Medium Range Discussion Winter 2011-12

[donsutherland1]

Below is, among other things, a composite chart showing analogs based on an AO in the +1 to +3 rangem PNA in the -0.50 to +0.50 range, and ENSO R3.4 anomalies in the -1.50 to -0.75 range for the 1/1-10 timeframe (1950-2011).

Below is a chart that reflects a PNA in the +0.5 to +1.5 range (now likely for the first week in January). All other factors remain the same.

As a result, my initial thinking is likely to be wrong. The first 1-3 days could still start somewhat mild, but a push of cold is likely to assure that overall anomalies in the eastern third to half of the CONUS will likely wind up cooler than normal. The recent expansion of a pool of cold anomalies in the Arctic (past week) suggests that the cold air mass might be sufficient to result in temperatures falling into the low 20s or even teens from Washington, DC northward at some point during the push of cold air.

Afterward, once the PNA declines, the cold could moderate and milder readings could again return. It's a little soon to speculate on that timing, but it could occur during the second week in January unless the PNA stays elevated, the AO becomes negative, and/or the EPO becomes negative.

[usedtobe]

Don, my guess is we still average above normal for the month though we certainly will have an arctic shot that we'll need to cancel out later in the month, that's always a dicey deal as most skill is early in any monthly outlook.

[donsutherland1]

Don, my guess is we still average above normal for the month though we certainly will have an arctic shot that we'll need to cancel out later in the month, that's always a dicey deal as most skill is early in any monthly outlook.

I agree with you, Wes. It will be interesting to see how things evolve. Hopefully, there will be some snowfall opportunities before the colder air departs.

[Neblizzard]

I agree with you, Wes. It will be interesting to see how things evolve. Hopefully, there will be some snowfall opportunities before the colder air departs.

Don as always great write up. If the ensembles in the long range are on to something, mid January and beyond may prove to be quite cold and potentially stormy. The trends are for the AO and NAO to decline over the next 2 weeks so we shall see...good luck with your forecast...

[winter_warlock]

I agree with you, Wes. It will be interesting to see how things evolve. Hopefully, there will be some snowfall opportunities before the colder air departs.

i agree, i hope this isnt one of those years where we always get the storms coming AFTER the cold air departs.

[Ed Lizard]

Pro-met on the local KHOU-TV 11 forum who has access to the Euro weeklies seems to be suggesting really cold air in Canada doesn't develop until the end of the month, and most/all of January is normal to slightly above normal temperature wise for much of the country.

Just a taste of what WxMan57 posted...

Week 4 (Jan 17-23)

Surface temps 4F above normal across SE TX and 6-8F above normal across most of the central and northern U.S. east of the Rockies through the Ohio Valley. Temps in western and NW Canada dropping to 2-4F below normal.

[bluewave]

One of the warmest looking Euro forecasts that I have seen in a while for January.

[usedtobe]

One of the warmest January runs of the Euro that I have seen in a while.

The GFS ensemble mean also looks pretty nasty in the longer ranges shifting the ridge back in the pacific and dropping heights over the southwest at least twice during the run. Hopefully the runs will be as bad as the euro faux snowstorm runs.

[ORH_wxman]

The GFS ensemble mean also looks pretty nasty in the longer ranges shifting the ridge back in the pacific and dropping heights over the southwest at least twice during the run. Hopefully the runs will be as bad as the euro faux snowstorm runs.

I think its going to be pretty warm in the Jan 7-10 time frame...there is good ensembles support for a warmup there. How intense it is remains to be seen. Euro ensembles showed a possible large scale change in the PAC...particularly EPO region after Jan 10th, but they often like to rush large scale changes so I won't be surprised if its more like a week later if it happens at all. Its been showing up the last several runs, so there is a bit of reason for some optimism on that front...but I think the warmup between 1/7 and 1/10 is real.

[usedtobe]

I think its going to be pretty warm in the Jan 7-10 time frame...there is good ensembles support for a warmup there. How intense it is remains to be seen. Euro ensembles showed a possible large scale change in the PAC...particularly EPO region after Jan 10th, but they often like to rush large scale changes so I won't be surprised if its more like a week later if it happens at all. Its been showing up the last several runs, so there is a bit of reason for some optimism on that front...but I think the warmup between 1/7 and 1/10 is real.

Let's hope because even after Jan 10, the gfs ens mean shows another warm look at the edn of the run, luckily it's so far out it is probably a fantasy (I hope). I'm not ready to jump on any pattern change. Right now it will almost have to hit me in the face before I'll bite.

[ORH_wxman]

Let's hope because even after Jan 10, the gfs ens mean shows another warm look at the edn of the run, luckily it's so far out it is probably a fantasy (I hope). I'm not ready to jump on any pattern change. Right now it will almost have to hit me in the face before I'll bite.

There is still a huge vortex over Baffin Island in the LR EC ensembles so even with a PAC shift, it would probably favor cold more in the northern tier with the -EPO/+NAO look...esp upper plains....but given the time range, I agree that jumping on any pattern change yet would be premature. I think the tendency for ensembles to rush such things makes me think we'll make it to Jan 15th with the current regime in the high latitudes.

[donsutherland1]

Even as the rise in the PNA has led to a situation that the East will likely wind up colder than normal during the first week in January, the overall pattern remains essentially similar to that which has been responsible for December's warmth. The AO remains generally positive. The EPO remains generally positive. The PNA is forecast to decline to neutral and then negative levels.

As a result, the upcoming fairly sharp shot of cold is likely to be an island of chill in a sea of warmth. In fact, the opening day of 2012 could see much above normal readings in many of the big cities in the East. It will likely be enough to tip the average to colder than normal in the East for the first week in January. But once the cold recedes, milder weather could again prevail, especially if the ensemble forecast for the teleconnection indices is reasonably accurate.

Below is the composite temperature anomaly map for all cases in the January 5-20 period (1950-2011) during which the ENSO Region 3.4 anomaly was -1.50°C to -0.70°C, the AO was 0 to +2.00, and the PNA was -1.00 to +0.50:

Had the PNA not risen above +0.5 approaching the upcoming week, that kind of pattern would likely have prevailed. However, it has risen to > +0.8 (new index) and that has contributed to a discharge of colder air that will likely send minimum temperatures into the teens in Boston, New York, Philadelphia, and perhaps even Washington, DC during the upcoming cold shot.

Finally, the near absence of snowfall in December is reinforcing the signal for a below to much below average snowfall in the major cities of the East Coast this winter.

[ayuud]

hey don thanks for your updates,are you seeing any hints of a pattern change in the long range?

[donsutherland1]

hey don thanks for your updates,are you seeing any hints of a pattern change in the long range?

Unfortunately, not yet. The failure of an Sudden Stratospheric Warming (SSW) event to develop reinforces the idea of the AO will likely remain predominantly positive for quite some time. There are hints that the PNA will shift to a primarily negative regime promoting the tendency for a trough in the west/ridge in the east. I still don't believe January will be as warm, relative to normal, as December.

[Ottawa Blizzard]

Don, you mentioned 1975-76. January 1976 was pretty cold in Ontario and Quebec I believe. Even Toronto saw -30C without the wind.

[donsutherland1]

Don, you mentioned 1975-76. January 1976 was pretty cold in Ontario and Quebec I believe. Even Toronto saw -30C without the wind.

Ottawa Blizzard,

1975-76 is only an example of La Niña winter that saw its coldest readings in January. I don't believe Winter 2011-12 will feature the kind of cold witnessed in January 1976, but January 2012 could be the closest to normal for the three winter months depending on how the La Niña continues to evolve. I believe January 2012 will wind up milder than normal in a large part of eastern North America (Toronto is included), though it won't be as mild as December 2011 has been.

[Chinook]

La Nina my foot! What kind of La Nina is this? By the way, I am not complaining! Because, of all people on this board, winter has hit me!

[nzucker]

The pattern for November/December 2011 almost looks Niño like with the cool anomalies in the Southwest/California and near average temperatures in the Gulf Coast. This is also reminiscent of the torch strong Niña winters like 98-99 and 99-00 where a large +EPO prevented any cold air from moving into the Northern Tier.

[Kevin Druff]

This weather is ****ing depressing as hell.

[Feb]

Even as the rise in the PNA has led to a situation that the East will likely wind up colder than normal during the first week in January, the overall pattern remains essentially similar to that which has been responsible for December's warmth. The AO remains generally positive. The EPO remains generally positive. The PNA is forecast to decline to neutral and then negative levels.

As a result, the upcoming fairly sharp shot of cold is likely to be an island of chill in a sea of warmth. In fact, the opening day of 2012 could see much above normal readings in many of the big cities in the East. It will likely be enough to tip the average to colder than normal in the East for the first week in January. But once the cold recedes, milder weather could again prevail, especially if the ensemble forecast for the teleconnection indices is reasonably accurate.

Below is the composite temperature anomaly map for all cases in the January 5-20 period (1950-2011) during which the ENSO Region 3.4 anomaly was -1.50°C to -0.70°C, the AO was 0 to +2.00, and the PNA was -1.00 to +0.50:

Had the PNA not risen above +0.5 approaching the upcoming week, that kind of pattern would likely have prevailed. However, it has risen to > +0.8 (new index) and that has contributed to a discharge of colder air that will likely send minimum temperatures into the teens in Boston, New York, Philadelphia, and perhaps even Washington, DC during the upcoming cold shot.

Finally, the near absence of snowfall in December is reinforcing the signal for a below to much below average snowfall in the major cities of the East Coast this winter.

Sorry Don but your posts of late remind me of the movie Groundhog Day. Same thing, over and over.

[donsutherland1]

Sorry Don but your posts of late remind me of the movie Groundhog Day. Same thing, over and over.

I hope things change and soon.

[Feb]

I hope things change and soon.

I believe the last two weeks of January and most of February will see a big turn around here in the east. I believe you are in the warm camp for February but i believe February could actually be a very cold and stormy. Of course if i'm wrong, this winter will have been one of the biggest duds in history for the east.

[QVectorman]

Since we have been stuck in phase 4 and 5 but mainly 5 of MJO for the month of December it matches up pretty well to the typical anomalies for phase 5. I believe there are other forces at work here besides the MJO and if this is coincidence or not or if the MJO is the dominate factor maybe someone else could chime in.

[usedtobe]

Since we have been stuck in phase 4 and 5 but mainly 5 of MJO for the month of December it matches up pretty well to the typical anomalies for phase 5. I believe there are other forces at work here besides the MJO and if this is coincidence or not or if the MJO is the dominate factor maybe someone else could chime in.

If you do the same kind of composite for a positive AO you get the same signature as you do with a positive west Pacific Oscillation index pattern. I certainly think the mjo being in phase 5 hurt us but also think the positive Ao was big factor.

[QVectorman]

Ya I was looking at that but the MJO phase 5 for DJF matches much more nicely than the +AO or even AO comparing the coolness in the West inching into Texas and then the hot spots in MN and ME, IMHO

[nzucker]

Ya I was looking at that but the MJO phase 5 for DJF matches much more nicely than the +AO or even AO comparing the coolness in the West inching into Texas, IMHO

Yeah I think the ridging so far west in the Pacific associated with the MJO-driven convection patterns (Phase 5) is allowing somewhat of a split jet with pieces breaking off and forming cut-off lows in the Southwest, keeping that region cooler than normal.

[BethesdaWX]

I believe the last two weeks of January and most of February will see a big turn around here in the east. I believe you are in the warm camp for February but i believe February could actually be a very cold and stormy. Of course if i'm wrong, this winter will have been one of the biggest duds in history for the east.

Based on? I would love for that to be true but I can't think of anything that could topple the vortex that soon, those things lock in for awhile but seeing the Pacific ridge coming in more amplified in the long range is a good sign if it isn't a false alarm.

I still wager 1967/68 and 2006/07 as the perfect analog blend.

[Coach McGuirk]

Looks like a brief cold, dry period from Tuesday to Thursday then it warms up again. Typical La Nina winter. At 144 hrs, the GFS has 10 C+ 850s all the way into Minnesota and northern Wisconsin. That's pretty anomalous.

[donsutherland1]

Courtesy of the general AO+ regime and MJO, winter has started off on an unusually mild note in the East. On account, when it comes to some flowering plants, fall has apparently given way to spring in terms of their flowering. From today's edition of The Washington Post:

What began as elevated temperatures at the start of fall in parts of the United States have become “dramatically” warmer around the Great Lakes and New England, according to Deke Arndt, chief of the Climate Monitoring Branch at the National Oceanic and Atmospheric Administration’s National Climatic Data Center. And in the Washington area, the region is on track for its fourth-warmest year on record, along with its seventh-warmest December.

That, in turn, has created conditions in which plants are blooming earlier and some birds are lingering before moving south.

http://www.washingtonpost.com/national/health-science/mild-weather-redefines-winter-landscape/2011/12/29/gIQAPV8vQP_story.html

For what it is worth, in Winter 2006-07, cherry blossoms burst into bloom in Boston's Public Garden in early January and bees were seen feeding on Central Park's cherry blossoms. So, such premature flowering is not unprecedented.

[winterymix]

Courtesy of the general AO+ regime and MJO, winter has started off on an unusually mild note in the East.

Happy, healthy New Year to you and yours, Don S.

The MJO is trundling into phase six.

http://www.cpc.ncep....O/whindex.shtml

If this trend continues, I wonder if the MA and SNE could enjoy some actual winter, perhaps three to five weeks from now.

Don, do you have any sense or feel for the AO trending neutral or mildly negative at that time based

upon analogs of long duration AO indices during La Nina?

It appears that the GFS ensembles are attempting to depict an east-based (-) NAO along with a mild

attempt at a split flow (notice the change in the Pacific flow west of California) but these seem to be anemic attempts

to jump start winter in the East; still no assertive cold airmass for the East.