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November 2012 Observations and Discussions


Snow_Miser

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Going to have to monitor AO/NAO development closely, as the stratosphere right now is still very cold, which is generally a signal against the initiation of strong blocking. However, we've seen it happen numerous times, that is, a distinct disconnect b/t the troposphere and the stratosphere. We often thing of the top-down effects w/ propagating warming event from the stratosphere, but we can have some perturbation of the stratosphereic vortex from the troposphere upward as well. The pattern persistence in the troposphere has been impressive regarding the neg NAO.

We'll have to watch it going forward the next couple weeks, as I'm beginning to think there's a possibility we deal w/ the SE-ridge quite often in December due to the poor PNA signalling. Troughs at least initially may dump into the West/Plains w/ storm tracks through the Lakes. Should be interesting to track.

70mb9065.gif

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Don't we tend to get the best storms when the NAO is transitioning to positive rather than when it's bombing negative?

Yes generally the + to - transitions feature rain events for the east coast, not all the time but usually. In Dec 2010, it took until the last couple weeks of the -NAO period to get the snowstorm. We had several weeks of a -NAO prior to that and a couple rainstorms.

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I'm very hesitant to believe the "cold and snowy" winter outlooks that have put out by both private and goverment sectors. It appears that we will have the development of a -NAO for the first half of December 2012. I suspect that it could be cold (normal to just below normal) for much of the first half of that month but with only several chances of 1-3 in. snow events. It appears that a more significant storm could develope by around December 20-26, 2012 as the NAO rises rapidly late in the month. In general, I don't get excited about snowy winters when November is either 1)cold or 2)produces multiple wintry events or even close calls.

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Anyone have what the following winters/prior Novembers looked like when compiling the following:

A: our crappiest winters

B: our coldest Novembers

In simpler terms I'd like to know what November looked like prior to our biggest winter duds and what winters looked like after our coldest Novembers.

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I'm very hesitant to believe the "cold and snowy" winter outlooks that have put out by both private and goverment sectors. It appears that we will have the development of a -NAO for the first half of December 2012. I suspect that it could be cold (normal to just below normal) for much of the first half of that month but with only several chances of 1-3 in. snow events. It appears that a more significant storm could develope by around December 20-26, 2012 as the NAO rises rapidly late in the month. In general, I don't get excited about snowy winters when November is either 1)cold or 2)produces multiple wintry events or even close calls.

November, 1995 produced a close call, and a wintry event.

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November won't end up that much below normal and will balance out october being a little above normal. In 1996 and 97 I believe both months were below normal. In 1996 we had a different setup than today and 1997 was a very strong nino obviously a totally different ballgame!

November is -5ish for all locations. That's a total departure of -90 through November 18th.

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Anyone have what the following winters/prior Novembers looked like when compiling the following:

A: our crappiest winters

B: our coldest Novembers

In simpler terms I'd like to know what November looked like prior to our biggest winter duds and what winters looked like after our coldest Novembers.

Coldest Novembers since 1971...

41.7 in 1976

43.0 in 1996

43.6 in 1995

44.4 in 1972

44.5 in 1997

44.6 in 1980

45.1 in 1971

45.3 in 2000

45.4 in 2007

45.7 in 1989

45.7 in 1986

45.8 in 2008

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I think after this week that will come down a bit and by months end we'll be around 2 below normal.

This entire week will be average to slightly above average. Then from Sunday on, forecasts are for major negative departures with high temps staying in the low 40's for days.

NYC should finish -4 to -6.

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This entire week will be average to slightly above average. Then from Sunday on, forecasts are for major negative departures with high temps staying in the low 40's for days.

NYC should finish -4 to -6.

It would be one of the largest departures in recent memory if that happens, especially for november which has been averaging above normal for the last 10 to 15 years.

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I think that Sandy was the main reason that we are running so cool here for November. Her massive

circulation pulled in cold air from the west under the block into our area that had been above normal

for so long. You can see how the pattern was altered after the landfall. The combination of snow

and cold this month is a real outlier compared to the kind of warmth that we have been generally

experiencing in November.

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It's becoming fairly obvious that the GFS is not having a good time with this, with every run being significantly different, although obviously the post-truncation factor goes into this as well.

Although I'll say those Euro ensembles are pretty nice, with the triple negative indices.

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The new 00z GFS now brings in the cold air by this weekend with what could be a rain/snow squall event in some spots with a cold frontal passage. The pattern is cold beyond it although the NAO blocking isn't specifically impressive.

Also interesting that the Euro ensembles are taking the MJO through a very familiar path -- running in circles.

ECMF_phase_51m_small.gif

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