Going Negative - Another Look

Last season/s five-part series 'Going Negative' took a look at the conventional wisdom (CW)...from the perspective of NEWxSFC snow storms...about the 'need' for the NAO to be negative or the PNA to be positive or both to get good snows in the Northeast and mid-Atlantic. The main conclusions were 1) there was no preference in sign for PNA...2) AO was generally negative...and 3) contest snow storms were more likely when the NAO was positive. The data set was limited by the number of years the contests have been held and the number of storms where PNA...NAO...and AO data were readily available.

The question has come up again recently...as it does in one form or another every year...about the teleconnection CW. Near-record and / or well-above period-of-record normal (PORN) snows were observed in the Northeast last month during 'unfavorable' conditions (-PNA...+NAO)...which suggests that region/s snows are not dependent on the CW.

So..if the CW does not apply to the Northeast...then does it apply to the mid-Atlantic or is it more a myth?

The Synoptiscope® has been in VCP 31 since JAN 02 and indications are it will stay that way for @ least another week. We/ll take another...broader look at the 'Big 3' teleconnection indices while we wait for the next snow storm to see if the CW can stand the light of data in the mid-Atlantic.

Daily snow fall data (1950 - 2007) from U of Utah and daily normalized indices for PNA...NAO...and AO will be analyzed to find the probabilities for +4" and 12/24hr warning criteria events for several contest stations in the M-A. UofU data has missing values for portions of '96 and '97...which is unfortunate b/c of the bonus snows observed in JAN '96...but it/s the best available free data.

First up: Philly!