Okay, I would like to begin by saying that I am not a "degreed" meteorologist. I am not paid by the government. I am not even in college *yet. I don't have much experience either. I've been attempting to forecasting the weather for about three or four years now, based upon my limited knowledge of atmospheric science and the countless hours I've spent reading books and participating in internet discussions. I'm certainly not a professional by any definition of the word.
With that being said, I would like to share a few of my thoughts on the National Oceanic and Atmospheric Administration's latest released winter-outlook.
Today, the Climate Prediction Center released its forecast outlook for the months of December 2014 through February 2015, which is generally considered the winter-outlook period by NOAA. Keeping consistent with CPC "tradition", they have released both the temperature outlook and the precipitation outlook.
For one thing, you'll notice that the CPC's outlooks are relatively similar to most other winter-outlooks; they both show expected precipitation and temperature anomalies.
However, the difference between the CPC's outlook and most other outlooks is that the CPC relies upon probabilities for the map. If you'll notice the maps [see above], the defining feature of the shaded regions is that of probabilities. The probabilities indicate the amount of certainty that climate forecasters at the Climate Prediction Center have for that particular forecast. For instance, in the case of the precipitation map, the "wetter" regions are actually regions where the CPC is MORE confident that higher-than-normal precipitation will occur during the winter months. In the case of the temperature maps, the "warmer" regions denote regions where the CPC is more confident that higher-than-normal temperatures will occur.
There is also a large region of "equal chances" on both maps. This is a category that the CPC uses when it is most uncertain about a specific forecast. In reality, it just means that the outlook for these regions is highly uncertain and could swing either way.
But I have a major criticism of this type of forecasting.
And take them for what they are-- opinions. That's it.
My problem with the CPC's forecast is two-fold. In the first place, the forecast is too general and vague for anyone in the general public to take seriously. The CPC would be better off not releasing a public forecast such as this and keeping quiet about press-releases. Of course, it is the job of the CPC to release long-range outlooks such as this. But it is all too easy for the general public to misunderstand what is actually being said. Most will take a first glance at the maps and then conclude that the Great Lakes will be dry and normal for the winter [probably good news for anyone who hates snowy, cold weather!]. Yet, that is precisely what the CPC is NOT saying! In other words, the CPC is about as bad at communicating statistical information to the public as USAToday is.
My second criticism has more to do with my own personal thoughts on the winter.
First, I think the forecast is too reliant upon the fact that an El Nino is developing in the Equatorial Pacific. While it is not certain how strong the El Nino will become in the next few months, recent strengthening of warm SST anomalies along the Equator has lead many forecasters to believe that a long-term El Nino is finally developing [having been forecast to do so two years ago].
According to what the "textbooks" say about a general El Nino pattern, a general rule of thumb for the winter-outlook is that the winter will feature above normal temperatures across the northern United States, Canada, and Western North America. Also included in this "rule of thumb" is that the Ohio Valley and Great Lakes will generally see below normal precipitation, along with equal chances of being warm or cold for the winter-months. Most importantly, an El Nino usually correlates with a cold, wet Southern winter.
As you can see, this "textbook" definition almost exactly matches the forecast released by the CPC today.
I agree that an El Nino is developing in the Pacific. A more dominant +PDO, along with warmer waters in the Western Pacific will definitely allow it to develop further.
However, given the weak state of the El Nino currently [in fact, it isn't even officially classified as an "El Nino" until SST anomalies have been consistently above +0.5 C for three months or longer], there is no reason to believe that it will be the main factor driving the winter-time pattern, as it was with last winter season. Generally, the stronger the El Nino, the stronger the response farther north. However, in this case, the response probably won't even develop in time for the early winter season.
From what I have seen, there are much greater factors that must be taken into account.
First, I think that we will see an active Pacific jet, with a stronger southern jet towards the end of the winter. Why? Because a strong Aleutian low will likely dominate off the West Coast of North America, likely leading to a stormy pattern along the coast and farther inland. With an active Pacific jet, snow-cover across Canada will likely have a much longer chance to build southward, allowing for the long-term development of a stronger Arctic air mass.
Secondly, I believe that a lack of blocking will characterize at least part of December. Unless we see a return to an overall blocking pattern soon, I see no reason why it should rebuild before December. Of course, it's very likely that blocking will redevelop by later in the winter [for several reasons], but December will likely feature near normal temperatures for most of the United States, with a general stormy trend.
Lastly, I believe that blocking will return by the latter portion of the winter. Stratospheric warming events have a much higher likelihood this winter, and when they do happen, they generally lead to an increase in blocking over the Arctic regions. If this is the case, I expect a downtick in storminess towards January and February, but with overall colder conditions. While storminess may increase along the East Coast and South, drier and colder conditions will likely prevail in the Northern Plains and Midwest.
Even though I have a lot of respect for the CPC and their forecasts, I do not believe that their winter outlooks are overly helpful, and in many cases, I strongly disagree with their conclusions.
*I am going to be going to college soon however. I will probably be going into the field of meteorology or some related mathematics/physical science.
With that being said, I would like to share a few of my thoughts on the National Oceanic and Atmospheric Administration's latest released winter-outlook.
Today, the Climate Prediction Center released its forecast outlook for the months of December 2014 through February 2015, which is generally considered the winter-outlook period by NOAA. Keeping consistent with CPC "tradition", they have released both the temperature outlook and the precipitation outlook.
For one thing, you'll notice that the CPC's outlooks are relatively similar to most other winter-outlooks; they both show expected precipitation and temperature anomalies.
However, the difference between the CPC's outlook and most other outlooks is that the CPC relies upon probabilities for the map. If you'll notice the maps [see above], the defining feature of the shaded regions is that of probabilities. The probabilities indicate the amount of certainty that climate forecasters at the Climate Prediction Center have for that particular forecast. For instance, in the case of the precipitation map, the "wetter" regions are actually regions where the CPC is MORE confident that higher-than-normal precipitation will occur during the winter months. In the case of the temperature maps, the "warmer" regions denote regions where the CPC is more confident that higher-than-normal temperatures will occur.
There is also a large region of "equal chances" on both maps. This is a category that the CPC uses when it is most uncertain about a specific forecast. In reality, it just means that the outlook for these regions is highly uncertain and could swing either way.
But I have a major criticism of this type of forecasting.
And take them for what they are-- opinions. That's it.
My problem with the CPC's forecast is two-fold. In the first place, the forecast is too general and vague for anyone in the general public to take seriously. The CPC would be better off not releasing a public forecast such as this and keeping quiet about press-releases. Of course, it is the job of the CPC to release long-range outlooks such as this. But it is all too easy for the general public to misunderstand what is actually being said. Most will take a first glance at the maps and then conclude that the Great Lakes will be dry and normal for the winter [probably good news for anyone who hates snowy, cold weather!]. Yet, that is precisely what the CPC is NOT saying! In other words, the CPC is about as bad at communicating statistical information to the public as USAToday is.
My second criticism has more to do with my own personal thoughts on the winter.
First, I think the forecast is too reliant upon the fact that an El Nino is developing in the Equatorial Pacific. While it is not certain how strong the El Nino will become in the next few months, recent strengthening of warm SST anomalies along the Equator has lead many forecasters to believe that a long-term El Nino is finally developing [having been forecast to do so two years ago].
According to what the "textbooks" say about a general El Nino pattern, a general rule of thumb for the winter-outlook is that the winter will feature above normal temperatures across the northern United States, Canada, and Western North America. Also included in this "rule of thumb" is that the Ohio Valley and Great Lakes will generally see below normal precipitation, along with equal chances of being warm or cold for the winter-months. Most importantly, an El Nino usually correlates with a cold, wet Southern winter.
As you can see, this "textbook" definition almost exactly matches the forecast released by the CPC today.
I agree that an El Nino is developing in the Pacific. A more dominant +PDO, along with warmer waters in the Western Pacific will definitely allow it to develop further.
However, given the weak state of the El Nino currently [in fact, it isn't even officially classified as an "El Nino" until SST anomalies have been consistently above +0.5 C for three months or longer], there is no reason to believe that it will be the main factor driving the winter-time pattern, as it was with last winter season. Generally, the stronger the El Nino, the stronger the response farther north. However, in this case, the response probably won't even develop in time for the early winter season.
From what I have seen, there are much greater factors that must be taken into account.
First, I think that we will see an active Pacific jet, with a stronger southern jet towards the end of the winter. Why? Because a strong Aleutian low will likely dominate off the West Coast of North America, likely leading to a stormy pattern along the coast and farther inland. With an active Pacific jet, snow-cover across Canada will likely have a much longer chance to build southward, allowing for the long-term development of a stronger Arctic air mass.
Secondly, I believe that a lack of blocking will characterize at least part of December. Unless we see a return to an overall blocking pattern soon, I see no reason why it should rebuild before December. Of course, it's very likely that blocking will redevelop by later in the winter [for several reasons], but December will likely feature near normal temperatures for most of the United States, with a general stormy trend.
Lastly, I believe that blocking will return by the latter portion of the winter. Stratospheric warming events have a much higher likelihood this winter, and when they do happen, they generally lead to an increase in blocking over the Arctic regions. If this is the case, I expect a downtick in storminess towards January and February, but with overall colder conditions. While storminess may increase along the East Coast and South, drier and colder conditions will likely prevail in the Northern Plains and Midwest.
Even though I have a lot of respect for the CPC and their forecasts, I do not believe that their winter outlooks are overly helpful, and in many cases, I strongly disagree with their conclusions.
*I am going to be going to college soon however. I will probably be going into the field of meteorology or some related mathematics/physical science.
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