibility of CAD stronger than any models are currently showing is a very real one.

500mb Days 5 - 7:




Surface Days 6 - 7:



850mb Temps Days 6 - 7:

[Chris the Weather Man]

Miller A.... Ahh, Like PD2! We could use a storm like that!

[Erica]

Great post Brett! Normally, the ECMWF has a problem holding back southern branch energy. But is best when dealing with a system that has both jets involved. The GFS doesn't do a great job no matter what.

Tonight's ECMWF has the kind pf phasing required to create a major winter storm, but the only poblem is it occurs too late. If tonight's ECMWF were to verify, this would be miss for areas north of Washington DC. A suppressed system.

There have been plenty of times this winter where phasing has ocured, but too late. It's not that we've had a problem getting phasing to occur this winter, It's all been a matter of timing. And this turn, it has not ben in the favor of major east coast snowstorms.

The Idea I've been fooling around with (as the reasoning behind why I think this has a chance to become a major winter storm, and even for places north of Washington DC) is that as the Southern branch s/w lifts up, the the jet strengthens, and the Polar vortex is forced to split. One piece goes out underneath the block and the other drops in which then phases with the Subtropical jet s/w, and you have a major winter storm for the eastern part of the country, with a deep low along the east coast.

But this depends on how strong the southern branch s/w is.

[Chris the Weather Man]

Erica, Do you a see a "March Madness" Pattern? ( Big Snows, Cold, the first 2 weeks of March 2004?)

[Erica]

Ok, lets put it this way. This mid-week event can be a major storm, but this is what has to happen is two things.

First, the s/w must come out of the four corners region as a closed low, and secondly the closed low at 500mb has to be below 546 decameters.

The next complication is phasing, which I think it is pretty safe to say will occur (the ECMWF and GFS both show it), but here, it's a matter of timing, and depends on whether the first to things I listed come to pass.

This is a complicated pattern, which usually doesn't lead to major winter storms, but it also doesn't mean they can't occur either. This will be a very challenging and exciting system to forecast over the next 5-7 days.

[Stormsfury]

The only problem right now that I see with the ECMWF is the fact is the redevelopment occurs right along the South Carolina Coast ... IF IF IF the wedging occurs as I expect (that is if the trend for stronger CAD does in fact develop), then the best baroclinicity HAS to occur further offshore ...

Also with that said, IF the primary SFC low is as strong as depicted, a ton of WAA would then ensue, and quite possibly would cause the coastal trough to indeed penetrate along the South Carolina coast, and hence, the depiction would be alright, even with strong wedging.

Another point is IF the s/w in the southern stream becomes a bit stronger and/or there's not much in the way of wedging, there would possibly be just a good ol' fashioned Miller A (with no development off the coast) ...

Just some scenarios for thought.

SF

[Guest]

IF IF IF This can run up the Apps then i am in Buisness! . <---------Funny arent i!

[Erica]

The only problem right now that I see with the ECMWF is the fact is the redevelopment occurs right along the South Carolina Coast ... IF IF IF the wedging occurs as I expect (that is if the trend for stronger CAD does in fact develop), then the best baroclinicity HAS to occur further offshore ...

Also with that said, IF the primary SFC low is as strong as depicted, a ton of WAA would then ensue, and quite possibly would cause the coastal trough to indeed penetrate along the South Carolina coast, and hence, the depiction would be alright, even with strong wedging.

Another point is IF the s/w in the southern stream becomes a bit stronger and/or there's not much in the way of wedging, there would possibly be just a good ol' fashioned Miller A (with no development off the coast) ...

Just some scenarios for thought.

SF

That same strong warm air advection would build the ridge ahead of the s/w and help it to turn up. If the s/w is very strong (closed at 500mb by maybe one or two contours and at or below 546 dm while over the southern Plains) the heat feedback pumps the ridge ahead of it and the system will have a better chance not only to phase further west, but also come further north. That also could lead to a Miller type A situation, with heavy snow from The Carolinas to Boston, Icing south of there, and a heavy rainfall south of that.

Even still, at this time, I don't think the system will ever reach the benchmark (best case scenario, it misses it by only 50 or so miles to the southeast), therefore this probably won't be anything too big for areas north of Boston, or between Boston and New york City, south of new york City this could easily be the biggest single event of the winter thus far.

[Erica]

IF IF IF This can run up the Apps then i am in Buisness! . <---------Funny arent i!

Jeez King, lol, turn up the Appalachains, I'm not even sure if I can get it to the benchmark and you want it up the Appalachains. That's a bit too much to ask don't ya think?