Roger Smith long-range forecast winter 2013-14 -- heavy snow inland

[Roger Smith]

I wanted to share this research forecast output, partly because not much is happening anyway, and partly because this sounds like a very active winter for the forum if it comes close to fruition.

 

My track record on seasonal outlooks is not the worst imaginable, that's about all I will say, but for example I predicted very mild weather for winter 2011-12 and a hot summer in both 2011 and 2012, a more average summer in 2013. My winter forecast 2012-13 wasn't very completely posted here as I recall and in any case was somewhat wide of the mark. I am not one of those gurus who claim infallibility but would like to think the track record has been better than just random chance in recent years.

 

So with that rather lame endorsement as a take it or leave it, here's the scoop on winter 2013-14.

 

I expect the pattern to lock into a fast flow from southwest oriented about ATL-HAT-40N/68W with variations on that theme but this should allow colder than average temperatures to lock into the Midwest and Great Lakes regions, and parts of the inland southeast and even Mid-Atlantic. It would likely be closer to normal or even slightly above towards the outer coast north of CHS, but with large and frequent variations.

 

In the expected pattern, the storm track would often run from the inland southeast up the crest of the Appalachians or just coastward but inland, and from there into Maine and New Brunswick. Some periods would see a more amplified flow that gave strong northward moving storms offshore. Other periods would be dominated by lake cutters or Colorado lows. So most regions would see occasional thaws even in below-normal January patterns, but it could be quite a harsh winter in the Great Lakes region and the Midwest which would often be on the snowy side of medium to intense low pressure systems. There would also be a lot of additional lake effect in a pattern such as this.

 

The far west would likely be dry under anomalous high pressure ridges with the storm track aimed well north of average, so that rainfall would probably be well below normal south of Vancouver, near normal in southern BC and above normal in central BC and Alaska. Snowfall would then be heavy in the BC Rockies and near normal in the northern US Rockies but there could be a secondary maximum over eastern Colorado where a cut-off low might be present at times. Temperatures would likely range from much above normal in Alberta and Montana to near normal in western Minnesota and Iowa, to below normal by 3-5 F deg in parts of the Midwest.

 

That probably doesn't require a map for illustration, but you get one anyway:

 

[WEATHER53]

Roger-I agree that this will be a year where storms pass off Virginia/Carolina Capes, frustrating DC people and likely producing a situation where Norfolk gets more snow than DCA and perhaps even more than NYC.

[Roger Smith]

May not be that frustrating if enough cold air banks up to immediate west of I-95, could see decent snows almost everywhere except possibly eastern LI and se MA in this sort of set-up. I went rather conservative on the depicted cold anomalies factoring in some remnant Pacific warmth in clipper type patterns and also the +2 recent bias of warming. So this is about as cold a winter in the GL and MW as I would imagine the current climate can sustain.

[Geos]

Nice winter discussion Roger!

 

Sounds like you're predicting a gradient pattern in the East/Midwest.

[Quixotic1]

Why the cold anomalies extending SW away from the main eastern trough?  Anticipating a more active STJ? 

 

Not that I wouldn't take it, mind you.  -4 and the jet stream right over N Texas would be happy time indeed. 

[franklin NCwx]

hope this forecast pans out, would be a great winter for us in the nc mtns. thanks for the write up.

[Roger Smith]

Why the cold anomalies extending SW away from the main eastern trough?  Anticipating a more active STJ? 

 

Not that I wouldn't take it, mind you.  -4 and the jet stream right over N Texas would be happy time indeed. 

 

The extension is based on strong negative anomalies during intervals of cut-off low formation that may lead to snow cover then followed by persistent high pressure even when heights recover. Further west the negatives are predicted due to inversion conditions under strong high pressure often found in these patterns near SLC. The anticipated pattern would be very much of a roller-coaster ride for temperatures in the plains states, with both extremes being reached. Some weeks might see the western warmth amplified and extending downstream to about IN-wKY while other weeks may find warmth confined to chinook zones and boundary closer to

wND/SD-wNE-neCO.

[Quixotic1]

The extension is based on strong negative anomalies during intervals of cut-off low formation that may lead to snow cover then followed by persistent high pressure even when heights recover. Further west the negatives are predicted due to inversion conditions under strong high pressure often found in these patterns near SLC. The anticipated pattern would be very much of a roller-coaster ride for temperatures in the plains states, with both extremes being reached. Some weeks might see the western warmth amplified and extending downstream to about IN-wKY while other weeks may find warmth confined to chinook zones and boundary closer to

wND/SD-wNE-neCO.

 

Thanks for the response and good luck with your forecast. 

[Subtropics]

Always appreciate your insight roger. One of the best on the board. Fingers crossed!

[nzucker]

Very El Niño type look despite cold ENSO.

[Roger Smith]

There's a very strong ridge on the west coast now and such features tend to persist, we've had days of inversion fog here and bright sunshine with very warm days on higher ground. Yesterday it was about 10 or 11 C at sea level and 20 C at 3,000 ft on the north shore mountains. Given that fact and the current ice distribution which is stronger on the Alaskan side than the Barents-Kara sector, I just sense that the flow over North America is going to go very high amplitude and drag down some exceptionally cold air at times into the central and inland eastern regions. But a warm Gulf and western Atlantic argue for a tight gradient and an active storm track. That blends with the numerical output of the research model, so I am basically in the "meh" camp on any ENSO signal at this point. Whatever that signal is or becomes, the jet stream looks to be heading for Alaska and the Yukon more often than usual this winter season. It can't stay that far north too long so from there it pretty much has to go south to southeast most of the time. With the chinook dynamics this can distort the anomalies somewhat but I would expect some monster gradients from SK to NE/IA at times this winter. There may be some intervals with tame clippers but also some deep diving lows that will make the turn around AL-GA and head back northeast. Should be an interesting winter for almost everyone (except here maybe).

[Roger Smith]

A factor not mentioned earlier is that the Great Lakes are 4-6 deg above normal temps after such a warm first three weeks of October. If very cold air does arrive in Nov-Dec, lake effect will be prodigious to say the least. It also tends to guarantee very heavy lake effect in January and more than usual in February because it will take many weeks to bring these temperatures back to normal and ice cover will be late to form whatever the temperature anomalies.

[Sampson]

Well done, Roger.

[Ottawa Blizzard]

I agree. Your forecast turned out very well Roger. Congratulations are in order.