My 2023 Summer Outlook for the Northeast and Northern Middle Atlantic Region.

 

What does this summer look to bring us? To prepare for the months ahead, here is my Northeast Summer Forecast.

To develop the summer forecast, I analyzed a range of factors, including a variety of analogues, sea- surface temperatures, and other information. This year, the ENSO (El Nino) pattern and water temperatures in the north Pacific Ocean are looking to be major factors affecting this summer’s temperature and precipitation outlook.

 

This Spring…

Despite several cooler than average days so far in April, those periods of record-breaking summerlike temperatures have resulted in April as a whole, being overall above average across the region. Seeing temperatures that warm is very rare, the pattern doesn’t support sustained temperature that high until we get into June.

 

Right now, it looks like May as a whole, will be overall average to slightly below average. But this time of year, slightly below average temperatures doesn’t have that much of an impact, so it will still be very springlike.

 

El Nino…

The Climate Prediction Center/NCEP/NWS has us in an El Nino Watch. This is the Warm Phase (Positive Phase) of the El Nino Southern Oscillation (ENSO).  

Historically when the CPC places us in an El Nino Watch, an El Nino developed half of the time. So, while El Nino is likely, the issuance of a Watch is no guarantee that it will develop.  

There is significant amount of warmer than average Sea Surface temperatures and Sub surface water temperatures in the equatorial Pacific. The SST anomalies continue to strengthen in the tropical eastern Pacific. Those very warm SST off the West Coast of South America will continue to push west into the Central Equatorial Pacific for June and July. East based El Nino's are typically warmer than their central based (modoki) counterparts. So how the El Nino ends up (if it does) developing will have a lot to say about temperatures. But based on what I'm seeing, I'm leaning toward the idea of a very strong El Nino by the time we get closer to the coming Winter.  

The Southern Oscillation Index (SOI)

When we look at the Southern Oscillation Index (SOI) index numbers. Negative numbers tilt toward El Nino which creates weaker trade winds over the Pacific. When the numbers are positive, they tilt toward La Nina which creates stronger trade winds over the Pacific.

As of this writing, the 30-day average is at -1.76.

The Pacific Decadal Oscillation (PDO)…

We currently have a warm blob in the western North Pacific. At the same time, we have cooler than average SST off the West Coast of North America. This places us in the cool phase (negative phase) of the PDO. 

 

The PDO has a big influence on the ENSO. If the PDO is in the same phase as the ENSO their Associated impact can be amplified. However, if they’re not in the same phase the associated impact can be reduced.  

Here is a chart showing the PDO index phase shifts from January 1854 Through March 2023.

Quasi-Biennial Oscillation (QBO)

This summer will likely feature a negative QBO. Typically, a negative QBO sets up ridging in the west, with a trough in the east, making a pattern where the Northeast has to deal with persistent upper-level lows impacting the region. A negative QBO also tends to lend support for predominate negative North Atlantic Oscillation (NAO) and negative Atlantic Oscillation. This would mean we could have higher odds of seeing high latitude blocking. While this would make for a great winter pattern, for snow lovers; it wouldn't be a good pattern for summer weather lovers. 

Analogues…

Here are the analogues I’m using for my 2023 Summer Outlook

1963, 1965, 1976, 1982, 1986, 1997, 2009, 2015

500mb Geopotential Height Composite Anomaly 1991-2020

 

The combined Composite years Geopotential Height Composite Anomaly for Jun – Aug

The individual analogue years Composite June through August Temperature Anomalies

The combined Composite years Temperature anomaly for Jun – Aug

 

The individual analogue years Composite June through August Precipitation Anomalies

The combined Composite years Precipitation anomaly for Jun - Aug

 

1963 was a moderate El Nino, 1965 was a strong El Nino, 1976 weak El Nino, 1982 very strong El Nino, 1986 was a moderate El Nino, 1997 was a very strong El Nino, 2009 was a moderate El Nino, 2015 was a very strong El Nino

1963 was a moderate cool phase, 1965 was a moderate cool phase, 1975 moderate to strong cool phase, 1982 was a weakening moderate cool phase, 1986 was a strong warm phase, 1997 was a very strong warm phase, 2009 was a moderate cool phase, 2015 was a moderate to strong warm phase.

When we look at the analogue years. We can see  El Nino and the PDO do have a temperature and precipitation correlation.  The Northeast and Middle Atlantic tend to be quite warm when both the ENSO and PDO are strongly positive.  When the ENSO and PDO are in opposite phases, the farther they are apart the colder the CONUS becomes. 

 

Temperatures…

 

Those well above average SST anomalies off the East Coast, should keep the Middle Atlantic and Southern New England Closer to the Coast warmer than the interior parts of the Northeast.

The middle Atlantic and southern New England should see overall temperatures averaging out to average to slightly below average. While interior areas of northern New England, New York State and Pennsylvania end up with overall temperatures averaging out slightly below average to below average.

  

Precipitation…

While the current soil moisture levels across the Middle Atlantic Region are quite low

With the overall precipitation setup that looks to unfold starting on today the 29^th and going into next week, we should see at least a partial recovery of the drought conditions over the Middle Atlantic into Southern New England for this Summer.  

 

Palmer Drought Severity Index

 

 

Precipitation looks to be largely average to slightly above average across western and central New York State and western Pennsylvania, while northern and eastern New York State, eastern Pennsylvania, New England and the Middle Atlantic end up averaging above average to well above average.

This doesn't mean we won't see any really hot days this summer. It just means we should trend toward overall cooler temperatures over the three month period. The same goes for Precipitation, during El Nino the Northeast and Middle Atlantic Region tend to see wetter summers. But that doesn't mean we won't see some dry stretches. This is all about climatical averages. 

Well that's it. Hope you enjoyed reading this.