"He's Baaaack!"; El Nino Returns

The El Nino, once thought to be gone, has made a sudden reappearance in the face of what could have been a growing threat of a La Nina.

This past week has brought a new body of warmer than normal water over the western ENSO region, and this can only mean one thing: the El Nino has returned. I declared a few months ago that the El Nino was dead, and I stand by that post. What it did was die off on the surface but remain 'dormant' underwater. It is only now that we are seeing this underwater warm pool move towards the surface, and in response we see this new El Nino-style body of water.

Remember when I started saying that there was cooling that resembled a La Nina? Well, it died off. It's still there, and you can see the blue blob off the coast of South America on the image above. However, as it began moving west, there was no sustained cooling in its original formation along the coastline. That said, this scare is over.

So, all is back to normal. The El Nino seems to have returned, and will strengthen if the underwater warm pool continues to move towards the surface. Considering it's west-based this time around, the temperature anomalies favor a warm West US and cool East US, as shown below.

Andrew

El Nino Is (Temporarily) Dead

The latest sea surface temperature anomalies across the Equatorial Pacific indicate that the El Nino has dropped off and disappeared, temporarily making this El Nino dead.

The reason I say temporarily is because underwater anomalies are still in an El Nino stage. However, these warm waters are not near the surface and are several dozen meters below the surface. As I have been saying for the last week or more, this El Nino is struggling, and this only continues to prove my case that the El Nino is dying off.

I believe that we still are in an El Nino, only because this is the first update that shows no warm SST anomalies. However, if the same scenario is shown next week, the probability of a neutral winter will skyrocket in my eyes.

ENSO monitoring regions are still hovering around positive-neutral temperatures (just below 0.5 degrees above normal), so we know that the El Nino is not completely killed off. However, this is a big step as far as the potential for a neutral winter, possibly hinting at a La Nina into spring or summer.

Andrew

Model Data Suggests El Nino Will Not Be Recognized This Winter

Table courtesy of BOM/AU.
Model forecasts can be found here: http://www.bom.gov.au/climate/ahead/ENSO-summary.shtml

New model data is suggesting that the El Nino being so tediously monitored in recent days will not be recognized in time for winter. Before we make any conclusions, let's divide these forecasts into a couple categories to enhance better understanding of the situation.

The first category will consist of the first 3 models- the Australian POAMA, the American CFSv2, and the French ARPEGE model. The crucial thing that must be noted with these models is that they started in early September, giving them an advantage over the other models that were started earlier than this. Also, note that these 3 models have a totally different viewpoint on the next 1-3 months, with all models indicating a neutral 1-3 months in terms of ENSO. More monumental is the 4-6 month forecast that covers the winter months. All 3 models now suggest a NEUTRAL winter is in store. Considering underwater cooling is appearing, at the atmosphere remains very stubborn on accepting this El Nino, I can definitely see this as a possibility.

The second category will hold the American GEOS-5 model, the European System 4 (off the ECMWF), the Japanese JMA/MRI-CGCM, and the United Kingdom's GloSea model. First off, note that all of these models started their forecasts on August 1st, meaning that they are at a disadvantage to the first 3 models. These models may not recognize the possibly-occurring downfall of the El Nino, thus flawing their forecasts. The first 1-3 months of these model's forecasts hold a consistent El Nino, but in the 4-6 month forecast, note that all but 1 of these 4 models are showing an El Nino still sticking around. In comparison to the first 3 models, I find these 4 at a significant disadvantage based mainly off when they started their forecast. While you may not see this as a big deal, a month can make a huge difference, and I feel that that is the situation ongoing here.

These are model forecasts, which I have never been too fond of in comparison to analogs and observed conditions. However, based on these observed conditions, I do not find the first 3 models' forecasts to be totally out of line. They are definitely possibilities come winter.

Andrew

Using the CFS to Pick Up on the Upcoming Fall Pattern

If you are in to long range forecasting, you know that the CFS model can be a pretty tough model to handle. On one hand, the forecasts can be ridiculous at times. At others, the CFS pays out pretty fairly. Me? I think we can check out what the upcoming fall pattern will hold for us by looking at more short range forecasts.

I was able to get my hands on a few perturbations of CFS 40 day precipitation forecasts. For those wondering what a perturbation is, think of it as an ensemble forecast- each member is from the same model, but starts with slightly different conditions.

These four forecasts are the four perturbations of the CFS 40 day precipitation forecast. We can use this to help define a future fall pattern, and possibly, find some hints to winter.

Analyzing this closely tells me that precipitation will be fairly heavy across two areas: The Southeast and up the East Coast, as well as the Midwest. In cases like these, I prefer to average out all forecasts to get the best possible solution. If we do that, we find the Midwest and East Coast to both be in above normal precipitation sectors into the end of October, suggesting a storm track(s) may be setting up in those areas.

However, forecasts are simply forecasts. We need some more solid evidence to prove if these areas could receive above normal precipitation in the next month or so. Let's look at observed conditions across summer in comparison to fall of this year.

This is the observed precipitation rate from June 1st to August 1st, typically observed as summer in popular culture. Over the summer, we saw a very dry northern Plains and Midwest, as well as parts of the Southeast. Even the Central Plains ended up on the dry end of the spectrum. On the other hand, the Gulf Coast got fairly wet, especially in Texas. The Northwest also breached the above normal line.

Overall, summer was a pretty dry period for the nation, with the jet streams more or less diverting storms into Canada or into the Gulf of Mexico, both of which observed above normal precipitation anomalies.
Now, let's take a glimpse into what August 1st thru September 1st has brought us.

Only a month has passed, and a drastic change has taken place for precipitation anomalies. We are now seeing a wetter then normal East Coast, as well as an above normal precipitation anomaly from the lower Mississippi Valley into the Midwest. This is a drastic change from only a month or two ago, when we were seeing extreme drought conditions prevailing throughout much of the nation. Is it a sign of the upcoming fall? Considering we are technically in an El Nino, this is a sign of a El Nino, as far as the wet East Coast goes. A different story must be presented for the Midwest, however, as that region is usually dry in an El Nino.

September is a transition month into fall, and everything must be watched closely for signs of what's to come as far as winter weather is concerned.

Andrew

Atmosphere May Be Sabotaging El Nino; Robust Winter Prospects Affected

**First and foremost, this post is dedicated to the victims of the September 11, 2001 attacks at the World Trade Centers, The Pentagon, as well as Shanksville, Pennsylvania. Also in this dedication are the first responders and Good Samaritans who both did or did not survive this tragedy.**

New data has come to my attention that suggests that the atmosphere may be trying to sabotage El Nino at this time.

As I reported in an earlier post, the El Nino is on differing pages as for the sea surface temperatures and the atmosphere. The SST's are showing an El Nino is present, while the atmosphere is not positively responding to such a revelation. Let's take a look at what I have found.

Refresh page if animation stops

The animation above shows temperature anomalies in the Equatorial Pacific waters, specifically over the ENSO monitoring area. At the beginning of the animation, we can clearly see an El Nino progress upwards from deeper waters, specifically from the 200 meter mark. The main body of warmer waters is centered further to the east, making this a central-east based El Nino.
However, take a look at the last few frames. We can see the warm waters over the central ENSO monitoring regions actually dissipating, and cold water anomalies forming right below this. These cool waters are actually slightly strengthening, posing a big question as to how formidable this El Nino really is. Could the waters be turning on the El Nino in addition to the atmosphere? Will the El Nino even be around for winter? Let's take a look at what the atmosphere says on that subject.

Let's start with 850 millibar wind anomalies. Above is what an El Nino would bring in terms of 850mb wind anomalies to the world. We want to focus in on the equatorial Pacific, where we see above normal wind anomalies in the fall months. That said, if we were to be looking for a sign that the atmosphere is on board with an El Nino, we would want to see stronger than normal winds at the 850mb level. Let's take a look at what 850mb winds are looking like right now.

Latest observed wind anomalies in the region suggest there is nothing significant suggesting that an El Nino is present. The chart above shows pockets here and there of stronger winds, but by the slightest of margins- and they aren't even in the right places! The fact that there are no lower level winds that would be in line with that of an El Nino greatly concerns me, and concerns my confidence in the potential for an El Nino to take hold in the next several weeks.

We can even look at a larger scale of wind anomalies for the world as a whole, and these results only add to the confusion. In what an El Nino would show as normal to below normal wind anomalies in the extreme southern Pacific, the observed wind anomalies depict a much windier than normal environment in that region. Even the typically-calmer than normal winds in southern India in the midst of an El Nino are replaced by strong winds- a bad sign for the El Nino.

Moving on, we can also use something called the OLR, or Outgoing Longwave Radiation, to measure the ENSO phase. In a nutshell, when the OLR is positive, a La Nina is likely to be present. However, in the negative OLR, an El Nino should be found. Let's take a look at the latest observed OLR values for the last few months, as well as the values for the last several days.

Monthly oLR values over the past several months suggest a low confidence level of the atmosphere, with fluctuations from positive to negative being observed from late spring to the current time.  July did have a low OLR which would signal the presence of an El Nino, but August dashed those hopes, with a +0.2 OLR being observed.
Looking at the last few weeks, fears of an un-Nino like environment are confirmed. Throughout the past several weeks, a notable absence of negative OLR values was observed. Positive anomalies were even found where the El Nino should be, conclusive to a lack of atmospheric support to an El Nino.

But wait- There's More!

Courtesy of University at Albany student 'Carl'

The chart above shows precipitation anomalies currently. Typically, we would expect to see above normal precipitation anomalies both in the circled area and just to the north of the same circled area, where the El Nino appears to be based. However, there is no above normal anomalies in the circled region, and only scattered anomalies across the region shaded in orange and red. This lack of widespread precipitation poses a problem to the development of the El Nino. A continued lack of above normal precipitation would lead to additional concerns over how much influence this El Nino could have over the winter.

In conclusion, this new suite of data I have discovered has led me to believe that the atmosphere is not on the same terms as the sea surface temperatures. Additionally, underwater cooling of the same warm water anomalies is only building concern for how far the El Nino can go, especially into this winter.

Climate models are beginning to back off as far as the intensity of the El Nino goes. In my opinion, this is a very wise choice- some further weakening may even be needed going into late fall and winter, as the El Nino is expected to die down further going into that time frame.

As for winter-- The analog year of 2006-2007 that I posted on the earlier referenced post is looking better and better to me, as long range forecasts encourage a stormy pattern over the central and east US, with ridging in the Northwest. Some of you may know a pattern called the LRC, or Lezak Recurring Cycle, and this may be a part of that cycle that is setting up this winter.

Here are the 2006-2007 winter anomalies.

The winter of 2006-2007 was a wet one for the Ohio Valley and Midwest into the Plains. The probability of this exact scenario is unlikely, and there are always additional margins for error with using only one analog year. However, with each day of the atmosphere and SST's differing on the Nino, the prospect for a 'fake' El Nino grows further.

Andrew

Long Range Arctic Oscillation Pointing Negative

Courtesy Kyle MacRitchie

A long range forecast for the Arctic Oscillation, an index commonly used to distinguish potentials of cold weather, is dipping into negative territory. As shown above, ensemble forecasts of the AO are bringing the index well into negative territory beginning in October and into the winter months.

A continuity of such a negative Arctic Oscillation would enhance cold weather potential over the nation. A negative AO also enhances the chances for a negative NAO, seeing as how close the two indices are. This does not necessarily mean that they will both go negative, but, because they are so close in how they function, they can move together.

This is still very long out and subject to major change, so take this and use it at your own risk.

Andrew

Winter's On The Way: First Cold Outbreak On The Horizon

Hour 192 of the 12z ECMWF

The first real cold outbreak of the season appears to be on the horizon, signaling winter is peeking around the corner.

The ECMWF is forecasting a strong disturbance to drop down into the northern Plains in mid-September, as depicted above. The 540 line on the upper right image is dipping down into the Northern Plains. The 540 line is commonly referred to as the rain/snow line, with snow being north of the 540 line. That said, if precipitation were ongoing in the northern Plains and this verified, some very early snow may fall in North Dakota/Minnesota.

After the system dips into the US, it will become closed off, and its cold pool will rotate around the western side of the storm. As it closes off, it will rapidly strengthen over south central Canada. This will likely produce some windy weather in the southern Canada and northern Plains regions, and cool air should continue to flow around the regions mentioned.

This is just one of a few signs being seen that show winter is inching closer to our region.

Andrew

Why We Aren't Truly In An El Nino, And What It Means For This Winter

Sea surface temperature anomalies have consistently been displaying an El Nino is in place. Anomalies of as high as 1 degree above normal are being spotted in the waters of the equatorial Pacific. However, the atmosphere is not acknowledging the presence of an El Nino, and this could be a problem going into winter.

As the regional SST anomalies from the Climate Prediction Center are showing, above normal water temperatures are present across the central ENSO regions (Region 3 and 3.4). These anomalies are inching up towards the 1 degree mark, which would make this a borderline moderate El Nino.

Animations of the water anomalies show a progression west of these warmer waters, and this is reflected by a sharp drop-off in the Nino 1+2 region, known as the most eastern region in the ENSO monitoring area.

Here, we see observed 850mb wind anomalies across the ENSO monitoring area. Looking at this chart, we do not see any significant anomalies suggesting any phenomena is ongoing in the area. Now, if we look at the typical El Nino 850mb anomalies, we see an enhanced area of winds in the central portion of the monitoring area in the September timeframe (image below).

This lack of 850mb winds is a curious feature, and would seem to confirm the proposition that the atmosphere is not on the same page as the sea surface temperatures. However, 850mb winds are only one card in the deck of factors we use to monitor the ENSO phases, so let's continue digging for information.

Something else we can use to watch for an El Nino or La Nina is the Southern Oscillation Index, or SOI. When the SOI is above 8, the atmosphere is indicating the presence of a La Nina. On the other hand, a -8 on the SOI shows that an El Nino is shown. Looking at this screenshot of recent SOI observations from the Australian government, we can see monthly average SOI values. In June, the average was -10.2, indicative of an El Nino. However, in July, the SOI was basically in neutral, only at 0.1- an oddity for El Nino-like SST waters. Then, in August, only -6.2 was registered on the SOI, further confusing forecasters on what the atmosphere is doing at the moment.

Only adding to the confusion is the lack of enhanced negative OLR values. Outgoing Longwave Radiation, or OLR, measures convection in the equatorial Pacific waters. During an El Nino, the enhanced convection brings about a negative OLR, and a positive OLR indicates a La Nina.

However, looking at observations from the NCDC and CPC (respectively) in the 2 images above, there is no definitive anomaly across where the El Nino would be showing up. More-so, a positive OLR is showing up over the 140W-160W region, where the El Nino has the most influence at the moment. This further confirms the potential that the atmosphere is not fully prepared to handle an El Nino.

In times like these, we turn to analogs to see what would happen in similar situations of a 'fake' El Nino, where it technically is an El Nino, but the atmosphere is not confirming the suspicion. The best analog going around at the moment is the winter of 2006-2007. Let's take a look.

Precipitation anomalies for 2006-2007 were much more La Nina-like than that of an El Nino, with both the Northwest and Southwest drier than normal. Given, the Northwest is typically wetter than normal in a La Nina, but remember, this winter was a 'fake' El Nino- therefore, it still will show some signs of an El Nino. The Plains, Midwest and Appalachians were all wetter than normal, another telltale sign of a La Nina, while the Eastern US was dry as a bone. Even though I am talking a lot about La Ninas, it is only for comparison. I am not indicating a La Nina is going to be present this winter.
As for temperatures, the western US was slightly cooler than normal overall, but much of the region was normal. The northern Plains and East Coast were warmer than normal, showing that an El Nino is influencing the weather patterns.

Looking at that year, one can definitely see telltale signs of an El Nino, such as a warmer northern Plains and dry Northwest, but some odd La Nina patterns are also observed, like a warm East Coast and wet Central US.

It will have to come down to the atmosphere getting its act together and saying that an El Nino is present, because without that, forecasters like myself may as well be shooting blind.

Andrew

Official 2012-2013 Winter Forecast: Great Lakes

The Great Lakes forecast will only be for precipitation.

I am expecting a snowy winter for the Great Lakes. Based on observations on the stratosphere, the lower strat. is at normal values for this time of year, indicating the possibility of a negative NAO. With the negative NAO, the jet stream buckles and sends frigid air south that typically ignites the lake effet snow machine for those in blue. An El Nino typically does enhance a negative NAO, and this, combined with the favorable stratosphere values, should bring more than a few shots of arctic air southward into the Great Lakes region. Add a couple of degrees above average that the Lakes are currently at, and this winter could be very white.

THIS ENDS THE 2012-2013 REGIONAL WINTER FORECASTS.

Andrew

Official 2012-2013 Winter Forecast: Ohio Valley

The winter forecast for the Ohio Valley, temperature-wise, looks to be on the cool side, especially on the eastern side. An average stratospheric temperature, combined with the recent -NAO trend has me believing that this winter will contain more instances of a negative NAO than we saw last year. Additionally, El Ninos are favorable for negative NAO's, altogether increasing the potential for the North Atlantic Oscillation to be in a negative phase. And that, my friends, leads to below normal temperatures. However, I only highlighted the eastern part of the region, as Nor'easters should pull down cool air from Canada as or after they pass through, lowering temperatures.

The precipitation forecast was not all that difficult. As mentioned above, the NAO is expected to be negative this winter, and this brings the possibility for big coastal storms. Should the big ones bring a wide precipitation shield, I would not be surprised to see the eastern Ohio Valley end up with more precipitation than normal. However, that is not as confident as I would like, as Nor'easters are big storms, and big storms are much harder to correctly predict. However, I have confidence that the negative NAO will bring lake effect snow to the eastern Ohio region, pumping out more snow than normal as the lakes are a few degrees above normal.

Andrew

Official 2012-2013 Winter Forecast: Central Plains

This winter, I am expecting a variety of temperatures in the Central Plains. I expect warm temperatures to keep a safe haven in the northern Nebraska region especially, where the ridge in the Northwest is likely to have some influence on that region. Down towards Arkansas, I am actually anticipating a cooler winter, as a constant sub-tropical jet stream keeps the skies cloudy and generally prohibiting large-scale warm ups. An average stratosphere and negative NAO will help with that.

In the precipitation department, expect wet conditions through winter, as the storm track keeps itself in the South and puts much of the region through a wet winter. The occasional snowfall cannot be ruled out. To the immediate northwest, in northwest Arkansas and southeast Missouri, drier conditions consistent with an El Nino will prevail. As I mentioned in the Midwest forecast, a large storm may be all it takes to wipe out the dry conditions.

Andrew

Official 2012-2013 Winter Forecast: Midwest

The forecast for the Midwest this winter is varied. In western states, such as Iowa and Minnesota, residents can expect a warmer winter than average, but likely only slightly. The provocation of a negative NAO appears likely, given the incoming El Nino and analogs suggesting such a situation may pan out. That said, the mentioned areas can expect shots of cold air to visit from time to time, but a warmer winter should emerge after all is set and done.
As for eastern sections of the Midwest, like Illinois and Indiana, a negative NAO situation should be able to force Alberta Clippers into the region, followed by cold Canadian air. There are signals from that that these areas may get a bit below average, but that remains to be seen.

Recent drought trends, and an impending El Nino tell me that there is a likelihood of below normal precipitation in areas away from the lake shores. However, this could easily be busted, should a big storm come through the area and drop a foot or two of snow (preferably the latter). Clippers could save this winter, and the -NAO may be able to help, but with the lack of a guarantee on that proposition, I have inserted dry anomalies into portions of the Midwest.

Andrew

Official 2012-2013 Winter Forecast: North Plains

Temperature forecasts for the Northern Plains this winter were a little on the tricky side, mainly trying to figure out how far east the ridge in the Northwest will extend. That said, I took a bit of a gamble and went against my analogs in deciding that the Northern Plains may end up warmer than normal. I find it likely that there will be some breaks in that warm trend and cold air will return, but for how long is the question.

In the precipitation department, the lack of a strong jet stream and displacement of that jet stream to the south will end up with a winter below normal. Clipper systems will still come and go, but the lack of stronger systems in the area will prove fatal to hopes for a wetter winter than is typical. I am watching this region closely, as the forecasts are a bit less confident than I would want them to be. That said, this is more of an educated estimate than a forecast at the moment.

Andrew

Official 2012-2013 Winter Forecast: Northwest

There is only one color on this winter's forecast for the Northwest, and that is red. The ridge typically present over the Northwest in El Nino's should strike again and bring the region warmer than normal conditions. because the sub-tropical jet stream will take over much of the work as far as storm track goes, the Northwest will get a break and be warmer than normal in the absence of cooler air being dragged onshore.

A similar story plays out in the precipitation forecast, with a dry winter ahead. As described above, the storm track will be redirected south, and this will easily hamper hopes for a wet winter. A ridge will be in place over the Northwest, helping to disarm any potential precipitation systems.

Andrew

Official 2012-2013 Winter Forecast: Southwest

Temperatures in the Southwest will be relatively normal throughout much of the region, but where there are anomalies, there will be big anomalies. The upper section of the Southwest will get in on warmer than normal temperatures in the presence of the ridge that plagues the region during an El Nino. On the opposite end, area in and around Southern California should end up on the cool side as the constant influx of storm systems pulls in cooler air. This cooler air may extend into the mountains as well.

Precipitation will be abundant in the southern half of the Southwest, with the storm train leaving its mark across the region. Wet conditions will be present in low lying areas, while the mountains should get snowier than normal, thanks to the El Nino and the sub-tropical jet stream. A dry winter is in store for the upper portion of the Southwest, as the ridge in the Northwest deflects precipitation chances and leaves the region high and dry.

Andrew

Official 2012-2013 Winter Forecast: South Plains

Temperature forecasts for the South Plains are relatively unsure, as a ridge in the Northwest could tip the scales for the upper part of the South Plains, but a cool down in the Southeast could also have an effect on the region in question. To be on the safer side, I decided to point the warmth in the north and the cooler weather more towards the Southeast. Be warned, this could go either way.

In the precipitation department, a charged sub-tropical jet stream will get the El Nino going and pump storm systems through the area. Severe weather is also possible with these systems, as the proximity to the Gulf of Mexico and jet stream winds may combine to form at least a couple active days of weather.
I did appoint a dry area of weather, as the Midwest and Ohio Valley's typical El Nino dryness will continue in the northeast reaches of the South Plains. Some icy weather may occur with a cool weather outbreak across the northern part of the nation.

Andrew

Official 2012-2013 Winter Forecast: Gulf Coast

Temperature forecast for the Gulf Coast this winter calls for a cooler than normal season, with a consistent storm track bringing an end to widespread sunshine and thus putting a damper on heating for the areas shown. Analogs I am using also show anomalies of at least 3 degrees below normal for this winter, should everything go as planned. I do not doubt a warmer than normal area in portions of Tennessee, due to the proximity to the Ohio Valley and expectation of a dry winter for them.

As for precipitation, a wetter than average winter will be the case right along the Coast, as the charged sub-tropical jet stream shoots storm systems through that corridor to cause many instances of both rain and severe weather should the set up be right. I put a drier than normal area in the far northwest portion of the region to connect to the Ohio Valley and Midwest expected dryness for the winter.

Andrew

Official 2012-2013 Winter Forecast: Southeast

The temperature forecast for the Southeast is pretty tricky. This winter, we will be in an El Nino which, as of now, looks like it has a shot of being west-based. Should we see a more west-based El Nino, I would expect temperatures to possibly get even cooler than what is shown above.
I am projecting cool temperatures to reign supreme this winter, as consistent storms push down a lot of sunlight that would otherwise heat the ground. Additionally, climatologically, an El Nino supports cooler than normal temperatures in the Southeast. This suspicion is confirmed on my analogs in the national winter forecast issued a half hour ago.
I am watching the potential for a warmer than normal spot of temperatures in the far northwest portion of the Southeast, as dry conditions in the Ohio Valley may contribute a warmer atmosphere to the region.

As for precipitation, the charged and active sub-tropical jet will continuously steer storms up the coast, soaking the Southeast in the process. My analogs for this winter confirm that history shows that situations like these end up wetter than normal for the Southeast. It should be noted that the Southeast may be in line for a severe weather risk, as jet stream winds combine with strengthening storm systems to produce a potentially active situation.
The proximity to the Ohio Valley puts the northwest corner of the region at a disadvantage in the precipitation department, as that region is not favored for heavier precipitation during an El Nino.

Andrew

Official 2012-2013 Winter Forecast: Mid-Atlantic

Temperatures for the Mid-Atlantic this winter should be below normal based on my analogs for this winter. The analogs I have are showing a strong negative NAO, and this will be able to buckle the jet stream and let cold air flow south. Additionally, the Southeast ended up cooler than normal in the analogs I am using, enhancing the probability that the entire East US will end up below normal in the temperature department.

As for precipitation, persistent coastal storms from a strong sub-tropical jet stream will enable the Mid-Atlantic to end up snowier than normal. A persistant negative NAO has led the stratosphere to average levels, which, unlike last year, will enable better chances for snow and cold in the Eastern US. In more inland areas, it can be expected that more of an ice risk will develop, thanks to warmer air in the South, combined with cool air from the North.

Andrew