I started looking at the computer models this morning, and I usually look at the GFS first since it appears first in the list of modes on the WeatherBELL site. I got out to around day 10-11 and and my jaw hit the floor. The GFS was bringing the whole arctic into the US.
The images are explained below, but what the GFS is showing are temperatures 40-50 degrees below normal. Lows in north Georgia would be in the single digits if not lower, and highs would struggle to get above 20.
But.... there is a possibility of a big storm during that period. THIS is the storm and period we can't afford to miss out on, so we'll wait and see if the low takes a more southern track. There is a lot of time for this pattern to evolve but it appears to be a prime period for winter weather. Just a reminder that these images are not a forecast, but one model run from one model. But we are certainly headed the correct direction for winter weather.
EDIT: In my total lack of foresight (read that as very little thought), I failed to remember I was looking at 5 day averages.... therefore this test is over. On to a new one.
I thought I'd run a little test to find out how reliable the new GFS Ensembles are this winter, so I'm collecting maps beginning 7 days out. I have the temp anomalies, 850 temp anomalies, and 500 mb anomalies, all 5 day averages for the period from the 8th through the 13th. Because they are 5 day averages, the changes "should" be slow to show up. I'll be adding to this daily, and the next go around I'll be looking at the operational runs as well to see how those compare. These start with the 12Z runs from today, Thursday, January 7th.
EDIT: I will be adding additional information to the bottom of this post until I do the next one around October 1. Please check back for updates, I'm sure they will be frequent!
As we approach meteorological fall (September 1), I thought it would be a good time to take a long range look at our potential for winter weather for this upcoming 2014-2015 winter season. I'm ready for winter, so I had to share what we currently believe may happen. The outlook is based on the factors that are currently in place, and/or expected to be in place by the time winter arrives. Keep in mind, no one has that crystal ball that will tell us what's going to happen this winter (although if you know of one for cheap, I'm in the market... :-)), but if we take the time to look at similar weather patterns from the past, we can use those analogs to help to predict what may be in store for us in the future.
One of my weather buddies is a weather statistician, particularly regarding Georgia weather. But Larry (aka "Brother Larry" if you've followed my past Patch.com blog) also keeps stats on Nina/Nino events as well as other types of weather information, and has been spot on in the past about statistically analyzing past winter weather seasons and providing probabilities for future events. Fun stuff! Larry has graciously allowed me to quote him about some of the statistical probabilities for the weather this winter in the Atlanta area, so many thanks to Larry and his hard work putting these statistics together.
In Larry's post, he makes reference to several teleconnection indices as well as the ENSO status. Here are some links to those indices that will help you better understand what he's talking about. Click on a specific bullet item for further information:
Right now, the highly touted "Super Nino" that many expected to materialize, has not happened and doesn't appear likely to happen. It now appears that a weak to neutral Nino may occur in it's place. Typically, weak El Nino's have brought great winter weather to the southeast (great meaning if you like winter weather!), and I have more on that below in Larry's post.
The PDO has been in a positive phase for the first 6 months of this year, and a +PDO (plus weak Nino) is what we want for winter weather here in the southeast. Note that with a +PDO, or positive phase, the "wintertime Aleutian low is deepened and shifted southward, warm/humid air is advected along the North American west coast and temperatures are higher than usual from the Pacific Northwest to Alaska but below normal in Mexico and the Southeastern United States. Winter precipitations are higher than usual in the Alaska Coast Range, Mexico and the Southwestern United States but reduced over Canada, Eastern Siberia and Australia". Keep in mind that a strong Nino would reduce precipitation here, but a weak one actually increase our chances for winter weather.
Keep these facts in mind as you read Larry's post.
Larry's Winter Weather Statistics for Atlanta...
In his free video from this weekend (click on the link below), Joe Bastardi shows a map with a prediction from WeatherBell.com of a very cold Southeast winter. He has much of the SE US near or even colder than 4 F below normal. In all of the years of following JB, I can't recall a forecast quite that cold for the SE. However, IF there really ends up being a weak Nino fall/winter peak, a +PDO, and a -NAO, I could see this or even colder than this actually happen. Perhaps he is already thinking somewhat along those lines.
You can see from Larry's post, it's not any one factor that determines what the winter is going to be like, it's the interaction between all of the different teleconnections (and a little luck) that determines what happens.
So for now, it looks like a possibility of below normal winter temperatures with normal to above normal winter precipitation for the Atlanta metro area.
All of this is dependent on the strength of the Nino during the fall and winter season, so as we get closer to winter, I'll have several additional blog post about how all of this is playing out. Look for another one around October 1 and again right around November 1.
UPDATE - 08/17/14