Winter 2015-2016 Medium-Term Discussion

[donsutherland1]

Don,

  Yesterday on the Weather Channel they were forecasting mild and wet in the east for Christmas week so their thoughts are similar to the GEFS for that week.

 

So far, that seems to be on course, at least with regard to the ensembles.

 

Grinch map courtesy of the 18z GFS ensembles:

[Poimen]

Don, I appreciate your posts, as always!

[donsutherland1]

Don, I appreciate your posts, as always!

Thank you.

[donsutherland1]

Though the first 10 days of December, the mild conditions would lead one to believe that the super El Niño underway has "stolen" winter. Already, the warm anomalies have been impressive, especially over the Northern Plains and parts of Canada.

 

 

Temperature anomalies for select cities (12/1-9) from the National Weather Service data are as follows:

Albany: +5.1°

Allentown: +5.6°

Atlanta: +5.3°

Baltimore: +3.6°

Bismarck: +14.1°

Boston: +5.5°

Bridgeport: +5.4°

Burlington: +5.5°

Charleston, SC: +4.7°

Chicago: +7.1°

Cleveland: +3.9°

Concord: +5.5°

Denver: +8.7°

Des Moines: +10.1°

Detroit: +3.9°

Harrisburg: +3.6°

Hartford: +4.5°

Houston: -1.8°

Islip: +5.6°

Kansas City: +7.1°

Los Angeles: +6.2°

Milwaukee: +8.4°

Minneapolis: +11.6°

Nashville: +4.1°

New York City: +6.4°

Newark, NJ: +6.1°

Norfolk: +3.7°

Orlando: +5.6°

Philadelphia: +6.2°

Phoenix: +2.6°

Pittsburgh: +3.9°

Portland, ME: +4.5°

Providence: +5.1°

Raleigh: +2.3°

Richmond: +1.9°

Savannah: +5.3°

Seattle: +7.6°

St. Louis: +5.1°

Washington, DC: +3.6°

Worcester: +6.1°

 

For the December 1-10 period, the Arctic Oscillation (AO) has averaged +1.544. For a meteorological winter average of -1.000 or below, the AO would need to average -1.314 for the remainder of winter. Currently, it is forecast to go negative in coming days. However, the ensemble guidance suggests that it could return to positive values later this month. This outcome could help limit the extent and duration of intrusions of colder air.

 

For now, even as we've progressed through the first 10% of meteorological winter, the weather seems to be stuck on autumn.

[donsutherland1]

This morning there continues to be some differences between the GFS ensembles and the operational GFS in the longer-range for the eastern U.S. As has been the case for the past two days, there remains good agreement that a large part of the western half of the CONUS and southern Canada will feature cooler than normal conditions in general. However, the ensembles continue to suggest that the eastern CONUS will remain warmer than normal, though nowhere near as warm as it will be during the next several days. On the other hand, the operational GFS shows one or two meaningful cold shots reaching the East.

 

In the longer-range, the EPO is currently forecast to shift from positive to neutral. As a result, more cold air should be able to move into a larger part of North America.

 

The latest teleconnection forecasts suggest that PNA- condtions will prevail during much of the second half of December. That outcome would favor the cold's being dumped into the West with only transient shots farther east. At the same time, the AO is forecast to go negative for a few days but then return to positive and perhaps strongly positive values.

 

This overall outcome suggests that the milder look on the ensembles for the East could be a more likely outcome than the colder ones on the operational GFS. However, the timeframe is very large, so things can still change. But right now, the kind of significant pattern change toward a sustained colder regime appears more likely to take place in the West than the East.

 

The AO forecast would be consistent with outcomes that saw more sustained blocking eventually develop in later January and then predominate in February. Interestingly enough, one of the objective analog dates from the GFS ensembles (Day 8) is 12/31/1965. Winter 1965-66 featured a strong El Niño coupled with the development of a short period of strong blocking in early January and then a strong and sustained period of blocking that lasted from 1/20 through 3/9. As the AO cannot be forecast accurately out more than a few weeks, point is that one might begin to expect more blocking than has been the case so far down the road. How much remains to be seen. A shorter-duration period of blocking similar to what occurred in 1994-95 is also plausible. Either outcome would produce more wintry weather than has been the case so far this meteorological winter.

[Isotherm]

Nice discussion, Don.

 

I wrote a new blog post:  http://www.lightinthestorm.com/archives/962

 

Strong-super El Nino conditions persist in the Pacific – and will remain that way – over the coming weeks. 850mb zonal wind anomalies are currently suggestive of more east-based forcing, as the tropical forcing pattern is once again temporarily disrupted by the development of an amplified/coherent MJO wave. This wave is forcing changes in the mid-latitude/polar jet and will result in a Southeast Asian trough and a concomitant downstream ridge over the mid-latitudes of the central-west Pacific. The development of a suppressed tropospheric Aleutian ridge is more consistent with intra-seasonal MJO forcing in La Nina’s; however, I don’t anticipate the MJO will remain coherent for a protracted period. Most model guidance prognosticates an eventual weakening of the phase 4/5 wave in a couple weeks, as 850mb zonal wind anomalies contemporaneously shift westward, retrogressing to their mean position for this El Nino. This should – in turn – cause the upper divergence cell and concomitant convection to return to the central tropical Pacific by the third/fourth weeks of December.

 

 

The expected responses to the tropospheric precursors have initiated over the past week, and are forecast to gradually become more apparent by mid-December. Specifically, the last post outlined the potential for the developing 500mb tropospheric regime to initiate wave-1 EP flux, with lower levels of wave-2 EP flux. The enhanced wave-1 is being detected in stratospheric guidance as we will see increased perturbation of the stratospheric vortex over the next week. However, the peak correlation with precursor patterns is generally 3 weeks later, and so, I continue to expect the most potent burst of wave activity flux to occur near the end of December/early January. The tropospheric pattern over the next 7-10 days continues to favor wave-1 activity, and this will be further enhanced by the development of a transient east based –NAO feature in the Atlantic. The European high heights will also aid in increased wave-2 flux as we head into mid/late December, further disturbing the vortex. Geopotential / heat flux values should spike within 1 standard deviation of the mean in mid-December, but a more significant spike should occur toward the end of the month.

 

 

However, as noted before, the primary obstacle to a favorable December pattern was the strong westerly QBO signal which retards poleward ozone transport and stratospheric Aleutian high develop. With that being said, the competing forces are such that the tropospheric conditions strongly favor enhanced energy transfer into the stratosphere, and consequently, an eventual weakening, likely displacement, of the stratospheric polar vortex in January.

 

 

Looking at prior years, the forecasted stratospheric evolution looks to be running ahead of the 1957-58 vortex split timing (which officially occurred January 30th, 1958), behind early January split/displacements, and roughly the same as the 1986-87 displacement timing (which officially occurred the third week of January). The tropospheric pattern began changing before the official date of displacement or split, however. The NAM shifted predominantly negative by the beginning of January in 1987 (3 weeks before official displacement), negative by early January 1958 (3 weeks before official split), and negative by February 1st 2007 (3 weeks before official displacement February 24th, 2007). Most events had tropospheric blocking in progress before the official date. The real key is not when the official displacement occurs, but the timing of significant stratospheric vortex / geopotential height / temperature shifts, which occur 1-3 weeks before the official event.

 

 

Thus, I anticipate that the increased wave-1/wave-2 flux will continue to gradually increase over the next few weeks. The maximum of wave activity flux anomalies should occur between the end of December and the first 10 days of January, effectively forcing the stratospheric vortex off of the pole by the middle of January.

 

Model data is beginning to detect the progression of this possible displacement event. CFS V2 weeklies for 10hpa suggest that higher than normal geopotential heights shift across the Pacific/Asian side of the pole by the first week of January. I expect that progression to continue, such that the 10hpa stratospheric vortex is displaced southward into Europe by mid January (I favor an “official” date around January 20th +/- 5 days).

 

 

Consequently, I anticipate that the stratospheric changes will fairly rapidly be realized in the troposphere, such that mid-level heights rise over the Arctic in the first week of January. The strong ridge over the Eastern US should propagate slowly poleward into Canada as the Alaskan vortex gradually retrogrades westward. Higher than normal heights should develop – particularly across the Pacific side of the pole – by early January. Thus, I anticipate a neutralization and reversal into a predominant negative modality of the northern annular mode in early January. The stratospheric vortex may remain near Greenland for 7-10 days thereafter as the potential displacement event progresses. Therefore, my best guess is that the NAO may not fully respond into a protracted negative state until the middle of January, following the AO.

 

 

As noted in the winter outlook, numerous tropospheric, boundary layer indicators were suggestive of a mean –NAO/AO modality for the DJF period. Nothing has changed on this front. I am still very confident that the reversal will occur due to the number of indicators suggestive of the same outcome. I would not be surprised to see a strongly negative AO/NAO period for at least 2-4 weeks in the mid to latter part of winter (most likely centered on the month of February).

 

 

Sensible weather translation:

 

The tropospheric weather pattern will continue to remain largely unfavorable for meaningful snow events in the coastal Northeast. The tropical forcing / MJO induced –PNA coupled with the positive AO in the means will maintain a SE-ridge, thereby making it very difficult to achieve significant snowfall. There will be a transient east based –NAO block / Scandinavian block in the December 16th-21st period. It’s possible that something minor/moderate occurs, though I wouldn’t forecast it at this time. Unfortunately, outside of the interior Northeast, it appears that the probability of a white Christmas is lower than normal this year due to the overall pattern. Of course, no guarantees can be made (there’s always a chance we get lucky with timing) but the pattern will be unsupportive of significant, 4”+ snow events through the end of December.

 

 

Early January should feature significant changes. Higher than normal heights should begin to develop across the pole, while concurrently, the positive geopotential height anomaly over the East shifts poleward into Canada. The neutralization and reversal of the NAM in early January should promote a much more seasonable pattern in the Eastern US. Recall that January was always predicted to be a near normal month temperature wise. The beginning of the month may start off quite warm. However, the pattern in the troposphere should rapidly improve through the first and second weeks. The sub-tropical jet should be more noticeable as storminess is permitted to undercut the ridge w/ the poleward propagation of positive geopotential heights.

 

In closing, everything appears to be largely on track. The month of January should be much closer to seasonable levels in the coastal Northeast, and coupled with a more active STJ, the potential will increase for wintry precipitation by early January. The “peak” of wintry weather relative to normal continues to look like the month of February. I don’t see any evidence at this point to suggest that winter should be “cancelled”, or that the original winter outlook won’t pan out.

 

 

 

January 1st, 1987 10hpa geopotential height anomalies:

January 20th, 1987, 10hpa geopotential height anomalies:

[donsutherland1]

An interesting development that could have implications for the longer-range pattern evolution...

 

From Accuweather:

 

A potent storm that will cross the Aleutian Islands of Alaska this weekend could become the strongest recorded storm to impact the region.

 

This storm comes a little over a year after ex-Super Typhoon Nuri became the most powerful system on record to cross Dutch Harbor, Alaska, which is located in the Aleutian Islands, with a central low pressure of 924 millibars (27.29 inches of Hg).

 

http://www.accuweather.com/en/weather-news/powerful-bering-sea-storm-potential-record-breaking-fairbanks-anchorage-alaska/54125652

 

The 12z ECMWF at 48 hours: 926 mb

Source: Tropicaltidbits.com

[leo2000]

An interesting development that could have implications for the longer-range pattern evolution...

 

From Accuweather:

 

A potent storm that will cross the Aleutian Islands of Alaska this weekend could become the strongest recorded storm to impact the region.

 

This storm comes a little over a year after ex-Super Typhoon Nuri became the most powerful system on record to cross Dutch Harbor, Alaska, which is located in the Aleutian Islands, with a central low pressure of 924 millibars (27.29 inches of Hg).

 

http://www.accuweather.com/en/weather-news/powerful-bering-sea-storm-potential-record-breaking-fairbanks-anchorage-alaska/54125652

What would the implications be if that does happen?.

[donsutherland1]

What would the implications be if that does happen?.

In the near to medium-term (6-14 days), one could see the storm cause the jet stream to buckle, dislodging Arctic air. Where the jet stream might buckle (Asia, Europe, North America) remains to be seen. It's plausible that a piece of Arctic air would be directed toward Asia/Europe and another piece toward North America.

 

Afterward, it could influence the evolution of the longer-term pattern. That impact is uncertain.

 

I suspect Nuri contributed to last winter's EPO- tendency. SSTAs strongly favored an EPO- state and Nuri might have been the catalyst to move toward that state. In the case of Nuri and another superstorm that affected Aleutians during 10/25-26/1977, the tendency for predominantly negative EPO values took hold roughly 30-40 days after the storms moved through the Aleutians. However, the sample size is very small. Were such an outcome to materialize, the timing would coincide closely with the timing related to the development of EPO and AO blocking during the 1965-66 El Niño.

[BuffaloWeather]

In the near to medium-term (6-14 days), one could see the storm cause the jet stream to buckle, dislodging Arctic air. Where the jet stream might buckle (Asia, Europe, North America) remains to be seen. It's plausible that a piece of Arctic air would be directed toward Asia/Europe and another piece toward North America.

 

Afterward, it could influence the evolution of the longer-term pattern. That impact is uncertain.

 

I suspect Nuri contributed to last winter's EPO- tendency. SSTAs strongly favored an EPO- state and Nuri might have been the catalyst to move toward that state. In the case of Nuri and another superstorm that affected Aleutians during 10/25-26/1977, the tendency for predominantly negative EPO values took hold roughly 30-40 days after the storms moved through the Aleutians. However, the sample size is very small. Were such an outcome to materialize, the timing would coincide closely with the timing related to the development of EPO and AO blocking during the 1965-66 El Niño.

 

November 2014 redux?

[raindancewx]

PDO crashed in November guys - much lower than last November going by JISAO.

 

http://research.jisao.washington.edu/pdo/PDO.latest

 

Oct 2014 1.49

Nov 2014 1.47

 

Oct 2015 1.72

Nov 2015 0.86

[donsutherland1]

November 2014 redux?

It's tough to say. The possibility that any cold shot into North America might have its largest effect in the western half of the CONUS with a lesser impact in the East is on the table. The potential longer-term implications for mid-January and afterward might be more important.

[leo2000]

It's tough to say. The possibility that any cold shot into North America might have its largest effect in the western half of the CONUS with a lesser impact in the East is on the table. The potential longer-term implications for mid-January and afterward might be more important.

Maybe but look what Typhoon Nuri did to the temperatures in the eastern half of the CONUS all the way down to Florida. 

 

http://boston.cbslocal.com/2014/11/06/super-typhoons-and-u-s-cold-theyre-connected/

[Met1985]

Great analysis Don and Isotherm. Really solid stuff guys.

[donsutherland1]

Maybe but look what Typhoon Nuri did to the temperatures in the eastern half of the CONUS all the way down to Florida. 

 

http://boston.cbslocal.com/2014/11/06/super-typhoons-and-u-s-cold-theyre-connected/

The 18z GFS seems to unload an Arctic air mass out west and then it spreads eastward from there. Its ensembles keep the cold bottled up in Alaska/northwestern Canada. It will certainly be interesting to see how things play out, both over the medium-term and then in January.

[1900hurricane]

Not sure this is the correct spot to post this, but that is one mean low winding up over the NPac right now.

 

[donsutherland1]

A few quick thoughts this morning...

 

1. The 12/12 0z and 6z runs of the GFS have now moved into good agreement with the ensembles over the 11-15 day period. Unfortunately, the operational model yielded to the warmer ensemble idea. If that outcome plays out, parts of the Midwest to the East Coast would have the potential to have their warmest December on record.

 

2. The Arctic Oscillation (AO) has fallen to +0.622 today. It will likely go negative in coming days. However, that period will likely be short-lived with the AO returning to values of +1 or above afterward. The PNA is forecast to be neutral to somewhat negative.

 

3. A storm impacting the Aleutians will deepen rapidly. Its long-term implications remain to be seen. But both a similar storm in late October 1977 and Nuri in 2014 led to the development of predominant EPO blocking 30-40 days afterward.

 

Overall, this kind of setup favors warm anomalies in the eastern part of the CONUS (and southern Canada) with colder anomalies in the West, when colder air moves into North America and the CONUS. If one rolls forward the trimmed objective analog pool from the GFS ensembles, it looks like parts of the Midwest, Mid-Atlantic, and New England areas will likely begin the New Year just as they ended 2015 with warmer than normal readings.

[Quixotic1]

Didn't we already have the -EPO tendency already in place before Nuri? 2013-14 had a ridiculously -EPO.

[donsutherland1]

Didn't we already have the -EPO tendency already in place before Nuri? 2013-14 had a ridiculously -EPO.

The SSTAs favored it. Nuri probably kick-started things. There's no guarantee the current storm could do so.

[Ginx snewx]

The SSTAs favored it. Nuri probably kick-started things. There's no guarantee the current storm could do so.

[donsutherland1]

December 13, 2015 saw a number of record temperatures in parts of the Middle Atlantic region.

 

Select record high temperatures included:

 

Allentown: 68° (old record: 62°, 1923)

Atlantic City: 73° (old record: 69°, 1991)

Baltimore: 72° (old record: 69°, 1889)

Bridgeport: 61° (old record: 58°, 1984)

Islip: 68° (old record: 60°, 1991)

New York City:

…Central Park: 67° (old record: 64°, 1923)

…JFK: 70° (old record: 63°, 1983)

Newark: 67° (63°, 1946)

Philadelphia: 71° (old record: 65°, 1923)

Washington, DC:

…DCA: 71° (tied old record: 71°, 1889)

…IAD: 73° (old record: 71°, 1984)

White Plains: 65° (old record: 61°, 1984)

Wilmington, DE: 67°, (old record: 64°, 1923)

 

Basking in the today’s record warmth

 

Looking ahead for the closing 10 days of December, the Arctic Oscillation, which has just gone negative for the first time this month, is forecast to rebound to strongly positive values.

 

 

The end result is that the closing part of the month will likely be warmer than normal across much of the eastern half of the CONUS and parts of Canada. The New Year could also begin on the warm side of normal. Already, the trimmed objective analog pool rolled forward from the GFS ensembles suggests a better than 2-in-3 chance that such cities as Detroit, Boston, and Washington, DC could start 2016 on a mild note.

 

However, this warm start does not mean that January should be written off immediately. The pattern forecast toward the end of the month bears some similarities to the mean pattern that prevailed during the December 29-31, 1965 period. Sustained and strong blocking developed later in January.

 

A look at the objective analog pool also finds dates from late December 1957 and early January 2007 in the mix. Winters 1957-58 and 2006-07 also featured the development of sustained blocking during the latter part of winter.

 

All of that is speculative right now, but at least there are some glimmers of hope for a more wintry type pattern at some point down the road. For now warmth predominates and many parts of the Midwest and East could see December 2015 challenge or even break the record for the warmest December on record.

 

Farther west, colder weather should be taking hold during the latter part of December. Cities such as Boise, Denver, Portland, Salt Lake City, San Francisco, and Seattle could witness colder than normal weather during the last week of the month.

[donsutherland1]

With each passing day of unseasonable warmth across much of North America, it is tempting to ask whether what seems like "endless October" will eventually yield to early spring-type weather. With the super El Niño only slowly fading from its peak and the Arctic Oscillation and Eastern Pacific Oscillation forecast to stay generally positive through the much of the rest of December, that may well seem like a reasonable question.

 

However, the case is not so clear-cut. While an exceptionally warm winter with much below normal snowfall remains among the prospects on the proverbial table, a turnaround with blocking and opportunities for at least periods of cold and snow also remain on the very same proverbial table.

 

If one takes a look at the latest GFS ensemble analog cases and selects those that featured a positive December Arctic Oscillation, one finds that 50% of those cases featured a predominantly negative Arctic Oscillation during the January 15-February 15 timeframe. Two-thirds of those cases that saw the Arctic Oscillation flip to predominantly negative occurred during El Niño winters.

 

*-through December 14.

 

In short, it's a little premature to assume that much of the U.S. will feature the noted lack of winter seen in such cases as 1997-98, 1998-99 or 2011-12. If there is a lack of sustained blocking on the ensembles as the calendar approaches mid-January, then the odds may be tilted toward a winter with the dreaded combination of excessive warmth and a significant snowfall deficit. Right now, that outcome is not cast in stone.

[ayuud11]

December 13, 2015 saw a number of record temperatures in parts of the Middle Atlantic region.

 

Select record high temperatures included:

 

Allentown: 68° (old record: 62°, 1923)

Atlantic City: 73° (old record: 69°, 1991)

Baltimore: 72° (old record: 69°, 1889)

Bridgeport: 61° (old record: 58°, 1984)

Islip: 68° (old record: 60°, 1991)

New York City:

…Central Park: 67° (old record: 64°, 1923)

…JFK: 70° (old record: 63°, 1983)

Newark: 67° (63°, 1946)

Philadelphia: 71° (old record: 65°, 1923)

Washington, DC:

…DCA: 71° (tied old record: 71°, 1889)

…IAD: 73° (old record: 71°, 1984)

White Plains: 65° (old record: 61°, 1984)

Wilmington, DE: 67°, (old record: 64°, 1923)

 

RECORD HIGH TEMPERATURES HAVE FALLEN AT ALL THREE CLIMATE SITES

IN WESTERN NEW YORK AS TEMPS CLIMBED INTO THE 60S AND LOWER 70S.

THE OLD RECORD HIGHS AT BUFFALO WERE 64F/1901...ROCHESTER

62F/1901...AND WATERTOWN 60F/1975. THE WARMEST TEMPERATURES EVER

TO OCCUR DURING METEOROLOGICAL WINTER FOR BUFFALO IS 74F

(12/3/1982) AND ROCHESTER IS ALSO 74F (1/25/1950). SINCE

1871...ONLY 7 TIMES DURING THE WINTER SEASON HAS A 70 DEGREE OR

WARMER TEMPERATURE BEEN RECORDED AT BUFFALO AND ONLY 8 TIMES AT

ROCHESTER.

[donsutherland1]

Select daily record high temperatures for December 14, 2015:

Allentown: 68° (old record: 60°, 2001)

Atlantic City: 65° (tied record: 65°, 1929)

Baltimore: 71° (tied record: 71°, 1929)

Binghamton: 61° (old record: 55°, 2006)

Bridgeport: 60° (tied record: 58°, 1991)

Buffalo: 71° (old record: 64°, 1901)

Harrisburg: 66° (old record: 64°, 1927)

Islip: 62° (tied record: 58°, 1991)

New York City:

...Central Park: 67° (tied record: 67°, 1881)

...JFK: 60° (tied record: 60°, 2001)

...LGA: 64° (old record: 63°, 2001)

Newark: 67° (old record: 63°, 2001)

Norfolk: 77° (old record: 75°, 2001)

Philadelphia: 70° (old record: 69°, 1881)

Raleigh: 75° (old record: 74°, 1918)

Richmond: 72° (old record: 71°, 2001)

Rochester: 69° (old record: 62°, 1901)

Syracuse: 66° (old record: 60°, 1975)

Washington, DC:

…IAD: 69° (old record: 67°, 2001)

Watertown: 67° (old record: 65°, 1901)

White Plains: 61° (old record: 57°, 2006)

Wilmington, DE: 69° (old record: 63°, 2001)

[winterymix]

Buffalo monthly temperature departure is +10.0.

 

The latest date on record for Buffalo to receive measurable snow is a record that has been

and continues to be shattered.

[Chambana]

Select daily record high temperatures for December 14, 2015:

Allentown: 68° (old record: 60°, 2001)

Atlantic City: 65° (tied record: 65°, 1929)

Baltimore: 71° (tied record: 71°, 1929)

Bridgeport: 58° (tied record: 58°, 1991)

Buffalo: 71° (old record: 64°, 1901)

Islip: 58° (tied record: 58°, 1991)

Newark: 64° (old record: 63°, 2001)

Philadelphia: 70° (old record: 69°, 1881)

Raleigh: 75° (old record: 74°, 1918)

Rochester: 69° (old record: 62°, 1901)

Washington, DC:

…IAD: 69° (old record: 67°, 2001)

Watertown: 67° (old record: 65°, 1901)

Wilmington, DE: 69° (old record: 63°, 2001)

Wow don, that record from 1881 that Philadelphia broke today is impressive. Always rare air (literally) when you break a 134 year old record.

[BuffaloWeather]

Buffalo monthly temperature departure is +10.0.

 

The latest date on record for Buffalo to receive measurable snow is a record that has been

and continues to be shattered.

 

BUFFALO...HIGH TEMPERATURE OF 71 SHATTERS THE OLD RECORD OF 64 SET

BACK IN 1901. THIS IS ALSO THE 2ND WARMEST DECEMBER TEMPERATURE

EVER RECORDED. THE WARMEST DECEMBER TEMP WAS 74 IN 1982.

[iceman56]

Wow don, that record from 1881 that Philadelphia broke today is impressive. Always rare air (literally) when you break a 134 year old record.

And another one fell today in Philly with 69 degrees breaking the 2008 record of 66.    Fourth record in a row, 3 days in a row of 70+ in December.

[donsutherland1]

Select record high temperatures (December 15, 2015):

Albany: 61° (tied record: 61°, 1901)

Allentown: 66° (tied record: 61°, 2008)

Bridgeport: 63° (old record: 59°, 1975)

Danbury: 65° (old record: 60°, 2008)

Islip: 62° (old record: 59°, 2008)

New Haven: 61° (old record: 60°, 1975)

New York City:

…Central Park: 68° (old record: 67°, 2008)

…JFK: 64° (old record: 61°, 2001)

Newark: 68° (old record: 67°, 2008)

Philadelphia: 69° (old record: 66°, 2008)

Pittsfield: 60° (tied record: 60°, 2008)

Poughkeepsie: 63° (tied record: 63°, 2008)

Providence: 64° (old record: 62°, 2008)

Trenton: 67° (old record: 66°, 2008)

Westhampton: 62° (old record: 59°, 2008)

White Plains: 62° (old record: 61°, 2008)

Wilmington, DE: 68° (tied record: 67°, 1971)

[donsutherland1]

The journey through Winter 2015-16 has now passed the mid-point of December. Much of North America has wandered horribly off course. Did North America lose its seasonal maps or GPS?

 

Rather than encountering the rising Arctic blasts and periodic blankets of snow typical of deepening winter, much of North America has instead found itself locked into a seemingly endless inferno relative to seasonal norms. As of December 16, cities such as Chicago, Detroit, Minneapolis, New York, and St. Louis have accumulated monthly temperature anomalies of 10° or more above normal. New York City has already shattered its December record for the most days on which the minimum temperature has remained at 50° or above. Buffalo has yet to experience a measurable snowfall.

 

Put simply, a nightmare is unfolding. A hypothetical scenario for a record-breaking El Niño (http://www.americanwx.com/bb/index.php/topic/46340-possible-strongsuper-el-ni%C3%B1o-forming/page-31#entry3660754) suggested that such a nightmare was plausible. Both the latest CFSv2 forecast for January and the January outcome from that hypothetical scenario provide little relief for those in search of winter.

 

 

The latest trimmed objective analog pool from the GFS ensembles suggest that cities such as Boston, Chicago, Detroit, New York, Philadelphia, and St. Louis have a high to very high probability of experiencing a warmer than normal January 1.

 

Some may well be tempted to write off winter even before it has had a chance to exert its influence. Yet, even as such a nightmare scenario cannot fully be dismissed (especially with the ensembles pointing to a continuation of the EPO+/AO+/PNA- teleconnection combination through the remainder of December), there remain suggestions that this nightmare can pass.

 

First, a number of El Niños (1957-58, 1965-66, and 2006-07) featured a dramatic turnaround from seemingly endless fall to winter.

 

Second, among the GFS ensembles’ objective analogs are cases from those three “turnaround” winters.

 

Third, even as it has been dented, the PDO remains positive. That scenario favors a PNA+ pattern, so it remains more likely than not that the PNA- regime will eventually yield to the return of the PNA+.

 

In short, even as Canadian and American snow geese alike have been worn down by day-after-day of unrelenting waves of warmth, there remains a reasonable prospect that Winter 2015-16 will awaken. Before then, the days ahead could bring more misery of warmth and hunger for snowfall.

 

Finally, winter is not absent from the entire continent. Alaska has been experiencing noted cold. The western third of North America is likely to experience often cooler than normal weather with prospects of above normal snowfall through much of the second half of December. In fact, the same objective analog pool suggested that Seattle had an implied 57% probability that January 1 would wind up colder than normal. In short, winter has a toehold in parts of North America. So long as all the cold is not driven to the other side of the hemisphere, there remains hope for a change, especially when the “turnaround” El Niño cases are considered. Therefore, I am not ready to "cancel" winter even as the mercury rises yet again into the balmy 50s as I post these thoughts.