North Atlantic Oscillation

Living in the northeast and being a meteorologist, you MUST know about the North Atlantic Oscillation since it is the main drive in our weather! We also need to go over the PDO, AMO, ENSO, PNA, AO, and Solar output. When we take this atmosphereic, ocean current, and solar trend, by putting them together we get a good picture of what this winter will be like. This is my winter forecast!

For the coldest and snowiest winter we want:

-A negative NAO
-neutral ENSO

-Cool PDO

-Warm AMO

-Low Solar output

-Positive PNA

-Negative AO

Lets start off with the ENSO, better know as the El Nino Southern Oscillation. During the past two we had a El Nino in 06-07 and a STRONG La Nina in 08-08. Neither of these winters were all that cold or snowy for our region. The El Nino is 06-07 brought warmer than normal temperatures and most of the winter precipitation was in the form of rain which in my book is not a very good winter. The colder and snowier the better, right? The la nina of 07-08 brought slighty warmer than normal temperatures but that wasn't why we lacked snow. We didn't recieve a lot of snow because the upper levels of the atmosphere were well above normal because of the ENSO. This made it much more difficult to support snow and ice and sleet was a more common type of precip. Now as we look toward the ENSO this year it is neutral, this means there is no el nino or la nina. Under the right conditions this type of winter could produce a lot of snow and cold. To learn in depth about the ENSO see the following: http://www.cdc.noaa.gov/ENSO/

Well now that the ENSO is in a perfect trend what about the PDO, know as the Pacific Decadal Oscillation. The PDO shifted into a cool phase this year after being in a warm phase for 30 years, and in fact it's the strongest cool PDO since 1955. The cool phase of PDO does have a global temperature affect and since the PDO turned cool world temperatures in 2008 dropped 0.56 degrees celcius. If you want to learn more about PDO check it out here: http://http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/ca-pdo.cfm

in with the PDO is the AMO (Atlantic Multidecadal Oscillation). The AMO and PDO need to be looked at together since different combinations of the two can influence our weather. The best possible conditions for a cold and snowy winter is having a cool PDO and a warm AMO. The warm AMO can produce stronger coastal storms and hurricanes while the PDO brings cooler weather. Well thats the trend we are currently in and depending on a few more things this can lead to a winter that is snowy and cold! For more on the AMO: http://nihongo.wunderground.com/blog/Weather456/comment.html?entrynum=107&tstamp=200804

This is the precip associated with AMO and PDO. We have a -PDO and +AMO which typically leads to more precip:

This just shows the general trend of the AMO and PDO over the past 100 years:

Next on the list is the PNA (Pacific North American Pattern). The PNA positive phase is a reinforcement for low pressure over our region and colder weather while the west is under high pressure and warmer weather. We are actualy in this positive phase now! check out more: http://www.cpc.noaa.gov/data/teledoc/pna.shtml

The Arctic Oscillation (AO) is another interesting topic of our climate. In fact many believe that since it has shifted phases 30 years ago it accounts for almost all of the ice loss in the Arctic region. Here is that link: http://uwnews.org/article.asp?articleid=3261 Ironically when the stratosphere is colder less cold air can move into the North American continent and for the past 30 years it's been in this trend, what we want is a negative or warm AO which leads to cooler weather. As of October 2008 we are in a mostly positive phase which means harsh long term cold is not expected. To read more on the AO see here: http://www.arctic.noaa.gov/reportcard/atmosphere.html

Another factor when it comes to climate is the sun. Since the sun has been very inactive, solar output is at extreme lows, solar magnetivity is at near record lows, and solar wind is at record lows. This means less energy is reaching earths surface and therefore cooling, also with a weaker solar wind more cosmic rays can enter our atmosphere. More cosmic rays create nucleation sites which leads to more clouds. These clouds will most likely mean the winter day time highs will be lower than normal but the night time lows will be higher than normal.

The North Atlantic Oscillation which happens to be one of my favorite meteo topics! The NAO has a strong influence over the coastal North Atlantic and when it is negative expect low pressure and cold. Check the latest NAO here: http://www.cpc.noaa.gov/products/precip/CWlink/pna/nao.shtml. This link provides information on both PDO and NAO http://www.ncdc.noaa.gov/paleo/ctl/clisci100.html. We are currently in a long-term positive trend which generally means warmer air and high pressure. But the NAO does go negative often in the winter but remains mostly positive. Hopefully things will change this year because the 30 shift should be happening fairly soon.

All these leads me to believe that winter temperatures will be near normal, day time highs will be below normal but the over night lows will be warmer than normal. With the AMO/PDO in their current phase it suggests that in working with the NAO winter will bring above average precipitation and season snow totals will finally get back to normal to above normal. Whenever the NAO goes negative in the winter I can almost say that a coastal storm will form! Thats a good thing for snow lovers. We will have some extreme cold days but because of the AO trend it doesn't seem likely that harsh long-term cold will be the case this year, which is good because really cold weather lowers seasonal snowfall. Remember check the NAO often! Here is the forecasted seasonal snowfall.

For the coldest and snowiest winter we want: we don't have our negative NAO or AO but they can trend negative for a brief time over the winter and this is when the action can get underway!
-A negative NAO

-neutral ENSO
-Cool PDO
-Warm AMO
-Low Solar output
-Positive PNA
-Negative AO