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CFS Long Range (as in Winter)


mitchnick

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that cold pool of water in the Pacific west of Mexico has been very persistent through the summer, though it is starting to show signs of weakening near the equator

a number of tropical systems may be the culprit, so I'm hoping those systems in the eastern PAC stop to give NINO 3.4 and 4 a shot at warming faster

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Was 06-07 an east based? I've searched and my results are no-- but for some reason it seems no one really thought it be a good winter to begin with and I can't recall why. That -EPO was nice in Feb, but little or no snow south of DC.

Yes it was. It was a strange Nino in the sense that it strengthened quite rapidly in fall and peaked pretty solidly moderate, but its peak was very short lived and it weakened rapidly after that so its tri-monthly peak wasn't impressive.

February had a pretty darn good longwave hemispheric pattern but we just were never able to get the smaller scale synoptic features to work out for big snows along I-95 east coast.

Its not a bad analog for this year except I don't think we will get as strong as that one on a shorter term peak. There's still a possibility this Nino does get more 3.4-centered as well...but my confidence in that has been waning steadily over the past couple weeks.

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Yes it was. It was a strange Nino in the sense that it strengthened quite rapidly in fall and peaked pretty solidly moderate, but its peak was very short lived and it weakened rapidly after that so its tri-monthly peak wasn't impressive.

February had a pretty darn good longwave hemispheric pattern but we just were never able to get the smaller scale synoptic features to work out for big snows along I-95 east coast.

Its not a bad analog for this year except I don't think we will get as strong as that one on a shorter term peak. There's still a possibility this Nino does get more 3.4-centered as well...but my confidence in that has been waning steadily over the past couple weeks.

I think that was a nino that the MJO and GWO helped kill or wound if I remember correctly. Klaus Wieckmann gave a talk where he discussed it. I may even have slides from his talk hidden away somewhere. The other killer was the epo which was positive much of the season.

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Got my initial winter analogs... I'll get the new thread started in the main forum later this week.

For the Mid-Atlantic, I have the following:

Month: Temp anom, Precip anom

December: +1, normal

January: -1, normal to dry

February: -2, normal to dry

I haven't looked at the snowfall from the analogs yet, but I would guess from the temp/precip anomalies that we would receive below normal snowfall.

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Got my initial winter analogs... I'll get the new thread started in the main forum later this week.

For the Mid-Atlantic, I have the following:

Month: Temp anom, Precip anom

December: +1, normal

January: -1, normal to dry

February: -2, normal to dry

I haven't looked at the snowfall from the analogs yet, but I would guess from the temp/precip anomalies that we would receive below normal snowfall.

May I inquire as to why the dry? Are you expecting the current warm ENSO phase to have no impact on the storm track? Just curious.

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Got my initial winter analogs... I'll get the new thread started in the main forum later this week.

For the Mid-Atlantic, I have the following:

Month: Temp anom, Precip anom

December: +1, normal

January: -1, normal to dry

February: -2, normal to dry

I haven't looked at the snowfall from the analogs yet, but I would guess from the temp/precip anomalies that we would receive below normal snowfall.

If jan and feb are cold and precip is normal to dry...why below normal snow?

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Dangerous talking about negative departures for both Jan and Feb. ;)

All years in the last 3 decades with negative Jan/Feb combos. Snowfall in Jan/Feb (total seasonal).

2010 - 39.5" (56.1")

2004 - 6.2" (12.4")

2003 - 33.2" (40.4")

1996 - 39.0" (46.0")

1994 - 6.6" (13.2")

1988 - 13.1" (25.0")

1987 - 31.1" (31.1")

1985 - 10.0" (10.3")

1982 - 20.6" (22.5")

Quoting my reply to zwyts earlier. When we go negative Jan/feb it is snowy.

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May I inquire as to why the dry? Are you expecting the current warm ENSO phase to have no impact on the storm track? Just curious.

I don't think ENSO will have too much of an effect, and I never really do. I just use my "method" and look at the precip analogs.

If jan and feb are cold and precip is normal to dry...why below normal snow?

They're not that cold. I know December isn't the big snow month, but considering I have them coming in more mild I'll assume December ends up with below average snow. If January and February both end up with near normal snow, the season as a whole will still end up slightly below normal.

Quoting my reply to zwyts earlier. When we go negative Jan/feb it is snowy.

EDIT: Had a reply to this but realized that I was in the mindset of having the years starting at the start of the winter in December instead of rolling forward while looking at your Jan/Feb snow years.

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Got my initial winter analogs... I'll get the new thread started in the main forum later this week.

For the Mid-Atlantic, I have the following:

Month: Temp anom, Precip anom

December: +1, normal

January: -1, normal to dry

February: -2, normal to dry

I haven't looked at the snowfall from the analogs yet, but I would guess from the temp/precip anomalies that we would receive below normal snowfall.

Snowfall is imposible to predict. Given that, I like your forecast for a good snow year.

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So I've refined my forecast and got my finalized analog years and weighted them (top has highest weight, bottom lowest weight)...

2006

2002

1994

1986

1953

Along with the updated anomalies and precip:

December: +2, normal

January: +1, normal to wet

February: -3, normal

Changed the game up a bit once I got everything weighted to my liking. Most of the U.S. and Canada are above normal in December with little blocking. This is still present but starts to fade in January and the southern U.S. turns neutral to cool. Blocking becomes more evident in February as cold takes over the eastern of the U.S. and most of Canada, with a warm West.

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So I've refined my forecast and got my finalized analog years and weighted them (top has highest weight, bottom lowest weight)...

2006

2002

1994

1986

1953

Along with the updated anomalies and precip:

December: +2, normal

January: +1, normal to wet

February: -3, normal

Changed the game up a bit once I got everything weighted to my liking. Most of the U.S. and Canada are above normal in December with little blocking. This is still present but starts to fade in January and the southern U.S. turns neutral to cool. Blocking becomes more evident in February as cold takes over the eastern of the U.S. and most of Canada, with a warm West.

I can't wait for my 7" of sleet in February

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doesn't make a ton of sense to me though it may be less of a factor this year....other people agree but they use analogs that are dissmilar enso states...why use all nino analogs if it doesnt matter much?

There's certainly a correlation, but I think people rely on ENSO climo too much when making forecasts. I should clarify that when I mean "relying on ENSO clmo" I mean the typical temperature and precipitation anomalies associated with Nino/Nina years. The blocking, or lack thereof, in the Atlantic along with things like the WPO and EPO have a much greater effect as a whole, but since it's very difficult to estimate those in the long range one has to fall back on things like ENSO and PDO for a starting point. As far as I'm concerned it's still mostly a guessing game even after establishing some of the background elements. It only takes one persistent signal like the +EPO we had this past winter to completely screw up an entire seasonal forecast (much to my dismay last winter :P).

I use recent ENSO trends and anticipated values to kind of get a baseline idea, then I use other factors to weed out the ones I want and weigh them according to my confidence in each analog. IMO its good to use as a starting point most of the time, but when it comes to actually picking out specific years and the resulting anomalies I do not weigh the typical ENSO climatology into my forecast. My original analog list had winters that were complete opposites of each other, but after refining my analogs some clearer signals emerged.

EDIT: Fixed the sign of the EPO

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So I've refined my forecast and got my finalized analog years and weighted them (top has highest weight, bottom lowest weight)...

2006

2002

1994

1986

1953

Along with the updated anomalies and precip:

December: +2, normal

January: +1, normal to wet

February: -3, normal

Changed the game up a bit once I got everything weighted to my liking. Most of the U.S. and Canada are above normal in December with little blocking. This is still present but starts to fade in January and the southern U.S. turns neutral to cool. Blocking becomes more evident in February as cold takes over the eastern of the U.S. and most of Canada, with a warm West.

I'd take my chances with that as far as snowfall goes

hopefully, any surprises this year go in our favor instead of against it like last year

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Don S has some great data irt to fall NH snowcover and EC blocking down the road. I plan on paying more attention to Oct snowcover this year. With a weakish nino the most likely scenario we're going to have to rely on the usual suspects to produce for us.

I pulled out 10 of the weaker ninos and looked at blocking in the Jan-Mar. The most recent ones (87,88, 95,07) all pretty much stunk with the monthly NAO index except for 87. Jan-Feb 87 was a great stretch. Feb 07 was "ok" in the blocking department but the year as a whole was a snoozer.

Some of the earlier years (54,59,69,70,77,78) had some great months in the NAO dept. I know this doesn't translate into snow but it's a necessary ingredient more often than not.

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February in El Ninos is almost guaranteed to have blocking...in that sense, enso can very very useful. I think there has been 1 Nino off the top of my head that didn't have it and that was Feb 1992. Feb '73 was kind of crappy so that may have lacked blocking as well, but I didn't pull up the maps. But literally all other Ninos...even the terrible ones...had it.

Obviously snowfall has some other factors in there. For DCA, the STJ is a big one.

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February in El Ninos is almost guaranteed to have blocking...in that sense, enso can very very useful. I think there has been 1 Nino off the top of my head that didn't have it and that was Feb 1992. Feb '73 was kind of crappy so that may have lacked blocking as well, but I didn't pull up the maps. But literally all other Ninos...even the terrible ones...had it.

Obviously snowfall has some other factors in there. For DCA, the STJ is a big one.

Feb 1973 had an ao of something like 0.7 and a nao of -0.2 or 0.3 so not much blocking where you wanted it even though there was a southern stream. There was nothing to hold in cold air.

post-70-0-53822200-1344443826_thumb.png

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The CFS (the new one) actually now shows a torch (relativel speaking) for the central and southeast US for winter...the temp pattern looks La Nina-ish minus February. The older version of the CFS continues to show a cold northeast throughout the winter.

whji2d.jpg

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The CFS (the new one) actually now shows a torch (relativel speaking) for the central and southeast US for winter...the temp pattern looks La Nina-ish minus February. The older version of the CFS continues to show a cold northeast throughout the winter.

whji2d.jpg

Let us reiterate what has been said on many a long-range thread: First, it's the CFS. Also, the CFS' forecast changes nearly day to day.

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