Winter 2013-14 medium range discussion

[Amped]

The Stratosphere won't effect the medium range, it is fun to watch though. The PV is taking a hit from both sides on the latest EURO.

 

[Cheeznado]

Wow, check out the Op Euro. Brrrrr

[andyhb]

Forget the cold, how about that massive bomb...

[donsutherland1]

Some afternoon thoughts...

 

I hope that all who celebrate Christmas will find a KU snowstorm for sometime this season among the gifts under the Christmas Tree. For some, the snow squalls that briefly brought low visibilities and blanketed the ground in white, also brought renewed hope for the winter as a whole. Certainly, a number of cities in the northern Mid-Atlantic region(unfortunately, not the long-suffering Washington area) have enjoyed above normal snowfall to date and such snowfall in December has often been a precursor of a snowy winter.

 

The guidance continues to show a generally cold start for the first week of 2014 across a large part of the CONUS and Canada. How the Arctic Oscillation (AO) evolves could play a large role in determining whether the first week cold is an appetizer for a main course of snow and cold.

 

Currently, the GFS ensembles have two ideas. The first hints a potential period of blocking. The second shows just a brief period, at best, with the persistent AO+ regime generally holding. The former could lead to a cold January in much of Canada and the eastern half of the CONUS. The second could see a finger of cold anomalies centered farther west, perhaps somewhere in the vicinity of the Plains States and Great Lakes region. Under that scenario, storms could more readily cut for the Great Lakes. Canada would be generally cold under both scenarios. The former would also have the potential to produce more widespread cold in Europe.

 

Given the remarkable persistence of the AO+, it makes sense to hedge somewhat away from the first scenario until more data for that idea becomes available. After all, as one approached December, one saw a "false alarm" for an appreciable period of blocking for December. That idea never verified.

 

In any case, no matter the scenario that plays out, it appears unlikely that January would see almost unrelenting warmth on a coast-to-coast basis. Absent that scenario, opportunities for winter weather should be available at least from time to time.

[wildweatherman179]

Sorry to bug the northeastern states with an eastern Oklahoma question but any thoughts on what to expect through January in my neighborhood. There aren't a whole lot of people who like to engage a longer range forecast around my neck of the woods but I value donsutherland1s opinion. Thanks, that is all. Merry Christmas everybody.

[donsutherland1]

Sorry to bug the northeastern states with an eastern Oklahoma question but any thoughts on what to expect through January in my neighborhood. There aren't a whole lot of people who like to engage a longer range forecast around my neck of the woods but I value donsutherland1s opinion. Thanks, that is all. Merry Christmas everybody.

From this point out, it's still a little soon to tell with much confidence. How the AO evolves, particularly the placement of the 500 mb anomalies, will probably be key, especially as odds now favor a less negative PNA (PDO has risen quite a bit in the November data and there can sometimes be a lag from that development and the state of the PNA). The EPO will probably remain predominantly negative but perhaps less negative than it has over the past two months. Odds of a colder outcome in eastern OK are probably higher than they are in western OK, but there's a lot of uncertainty. The uncertainty there is probably greater than it is farther west and also in Canada.

[wildweatherman179]

Thanks Don. Very much appreciated. I guess I'll just be taking this winter 1 week at a time til something larger appears on the horizon. I both love and hate the pattern we are in right now. Hard to get a well-developed low around these parts. I guess I'll have to hope for some luck as well. I would be a little happier if the Alaskan ridge would shift west a little but that is probably not going to happen for awhile.

[donsutherland1]

Some morning thoughts...

 

1. The GFS ensembles have returned to showing the redevelopment of a PNA- pattern by around 240 hours. Such a pattern would lead to ridging in the East and cold shifting farther west. Subsequent GFS ensemble forecasts show a trough in the West/ridge in the East configuration.

 

2. The reforecast ensembles show a similar development.

 

3. The ECMWF ensembles are not as keen on that idea through 240 hours. Neither are the objective analogs based on the GFS ensembles.

 

No matter the outcome, a large part of the eastern CONUs except Florida and perhaps a portion of the Gulf Coast and Southeast will wind up colder than normal, on average, for the first week of January with the Great Lakes Region, Ohio Valley, northern Mid-Atlantic, New England, Ontario, and Quebec seeing perhaps a brief bout of severe cold. The GFS ensembles show a small portion of Quebec having temperatures 3 standard deviations below normal on 1/1 and a large part of the East having readings at least 1 standard deviation below normal.

[donsutherland1]

More on the Upcoming Cold Start for January...

 

This message builds on the data from Message #388.

 

First, the 12/27 12z GFS ensembles and 12/27 12z ECMWF are in good agreement that a potentially severe shot of cold will impact the Great Lakes region to the Middle Atlantic and New England areas during the 1/1-3 period. The 12/27 12z run of the GFS delays the cold shot for several days beyond either the GFS ensembles or ECWMF. Hence, I cautiously favor the GFS ensemble-ECMWF combination for the timing of the cold.

 

Second, the latest run of the GFS ensembles now shows an area of cold anomalies in a narrow portion of Quebec that is 3 or more standard deviations below normal. Below are charts for the operational GFS and temperatures for select cities relative to the standardized anomalies (this table supplements the table for a number of additional cities that was posted in Message #388.

 

 

In addition, below are the lowest temperatures forecast by the 12z run of the ECMWF for all the cities in both tables:

 

Albany: -25.4°C (-14°F)

Boston: -24.1°C (-11°F)

Burlington: -33.3°C (-28°F)

Columbus: -13.8°C (7°F)

Detroit: -16.3°C (3°F)

Montreal: -37.0°C (-35°F)

New York City: -13.0°C (9°F)

Philadelphia: -12.1°C (10°F)

Toronto: -24.4°C (-12°F)

Washington, DC: -11.0°C (12°F)

 

For perspective, the Montreal temperature would be an amazing 3.54 standard deviations below normal, if it verified. New York City would have its first single-digit low since January 24, 2011 when the mercury fell to 6°. Boston would have its first subzero low since January 24, 2011 when the temperature reached -2°. The last time Boston had a temperature of -10° or lower was January 15, 1957 when the temperature bottomed out at -12°.

 

In sum, while it remains to be seen whether the ECMWF is overdone with some of the temperatures, the agreement between the GFS ensembles and ECMWF provide some degree of confidence that a potentially severe shot of cold lies ahead and that it could produce the colder readings in some major cities than one has witnessed during the most recent winters.

[Ginx snewx]

More on the Upcoming Cold Start for January...

This message builds on the data from Message #388.

First, the 12/27 12z GFS ensembles and 12/27 12z ECMWF are in good agreement that a potentially severe shot of cold will impact the Great Lakes region to the Middle Atlantic and New England areas during the 1/1-3 period. The 12/27 12z run of the GFS delays the cold shot for several days beyond either the GFS ensembles or ECWMF. Hence, I cautiously favor the GFS ensemble-ECMWF combination for the timing of the cold.

Second, the latest run of the GFS ensembles now shows an area of cold anomalies in a narrow portion of Quebec that is 3 or more standard deviations below normal. Below are charts for the operational GFS and temperatures for select cities relative to the standardized anomalies (this table supplements the table for a number of additional cities that was posted in Message #388.

In addition, below are the lowest temperatures forecast by the 12z run of the ECMWF for all the cities in both tables:

Albany: -25.4°C (-14°F)

Boston: -24.1°C (-11°F)

Burlington: -33.3°C (-28°F)

Columbus: -13.8°C (7°F)

Detroit: -16.3°C (3°F)

Montreal: -37.0°C (-35°F)

New York City: -13.0°C (9°F)

Philadelphia: -12.1°C (10°F)

Toronto: -24.4°C (-12°F)

Washington, DC: -11.0°C (12°F)

For perspective, the Montreal temperature would be an amazing 3.54 standard deviations below normal, if it verified. New York City would have its first single-digit low since January 24, 2011 when the mercury fell to 6°. Boston would have its first subzero low since January 24, 2011 when the temperature reached -2°. The last time Boston had a temperature of -10° or lower was January 15, 1957 when the temperature bottomed out at -12°.

In sum, while it remains to be seen whether the ECMWF is overdone with some of the temperatures, the agreement between the GFS ensembles and ECMWF provide some degree of confidence that a potentially severe shot of cold lies ahead and that it could produce the colder readings in some major cities than one has witnessed during the most recent winters.

be careful with the Euro 2m temps Don they have been wacky cold. Big cold coming but have to question Euro surface low temp output based on performance up here this winter. Goes crazy in snow covered areas.

[donsutherland1]

be careful with the Euro 2m temps Don they have been wacky cold. Big cold coming but have to question Euro surface low temp output based on performance up here this winter. Goes crazy in snow covered areas.

I agree with you and suspect that at least in parts of the Northeast those numbers may be overdone.

[donsutherland1]

January 8-15, 2014 Thoughts

 

After a cold first week of January, highlighted by a bout of severe cold, along with at least some accumulating snow across parts of the eastern CONUS, the pattern appears poised to see the cold anomalies shift westward. There had been some question about the PNA, with the GFS ensembles having reverted back to a primarily negative PNA after having forecast a positive PNA for several runs. Overnight, the ECMWF ensembles yielded and they now forecast a PNA- developing by 240 hours. Both sets of ensembles shift the coldest anomalies westward, as well. Nevertheless, the ensembles have maintained good run-to-run continuity on the idea of an EPO-/AO-. This could become important beyond mid-month.

 

Below are charts showing cold/warm anomalies based on the forecast teleconnections and the NAEFS. A positive PNA would have led to the cold's being centered farther east.

 

 

What's interesting among the teleconnection dates is that January 13-16, 1994 and January 11-15, 2013 are among them. In both cases, the cold again came eastward, so that will be something to watch for. If so, the period of moderation could be temporary. More data will be required, but what appears likely is that moderation won't mean that winter is finished even if the milder temperatures might tempt one in that direction.

 

In terms of outcomes, I expect the Northern and Central Plains, along with much of Canada to turn out colder than normal. The Mid-Atlantic, Southeast and Gulf Coast should be warmer than normal. The Southwest could also be near normal to somewhat warmer than normal. New England and the Pacific Northwest will probably be near normal.

[Srain]

Don, we in the Western/Central region are carefully watching the telecommunication indices as they are very similar to what we experienced in the late November/early to mid December time frame where temperature departures in the -10 to -20 range were common across the Great Basin/Inter Mountain West and the Plains extending well south in to Northern Mexico and Texas. The wild cards appear to be just how negative the AO will actually drop as well as the appearance of tropical convection near the dateline. Heights remain rather elevated across the North Pacific/Gulf of Alaska where current SST values remain very high. It appears that temperature departures for the month of December will end up below normal and there is a chance that DFW will tie a record set in 1989 with a total of freezing days at or near 23 which is rather impressive. It will be interesting to see if this pattern change is transient, or if it signal of a return to a more prolonged cold and stormy regime with an active sub tropical jet and strong, slow moving 5H lows dropping well S into Northern Mexico and tapping into that Pacific moisture with cold air in place at the surface as a general trough pattern returns to the Western 2/3rds of North America.

[Ottawa Blizzard]

Here is JB's Saturday discussion video from the Weatherbell free site. He appears to be calling for a similar pattern to January 1994 in eastern North America. It's an interesting video.

 

http://www.weatherbell.com/saturday-summary-december-28-2013

[donsutherland1]

Don, we in the Western/Central region are carefully watching the telecommunication indices as they are very similar to what we experienced in the late November/early to mid December time frame where temperature departures in the -10 to -20 range were common across the Great Basin/Inter Mountain West and the Plains extending well south in to Northern Mexico and Texas. The wild cards appear to be just how negative the AO will actually drop as well as the appearance of tropical convection near the dateline. Heights remain rather elevated across the North Pacific/Gulf of Alaska where current SST values remain very high. It appears that temperature departures for the month of December will end up below normal and there is a chance that DFW will tie a record set in 1989 with a total of freezing days at or near 23 which is rather impressive. It will be interesting to see if this pattern change is transient, or if it signal of a return to a more prolonged cold and stormy regime with an active sub tropical jet and strong, slow moving 5H lows dropping well S into Northern Mexico and tapping into that Pacific moisture with cold air in place at the surface as a general trough pattern returns to the Western 2/3rds of North America.

it will be interesting to see if we have at least a mini-episode of what happened from late November into December. There's a lot of uncertainty. Hopefully, in coming days, the ensembles will paint a clearer picture.

[donsutherland1]

Morning thoughts...

 

1. A bout of severe cold for the Great Lakes, Ohio Valley, Mid-Atlantic, New England, Ontario, and Quebec is now a high confidence idea. The ensembles have maintained the idea of a broad area of cold 1-2 standard deviations below normal with a small area of 3 standard deviations below normal during the first week of January.

 

The idea of a subzero low in Boston and single-digit reading in New York City is a growing possibility. The last time that happened in both cities was January 24, 2011. Already, the GFS MOS shows a low of 12° in NYC and 6° in Boston. It also shows low temperatures of -4° in Albany, -9° in Burlington, 12° in Columbus, 7° in Detroit, -27°C (-17°F) in Montreal, 14° in Philadelphia, and -19°C (-2°F) in Toronto.

 

2. Ahead of the Arctic front a Miller B-type system will likely form somewhere off the Mid-Atlantic Coast with a primary system moving into the Ohio Valley. Climatology and the ECMWF, which with its higher resolution should have a better idea of what is a complex set of variables in a fast flow, both favor a higher impact on some portion of New England than the Mid-Atlantic. There remains a lot of uncertainty, but at least some accumulations appear possible from Philadelphia to New England.

 

3. Some guidance features a second shot of cold, perhaps behind another period of snow, toward the end of the first week in January.

 

4. In the longer-range, the coldest anomalies could shift westward some time after the first week in January for a time.

[Amped]

Modles certainly have switch to a colder look in the 2nd week of January.

[donsutherland1]

January 2014 Thoughts:

 

There have been some winters where extremes in one or another teleconnection largely shaped the predominant pattern. For example, extreme blocking during winters 2009-10 and 2010-11 led to cold and snowy outcomes across parts of North America, in the former case during an El Niño and in latter with a La Niña. Since late autumn, it has been the negative to strongly negative EPO that has largely shaped the outcomes.

 

My assumption has been that the EPO would be generally negative or neutral for the winter as a whole and I have little reason to see any radical shifts in the EPO’s tendency for negative values to date through much of January. At the same time, a period of sustained blocking (AO) now appears likely for at least a part of January. In fact, it is plausible that the monthly average could be somewhat negative even if positive values return at some point.

 

The outcome of such a combination would be cold across much of Canada and probably the eastern third to half of the CONUS. An exception would be Florida, parts of the Southeast, and the Gulf Coast, unless blocking is deeper or more sustained than what I assume will be the case.

 

Below are charts for the teleconnections as I see them for January (EPO: -1.75 to +0.25; AO -2.5 to +0.5; PNA: -0.5 to +0.3). I also produced a map using the teleconnections excluding the EPO just to illustrate the importance of the negative EPO this time around. The last chart is the latest CFSv2 forecast. The CFSv2 is now in the skillful range of its monthly forecasts.

 

 

Overall, I expect the following:

 

Canada: Colder than normal, except northwestern Canada and parts of Atlantic Canada. The severe to extreme cold that will impact Quebec and New Brunswick should assure negative temperature anomalies there even if blocking eventually leads to some warming across northern Quebec, Labrador and Atlantic Canada.

 

Great Lakes, Northern Plains, Central Plains, Ohio Valley, New England, Mid-Atlantic region: Colder than normal, with the coldest anomalies probably centered from the Northern Plains, across the Upstate New York, and northern New England.

 

Southern Plains: Somewhat cooler than normal to near normal

 

Southeast, Gulf Coast: Somewhat warmer than normal to warmer than normal.

 

Southwest and Pacific Northwest: Near normal to somewhat warmer than normal

[Hoosier]

Don, the 12z Euro has a pretty barbaric cold shot into the northern tier at 192 hours and beyond.  Do you think something that extreme is on the table?

[Harry]

Don, the 12z Euro has a pretty barbaric cold shot into the northern tier at 192 hours and beyond.  Do you think something that extreme is on the table?

 

That would be brutal.  Have never seen 850s drop to -33 and the PV waving at me imby which the 12z showed.

[Hoosier]

That would be brutal.  Have never seen 850s drop to -33 and the PV waving at me imby which the 12z showed.

 

 

You haven't seen it since you've lived there but something like that has happened before.  A Euro type solution is one of those things that would be talked about years if not decades from now.  Thing is, the 12z GFS wasn't too far behind in its depiction.

[Harry]

You haven't seen it since you've lived there but something like that has happened before.  A Euro type solution is one of those things that would be talked about years if not decades from now.  Thing is, the 12z GFS wasn't too far behind in its depiction.

 

 

Correct.. I believe Jan 2009 would be the closest i have seen here and with that the temp did manage to get down to -18 which is very hard to do with the lake nearby..

[Hoosier]

Correct.. I believe Jan 2009 would be the closest i have seen here and with that the temp did manage to get down to -18 which is very hard to do with the lake nearby..

 

 

January 2009 performed very well considering the temps aloft.  850's were pretty cold but much warmer than what the Euro is advertising for next week.

[Ottawa Blizzard]

Don, the 12z Euro has a pretty barbaric cold shot into the northern tier at 192 hours and beyond.  Do you think something that extreme is on the table?

JB was tweeting about that today. He says it looks similar to the cold shot of January 1994. A stopped clock is right twice. Perhaps this will be one of those instances where he is right? It would be something if Lake Ontario could perhaps 50-75% freeze over.

[Harry]

January 2009 performed very well considering the temps aloft.  850's were pretty cold but much warmer than what the Euro is advertising for next week.

 

Yeah the winds actually turned to the sw/ssw very briefly and brought up some of the really cold stuff from down your way ( pushed the lake stuff away too ) and then they went calm. IF the PV ended up where the euro showed it the winds would have a much harder time doing that and thus would remain west which could limit how cold it gets here. It is actually a awesome LES set up for here BUT with one HUGE exception and thus the cold which would kill the flake size..

[donsutherland1]

Don, the 12z Euro has a pretty barbaric cold shot into the northern tier at 192 hours and beyond.  Do you think something that extreme is on the table?

I suspect that the ECMWF might be a bit overdone, but given the ensemble runs in recent days, it wouldn't surprise me Lafayette sees at least a day with highs below 20° and a low temperature in the single digits to perhaps even below zero.

 

Note: This concerns the first shot of cold. The second shot seems even more dramatic on the Euro, but I want to see how things look a few more days down the road before commenting on that shot.

[Jonger]

You haven't seen it since you've lived there but something like that has happened before.  A Euro type solution is one of those things that would be talked about years if not decades from now.  Thing is, the 12z GFS wasn't too far behind in its depiction.

 

Lake Michigan hasn't froze over since 1979.... I'm really wondering if this year might break that streak. One or two nights of the euro cold depiction and we could see a lake wide glaze over.

[Ottawa Blizzard]

Lake Michigan hasn't froze over since 1979.... I'm really wondering if this year might break that streak. One or two nights of the euro cold depiction and we could see a lake wide glaze over.

Michigan didn't freeze in January 1994?

[roardog]

Lake Michigan hasn't froze over since 1979.... I'm really wondering if this year might break that streak. One or two nights of the euro cold depiction and we could see a lake wide glaze over.

i thought the lake froze over in 02-03?

[mnweather]

According to Environment Canada and the U.S. National Weather Service, Lake Michigan ice coverage reached 90 percent to 95 percent in the winters of 1903-04, 1976-77 and 1978-79.

Data indicate that three of the Great Lakes (Superior, Huron and Erie) have totally frozen over in a few of the very harshest winters since 1900, but Michigan and Ontario have never achieved complete ice coverage.