The Climate Prediction Center (CPC) released an updated winter forecast last Thursday. Most of the year they were forecasting a higher than normal probability of a warmer than average winter, but with their latest forecast, they are now predicting a higher than normal probability of a colder than average winter.
Why the change? I can not say for sure, but it is probably because the El Nino the CPC thought was going to form, in turn, has not yet formed and there are significant doubts one will form in the upcoming months. An El Nino, the warming of the equatorial waters in the Pacific Ocean, often brings warmer than average winter temperatures to this area, although, the last El Nino in 2009-2010 did not.
Seasonal weather patterns tend to be dominated by a number of factors, not just one and most of those influences are very difficult or impossible to forecast more than a couple of weeks in advance.
Here is the latest forecast from the CPC.
In the spring, we are often looking forward to recording our first 60, 70 or 80 degree day of the year. In the autumn on the other hand, it is difficult to know when we have experienced the last such day of the year.
This past Saturday, the official high temperature was 88 degrees and based on a few conversations, many of you probably felt that was the last hurrah of the season. The average last 80 degree day is September 29, yet, historically an 80 degree high temperature has been recorded approximately every other year during the month of October. Plus, the last day with a record high in the 80s is on October 25.
Although we have cool off in recent days, considering how dry the top soil continues to be, plus the overall warmth we have experienced much of the year, another day or two in the 80s will likely not surprise any of us.
With most North Dakota schools starting this week and Labor Day weekend just a week away, many of you are perhaps thinking about autumn and winter more than the last remnants of summer that we have been experiencing lately. This has been evident in numerous short conversations I have had in recent days as nearly every place I go, the same question comes up. “What will our winter be like?”
With an El Nino developing in the Pacific Ocean you will likely hear that the upcoming winter will be another mild one in this area. Yet, the winter of 2009-2010 was an El Nino winter that ended up very cold and snowy because one single parameter does not guarantee certain weather conditions as many forecasters learned that year.
Therefore, it is too early for a prediction, but one thing I can almost guarantee is this area will probably not experience another record breaking warm winter, meaning, that even if temperatures are near normal this cold season, it is going to feel brutal in comparison to last year.
The phenomenally warm temperatures that we have been and will continue to record this month has many wondering if this has any implications for the upcoming summer. With every year being unique you can never make a definitive forecast. What happens in the upcoming months will be unlike any other year, yet, it will probably at least resemble or as I like to refer to it, rhyme with other years.
Looking back to the 20 warmest Marches on record, 16 of them, or 80%, in turn were followed by a summer that finished with a below average temperature. Granted, several of those years were close enough to the average to be considered “near normal”, but nevertheless finished on the low side of the average. Plus, for those of you who like hot summers, only 1 of those 20 years did the summer finish with a well above average temperature. Precipitation wise, only 2 of those twenty years finished with excessive rainfall contrary to many recent summers.
This should not be considered a forecast, but just an observation.
Once again I was asked by the State Climatologist in North Dakota to write a summary to what I expect for the upcoming season. What I wrote can be found below. It can also be found in the State Climate Bulletin to be published soon.
Spring and autumns are always the most difficult to forecast because of large swings that can and do occur on both daily and weekly time scales. Plus, with so much cold elsewhere on the planet, this spring in particular has the potential for giant swings from warm to cold. These temperature swings can also lead to prolong periods of dry weather intermixed with brief periods of significant precipitation.
Using that as a backdrop, after a mild March that may end up as one of the warmest on record for the region, April looks to be transitioning to colder weather, followed by a near average May. That would mean, overall, an above average temperature for the season, but we always need to remember, that does not mean consistently above average and a poorly timed cold front can easily hamper the planting season.
Although historically when a La Nina is present is the Pacific, this area has a higher than normal likelihood of recording above average precipitation in the spring, the current La Nina is fading quickly and therefore, the odds favor this season to finish nearer to the long-term average for rain and late season snowfall. If that forecast holds, it would be a welcome change from the excessive spring moisture many areas have recorded in recent years.
The latest spring outlook from the Climate Prediction Center (CPC) for the next three months can be seen below.The CPC is forecasting a slightly higher than normal probability of above average temperatures and equal changes of above, below or normal precipitation. You can find the current and future outlooks, when new ones become available, athttp://www.cpc.ncep.noaa.gov/products/predictions/90day.
Also, the North Dakota State Climate Office has links to the National Weather Service’s local 3-month temperature outlooks for the upcoming year. Those forecasts can be found at:http://www.ndsu.edu/ndsco/outlook/L3MTO.html.
Yesterday in this space, I mentioned that our just completed first half of winter was the warmest such stretch since 1881. As the old saying goes, records are made to be broken, plus, as I wrote about earlier in the week, the winter of 1877-1878 may have started even warmer, so the term record is a relative term with a database of only 130 years.
Yet, the past several weeks was still impressive to me in the sense that these exceptionally mild temperatures occurred during a time-frame when many atmospheric and oceanic signals suggested that temperatures would be colder, or at least nearer to the long-term average. Again, our database of past events is limited, especially when it comes to oceanic conditions which have the largest overall impact on our weather, yet glancing through the data, I could not find a winter that started off well above average with similar overall conditions to what is currently present in the oceans and in several atmospheric oscillations currently in play.
Simply put, this winter is a prime example of our limited skill in forecasting beyond 1 or 2 weeks.
You do not need to live in this area very long to learn that weather patterns come and go quickly. Weeks of rain or snow, suddenly turn to weeks with little if any moisture. Cold and warm stretches come and go. Therefore, this winter could quickly turn cold and snowy; yet, using the past as our guide, the snow season will likely finish with below normal snowfall.
Since records have kept, Fargo Moorhead has never recorded the first one inch of snow after December 12 with the seasonal snow total exceeding 50 inches. With our current 30 year average snowfall at 50.1 inches, we therefore would have to do something not done in the past 120 years of snow records to end up with an above average snow season. Plus, if by chance we can make it through the rest of this month without a 1 inch or greater snow event, then historical precedent would suggest our seasonal snowfall would stay under 30 inches.
But in our climate, you never know for sure.
I have been busy with other projects and have not blogged much lately. One of the projects is a WDAY/WDAZ weather calendar that should be available soon at area US Banks. Proceeds will go to Charity. I also put together my annual outlook for North Dakota’s State Climatologist. I have that posted below.
Before General Motors discontinued their Oldsmobile division, they had a marketing campaign with the slogan “this is not your father’s Oldsmobile” to entice younger people to consider the brand. I use this as a reference to the current state of the equatorial Pacific Ocean. Although there are currently La Nina conditions present, just like last winter, to steal that phrase from Oldsmobile, this is not last year’s La Nina. If fact, conditions are barely within the realm of what is considered to be a La Nina, so in other words, it is a borderline event.
During the past few months a persistent ridge of high pressure has resided over the northeastern part of the Pacific Ocean. This has brought generally mild and dry conditions to North Dakota. The flow around that upper-level high pressure system creates a dominant flow from the northwest aloft where little moisture is available to be drawn into the state. Plus, a persistent subtropical jet stream has been locked into place well to our south and that is where most of the moisture-laden storms have been tracking. This pattern has been so persistent that parts of the region have transitioned from very wet into mild drought conditions during the autumn season.
During the next three months, this dominant Pacific ridge should weaken. This in turn will help increase the amount of available moisture, yet still keep us in a normal to below normal precipitation pattern. Also, a transition into more frequent colder than average temperature periods is expected as we head into January and February. For sensible weather this means the odds favor less snowfall then last year, plus, temperatures not as cold as the 2010-2011 winter. Being North Dakota, it is going to snow and of course be cold, but it appears it will not be as harsh as the past couple of winters.
The latest winter outlook from the Climate Prediction Center for the winter currently has a classic La Nina signature to them. These may be adjusted slightly when the newer forecasts come out. You can find the current and future outlooks, when new ones become available, at http://www.cpc.ncep.noaa.gov/products/predictions/90day.
As a reminder, the North Dakota State Climate Office has links to the National Weather Service’s local 3-month temperature outlooks for the upcoming year. Those outlooks can be found here: http://www.ndsu.edu/ndsco/outlook/L3MTO.html.
Yesterday I wrote about how a persistent ridge of high pressure has been present in the northeastern part of the Pacific Ocean for the past few months. There has been some research that has correlated both the location of warm and cool pools of water in the oceans (especially the Pacific) and also on how certain solar conditions help create specific weather patterns around the globe.
Although solar influences are still somewhat controversial, the impact that changes in oceanic temperatures have is not. Although there is a very weak La Nina in the Pacific at the moment, a warm pool of water resides west and north of Hawaii that may be one of the reasons for our current dry weather locally. In fact, similar oceanic conditions were observed during the drought in the late 1980s.
By no means am I saying we are headed for a drought, as this pattern resided for years, not weeks during the 1980s. This setup could easily be a temporary aberration in our current wet phase, but you never say never when predicting the future.