Potential Record Breaking Cold Sunday/Sunday Night---Late Nov Discussion

[ORH_wxman]

That's PDO. EPO is more the area from the beaches of western Canada through the Aleutians..especially east of the dateline I believe.

 

 

Here's the official loading pattern

 

 

[jamesnichols1989]

That's PDO. EPO is more the area from the beaches of western Canada through the Aleutians..especially east of the dateline I believe.

 

 

That's what I was thinking, from the Gulf of Alaska through the Aleutian Islands, or roughly 20-35N: 160-125W.

[CoastalWx]

That's what I was thinking, from the Gulf of Alaska through the Aleutian Islands, or roughly 20-35N: 160-125W.

 

Will gave the loading pattern, but CPC also changed it to call it Just the EP oscillation. For whatever reason, they switched signs so a +EP = -EPO.

[CoastalWx]

Here's the official loading pattern

 

 

 

Still mad they changed the designation to just EP.

[powderfreak]

BTV's long term discussion on the storm...

&& Long term /Monday through Friday/... as of 300 PM EST Friday...extended portion of the forecast will continue to feature cold temperatures and possibility of a significant storm impacting the north country on Wednesday. Monday will be mainly dry and cold with surface ridge of high pressure sliding southeastward during the daytime hours. A weak low pressure system passing north of our forecast area Monday night into Tuesday will bring a chance of snow showers to the County Warning Area...especially our northern zones. Coastal storm is taking shape during this time period over the Gulf Coast and slowly tracking eastward Tuesday night to the Carolina coast by Wednesday morning. European model (ecmwf) brings this low across our Sweet spot...right off the coast of Cape Cod on Wednesday afternoon. GFS is slower and further east with this system...keeping the low center further out to sea. The European model (ecmwf) brings up possibility for significant snow across Vermont from Tuesday night through Wednesday night. A lot of the details are still unclear...as the previous forecaster mentioned...there is potential for phasing between the northern and southern stream troughs and a strong vorticity/closed low involved. The GFS and European model (ecmwf) are closer than they were this time yesterday...but still not exactly in agreement on timing or track of low. Phasing events are very difficult to forecast...but it is Worth mentioning that there is potential for deep Gulf moisture...strong baroclinicity at 850 and a favorable synoptic pattern. These ingredients mean that potential exists for significant East Coast cyclogenesis possibly bringing the first significant snowfall of the winter to Vermont...especially eastern and central. Northwesterly flow following this departing low for Thursday...so will have upslope snow showers on northwesterly flow and more colder than normal temperatures. "

[jamesnichols1989]

WHat does loading pattern refer to?  I mean I would like to get the terminology back that I used to know.  My illness has stripped me of my basic knowledge of weather, and my technical discussion aspects.

[ROOSTA]

That's PDO. EPO is more the area from the beaches of western Canada through the Aleutians..especially east of the dateline I believe.

My bad. Ah, how does one recover....could always use some light reading.

Man it's going to be cold at the football games Thursday. 

[RUNNAWAYICEBERG]

so a -EPO is a +EP, which is good for us? and vis versa. and wouldnt a +EP lead to a +PNA? gee this isnt confusing for amateurs.

[CoastalWx]

WHat does loading pattern refer to?  I mean I would like to get the terminology back that I used to know.  My illness has stripped me of my basic knowledge of weather, and my technical discussion aspects.

 

The pattern Will showed is the classic loading pattern or look for a +EPO. The exact opposite would be a -EPO.

[jamesnichols1989]

The pattern Will showed is the classic loading pattern or look for a +EPO. The exact opposite would be a -EPO.

So ridging near the Gulf of Alaska would favor an East Coast Snowstorm?

[CoastalWx]

So ridging near the Gulf of Alaska would favor an East Coast Snowstorm?

Well ridging near AK favors cross polar flow and a dump of colder air into the CONUS. Getting a snow event means getting a s/w to track in the right spot, but yeah obviously having the cold would help in getting snow.

[jamesnichols1989]

Man if only we had a northerly wind direction, we would have a nice period of OES, but no the wind has to westerly.

[OceanStWx]

For Ginxy...

 

Once in a decade type chill.

 

[dendrite]

Still mad they changed the designation to just EP.

Yeah...most of the other indices are 3 letter acronyms. I refuse to call it EP. Maybe in a few years we'll be cheering on a +NA for winter. lol

[jamesnichols1989]

Well ridging near AK favors cross polar flow and a dump of colder air into the CONUS. Getting a snow event means getting a s/w to track in the right spot, but yeah obviously having the cold would help in getting snow.

 

Does trough positioning have an impact on the potential for OES?  Like say for instance, the trough centers over the region, does that impact surface winds?

[It's Always Sunny]

Does trough positioning have an impact on the potential for OES?  Like say for instance, the trough centers over the region, does that impact surface winds?

The EPO in simple terms refers to whether there is ridging or troughing over Alaska/Gulf of Alaska. We are currently in a -EPO phase which means ridging over Alaska/Gulf of Alaska which helps stream colder air into the Central/Eastern US. The position of the trough does impact the potential for OES depending on how negatively tilted it is. Surface winds will be impacted depending on the position of the trough and your location relative to it.

[ORH_wxman]

The Euro ensembles are pretty damned cold in the long range. That is a really nice pattern for the CONUS...esp northern tier. Great cold air supply and it bleeds pretty far south.

[TauntonBlizzard2013]

The Euro ensembles are pretty damned cold in the long range. That is a really nice pattern for the CONUS...esp northern tier. Great cold air supply and it bleeds pretty far south.

Excellent news, our time will come down here if not next week

[CoastalWx]

The Euro ensembles are pretty damned cold in the long range. That is a really nice pattern for the CONUS...esp northern tier. Great cold air supply and it bleeds pretty far south.

 

That is an awesome H5 look in the Pacific.

[dendrite]

Qpf?

Man what a horrible name change. lol

The mean is 1-1.50" for you, but obviously most of the juicy members are mostly rain.

[OceanStWx]

Went digging a little bit into the NCEP pytpe algorithms (no such luck for the ECMWF).

 

The GFS uses a combination of 4 algorithms (tie going to the most dangerous ptype). One is biased towards snow to eliminate lots of occurrences of IP and ZR. Two others use wet bulb temps, and we know how well models handle moisture (especially in the longer ranges).

 

And keep in mind GFS and ECMWF both have 6 hourly time steps. So if the model sees snow at 06z (or 12, 18, 00) all that QPF prior to that hour will be converted to snow. We know this is not always the case. Always best to view soundings to confirm ptype.

[Bostonseminole]

The Euro ensembles are pretty damned cold in the long range. That is a really nice pattern for the CONUS...esp northern tier. Great cold air supply and it bleeds pretty far south.

 

has that ridge south of AK the whole period it seems..

[jamesnichols1989]

The EPO in simple terms refers to whether there is ridging or troughing over Alaska/Gulf of Alaska. We are currently in a -EPO phase which means ridging over Alaska/Gulf of Alaska which helps stream colder air into the Central/Eastern US. The position of the trough does impact the potential for OES depending on how negatively tilted it is. Surface winds will be impacted depending on the position of the trough and your location relative to it.

 

Thank you for the explanation.  Just trying to clear up a few questions I had.

[Tropopause_Fold]

Went digging a little bit into the NCEP pytpe algorithms (no such luck for the ECMWF).

The GFS uses a combination of 4 algorithms (tie going to the most dangerous ptype). One is biased towards snow to eliminate lots of occurrences of IP and ZR. Two others use wet bulb temps, and we know how well models handle moisture (especially in the longer ranges).

This is the case even though they compute three-hour qpf?

And keep in mind GFS and ECMWF both have 6 hourly time steps. So if the model sees snow at 06z (or 12, 18, 00) all that QPF prior to that hour will be converted to snow. We know this is not always the case. Always best to view soundings to confirm ptype.

[It's Always Sunny]

Thank you for the explanation.  Just trying to clear up a few questions I had.

Anytime man. Feel free to PM me too if you have any questions.

[Ginx snewx]

For Ginxy...

 

Once in a decade type chill.

 

No pic, dont hot link, copy the pic and post it

You don't have permission to access /satable/images/naefs_2013112200_ne_freq_t_850_60.png on this server.

[dendrite]

Went digging a little bit into the NCEP pytpe algorithms (no such luck for the ECMWF).

 

The GFS uses a combination of 4 algorithms (tie going to the most dangerous ptype). One is biased towards snow to eliminate lots of occurrences of IP and ZR. Two others use wet bulb temps, and we know how well models handle moisture (especially in the longer ranges).

 

And keep in mind GFS and ECMWF both have 6 hourly time steps. So if the model sees snow at 06z (or 12, 18, 00) all that QPF prior to that hour will be converted to snow. We know this is not always the case. Always best to view soundings to confirm ptype.

Don't the ec/gfs run 3hrly steps now?

[Bostonseminole]

impressive temp changes down in TX

 

 

[ORH_wxman]

That is an awesome H5 look in the Pacific.

 

 

First half of December is starting to have some real promise...still have to get through the next week though without big changes for the worse.

[CoastalWx]

First half of December is starting to have some real promise...still have to get through the next week though without big changes for the worse.

 

I sure hope we can see that in January and February too.