ECMWF screaming MAJOR overrunning event (CAD) on Day 7

[Stormsfury]

for the Southeast ... as more details come out from the vortex site, I'll post back ... in the meantime, here's the Day 7 500mb Geopotential height map from ECMWF ... and 850mb/MSLP chart below ...



Strong CAD signature down the Eastern Slopes of the Appalachians (we're talking Dec 14th, 2003 ... things just get quite interesting ...

[QCWx]

Also, much colder air could be transported down this time IF a good bit of the snowcover remains.

[Stormsfury]

Umm.... Holy crap, QCwx ... IF the GFS is picking up on the ageostrophic gradient signature this far out, this COULD be QUITE an event ...

SF

[greg81988]

Could this give snow to central Virginia?

[Stormsfury]

EURO day 7 MSLP and 500mb Heights

--- strong SW flow over the top of a cold dome setting up shop for later in the timeframe ... 850mb temperatures across the Southeast are above 0C ... however, with that kind of signature, the EURO would imply the potential for a significant icing event ....

[url=http://cyclone.plymouth.edu/cgi-bin/gen_grbcalc.cgi?re=us&mo=ecmwf&le=850&va=temp&in=2&pl=cf&ft=7day&cu=latest&overlay=no&mo=&le=&va=&in=&pl=ln&ft=&cu=latest]EURO Day 7 850mb Temperatures

EURO Day 7 RH values ...

SF

[QCWx]

1041 High over Northern VT on Day 7. Thats a bit too north for my tastes but we'll see how this thing evolves.

[RNS]

Umm.... Holy crap, QCwx ... IF the GFS is picking up on the ageostrophic gradient signature this far out, this COULD be QUITE an event ...

SF

Don/t count on it to find the ageostrophic gradient next run...but yes i do agree this could be an ice situation across the southeast and snother SECS threat for the northern Mid-Atlantic and northeast. Pure STJ energy...Looks like a Miller B

[RNS]

Could this give snow to central Virginia?

Quite possibly...

[RNS]

Its tough to say right now...but the EC may bee to warm. 500 hPa heights across the northeast are as high as 564 DM...which given the positive tilt to the trough the EC depicts would be lower and the environement colder.

[QCWx]

Didnt the PDS high start out progged as being around 1041 or so?

[Stormsfury]

Didnt the PDS high start out progged as being around 1041 or so?

Yes it did ...

SF

[Stormsfury]

Notice the 12z GFS/12z ECMWF match almost identically, and hell, even the 12z GFS even picks up on the AG 7 days out ... and if the ECMWF continues to stay consistent and indeed the solution verifies, the run will trend colder and colder along the damming regions ... we're talking about a LOT of dry air to overcome ... look at the Day 6 EURO RH map ...

EURO day 6 Rel Humidity ... - Notice just how DRY it is in the Southeast - RH's at 850mb, less than 10% ... the very next day ...

EURO Day 7 Rel Humidity ... - Now look at the moisture return at the 850mb level ... there's gonna have to be a LOT of evaporational cooling and moistening of the lowel levels and FWIW, temperatures would probably trend colder and colder ... even the latest surge of cold air this morning was underprogged (I don't have verification numbers, but the forecast only called for mid 30's and it fell to 28º this morning in CHS ...

SF

[Stormsfury]

And the Day 10 EURO's 3 day average quite interesting as well ...

EURO 3 day average - days 8-10

If anyone is tired of making a lot of maps for the EURO themselves, I would recommend using this

http://www.stormsfury1.com/Weather/Models/ECMWF.html

Every makable US ECMWF map is already prepped and all you have to do is click and choose ... piece of cake!

[RNS]

And the Day 10 EURO's 3 day average quite interesting as well ...

EURO 3 day average - days 8-10

If anyone is tired of making a lot of maps for the EURO themselves, I would recommend using this

http://www.stormsfury1.com/Weather/Models/ECMWF.html

Every makable US ECMWF map is already prepped and all you have to do is click and choose ... piece of cake!

And whatever is down there in the STJ next week IS coming up the coast...NAO is positive...and slight ridging is present east of spain which should mean that the SE ridge is stronger...so the resulant action would force whatever is down there up the coast.

Also watch the probelms the EC will have with the closed H5 low off the the Baja.

[DCmetroraleigh]

What does it portend for Northern Virginia and Winston-Salem?

[RNS]

What does it portend for Northern Virginia and Winston-Salem?

POSSIBLE significant snowfall...

[Stormsfury]

What does it portend for Northern Virginia and Winston-Salem?

POSSIBLE significant snowfall...

I second that...and with the overall mean flow would imply that the energy would eject out of the SW and maybe just in time ...

There's potential, folks ...

SF

[RNS]

Based on the look of the EC at 168hrs (Sun 12/14)...i think its another miller B...and coming up the coast. Low pressure develops in the western gulf as the inverted trough develops along the east coast due to the resistance from the VERY strong high to the north...transfers to the coast where the thermal gradient is establised and comes up.

[WEATHERGURU]

What is a Miller B? :-?

[RNS]

A Miller "type B" Major east coast snowstorm occurs when low pressure develops in the gulf of mexico and encounters high pressure to the north of it which forces cold air to become firmly entrenched east of the appalachains. this cold air forces the surface low pressure area to transfer to the east coast where the thermal gradient allows it to deepen. the system then either moves out to sea or comes up.

Classic Metter type B system:



For additional Info on the othe rmiller types - SF has an awesome write-up and discription on his site:

http://www.stormsfury1.com/Weather/Cyclogenesis.html