Winter 2013-14 medium range discussion

[donsutherland1]

Morning Thoughts...

 

1. The latest data continues to indicate that the impressive shot of cold air could challenge record daily maximum low readings for November 24 and possibly approach or surpass the lowest daily maximum readings in November since 2000 in parts of the Mid-Atlantic and New England areas.

 

 

2. The partial teleconnection cases rolled forward indicate a cold December for the 2nd of the past 3 days. The look this morning is a thing of beauty for cold weather lovers:

 

 

3. Historical experience for years with the kind of strong cold shots that occurred in late November and is modeled for the start of December have typically seen the affected region wind up colder than normal in December.

 

All said, IMO, odds have shifted toward a colder December in large parts of the East, Ohio Valley, and Great Lakes region (historical experience + increasing tendency for cold on the partial teleconnection cases). Early month cold anomalies may be difficult to completely erase if or when a pattern shift to milder takes place.

[Srain]

A quick update from the Central/Western Region this morning:

 

The Arctic front is nearing the Texas Coast and has brought a verity of wintry weather this morning across New Mexico extending E into the TX/OK Panhandle Region as well as N Central Texas where some icing of elevated surfaces has began. Currently the main storm is rapidly deepening across Southern California and will meander E across Arizona and New Mexico on Saturday before enter Texas and developing a potentially widespread sleet and freezing rain event that is rare this early in the season. Significant sleet and freezing rain is expected to begin on Sunday as a well developed Coastal Low forms Corpus Christi and heads NE spreading abundant moisture over the very shallow Arctic air mass trapped at the surface.

 

[tacoman25]

The GFS and Euro and their ensembles are worlds apart right now past day 7-8.

[Harry]

ftp://ftp.cdc.noaa.gov/Public/gbates/teleconn/epo.reanalysis.t10trunc.1948-present.txt

when the EPO goes very negative, like it is right now,  don't expect the EPO to return to a very negative state for the next months.  -250 november 13th, I don't think you will see another -250 for the entire winter. Usually, the very negative state of the EPO can fit inside 45 days.

 

Ummm?? Did 77-78/78-79 slip on past you? And to some degree 66-67 but in the case the very negative epo did not return till March 67.. A few others ( 85-86 i believe is one and 2010-11 BUT 10-11 was a big Nina winter )  but they stand out the most..

[Chinook]

ftp://ftp.cdc.noaa.gov/Public/gbates/teleconn/epo.reanalysis.t10trunc.1948-present.txt

when the EPO goes very negative, like it is right now,  don't expect the EPO to return to a very negative state for the next months.  -250 november 13th, I don't think you will see another -250 for the entire winter. Usually, the very negative state of the EPO can fit inside 45 days.

 

The CFSv2 has a strong 500mb ridge on the Aleutians on the 6-10 day all the way to week 4 (Nov 21 run). That (-EPO) seems to be the thing that's the most consistent in recent CFSv2 weekly runs.

[QcSevereWx]

 

Did 77-78/78-79 slip on past you?

77-78,

1977 11 23 -235.56

1977 12 08 -290.86     very close to each other

1978 01 31 -194.56     but -290 was the minimum. 

1978 03 02 -257.19     but it's in march

78-79,

1978 11 20 -211.62

1979 01 07 -304.46   minimum for the winter    +-45 days between each other 11.20 01.07

1979 01 31 -181.19   

once you get -250 or lower, that's often your winter minimum. No saying it's impossible to go even lower, but less likely.

 

 

 

The CFSv2 has a strong 500mb ridge on the Aleutians on the 6-10 day all the way to week 4 (Nov 21 run). That (-EPO) seems to be the thing that's the most consistent in recent CFSv2 weekly runs.

I know the EPO is forecasted to be negative for some time, hoping to see lower numbers than -250. If we go -300, it should be before january 1st,

[Harry]

 

77-78,

1977 11 23 -235.56

1977 12 08 -290.86     very close to each other

1978 01 31 -194.56     but -290 was the minimum. 

1978 03 02 -257.19     but it's in march

78-79,

1978 11 20 -211.62

1979 01 07 -304.46   minimum for the winter    +-45 days between each other 11.20 01.07

1979 01 31 -181.19   

once you get -250 or lower, that's often your winter minimum. No saying it's impossible to go even lower, but less likely.

 

 

I know the EPO is forecasted to be negative for some time, hoping to see lower numbers than -250. If we go -300, it should be before january 1st,

 

 

Well that is going the extreme for one which will really limit your data set. Thing is those winters i pointed out did have some decent -EPO periods later on and the ones that didn't had a -QBO east ala 05-06..

 

Thing that terrifies me with going warmer is that 78-79 analog. It not only had this EPO but ala also had a insanely positive AO that Nov and was enso neutral. I doubt we see such - temp departures like we had that winter across the lower 48 but still. Ofcourse in this case the really cold stuff did not arrive till Jan. Dec actually ended up a tad above normal with temps in the OV/MA/SE states and the colder stuff ended up in the GL on west.. Something to watch for i suppose?

[QcSevereWx]

The -EPO in november is coupled with a +AO, -PNA, +NAO. They all peak at the same time. november 14-16th.

We are 1.9c above normal here in Montreal in november. I expect december to be colder and dry.

[donsutherland1]

Some quick morning thoughts...

 

1. It appears that the MET (NAM) MOS is performing better than the MAV (GFS) MOS this morning. The big question concerns this afternoon. If that trend holds up, then it's possible that the colder NAM's MOS might be a little closer to tomorrow's high temperatures in the East.

 

2. For the 3rd out of the last 4 days, the partial teleconnection analogs suggest cold in a large part of the East for December. The look on that map is fairly similar to the latest CFSv2 forecast for December.

[Damage In Tolland]

It appears December is going to be a very fun month for winter wx lovers

 

 

 

PAIN TRAIN...AK RIDGE UP TO ARCTIC CIRCLE. Very cold DEC pattern East of Rockies.

http://www.cpc.ncep.noaa.gov/products/predictions/short_range/tools/gifs/500hgt_comp_sup814.gif

www.cpc.ncep.noaa.gov

[donsutherland1]

December 2013 Idea:

 

Given the evolution of the major teleconnection indices, which offer a quick representation of the pattern (they are not a substitute to the pattern but help provide insight into it) and historic experience concerning strong cold shots in November, it appears likely that much of North America will feature a colder than normal December. Colder than normal readings are likely in such cities as Baltimore, Boston, Chicago, Cleveland, Detroit, Montreal, New York City, Ottawa, Philadelphia, Providence, Richmond, Quebec City, Toronto, and Washington, DC.

 

The most recent run of the CFSv2 shows cold anomalies that are remarkably similar to those that occurred in the December 7-8, 1989 period. The partial teleconnection cases, which are used for observing trends, show widespread cold.

 

 

In addition, since 1950, there were 7 years that featured cold shots during the 11/20-30 period of similar magnitude to what is likely to occur over the next week and then a cold December 1-10 period. All 7 years featured cold in the areas that saw a cold 11/20-30 period. The composite temperature anomalies are shown below.

 

 

Given the above data, historical cases, and extended range of the ensembles, my guess is that the eastern half of the U.S. with the exception of the Southeast and Gulf States is likely to be colder than normal for December. The Southeast and Gulf region will probably wind up with near normal readings. The western third of the U.S., including the Pacific Northwest could be warmer than normal. Most of Canada except for western/northwestern Canada will likely be colder than normal. The excepted areas could be warmer than normal. Alaska should wind up warmer than normal.

 

Even as the pattern could shift to a milder one toward mid-month if some of the ensemble guidance is correct, the cold anomalies from the first half of the month are likely to be too great to overcome in the areas noted above as likely to be colder than normal.

[tacoman25]

 

77-78,

1977 11 23 -235.56

1977 12 08 -290.86     very close to each other

1978 01 31 -194.56     but -290 was the minimum. 

1978 03 02 -257.19     but it's in march

78-79,

1978 11 20 -211.62

1979 01 07 -304.46   minimum for the winter    +-45 days between each other 11.20 01.07

1979 01 31 -181.19   

once you get -250 or lower, that's often your winter minimum. No saying it's impossible to go even lower, but less likely.

 

 

I know the EPO is forecasted to be negative for some time, hoping to see lower numbers than -250. If we go -300, it should be before january 1st,

 

 

I see what you're saying...but you don't need the EPO to go sub -250 to be a major player.

[skierinvermont]

Euro seems to have trended to a west coast trough D10.. east coast not looking too cold. 

 

Looks like there is some GEFS support. What do the Euro ensembles show?

[Jonger]

Euro seems to have trended to a west coast trough D10.. east coast not looking too cold. 

 

Looks like there is some GEFS support. What do the Euro ensembles show?

 

The GFS has a similar idea, but its more east on their depiction... Either way, it slides east almost immediately... causes a brief zonal on day 10 before a deep cold trough plants itself.

 

Looking like a very cold month.

[Wow]

Euro seems to have trended to a west coast trough D10.. east coast not looking too cold. 

 

Looks like there is some GEFS support. What do the Euro ensembles show?

 

it's transient.  You can see the ht contours tightening at the base. The ensembles have a mean trough in the middle of the US, so it a moving feature. -EPO/WPO holds.

[donsutherland1]

Euro seems to have trended to a west coast trough D10.. east coast not looking too cold. 

 

Looks like there is some GEFS support. What do the Euro ensembles show?

 

There have been indications on the ensembles and also the CFSv2 hinting at a shift toward a zonal flow as December progresses. It will be interesting to see if it is sustained or gives way to another round of cold afterward.

[Midlo Snow Maker]

Impressive temps departures this am

[JoMo]

Euro seems to have trended to a west coast trough D10.. east coast not looking too cold. 

 

Looks like there is some GEFS support. What do the Euro ensembles show?

 

00z Euro ensembles show it doesn't stick around. Overall, it's a cold look for much of the US through day 11-15 with the really cold anomalies hanging out west of the Mississippi. The coldest air by far hangs out over SW Canada and down into Montana and NW North Dakota.  Might be a small sign of a weak SE Ridge. 

[Isotherm]

Looks like the record low for NYC tomorrow morning is 19F set in 1938 (someone correct that if not). Current point and click shows 20F for Central Park. Going to be close but very impressive nonetheless.

[Harry]

Impressive temps departures this am

image.jpg

 

 

Was down to 13 this morning here vs a normal low of 27. We may not even get that high today as the temp is hanging at 23 currently which is the high so far. Normal high is 44.

 

Not close to any records though as they are -4 for the low and 9 for the record cold max which are both tied to that 1950 blast and apps bomb.

[donsutherland1]

Looks like the record low for NYC tomorrow morning is 19F set in 1938 (someone correct that if not). Current point and click shows 20F for Central Park. Going to be close but very impressive nonetheless.

Yes. That's correct.

[donsutherland1]

Record Daily Low Maximum Temperatures from 11/24:

 

Baltimore: 32° (tied record set in 1880)

Bridgeport: 31° (old record 35°, 2000)

Danbury: 28° (old record: 32°, 1970)

Islip: 31° (old record: 34°, 1989)

New York City:

...Central Park: 30° (tied record set in 1880)

...JFK: 32° (old record: 35°, 1970)

...LGA: 32° (old record: 34°, 1956)

Newark: 31° (old record: 34°, 1938)

Philadelphia: 32° (old record: 34°, 1956)

Trenton: 31° (old record: 37°, 2000)

White Plains: 29° (old record: 31°, 1972)

[Ottawa Blizzard]

Really impressive cold for late November here in Toronto. I got down to about -13 Celsius this morning. That's average for January in these parts.

[donsutherland1]

Really impressive cold for late November here in Toronto. I got down to about -13 Celsius this morning. That's average for January in these parts.

Toronto may have tied the 2005 record at Pearson Airport with a low of -12°C.

[The_Global_Warmer]

Medium to long range has been trending back to a more positive AO after this one breaks down.  it looks like December won't be starting with a negative AO. 

 

 

We will probably see this repeat most of the winter.  AO+ builds peaks crashes.  But goes right back.  For the folks along the 38-40 degrees in the Ohio Valley and Midwest.  This is a bad thing for our snow.  We will require timing and the STJ to be involved.

 

But its an even bigger killer for snow cover.  Which is at 10-15 days now if I am lucky.  And that is typically with a -AO/-NAO winter. 

 

 

I keep seeing so much glee over the Pacific.  Yeah it's cold.  Its been 10 to 20F below normal during the coldest times.  So my power bill will go through the roof and there is nothing to do outside. 

 

But mostly there is no snow?  Don't tell me it's November.  It's cold as hell.  But no one is getting snow East of the Mississippi unless you live far North.

 

The GFS snow cover on Dec 1st.  Shows the typical NE interior snow.  With snow at higher elevations as you go South of 40N.

 

But with the down-slope after these large bombs move out the Midwest snow cover gets fried off quick.  Then it feels like rinse and repeat with nothing coming out of the South.

 

As the winter goes on this situation will get warmer as well.  What has to happen for more chances of winter precip instead of useless cold.

 

[Jonger]

Medium to long range has been trending back to a more positive AO after this one breaks down.  it looks like December won't be starting with a negative AO. 

 

 

We will probably see this repeat most of the winter.  AO+ builds peaks crashes.  But goes right back.  For the folks along the 38-40 degrees in the Ohio Valley and Midwest.  This is a bad thing for our snow.  We will require timing and the STJ to be involved.

 

 

The next 10 days won't be so good for the southern posters, but that elongated trough in the west is supposed to drift east after 240hrs.

[tacoman25]

The GFS snow cover on Dec 1st.  Shows the typical NE interior snow.  With snow at higher elevations as you go South of 40N.

 

But with the down-slope after these large bombs move out the Midwest snow cover gets fried off quick.  Then it feels like rinse and repeat with nothing coming out of the South.

 

As the winter goes on this situation will get warmer as well.  What has to happen for more chances of winter precip instead of useless cold.

 

 

 

Of course snow cover in November is going to melt in the Midwest pretty easily. Why do you think "this situation" will get warmer as the winter goes on? 

 

And yes...complaining about cold without snow where you live right now is pretty silly. It's pretty rare to have as widespread of snowcover as we have right now in the U.S.

[Jonger]

Of course snow cover in November is going to melt in the Midwest pretty easily. Why do you think "this situation" will get warmer as the winter goes on?

And yes...complaining about cold without snow where you live right now is pretty silly. It's pretty rare to have as widespread of snowcover as we have right now in the U.S.

Don't waste your time with TGW

The only snow that's going to melt is in areas that have average high temps above 40 degrees still. The upper peninsula of Michigan and northern Wisconsin don't lose anything.

[donsutherland1]

Morning thoughts...

 

1. The CFSv2 December 2013 forecast continues to closely resemble the 12/7-8/1989 anomalies (#131). This outcome would be consistent with the idea of a weak southeast ridge for at least a portion of December.

 

2. The guidance continues to insist on an EPO- for the foreseeable future. The brief PNA+ pattern that is currently underway is forecast to revert back to a PNA- in coming days. Very likely the PNA will wind up negative to neutral, on average, for the winter given the PDO-. The ensembles are split in the extended range as to whether the AO will stay positive once it rises from current negative levels or whether a brief positive period would be followed by a renewed round of blocking. While at least part of December could see intervals of blocking, odds still favor a general AO+ for the winter as a whole. Hence, the recent return of AO+ for the extended range on the ensembles isn't entirely surprising.

 

3. Near the end of their forecast range, the GFS ensembles hint at another progression of an area of cold that would develop in northwestern Canada and then come south and eastward, similar to what happened with the now departing cold air mass that produced widespread record low maximum readings from the eastern Ohio Valley across the northern Mid-Atlantic region and into New England.

 

In terms of extremes, yesterday saw Mt. Washington set a record low daily maximum temperature (-4° around midnight) and minimum temperature (-15°), even as the wind was sometimes sustained at more than 100 mph. This morning saw Mt. Washington set another record low temperature of -16°.

[donsutherland1]

In Message #131, I posted my idea for December, which was that the eastern half of the U.S. with the exception of the Southeast and Gulf States is likely to be colder than normal for December. The Southeast and Gulf region will probably wind up with near normal readings. The western third of the U.S., including the Pacific Northwest could be warmer than normal. Most of Canada except for western/northwestern Canada will likely be colder than normal. The excepted areas could be warmer than normal. Alaska should wind up warmer than normal.

 

This morning's forecast shows a large split among the ensemble members as it relates to the evolution of the Arctic Oscillation (AO) in early December.

period.

 

 

I ran partial teleconnection cases, but in addition to taking an unusually wide spread for the AO members, I also ran two scenarios, one in which the AO reverts to predominantly positive values and the other in which the AO periodically returns to negative values in a back-and-forth fashion or sees the development of persistent blocking. The closest match to the first scenario was 2008. The closest matches to the second scenario were 1995, 1996, and 2010.

 

The composite maps for November and December for North America and Europe are posted below.

 

 

 

IMO, given the SAI and new OPI, something closer to the first scenario is still more likely than the second one. Hence, the idea that the Southeast and Gulf Coast likely wouldn't wind up cold, though I compromised with near normal temperatures in my December forecast, is probably not implausible. There is probably greater risk that those areas would wind up somewhat milder than normal rather than colder than normal.

 

Again, it's important to emphasize that the partial teleconnection cases do not incorporate ENSO. They are used primarily for trend analyses.