Bill Steffen's Winter 2009-10 Forecast

GRAND RAPIDS, Mich. (WOOD) - Let’s see how I did in the 2008-09 forecast: I got the above-normal snowfall right. I wasn’t quite high enough on the totals, but I don’t think I’d ever forecast +100″ in a mid-fall forecast.

There is so much to study when making up a winter forecast. I look at the prevailing upper level winds, world sea-surface temperatures, the cold that builds up by mid-Autumn in the Arctic, sunspot cycles, the Atlantic, Arctic and Pacific Decadal Oscillations, 2009 Atlantic hurricane patterns (a very wimpy year for tropical storms), the number of 90-degree days we’ve had during the previous summer (7 in the last 2 summers combined, average is 9.5 for one summer), and the current state of La Nina/El Nino. We look back through our weather history to find correlations to the current conditions around the northern hemisphere and years when similar conditions were prevalent in the fall.

Any forecast is a guess, an “educated guess”. The data base and the computer models aren’t good enough for near perfect forecast (won’t be in my lifetime), but long range forecasting has improved with new technology over the past 30 years, especially with weather satellites.

An interesting note: over the past 10 years, snowfall has trended upward in Grand Rapids and Muskegon.

First of all, we are moving back toward La Nina. Last year was one of the snowiest (if not THE SNOWIEST) winter in North America. I don’t think we’ll have a repeat of that, but the pattern would suggest near to above normal snowfall for the Great Lakes.

Winter has come on strong in parts of the Arctic. There is already an extensive snow cover across much of Alaska and Canada.

We have had a very weak severe weather season this year. We’ve only had one tornado fatality in the U.S. since May 13th, and only 22 tornado fatalities for the year. The hurricane season has also been weak over not only the Atlantic/Caribbean, but pretty much worldwide with the exception of the western Pacific.

I also checked many years when we had notable climate events, like the wet weather in October. The wettest years in October have usually brought us above normal snowfall in the following winter.

I think the El Nino will produce above average cloud cover and precipitation across much of the southern U.S.

Having digested all of this and more, I think snowfall this winter over the area will be above average, but less than the totals we reached in 2007-8 and 2008-9.

Here’s the estimated winter snowfall for this year. The first estimate is for 2009-10 (first) compared to the winter snowfall for last year: Grand Rapids – 83″ (104.9″)

• Muskegon – 110″ (148.2″)
• Holland (Tulip City) – 96″ (122.4″)
• Kalamazoo 77″ (103.9″)
• Battle Creek – 58″ (77.7″)
• Lansing 53″ (70.7″).

I think it’ll be warmer than average between now and about Nov. 20, with cold and snow moving in.

The Lake Michigan water temperature is still in the low 50s, still fairly mild. The lake temperature will stop for a week or two around 39 degrees as the lake water “overturns”. This will set the stage for some significant lake-effect snow in very late November into the first three weeks of December. This will likely be with northwest flow, bringing the most significant snow to the lakeshore counties, west of a line from Hesperia to Fruitport to Hopkins to Kalamazoo. We have a 57% chance of a White Christmas in Grand Rapids. Once again his year I think the chance of a White Christmas (snow on the ground) will be at least 75%.

We will see a January thaw with the temperature into the 40s briefly, but I think overall this winter will be 1-2 degrees colder than average.

There is a better chance for a March snow event this year. I’ll add that weak El Ninos usually bring a fairly sharp move to spring, featuring warm weather by May.

All this will mean we’ll have to spend a fair amount of money on plowing, sanding and salting. That will be a concern as the winter drags on during these financially lean times. So, don’t be afraid to get the season ski pass, get the snowmobile or cross country skies ready or find the ice fishing equipment. Winter is definitely on the way!

This pattern will mean only brief incursions of cool air to central and southern Florida, so if you want to escape the cold, that would be a nice place to be.

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