This post will go over the seasonal models and show how they support what I've been saying in the last several posts I've done for winter 2025 and 2026. I will also touch on our current drought situation here in the Northeast and Middle Atlantic.
We are still officially in a La Nina Watch. Which means conditions in the eastern into central tropical equatorial Pacific are around average, but the indicators are saying La Nina is possible.
Here is a look at the current Sea Surface Temperatures (SST) and subsurface temperatures in the equatorial Pacific.
As I've said before many times, El Nino, La Nino and Neutral are all phases of the El Nino Southern Oscillation. These different phases are created by the interaction between the ocean surfaces and the atmosphere in the Pacific. The ENSO is a major player in the global climate pattern. The Neutral phase is when SST's in the equatorial pacific are considered average. Whereas El Nino is when equatorial pacific SSTSs are above average. La Nina is when equatorial pacific SSTs are considered the below average.
The following chart shows the four ENSO regions across the equatorial Pacific.
What goes on inside these individual regions helps determine if we're heading towards a La Nina or an El Nino. The onset of an El Nino Is declared when we see at least 0.5 ° C temperature anomaly for three consecutive months in region 3.4. For a la Nina to be declared we have to see at least a -0.5 ° C temperature anomaly in region 3.4 over three consecutive months. In order to be declared a full fledged El Nino or La Nina these onset conditions must last for at least five consecutive months
This chart shows The various strengths When we've had El Nino's and La Nina's
When looking at the above chart. A weak El Nino is considered between +0.5 And +1.0, a moderate El Nino is considered between +1.0 and +1.5, a strong El Nino Is a +1.5 to a +2.0. Find a super El Nino is considered anything over a +2.0. La Nina would be the exact opposite as far as the scale goes. Neutral is when it's between a +0.5 and a -0.5
In these winter post I've been saying it looks like a weak La Nina will develop. The question is will it have any staying power. The teleconnections are indicating the La Nina could be very short lived; If it even officially develops.
Looking at the North American Multi Model Ensemble (NMME) chart. We can see It dips into La Nina territory Between -0.5 and -1.0 For October into December. Then it drifts above -0.5 to around 0 for January February and March becoming more neutral.
Looking at the European ECMWF (Euro) sea surface temperature anomally for October, November and December we can see the equatorial Pacific is cooler looking more like a La Nina.
Then the Euro Shows December January and February Equatorial Pacific SSTs looking much warmer and very neutral like.
The North American multi model Ensemble (NMME) is showing the same idea of La Nina conditions For the first part of winter. And then changing to a neutral ENSO for the second half.
The global SST chart shows the coolest in the Northwest Indian Ocean and across the Equatorial Pacific. This shows a very typical La Nina pattern.
There is snow falling across parts of northern Alaska. The persistent Aleutian Lows we've seen looks to continue. So this will continue to add to the snow pack In Alaska.
The very warm northern Pacific.
Image courtesy of tropical tidbits.
I've talked about the Northern Pacific warmth for quite some time now. I think this will be very important as we move through the upcoming winter. It could even be more Important than the La Nina that may or may not develop.
When we look back at years that had a similar pattern in the North Pacific. We come up with a pattern for December to February that looks something like this.
Now taking years That had a similar look in the north pacific We come up with a temperature and precipitation pattern That looks similar to this.
Similar years saw a preference for miller B. type nor'easters, with a chance For some miller a Nnor'easters as well. As I said in pass post, the pattern that looks to be setting up would favor increase chance for quite a few clippers To move through our region. The analog seasons Look to favor colder than average overall winter temperatures, These past winters Also point to the chance we have average to slightly above average winter time precipitation, with only Southwest Pennsylvania back into the Ohio Valley Showing less than average precipitation. If things go the way the pattern seems to be indicating. It could very well be an above average snowfall year for much of our region. With the snow belts really cashing in maybe even more than last year. Right now we will have to wait and see.
Abnormally dry and drought conditions.
Looking at jet stream pattern. We see the North Pacific jet weakening then coming into Pacific northwest where it then arches up into the Canadian Northern Territories. This creates a pattern with a lack of flow over the CONUS, promoting more in the way of heat and lack of rain. The pattern will allow for some cut off low troughs. But, these will be very hit and miss as far as prolonged precipitation. It's not the kind of pattern you want when you're experiencing drought like conditions.
How we got here
The Advanced hydrologic Prediction Service (AHPS) 30 day departure from average image shows the region is in need of water.
The above temperature departure from average maps show that while the summer was quite warm overall. The last two weeks or so, have seen a big departure from the earlier warmth, with temperatures become quite chilly for this time of year. Looking at what the pattern is hinting at Warming in the pattern develop over the eastern half of the US As we get closer to the end of September. But I honestly believe Won't last super long, maybe 10 To 14 days. Before we return to the same pattern we're experiencing now General trotting over the eastern half of the US and ridging out west.
The most recent drought monitor.
Looking at the northeast throat monitor image we can see conditions deteriorated across a vast part of the region. This is the result of a lack of meaningful rain, vastly reduced stream flow add lower ground water levels. Most areas saw drought categories increased Along with the introduction of extreme drought western New Hampshire. However there was some improvement for some coastal areas that have seen more in the way of meaningful rain. These areas include parts of northern Maine, New Jersey, Northern Delaware and southeast Maryland. The drought monitor that was released today Shows less than 1% of the region is under extreme drought, 15% is under Severe drought, 21%Under moderate drought and 36% experiencing abnormally dry conditions.
We're going to be stuck in the same general pattern we've been experiencing for the last several weeks. Looking at the models precipitation anomalies projections we can expect drought conditions to continue to deteriorate over at least the next few weeks.
