It's that time of the year once again, to talk about the upcoming winter season. Please keep in mind this is a rough overview and preliminary Call at this time.
My official 2009-2010 Winter Forecast will be issued in early to mid October. More details, discussion and maps, will be presented during that time, but for now let's keep it short and sweet.
As many of you know, the past 2 Winter Seasons have been powered by moderate to strong La Nina Patterns, which don't prove to be snow lover friendly for the M/A States, but are great for the Midwest, G/L's, and New England. These regions enjoyed above average snowfall and colder than normal temps over the past 2 winter seasons. The M/A, well not so great, with near and below normal snowfall and near to above normal temps. This is text book material, that panned out as forecasted for the most part.
The ENSO and other key factors have changed and switched over during the spring and summer months, which should produce a quite different result for this upcoming winter season. Over the next couple of months, I'll continue to monitor these changes, and put it all together in October with my official call.
The latest ENSO and key Teleconnections:
Many have questioned me why such a cool/wet, spring and summer this year. Too sum it up, we've had a big switch from a moderate La Nina, to a weak El Nino pattern transition from last winter into the spring and summer months. This has allowed the jet stream to be more suppressed during the spring months. This allowed for more cooler Canadian air to affect the Midwest, M/A, and Northeast. In addition with teleconnections, a negative AO and NAO couplet developed and maintained itself from spring and into the early/mid summer months. The PNA was mainly positive during this time as well.
All these factors/combinations, have kept it Hot and Dry with ridging over much of the west and deep south, and cool and wet, with a mean trough placement from the Midwest and much of the east as a result.
As of now in the month of August, the ENSO state is in a weak/moderate El Nino threshold, and headed for moderate El Nino for the fall months. The AO and NAO couplet are now near neutral. These important factors can give us and idea of where we're going this winter. There's no doubt the ENSO state will be El Nino this winter, but will it be a combination of: weak/moderate or moderate to possibly Strong El Nino is the big question ??? These two combinations can produce tricky forecasting in the M/A and NE regions, but in both cases a more active subtropical/Southern branch will usually produce more storm systems to our south, and more GOM and SE coast development.
The Midwest & much of New England would usually be drier than normal with many of these storm systems sliding to the south. So with this in mind, I have a pretty good idea of where the most active storm track will likely be setting up this winter.
Now comes the teleconnection part of the puzzle ! This can give the clues for how temperatures may react with El Nino, and how much the northern branch gets involved with the southern branch. Phasing of the streams along the east coast and colder than normal temperatures for the Deep South, TENN Valley, The SE, and M/A States are very possible if we can maintain a Negative AO/NAO couplet during the winter months. At this point I think this is doable at this time, but will not fully commit to this solution until I see the trends in the fall months. Thus I'll wait until I make my final call in October, to say a possible blockbuster winter is coming. Even a neutral NAO with weak/moderate El Nino conditions could prove quite well for the M/A States.
The M/A States:
Including NYC, PHL, DCA, and RIC.
So with all that being said, I'm thinking the Mid Atlantic States do well this winter, with near to above normal snowfall and slightly below normal temperatures.
For New England and much of the Northeast.
Temperatures will be near to above normal, and snowfall near normal over SE New England and below normal snowfall for the remainder of New England and the Northeast.
Check back in early to mid October for my Official 2009-2010 Winter Forecast. This will include more details, maps, and a National Call.