The January 5-12, 2007 Warm Spell: Some Thoughts

[Ptarmigan]

Don't get used to it those in the Northeast. The AO is becoming negative. Lows in the 20s in a couple of days with highs in the 30s....second half of winter should be cold. That is what usually happens to make up for the abnormal warmth.

I know that for sure. In Southeast Texas, before there is a freeze, it is warm, sometimes with record warmth.

[JBG]

Don't get used to it those in the Northeast. The AO is becoming negative. Lows in the 20s in a couple of days with highs in the 30s....second half of winter should be cold. That is what usually happens to make up for the abnormal warmth.

I know that for sure. In Southeast Texas, before there is a freeze, it is warm, sometimes with record warmth.

That often happens in the Northeast's I-95 belt. Prior to the immediate passage of a cold front, for the day or two before we'll get what DonSutherland refers to as a "blowtorch", or a warm surge resulting from the west/southwest flow.

The problem is, with AO+, the cold air behind the front is rarely all that cold, and even if it is it only sticks around for about 24-48 hours. This happened often during the La Nina winter of 1988-9, and the Super El Nino winter of 1997-8. The AO in both of those winters was, on balance, positive, so the cold snaps were very short lived.