December Discussion Thread

[Snow_Miser]

What is causing our cold shots to be so strong? We did not have that in 11-12

The poleward -EPO.

[forkyfork]

What is causing our cold shots to be so strong? We did not have that in 11-12

the epo. but it's not enough to force the storm track south of us so the cold outbreaks are bookended by systems that cut west

[Allsnow]

the epo. but it's not enough to force the storm track south of us so the cold outbreaks are bookended by systems that cut west

Thanks.

[SnoSki14]

But there's always hope if the PV is nearby and we continue to average a -EPO.

[Quakertown needs snow]

12 euro goes more zonal after our cold shot mid next week with plenty of cold hanging across Canada just waiting to hopefully drain south again..

[IsentropicLift]

12 euro goes more zonal after our cold shot mid next week with plenty of cold hanging across Canada just waiting to hopefully drain south again..

It's disappointing that the extreme cold in the long range has been muted. The pattern at day ten kind of looks like what we have now as we get stuck on the gradient.

[PB GFI]

It's disappointing that the extreme cold in the long range has been muted. The pattern at day ten kind of looks like what we have now as we get stuck on the gradient.

Dont get stuck on a day 10 Euro  this AM  0z Euro  day 9 had  a snowstorm here , LR is always a  dice roll even for the Euro  . 

This past weekends Euro 10 day showed the same thing , and in 7 days you`re looking at record cold in the interior  Northeast .

NEG EPO  saves us from a full out torch , and if you get one its only for a few days max .

[bluewave]

An MJO 3-4 push would mean that the cold departures next week will probably be the lowest that we see for a while as the

pattern moderates for the third week of the month.

Eh it doesn't look so clear to me and it seems to collapse after it goes into phase 3. I think signals are still fairly mixed with no clear cut weather pattern for us.

 

What it will probably do is cause the EPO to get closer to neutral and restrict the Arctic air to Canada as the Pacific

Jet is able to cut  underneath. So with the lag that we can often see with these signals, the milder temps could

develop some time during week 3 and possibly persist past December 20th. The GFS ensembles have

had a cold bias in the long range as we seen with it underestimating the warmth that we are seeing

this week. 

 

 

8-15 day  forecast was too cold

 

 

Warmed up as we got closer

 

[Allsnow]

Man what a early start to the snowfall in the lower Midwest. OKC and Springfield going to get 8-12

[jm1220]

It's disappointing that the extreme cold in the long range has been muted. The pattern at day ten kind of looks like what we have now as we get stuck on the gradient.

Typical rinse/freeze/repeat Nina pattern we've been having. The Midwest and maybe New England do great, from here south rains.

[ADKweather27]

I don't see a great cold pattern here looks cold and cutters with possible torch 3rd week of December

[NEXtreme]

the epo. but it's not enough to force the storm track south of us so the cold outbreaks are bookended by systems that cut west

Joe B :

WPO , more the driver than EPO, as source region of cold air off asia, vs warm pacific bigger. WPO neg, EPO goes pos pic.twitter.com/fq6wAVs394

 

[Ralph Wiggum]

It's disappointing that the extreme cold in the long range has been muted. The pattern at day ten kind of looks like what we have now as we get stuck on the gradient.

Typical rinse/freeze/repeat Nina pattern we've been having. The Midwest and maybe New England do great, from here south rains.

Wasn't 95-96 a nina year? We all seemed to fare well that winter from what I recall. I wonder how much the nao and epo had a role in that winter?

[Snowshack]

What is JB trying to say there?

[Rjay]

What is JB trying to say there?

Please pay for my forecasts

[Momza]

Please pay for my forecasts

Sport

[donsutherland1]

Joe B :

With respect to EPO+/WPO- combinations in December, such outcomes are not very common. Below is a table showing the frequency of WPO < 0 when the EPO is positive, the composite temperature anomalies for all December (1981-2012) dates when the EPO was positive and the WPO was negative, and the GFS ensemble 360 hour forecast (which shows the main area of cold displaced away from the CONUS and reasonably consistent with the EPO+/WPO- composite):

 

[donsutherland1]

Wasn't 95-96 a nina year? We all seemed to fare well that winter from what I recall. I wonder how much the nao and epo had a role in that winter?

The EPO was neutral for the winter as a whole, with numerous negative days. The AO was predominantly negative (December, January, and March were strongly negative as a whole; February was slightly positive, on average).

[Ralph Wiggum]

Wasn't 95-96 a nina year? We all seemed to fare well that winter from what I recall. I wonder how much the nao and epo had a role in that winter?

The EPO was neutral for the winter as a whole, with numerous negative days. The AO was predominantly negative (December, January, and March were strongly negative as a whole; February was slightly positive, on average).

Thanks Don!

[PB GFI]

With respect to EPO+/WPO- combinations in December, such outcomes are not very common. Below is a table showing the frequency of WPO < 0 when the EPO is positive, the composite temperature anomalies for all December (1981-2012) dates when the EPO was positive and the WPO was negative, and the GFS ensemble 360 hour forecast (which shows the main area of cold displaced away from the CONUS and reasonably consistent with the EPO+/WPO- composite):

 

 

Don ,

 

With all the warm water south of the Aleutians does this strike you as just transient ?  The  0z Euro ensembles  takes the EPO to Nuet day 15 as well

but it still looks like all of Canada`s flow is still being seeded by the Arctic and not the PAC so it remains frigid .

 

Neither model looks good on the Atlantic side yet  , but I`m thinking there will so much NW flow just to our N that any blocking and buckling of the jet

and the cold is a stones throw away after the 20th .

[weathermedic]

Wondering why NWS hasn't issued a dense fog advisory. At least for the south shore areas of Brooklyn, Queens and Nassau. Visibility down to 1/4 mile or less.

[IsentropicLift]

Wondering why NWS hasn't issued a dense fog advisory. At least for the south shore areas of Brooklyn, Queens and Nassau. Visibility down to 1/4 mile or less.

The visibility in NNJ is pretty bad too.

[CIK62]

The visibility in NNJ is pretty bad too.

Coney Island has only a few hundred foot visibility.

[BlueSkiesFading]

Upton just issued a Dense Fog Advisory for the entire area.

[weathermedic]

Just Issued:

 

...DENSE FOG ADVISORY IN EFFECT UNTIL NOON EST TODAY...

THE NATIONAL WEATHER SERVICE IN NEW YORK HAS ISSUED A DENSE FOG
ADVISORY...WHICH IS IN EFFECT UNTIL NOON EST TODAY.

* LOCATIONS...NORTHEAST NEW JERSEY...THE LOWER HUDSON VALLEY...NEW
  YORK CITY...SOUTHERN CONNECTICUT AND LONG ISLAND.

* HAZARDS...DENSE FOG.

* VISIBILITIES...1/4 OR LESS.

* TIMING...THROUGH NOON. THE DENSE FOG MAY CONTINUE INTO THIS
  AFTERNOON AND EVENING...ESPECIALLY ACROSS COASTAL LOCATIONS.

 

[NEG NAO]

Looking ahead New AO - PNA - NAO forecast does not look good for any significant I- 95 snowstorms

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml

[bluewave]

It looks like after the cold next week that the temperatures moderate as the EPO returns to around

neutral to positive with the Pacific Jet bringing milder temperatures. Maybe we can pick up some

much needed rainfall as the big -EPO bloc relaxes and Pacific storms track across the country.

The Euro ensembles show mild Pacific air spreading across the U.S. by around day 10.

 

 

[donsutherland1]

Don ,

 

With all the warm water south of the Aleutians does this strike you as just transient ?  The  0z Euro ensembles  takes the EPO to Nuet day 15 as well

but it still looks like all of Canada`s flow is still being seeded by the Arctic and not the PAC so it remains frigid .

 

Neither model looks good on the Atlantic side yet  , but I`m thinking there will so much NW flow just to our N that any blocking and buckling of the jet

and the cold is a stones throw away after the 20th .

 

My assumption is that the EPO will probably be predominantly neutral to negative this winter and the SSTAs are a large factor. Unfortunately, there's nothing like the SAI or possibly OPI to predict the predominant seasonal state of the EPO with reasonable accuracy, so my confidence in that idea is low.

[PB GFI]

My assumption is that the EPO will probably be predominantly neutral to negative this winter and the SSTAs are a large factor. Unfortunately, there's nothing like the SAI or possibly OPI to predict the predominant seasonal state of the EPO with reasonable accuracy, so my confidence in that idea is low.

Thank you ,

[PB GFI]

It looks like after the cold next week that the temperatures moderate as the EPO returns to around

neutral to positive with the Pacific Jet bringing milder temperatures. Maybe we can pick up some

much needed rainfall as the big -EPO bloc relaxes and Pacific storms track across the country.

The Euro ensembles show mild Pacific air spreading across the U.S. by around day 10.

 

Geopotential3250032hPa32and32Temperature32at3285032hPa_North32America_168.gif

 

ECH100-240.gif

 

 As long as Canada is cold , keeps hope alive that mayb the warm ups are muted .  If week 3 relaxes thats ok , if that water stays warm in the northern PAC  then mayb we reload. Its really been 6 week period below normal , prob  overdue