2013 Fall Medium Range Discussion

[donsutherland1]

Near Year-End Wrapup...

A brutally warm year for North America is coming to a close. December has already produced some winter highlights in the Plains States, Midwest, and portions of Quebec. Madison and Montreal were among the cities receiving substantial snowfalls. A storm is currently poised to bring a moderate to locally significant snowfall to portions of New England.

Looking ahead, the PNA is continuing to rise. The long anticipated Arctic outbreak appears likely to occur during the first week in January. Ahead of the Arctic outbreak, some snow flurries and snow showers might occur, but a big storm probably won't.

Portions of southern Canada and the eastern half of the U.S. will likely see their coldest readings of the winter so far. Some areas, perhaps including New York City, Albany, and Ottawa could see their coldest temperatures since Winter 2010-11. A subzero low in Albany and single-digit low in New York City (even with little or no snow cover) remain on the table.

However, after the Arctic outbreak, with the Arctic Oscillation likely to go positive and the EPO also likely to become positive, a period of moderation is likely to unfold, beginning in the Plains States and than spreading eastward. Unlike last winter, it does not appear that a bout of exceptional warmth is underway. More importantly, it is likely that this will be the kind of moderation that lasts about two weeks. Hence, winter will not come to an end. Moreover, January is likely to have cold monthly anomalies for perhaps the eastern two thirds of the U.S., as well as southern Ontario and southern Quebec.

Finally, the upcoming storm should not be viewed as a missed opportunity for snowfall from which lightly or non-impacted regions cannot recover. It is not a final verdict that Winter 2012-13 will continue the misery of a general absence of snowfall in those regions e.g., the Mid-Atlantic where the last snowy winter was 2009-10. There will be more opportunities for snowfall and analog cases continue to suggest that a KU-type snowstorm is not out of the question before the winter is completed.

[Chicago WX]

Don, always appreciate your thoughts and analysis.

Interesting tidbit from here in the Midwest. Indianapolis IN and Madison WI are both having a top 10 snowiest December on record (currently 9th place for both)...despite the overall very warm December temperatures. A tale of two halves to be sure.

December average temperatures and departures:

IND through yesterday: 39.7º +7.8º

MSN through yesterday: 31.0º +7.6º

Top 10 snowiest Decembers (records since 1884 for both):

Indianapolis

27.5" in 1973

21.5" in 1895

16.6" in 2010

16.3" in 2000

15.6" in 1981

15.2" in 1977

14.6" in 1996

14.1" in 2005

14.0" in 2012

13.1" in 1915, 2004

Madison

40.4" in 2008

35.0" in 2000

33.5" in 2007

32.8" in 1987

26.8" in 2009

24.6" in 1977

24.0" in 1985

23.9" in 1887

23.3" in 2012

23.1" in 1909

EDIT: it appears that Green Bay WI is 0.1" shy of 10th place on their snowiest December on record as well.

[The_Global_Warmer]

Shows how marginal the cold has been, even with the 'change'. Can't kill the 1-20 nightmare.

STL is averaging 42.8F and that is 7.8F above normal through the 28th

forecast calls for -4, -3, +2 the rest of the month.

So we will actually finish December like 42.0F or so and be warmer than last year. Which was 40.8F

42.0F was the 8th warmest on record.

[tacoman25]

Shows how marginal the cold has been, even with the 'change'. Can't kill the 1-20 nightmare.

The last week has been pretty chilly for much of the country, and that was without real favorable blocking. If everything comes together next month, look out.

[Ottawa Blizzard]

18z GFS looked quite mild in the long range and not as severe with the New Years cold shot.

[WEATHER53]

DC area will not be receiving any arctic outbreak. 3-5 days of highs in the 30's and lows in the 20's is Arctic Not.

[Ottawa Blizzard]

0z GFS continues its major backing off of the severe cold threat for southern Ontario. Even for Toronto, highs in the low 20s does not constitute severe cold. I was hoping for something along the lines of January 2 of this past year, when midday temperatures were around -15C/2F.

[Ottawa Blizzard]

I'm wondering if this winter could turn out similar to 1996-97? That year had a cold November and a mild December which turned around just after Christmas (in Ontario and Quebec that is). There was even a Boxing Day storm for Toronto that year.

[tacoman25]

I don't think the real severe cold will make it to most of the East until late January and February. Current pattern analogs suggest a major cold air outbreak or two is possible from Jan 10-20 in the West/Central part of the country, and then the cold shifts east...with possibly a very cold February.

[thenewbigmack]

I don't think the real severe cold will make it to most of the East until late January and February. Current pattern analogs suggest a major cold air outbreak or two is possible from Jan 10-20 in the West/Central part of the country, and then the cold shifts east...with possibly a very cold February.

Which pattern analogs are you referring to? Thanks!

[QcSevereWx]

No. Montreal saw 45cm of snow in one day, on top of what they already received earlier in the month. It's the greatest one day snowfall in Montreal's recorded weather history, and that's saying something!

In 24h... it started around 3-4am, and by 5pm, it stopped. So it's 45cm in +-12hrs. It was bad, but not as bad as the 2008 March 8-9th blizzard.

http://meteocentre.c...&MIN=00〈=fr

to

http://meteocentre.c...&MIN=00〈=fr

[Ottawa Blizzard]

The 6z GFS depicts a torch for pretty much all of southern Canada and the US.

[cbmclean]

I don't post much, as I am just an interested layman. I don't even consider myself knowledgable enough to be a "weenie". However there is something about which I am curious. This thread is devoted to prediction in the 7-30 day time frame. Exactly what is the state of numerical weather prediction in that time frame? If I were to ask you to predict the average temperature at any given location over a 24 day period from 7 to 30 days in the future, how much closer would you expect to be than climatology? Does it vary with location? With time of year? With general weather pattern (ie is skill higher in a strong El Nino or La Nina year)?

[skierinvermont]

I don't post much, as I am just an interested layman. I don't even consider myself knowledgable enough to be a "weenie". However there is something about which I am curious. This thread is devoted to prediction in the 7-30 day time frame. Exactly what is the state of numerical weather prediction in that time frame? If I were to ask you to predict the average temperature at any given location over a 24 day period from 7 to 30 days in the future, how much closer would you expect to be than climatology? Does it vary with location? With time of year? With general weather pattern (ie is skill higher in a strong El Nino or La Nina year)?

Take a look at the monthly temp prediction thread which has guesses from amateurs and some more knowledgeable people alike. Some people have been significantly better than climo for several years.

[donsutherland1]

Some morning thoughts...

1.. Although the PNA went positive, my idea concerning an Arctic blast prior to the moderation that lies ahead will prove incorrect, even as the colder period has worked out.

2. The moderation is likely to be temporary (already there is a strong ensemble signal that the Arctic Oscillation, after going positive in the near-term could go negative by the end of the extended range). Some guidance also suggests a negative EPO by the end of the extended range, but there is more uncertainty.

With the warmest year since recordkeeping began in the CONUS now in the past, rather than reflecting back at the misery that year inflicted on snow geese, I will share a passage that was written by a woman from Monroe, Virginia following the wild, wintry weather of December 1839:

Never before did winter visit this sunny valley in such wrathful mood. He raved and roared, as from his chariot of the storm, he showered down snow and hail, and icicles, amid the shivering forests, which bent and bowed before his hurricane flight, as if but just broke loose from his drear arctic regions.

Once the cold returns, may winter "rave and roar" in its best fashion, showering down the snow in great abundance.

Happy New Year to all.

[uncle W]

Some morning thoughts...

1.. Although the PNA went positive, my idea concerning an Arctic blast prior to the moderation that lies ahead will prove incorrect, even as the colder period has worked out.

2. The moderation is likely to be temporary (already there is a strong ensemble signal that the Arctic Oscillation, after going positive in the near-term could go negative by the end of the extended range). Some guidance also suggests a negative EPO by the end of the extended range, but there is more uncertainty.

With the warmest year since recordkeeping began in the CONUS now in the past, rather than reflecting back at the misery that year inflicted on snow geese, I will share a passage that was written by a woman from Monroe, Virginia following the wild, wintry weather of December 1839:

Never before did winter visit this sunny valley in such wrathful mood. He raved and roared, as from his chariot of the storm, he showered down snow and hail, and icicles, amid the shivering forests, which bent and bowed before his hurricane flight, as if but just broke loose from his drear arctic regions.

Once the cold returns, may winter "rave and roar" in its best fashion, showering down the snow in great abundance.

Happy New Year to all.

Happy New Year Don...Best wishes to you and your family...

[DaculaWeather]

Happy New Year to Don and everyone else. And thanks for another year of your excellent insight Don! Look forward to another year!

[Srain]

Don, first of all Happy New Year to you and and all our Amwx Community. My hunch is after a brief relaxation to a bit more zonal split flow pattern, the sub tropical jet will once again become active and potential for the Polar Jet to drop S into the West/Great Basin and Plains as the pattern reloads near the 12th, +/- a couple of days. I do believe that an active pattern that we have seen across the West Coast/Intermountain West into the Plains will once again set the stage for folks along the I-95 Corridor as we head further into January/early February.

[Ottawa Blizzard]

Does anyone have access to the European weeklies? I've heard through the grapevine that JB is depressed about them as they essentially call for the end of winter for this year.

[easternsnowman]

Does anyone have access to the European weeklies? I've heard through the grapevine that JB is depressed about them as they essentially call for the end of winter for this year.

I would'nt worry about them after they have'nt done so well the past few months.

[Snowshack]

Does anyone have access to the European weeklies? I've heard through the grapevine that JB is depressed about them as they essentially call for the end of winter for this year.

Dont they only go out 30 days? That would only take us to 2/1, plenty of time left after that, especially for your area

[blizzard1024]

The 00Z GFS 02 Jan 13 FWIW does not have a torch pattern...just one lake cutter storm that is quickly followed by

arctic air. Heck day 16 has a big nor'easter! LOL.  If you look at the GEFS ensembles...the op GFS is the coldest of course! 

But the GEFS is not as warm as the euro ensembles which essentially by day 10 torches the east with strong reverse PNA pattern. 

I do not have access to the euro weeklies but I read JB's blog and it is the first time I have ever seen him so depressed

about mild weather. he always finds a way to forecast cold. I would bet on the euro at least thru day 10...beyond that

not so sure. If it gets mild and stays that way for a while...it will soon be February and then we can root for spring.

Maybe another March heat wave. Yay. 

[easternsnowman]

Most people thought February will be our coldest and snowiest month.

[Srain]

With the AMS Annual Meeting being held in Austin, TX next week some attention may be warranted for those attending. A rather strong 5H upper low is forecast eject out of the Great Basin crossing Arizona and New Mexico. A SW flow aloft from a noisy sub tropical jet that has plagued our region for the last 10-12 days will continue. Returning moisture from a SE flow off the Western Gulf will develop late Sunday into Monday across Texas. As we saw down here with the Christmas Storm, a severe weather episode may lie ahead for those attending the Meeting. Sam has a thread in the Central/Western sub forum for those interested in the updates…

 

http://www.americanwx.com/bb/index.php/topic/38630-ams-strong-to-severe-thunderstorms-heavy-rain/

[Ender]

<blockquote class='ipsBlockquote'data-author="Ottawa Blizzard" data-cid="1975983" data-time="1357063824"><p>

Does anyone have access to the European weeklies? I've heard through the grapevine that JB is depressed about them as they essentially call for the end of winter for this year.</p></blockquote>

The CFS, which was harping on a very warm December as of early Nov, was somewhat insistent on a cold January. At least through its 12/25 forecasts. It's been emphatic about a cold, to even brutally cold, February for the last week and a half. Interestingly it was going for a cold/very cold Jan followed by a warm/very warm Feb until about 12/20 when it started to back down towards moderately cold for Jan and very cold for Feb.

I've only been following the CFS for the last 6 months or so. It seems that its "1 month lead forecast", which should be for weeks 4 - 8 from now, usually ends up being a "week 3/4 - week 6/7" forecast. With that caveate the "cold January" forecasted between Dec 1 and Dec 10 would be coming to an end here around Jan 6th. While the "warm Feb" from the same time range is about to start 1/6 and run until at least 1/20. After which the CFS's past week's forecasts of a "cold Feb" will start and run until 2/7 - 2/14.

[Ji]

<blockquote class='ipsBlockquote'data-author="Ottawa Blizzard" data-cid="1975983" data-time="1357063824"><p>

Does anyone have access to the European weeklies? I've heard through the grapevine that JB is depressed about them as they essentially call for the end of winter for this year.</p></blockquote>

The CFS, which was harping on a very warm December as of early Nov, was somewhat insistent on a cold January. At least through its 12/25 forecasts. It's been emphatic about a cold, to even brutally cold, February for the last week and a half. Interestingly it was going for a cold/very cold Jan followed by a warm/very warm Feb until about 12/20 when it started to back down towards moderately cold for Jan and very cold for Feb.

I've only been following the CFS for the last 6 months or so. It seems that its "1 month lead forecast", which should be for weeks 4 - 8 from now, usually ends up being a "week 3/4 - week 6/7" forecast. With that caveate the "cold January" forecasted between Dec 1 and Dec 10 would be coming to an end here around Jan 6th. While the "warm Feb" from the same time range is about to start 1/6 and run until at least 1/20. After which the CFS's past week's forecasts of a "cold Feb" will start and run until 2/7 - 2/14.

 

so we are in good shape for PD3?

[blizzard1024]

With the AMS Annual Meeting being held in Austin, TX next week some attention may be warranted for those attending. A rather strong 5H upper low is forecast eject out of the Great Basin crossing Arizona and New Mexico. A SW flow aloft from a noisy sub tropical jet that has plagued our region for the last 10-12 days will continue. Returning moisture from a SE flow off the Western Gulf will develop late Sunday into Monday across Texas. As we saw down here with the Christmas Storm, a severe weather episode may lie ahead for those attending the Meeting. Sam has a thread in the Central/Western sub forum for those interested in the updates…

 

http://www.americanwx.com/bb/index.php/topic/38630-ams-strong-to-severe-thunderstorms-heavy-rain/

 

This is as bad as it gets for the east. There goes all our snowcover...nice solid 12" of snowpack. beautiful winter scenes and great skiing. soon to be ravaged. what a shame.

[Quincy]

It looks like we could have some widespread 50's and 60's across the Northeast and mid-Atlantic region later next week. Strong signal on the models, especially EC 850mb temps getting up to around 10C by day 10.

[wxmx]

Days 8-20 look quite cold for the CONUS as a whole, but mostly for the central CONUS, with possibly cross polar flow involved ...The E, and especially the NNE look warmish in this period. After that, my guess is for the mean trough to shift E.

[usedtobe]

It looks like we could have some widespread 50's and 60's across the Northeast and mid-Atlantic region later next week. Strong signal on the models, especially EC 850mb temps getting up to around 10C by day 10.

 

 

I agree and wrote an article for the DC area pretty much saying meaningful snow looks unlikely for the 1st half of January.   Looks like the plains western 2/3 of the country will start cooling down as the ridge builds across Ak again in the longer range.  For the mid Atlantic, we still need some blocking across the Baffin Bay area and Greenland before I get too excited about the pattern.  If the Pac ridge shifts a little east and the downstream trough does likewise than we at least get cold but that is still not guaranteed.