Northern US Mild December Hinting At January Pattern

[bluewave]

The warmer than normal pattern across the Northern US is forecast to continue with the milder temperature anomalies

increasing further west back toward the Dakotas and Montana during the next week and beyond.

I found 20 matches for this pattern since 1950 and rolled the composite forward into January.

The January pattern featured the relative warmth shifting more toward the west than had been the case

in December. Within the composite, there were several years where colder temperatures

relative to the means were able to push into the East than had been the case in December.

December 2011 so far

GFS 7 day forecast

December composite

January composite

[KEITH L.I]

The warmer than normal pattern across the Northern US is forecast to continue with the milder temperature anomalies

increasing further west back toward the Dakotas and Montana during the next week and beyond.

I found 20 matches for this pattern since 1950 and rolled the composite forward into January.

The January pattern featured the relative warmth shifting more toward the west than had been the case

in December. Within the composite, there were several years where colder temperatures

relative to the means were able to push into the East than had been the case in December.

December 2011 so far

GFS 7 day forecast

December composite

January composite

Strange thing in that January composite is most of those years are nino winters and strong ones too

[SnowGoose69]

Strange thing in that January composite is most of those years are nino winters and strong ones too

The composite map for December so far looks alot like an El nino with more of the southern areas being cooler.

[donsutherland1]

The composite temperature anomaly for January during La Niñas (R3.4 anomalies of -0.75°C or lower similar to the current event) with widespread warmth in the East is as follows:

However, 50% of such events saw large areas of cooler than normal readings in the East (60% had AO- in January) and 50% saw large areas of warmer than normal readings (sometimes except for New England). All of the "warm" cases had an AO+ for January.

Considering this data (I'm expecting January to have a positive average for the AO), among other data, I believe January will probably be coldest relative to normal among the winter months in the East (something I've mentioned in a few other threads). The potential for a warm or very warm February still lurks, but that isn't yet cast in stone.

[bluewave]

The composite temperature anomaly for January during La Niñas (R3.4 anomalies of -0.75°C or lower similar to the current event) with widespread warmth in the East is as follows:

However, 50% of such events saw large areas of cooler than normal readings in the East (60% had AO- in January) and 50% saw large areas of warmer than normal readings (sometimes except for New England). All of the "warm" cases had an AO+ for January.

Considering this data (I'm expecting January to have a positive average for the AO), among other data, I believe January will probably be coldest relative to normal among the winter months in the East (something I've mentioned in a few other threads). The potential for a warm or very warm February still lurks, but that isn't yet cast in stone.

Don, that's why I mentioned the potential for colder in the East in my original post. FWIW the last time we saw

something resembling this +AO pattern during a La Nina was back in December 1999. The January 2000 temperature

composite overlaps well with the 20 year composite.

December 2011 so far

December 1999

January 2000

January composite

[bluewave]

Strange thing in that January composite is most of those years are nino winters and strong ones too

Yeah, it a blend of Ninos, Ninas, and neutral years.

The composite map for December so far looks alot like an El nino with more of the southern areas being cooler.

The +AO temperature pattern really overlaps with the El Nino December composite.

December El Nino composite

Winter AO composites