*Highlights Compared To Last Winter
We are coming off one of the harshest winters in the past 50 years, but this winter season will be much different. The average temperature will be nearly 6 degrees warmer than last winter and that means big savings. The average family living in a 1600 sq ft home that spent a total of $530 on their energy bill from December to February last year may only pay around $437 this year which is a $93 savings (about $1 a day), based on the expected heating degree days. In other words, energy bills in our area are expected to be 15 to 20% lower this year compared to last year. Fort Smith saw 18″ of snow last year, this year a yearly snow total of 3″ is more likely. Northwest Arkansas picked up on 25″ of snow last year but this year totals will likely fall short of the 10″ mark. Before you think Old Man Winter will leave us alone this year consider this, we have a 60% chance of a significant ice storm. This is much higher than the risk during last winter season. More details are below!
The Super Doppler Storm Team has been hard at work over the past few weeks putting together the winter forecast. The temperature forecast for Eastern Oklahoma and Western Arkansas this winter is for above average temperatures. The active storm track across the northern part of the country will lead to warmer than normal conditions across the south and the Midwest. Below normal temperatures are expected for the Pacific Northwest and Alaska.
Precipitation & Snowfall
Precipitation across Eastern Oklahoma and Western Arkansas is expected to be near average to slightly below average. Snowfall is expected to be below average across the river valley and near average to slightly below average in northwest Arkansas. The River Valley averages about 3 -7″ of snow a year, this year we are forecasting 2-4″ for the entire year. Northwest Arkansas averages between 6 – 14″ of snowfall a year with Gravette picking up the most snow with an average of 16.2″ each season, we are forecasting that much of northwest Arkansas will pick up an average of 6-10″ this season. This year’s snowfall forecast is a huge difference from last season when an average of 18-20″ of snow fell in the river valley and over two feet fell in northwest Arkansas during the winter season.
Around the nation, Southern California is expected to see dry conditions while the Pacific Northwest will see very wet & snowy conditions. The Midwest will likely see warm but stormy conditions with above average snow this season. Severe drought is expected to develop across much of Texas due to warm and dry weather lasting through at least spring.
Ice Storm Risk
Unlike last year, the average placement of the jet stream will be much further to the north across the central part of the country this year. This is a favorable pattern for significant ice storms (at least a 0.25″ of ice accumulation over a large area). In the past 60 years, we have only had a strong El Nino followed by a strong La Nina the following year 3 times. Out of those La Nina seasons, every one of them brought a significant ice storm. Out of the 5 strongest winter La Nina events in the past 60 years, 3 of them produced a significant ice storm, and one of them produced 2 significant ice storms. So what does all of this mean? The risk this year will be higher than normal. In fact we feel that there is a 60% chance for a significant ice storm during the 2010-11 winter season.
Normally the severe weather season begins after the last day of winter, but that probably won’t be the case this year. Spring will probably come early with severe weather possible during late February and March this year. Normally our busiest part of the severe weather season comes in April, but hot & dry weather could dominate the latter half of the spring season.
*Ingredients Leading To This Winter’s Forecast
There are a few key factors that will impact the winter forecast. The biggest factor is the intensifying strong La Nina. This will likely become the most dominate ingredient to the upcoming winter season. Another factor is the ongoing warm & dry pattern that is currently affecting the area. We also took into consideration the latest CFS projections (a short term climate model). On most years there is a number of other factors that often make a big splash to the winter pattern’s such as the Gulf of Mexico water temperatures, NAO, PDO, AO, soil moisture, and the current snow pack in Canada. At this point, all of these levels are at or near normal. As a result, we don’t expect any of these factors to make a huge impact on the overall winter pattern this season.
*Winter’s Of The Past
After taking all of this data we found 14 years since 1950 that have had similar set ups. These 14 winter seasons then became our analog years. Out of these 14 years, 10 of them had a similar summer and fall pattern compared to this year. We also looked very closely at our top 3 analog years which are the only 3 other times in the past 60 years that we have followed up a strong El Nino by a strong La Nina within one year. All of this helped give us some insight into the upcoming winter’s forecast.
The 14 analog years are in order of similarity compared to the current and expected winter pattern this season 1988-89, 1999-00, 1998-99, 1975-76, 1973-74, 1949-50, 1954-55, 2007-08, 1962-63, 2000-01, 1995-96, 1970-71, 1955-56, and 1964-65.
Out of these years there is a wide-spread in snowfall totals, precipitation, and temperatures. In the river valley only two seasons produced above normal snowfall, half of these years had above normal snowfall in northwest Arkansas and the other half had below normal snowfall. However, 4 out of 7 of those below normal snowfall seasons in northwest Arkansas only had a couple of inches for the seasonal totals. While a few years were at or below normal for temperatures, most were above normal averaging about 2 degrees above normal. Significant ice storms occurred twice as often during our analog years than normal. However, rainfall totals were all over the place in our analog years from the driest winter season on record in 1962-63 with only 2.5″ of rainfall over the entire winter season to over 12″ in a couple of the years.
*Detailed Forecast By Month
December will be cold in the eastern part of the country and warm in the west with us right in the middle. A couple of brief arctic blasts are expected before moderating quickly in temperatures. All in all, it should be near average in temperatures and below normal in precipitation for both the river valley and northwest Arkansas. Below is what happened during our analog years.
The overall weather pattern across the country will moderate in January. The trough will flatten across the east and a powerful pacific jet will take over dumping lots of cold & snow in the Pacific Northwest and allowing warmer than normal weather to move across our area. Temperatures are expected to be about 1.5 degrees above normal with average precipitation. The most interesting time frame during our analog years was during late January when an active pattern develops and snow and ice chances go up. Below is what happened in our analog years.
February will likely be our most active month. A powerful jet stream will stay just to the north of our area. The storm track is favorable for more ice chances at the start of the month, however we may quickly jump from winter to spring throughout the month. An active jet stream and a strong southerly wind should bring moisture and warmth into our area frequently. This is a favorable set up for not only ice, but also severe weather in late February. Temperatures are expected to be 2.5 degrees above normal along with above average precipitation. Below is what happened during our analog years.
Near seasonable weather is expected here at home with no clear signal to whether it will be an active month. Severe weather chances will continue at times. Here are the analog maps.
April & Beyond
The analog maps become concerning in April through June. Keep in mind a lot could change between now and then but at this point very dry conditions could dominate the spring season. Here are the analog maps for April.
A death ridge is expected to develop during April keeping severe weather chances and precipitation much lower than average along with above normal temperatures. Some of the latest model forecasts have the potential for this La Nina event to become the strongest on record and peak in April. If that really occurs the dry & hot summer weather will likely start even earlier in 2011. Again, these forecasts may change drastically and in fact just a month ago the models showed this La Nina fading away by spring, so we will have to wait and see. If the La Nina does hit near record levels during our rainy season and stay that way through the summer, drought will become a huge concern!
Ross Ellet & Drew Michaels
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