KA Releases Outlook for Washington, DC

[donsutherland1]

Yesterday, Keith Allen, who has established a very strong track record in seasonal forecasting for the Washington, DC area, issued his Winter 2004-05 forecast for that region.

Briefly, Keith Allen's seasonal forecast calls for a warmer-than-normal winter (defined as December through February) with below normal snowfall for the entire season.

There has been some comment concerning Keith Allen's primary analog for Winter 2004-05 (it comes from a La Niña winter). However, one should bear in mind that his approach to analogging does not necessarily rely on any single global index, but places considerable weight on past weather events. It also considers historical probabilities. Thus, it is entirely possible that Keith Allen's analog might not be an El Niño one.

Having said that, I will note that the use of global indices does not necessarily produce a substantially different outlook in terms of snowfall for the DCA area. Some scenarios are much better in terms of greater snowfall. But others are well within the realm of the KA idea e.g., the possible 1969-70 analog that has been discussed previously here and elsewhere.

As for my ideas:

Very briefly, an initial glance at the global indices--I'm currently beginning to refine and reduce the pool of prospective analogs and factoring in the tropical season--suggests that Winter 2004-05 will more than likely be cooler than normal in the eastern half to third of the USA and warmer than normal in the western third of the country.

There are some intriguing indications with respect to snowfall. Unfortunately, while some areas (possibly eastern New England) might see above to much above normal snowfall, it does appear possible that some parts of the USA will see another season with below normal snowfall. Moreover, the cut-off line between those regions could be quite sharp.

I'll have a much clearer idea by around October 15 (at which time I'll post my winter outlook) once all the September data is in and trends in snowcover have become more evident.

For now, I'll note that the data is in stronger agreement with respect to eastern Canada, so I'll provide my ideas concerning eastern Canada.

Based on similar past seasons (global indices and tropical landfalling activity), at first glance it appears that Winter 2004-05 could break down as follows across eastern Canada:

Northern Quebec: Normal to above normal temperatures/normal precipitation

Rest of Quebec, New Brunswick, Nova Scotia, and Prince Edward Island: Below normal temperatures/near normal precipitation

New Foundland: Near normal temperatures/near normal to somewhat above normal precipitation

[donsutherland1]

The following are some of the sharpest cut-offs between Washington, DC and Boston, Washington, DC and New York City, and New York City and Boston:

Boston vs. Washington, DC:

Boston's Snowiest Winters when Washington, DC has received less than 15" of snow for the season:

1993-94: DCA: 13.2" BOS: 96.3"
1992-93: DCA: 11.7" BOS: 83.9"
1919-20: DCA: 11.9" BOS: 73.4"
1955-56: DCA: 11.3" BOS: 60.9"
1926-27: DCA: 2.3" BOS: 60.3"

All said, the following winters saw Washington, DC receive less than 15" snow and Boston 50" or more of snow:

1897-98
1919-20
1926-27*
1937-38*
1944-45*
1955-56
1956-57
1968-69*
1970-71
1976-77
1992-93
1993-94
1996-97*

* - denotes winters in which Washington, DC received less than 10" of snow for the season

New York City vs. Washington, DC:

New York City's Snowiest Winters when Washington, DC has received less than 15" of snow for the season:

1993-94: DCA: 13.2" NYC: 53.4"
1919-20: DCA: 11.9" NYC: 47.6"
1895-96: DCA: 9.3" NYC: 46.3"
2003-04: DCA: 12.4" NYC: 42.6"

All said, the following winters saw Washington, DC receive less than 15" snow and New York City 30" or more of snow:

1895-96*
1901-02
1919-20
1938-39
1955-56
1968-69*
1993-94
2000-01*
2003-04

* - denotes winters in which Washington, DC received less than 10" of snow for the season

Boston vs. New York City:

Boston's Snowiest Winters when New York City has received less than 20" of snow for the season:

1970-71: NYC: 15.5" BOS: 57.3"
1987-88: NYC: 19.1" BOS: 52.6"
1996-97: NYC: 10.0" BOS: 51.9"
1937-38: NYC: 15.1" BOS: 50.6"

All said, the following winters saw New York City receive less than 20" snow and Boston 40" or more of snow:

1928-29
1930-31
1937-38
1961-62
1967-68
1970-71
1975-76
1987-88
1996-97

[WEATHERGURU]

Hey Don what about lower Michigan? I know your official forecast comes out on Oct. 15th. Could you please give a little insight to the lower lakes (Lower michigan) THanks. Your insight you give is very Kowledgeable and informitive. Thanks..

[weatherfan]

Part of the reason of this Don is because most of the time those not all the time the years when Places like Boston has seen more then then Middle Alantic is the main storm pattern for some of those years were more miller B type storms.Normally miller B are ofton to late for effect places like DC south word but are better North word.Dc and most the middle Alantics best snow storms and blizzards are those that are Miller As with forms in the gulf and is a huge rain storm in Ga and comes up the east coast.Or storms that form off SC/NC 2000 janaurey Dc got berryed by that while up north got reather screwed.Another thing that many for got with winter of 94 while snow fall was below normal.We got tons and hit hard by huge ice storms that year.I remember that clearey we had about a few inchs of ice with storm after storm.In the middle Alantic sometimes we are right on that line and in some storms you can have mixing problems here which can effieck how much snow your going to get in any giving season.To get all snow you need all laryers to be below that 32 mark.It can be below 32 down at the ground but if its above 32 up above in the Layers then its going to support eather sleet or frezzeing rain.And that what happen in a lot of cases in 94.

[donsutherland1]

Weatherfan,

I agree that Miller A storms are far better for the Mid-Atlantic, especially lower Mid-Atlantic, than Miller B systems.

[weatherfan]

Another interisting note is that I look at the qbo in the winter of 94-95 and it was Acually a El nino west but yet that winter sucked in the Northeast and middle Alantic.But when you look at the NAO and AO that winter it was predomantey postive as the 70s-90s seemed to be in a mostey postive NAO winter time mode doing this past decade.A El nino West 90 percent of the time those are good if you like cold and snowey winters however there are always exceations to the rule.If there are one or more other factors that are against a cold pattern like the NAO,AO EPO then a West QBO in that winter even doing an El nino is going to mean squte as you need pretty much most of the factores that support the cold pattern along with it.So this winter of 95 was the exceation with the El nino West rule.It really depends on other factors.One factore does it have all the in all.There are other factors as well that plays into it.

[Anonymous]

Don, excellent post as usual!

Living in the MA and South of the Mason Dixon Line, it should be no surprise that DC will have much less snow then our cities to the North. It was quite obvious early last winter that "winter was over from Richmond to BWI" by late January, and indeed it was, not even 4" snows in this region.

As far as this season in the MA:

Average to slightly below average temperatures and below to much below average snowfall.

Don, I look forward to your thoughts on Oct 15th.

[donsutherland1]

Thanks, BEF.

It will be interesting to see how things turn out. Recently, ENSO Region 1+2 has seen almost all of its cool anomaly disappear. That could have implications, if this trend is sustained.

[Guest]

Thanks, BEF.

It will be interesting to see how things turn out. Recently, ENSO Region 1+2 has seen almost all of its cool anomaly disappear. That could have implications, if this trend is sustained.

Very true especially in southern and coastal areas from the west coast to the east coast. This could be a huge plus in droght stricken areas of the west.