One of the things I did when I worked in Utica was work with our other meteorologists and devise a winter outlook for our region. Long-term forecasting has very little use or purpose in television, so this was mainly for giggles. And there were a couple instances where things worked out pretty well. I took it seriously last year...wrote a whole blog entry on it...some things worked..others didn't.
January worked. Here was our January forecast: http://bimedia.ftp.clickability.com/wktvwebftp/JanuaryTemps.JPG
Here's how January verified: http://www.hprcc.unl.edu/products/maps/acis/Jan09TDeptUS.png
December didn't work out too well...
December Forecast: http://bimedia.ftp.clickability.com/wktvwebftp/DecemberTemps.JPG
December Actual: http://www.hprcc.unl.edu/products/maps/acis/Dec08TDeptUS.png
You get the idea. There's an art to seasonal forecasting...usually no one ever gets it really right. I attribute the stuff that did work last year to dumb luck more than anything else.
Now that I'm in a field where there is a bit of a premium on longer range forecasting, I've learned a few new things, adapted some new ideas, etc. But I still have miles to go.
That said, I was hoping I would be able to do a seasonal forecast for work, but we go month by month, rather than a full season. Different than a lot of other places. But in a sense, it's a positive, because I can groom myself more without risking hurting my company...and I get good practice in devising an outlook. Kind of fun. Not a bad trade off.
So let's talk about winter. Since this is mainly written for a handful of people that ask me about this stuff, it will be pretty straight-forward. If you want to know more about how some of it all works, just ask.
The single biggest influence on the weather here in the US comes from the Pacific Ocean. Think of the atmosphere like a river. What happens upstream tends to impact what happens downstream. Weather generally moves from west to east across the continent, so upstream for our purposes would be the Pacific Ocean and also western Canada. The image below shows the temperatures compared to normal since the beginning of October in the US and Canada. Blue means below normal, and green or yellow means above normal. White means near normal. One thing you'd like to see for a cold, snowy winter, is cold air in Canada. Cold air leads to snow cover build up, which ultimately can act as a reservoir for cold air. Since October, we really haven't had that:
So we really don't have any "significant" cold air buildup that has occurred in that part of the world. Thus, we don't have much snowpack either. The image on the top shows snow cover from November 11th of last year. The one at bottom is this year (click to open them)...
The main differences that become apparent are in Canada and Asia. Last year, Alaska and the NW Territory/Yukon were pretty much rock solid in snow. Snow extended into much of Central and Eastern Canada too. This year, it's not as far south (except in a handful of spots in the British Columbia mountains). Nor is it as solid as it was last year. However, on the top of those maps, China and Mongolia show a distinct difference. Lots of snow this year...none last year. What does that mean? It's been cold on the other side of the Pole...not on this side. This may mean that the first half of winter is going to struggle to see much cold and snow. And in fact, the weather forecast for the next two weeks reflects that. However, this could also mean that once the pattern does change toward cold, we do get some impressive cold shots.
Next up is the Pacific. We have a few things going on. You can see a map of global sea surface temperature anomalies; basically, how much warmer or colder the oceans are compared to normal (click to make it bigger).What do we notice here? Well the first thing is that in general, the waters of the North Pacific are a bit cooler than normal south of Alaska. There is some warmer water as well near the Aleutians and creeping up the West Coast. But overall, the North Pacific can be characterized as "neutral." That means when you average it all together, it comes out near zero. That muddies the picture a bit, because typically you'd like to see some sort of strong signal from the Northern Pacific to help determine what the predominant weather pattern would be.
So then by looking for other signs, you notice the equator. And that's likely to be the biggest driver this winter: El Niño. Warmer than normal water stretches from a belt off Peru west to the Dateline along the Equator. In the last four weeks or so, we've seen a tremendous uptick in the intensity of this. In September it appeared we had a wimpy El Niño. The month of October developed a formidable one. This isn't an epic El Niño. But this is certainly strong enough to have an impact on our weather. And it probably will. The strength of the El Niño often determines how much cold and snow the Eastern US sees. In general, the southern states see more precipitation than normal (and we've seen this already in Arkansas, Louisiana, Mississippi, Alabama, Georgia and Tennessee with many areas seeing 150-300% of their normal rainfall since August and September). In general, the weaker the El Niño, the more cold and snow in parts of the East.
So we have that out of the way. I also looked at a few other things, included the pattern in the North Atlantic and Arctic. I tried to find some years that have been similar in those regions to see what they generally did. I biased my forecast in the East part of the way toward that (~ 30% weighted). But primarily I focused on the Pacific, the El Nino and what's happening south of Alaska (~70% weighted on that in the East). I like to say that seasonal forecasting is not always a science, but an art, so there's a modest amount of "gut" built into this as well.
So here we go. I'll start with some temperature maps for the next few months, and then I'll talk a little more about snow/temp specifics for a few places.
Apologies for the formatting. Not exactly what I was hoping for, but click any image to open up a better quality one. So I've got the winter backloaded in the East. Now, above normal doesn't mean you can't get periods of cold and snow. I just question if anything is going to be sustained for more than three or four days in any one place.
So let's talk snow. In the years I looked at for "best matches," I checked out the snowfall totals for various places. The range I predict is the first number. What is "normal," for a season is the 2nd number.
Syracuse: 120-130" (121")
Utica: 95-105" (98")
Albany: 65-75" (63")
Boston: 45-55" (43")
New York City: 25-35" (22")
Philadelphia: 20-30" (19")
Washington DC: 16-26" (15")
Atlantic City: 15-25" (13.5")
The bottom line this winter may end up being that we see an active southern branch of the jet stream (which often happens in El Niños). The question becomes then whether or not we see enough cold air in place in concert with that active southern branch to produce good snow in places from DC north. I would bias a snowfall forecast slightly higher than normal, given this setup and the fact that we've already had a couple decent nor'easters this autumn (sometimes that pattern carries over into winter). Snow totals may fall short in the Lakes though, as there may not be quite enough cold to general real good lake effect snow. However, 2006-2007 was an El Niño year, and that produced incredible lake effect snow...primarily from Jan 20th onward. So something to watch.
One thing I did notice in the years I looked at were some extremes...on both sides of the coin...years with no snow, years with oodles of it. So that would be a major caution going forward.
So there you have it. Again, just for fun and for my own practice. We'll see what ultimately happens.
