Mid-Atlantic Prospects

[donsutherland1]

A question arose elsewhere as to how things are shaping up with respect to the Mid-Atlantic region, namely the greater Washington, DC area. My brief thoughts are as follows:

There are some encouraging signs that suggest that the Mid-Atlantic region including DCA and PHL may be moving toward a winter with above normal snowfall (PHL has better odds at this point in time but DCA is looking a little better).

• PDO: Has shifted to < 0. If the winter averages below < 0, given the weak El Niño, ENSO regional anomalies, QBO, increasingly likely NAO < 0, 1963-64 looks more attractive. That was a great winter from the Plains to the East. JB has been pounding this season as a possible analog in recent days.

• NAO: Increasingly, it appears that the NAO will average < 0 both for the December-March and December-February periods.

• Northern Hemisphere and North American snowcover trends: so far things are continuing to progress in a fashion that may suggest the potential for above-normal snowfall into the Mid-Atlantic.

Once the November data is out, I'll have a firmer idea on the NAO and PDO. The snowcover data will also be helpful.

If one is looking for December milestones, an especially encouraging indication of a snowy winter would be for December to see 5" or more snowfall in DCA. Here are the seasonal statistics for winters that saw 5" or more snowfall in December:

December: 5" or More Snowfall:
Less than 10": 1/28 (4%)
Less than 20": 8/28 (29%)
20" or more: 20/28 (71%)
30" or more: (46%)

Recent prominent winters that met such criteria: 1960-61, 1963-64, 1966-67, 2002-03

Recent prominent winters that did not meet such criteria: 1978-79 (November snow), 1986-87, 1995-96 (November snow)

All Winters:
Less than 10": 30/116 (26%)
Less than 20": 71/116 (61%)
20" or more: 45/116 (39%)
30" or more: 21/116 (18%)

[wxguy25]

Don, GREAT post and congratulations on your Member of the Month Victory!

What are your thoughts on my use of 1968-69 as an analog based on the strong similarity between it and this year's NPAC SSTA configuration? In SPITE of the QBO which was strongly negative in most of that winter.

As you probably know, w/o any strong ENSO signal the NPAC SSTA configuration is most important. In the last few days SOME warming has taken place in the GOA but it’s still not a ridging signal, or one which is particularly favorable for the development of a strong Aleutian low. Overall it looks A LOT to me like 1968-69.

ASSUMING 1963-64 is the BEST analog all around this should change in DEC but may not get to the point that it did in DEC 1963 since the SSTA configuration over the NPAC that year was SLIGHTLY more favorable.

In 1993, and 2002 when the ENSO signal was also for the most part suppressed, the strong warm pool in the GOA supported a strong +PNA pattern. 1968-69 is the opposite, where the EPAC signal totally overshadowed the weak EL NINO and forced a sustained RNA pattern through much of the winter.

IF it continues to be the case we will probably be dealing w/ a war for dominance between the NAO and EPAC pattern. In 1968-69 the NAO won.

[wxguy25]

1968-69 had the Lindsay Storm which buried NewYork City and New England, as well as another VERY long lasting event in the Gulf Of Maine. It was By no means a boring winter NORTH OF PHL.

South of there its another story alltogether.

[donsutherland1]

Thanks. I shared MOTM with Southerngale who has consistently done a great job.

I also agree with you concerning the similarities to 1968-69 in terms of the SSTAs. It will be interesting to see how this evolves. Hopefully, for the sake of our friends in the MA and parts of the Plains, this won't remain the case given the low snowfall there even as New England had a feast of snowfall thanks to the strongly negative NAO (-1.150 average for December through March).

[wxguy25]

Thanks. I shared MOTM with Southerngale who has consistently done a great job.

I also agree with you concerning the similarities to 1968-69 in terms of the SSTAs. It will be interesting to see how this evolves. Hopefully, for the sake of our friends in the MA and parts of the Plains, this won't remain the case given the low snowfall there even as New England had a feast of snowfall thanks to the strongly negative NAO (-1.150 average for December through March).

I can't find any reasons to think the NAO would average even neutral this winter let alone positive. That would probably be one of the only ways the Midwest, GL, and OV could get in on the heaviest snowfall.

Winters w/ a Positive NAO and RNA pattern tend to have storm tracks which favor above normal snowfall in those areas. There is little doubt in my mind that the aforesaid areas will do better snow wise than they have the past three years BUT the core of the anomalous snowfall should be in the Northeast when its all said and done. ESPECIALLY away from the coast/I-95.

May see alot of Miller B events/storm tracks into the OV jumping to the Mid Atlantic or New England coasts this year not unlike the past few years.