We are now just one week away from the start of winter. You may think winter begins on December 20th, the shortest day of the year, but from a weather perspective, winter is the three month period of December, January and February. We’ve enjoyed a relatively mild (albeit wet) fall, with temperatures yet to drop below freezing in the metro Atlanta area, but that will change soon.

The latest predictions from the weather service for winter are pretty much in line with earlier forecasts. Much of the South and Mid-Atlantic states have a 40% chance of colder than normal weather, while the upper Midwest and northern states should be warmer than normal. This is a typical winter pattern in El Nino years like we have this year.

The precipitation forecast also reflects typical El Nino conditions, with wetter than normal conditions stretching from California along the southern US border to South Carolina, and drier than normal conditions centered over Tennessee and Kentucky. This puts Georgia right in the middle, with the north likely dry, normal in the middle, and wet in the south. Exactly where the dry/wet lines fall could make a big difference in how the weather plays out.

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The winter weather forecasts for 2009-2010 have arrived, and there appears to be a lot of agreement between the three I have reviewed so far. This winter (December through February) is likely to be affected by an El Nino episode that alters the jetstream patterns, especially the southern branch, bringing a colder, wetter winter for most of the southeast and mid-Atlantic States.

The Weather Service predicts a better than 40% chance of cooler than normal weather in Virginia, North Carolina and Georgia, and the southern half of Alabama, Mississippi and Louisiana. Kentucky, Tennessee, and the northern half of the deep South are also likely to be cooler than normal. Much warmer than normal conditions are expected in the northern Great Plains and Rocky Mountain states, with warmer than normal conditions in Wisconsin, and stretching south into Nebraska and New Mexico.

The Accuweather winter forecast restricts the much below normal temperatures to Tennessee, Alabama and Mississippi, along with northern Georgia, western Virginia, and the western Carolinas. They predict above or below normal temperatures for the entire country, with no area set for normal temperatures.

The Weather Service precipitation outlook calls for a much greater chance of rain in Florida south of Orlando and in south Texas, with above normal precipitation in southern Georgia, most of Texas, and in California. Drier than normal weather is expected in the mid-Mississippi valley and in the northwest. The rest of the country has equal chances of above or below normal precipitation.

The Accuweather forecast brings the above-normal precipitation chances further north, covering the Carolinas, Georgia, Alabama, Mississippi, and west to New Mexico, and north into California. Dry conditions are expected in the midwest and upper Northwest.

All of this means that the metro Atlanta area has a better than normal chance of seeing snow or ice this winter, especially when compared to the last few years. And that is what WSB Radio meteorologist Kirk Melhuish says in his preliminary winter outlook. Melhuish predicts normal temperatures and above normal precipitation in the Atlanta area, with an above normal chance of ice and snow. He will issue a final outlook around Thanksgiving.

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Our friends at the Climate Prediction Center have finally released their 2008/2009 winter outlook, which calls for warmer then normal temperatures for much of the Mississippi Valley states, and drier than normal weather for most of the southeast and Gulf Coast. Here’s the temperature outlook:

And here’s the outlook for precipitation:

The CPC admits that without strong signals for either an El Nino or a La Nina winter, it presents a challenge to create its outlook, and admit that there could be a lot of variability in the weather this winter:

“These patterns are only predictable a week or two in advance and could persist for weeks at a time,” said Michael Halpert, deputy director, Climate Prediction Center. “Therefore, we expect variability, or substantial changes in temperature and precipitation across much of the country.”

if the outlook holds true, Georgia will experience a warmer than normal winter in the northwest part of the state, extending through the Atlanta metro, with less than normal precipitation, especially in the southern part of the state. The winter outlook is based on the CPC’s normal 3 month outlook for December, January and February which was released on Thursday, and pretty much follows the ideas they have had for the past few months.

I don’t know how much faith I have in their outlook, though. So far in November, Atlanta is running about 2.6 degrees cooler than normal, and I don’t see that trend changing through December. (The rainfall deficit seems to match the weather service’s ideas, though.) So if December is cooler than normal, we’re going to need a warm January and February to make up for it.

Updated winter forecasts from Accuweather and others will be available soon, and I’ll keep you posted.

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With winter just a month away from a meteorological perspective, it’s time to take a look at some of the forecasts that have been issued for a glimpse of what the season will bring.

We’ll start with the always interesting and sometimes reliable Old Farmer’s Almanac’s prediction for the southeast, which includes much of North Carolina, South Carolina and Georgia. Overall, they expect cold temperatures and normal to above normal precipitation, with more precipitation in the south. Look for above average snowfall, and the coldest weather in mid to late December, mid-January and mid-February.

On the other hand, Accuweather’s Joe Bastardi says to expect colder than normal weather for much of the east, with December being the coldest month relative to normal, a January thaw, and then cold again in February. The East can also expect more snow than last year.

WSB Radio forecaster Kirk Melhuish released his preliminary winter outlook this week, and it is similar to Accuweather, with ‘bookends’ cold spells at the beginning and end of the season, and less snowfall and slightly less rainfall than average. Kirk will issue his final winter forecast at the beginning of December.

Finally, what does the Weather Service say? They haven’t done a press release on their outlook as they have done in past years, so all you can do is look at their 3 month outlook for December-January. Unlike the other forecasts, the Climate Prediction Center thinks we have a better chance than normal for warmer weather. They also predict a 33% chance of drier weather, especially in mid and south Georgia.

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Reader Morgan wanted to know if we were likely to see some relief from the drought and any changes to the climate patterns we’ve been seeing over the past few years.  While I wish I was as prescient as he makes me appear, let’s take a look at what might happen this winter.

We’ll start with the three month outlooks from the Climate Prediction Center. The three month outlook from October through December calls for equal chances of above or below normal temperatures and precipitation for the period east of the Mississippi River.  Note this doesn’t mean a ‘normal’ fall season–it’s more like the indicators they are using for the outlook don’t point strongly one way or another.

For the winter proper, from December, 2008 through February 2009, the CPC says we’re likely to see warmer than normal temperatures for most of the US, and drier than normal conditions in the southeast, including Georgia. Based on what I’ve seen in the past, this prediction is likely to become the ‘official’ winter outlook that the Weather Service will release in Mid October.  You’ve got to take these outlooks with a grain of salt.  In their Winter 2007-08 outlook, they predicted a warm and dry seaon, while in actuality, the results show we did have above normal temperatures in Georgia, but we also had above normal rain.

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