Lead Forecaster Daniel Crawley
We had a follower of our weather pages recently send us a question about the lack of tropical activity so far in the Atlantic basin and if there is any correlation to the weather later in the year, namely as we get into the upcoming winter.
Specifically, this person asked if unused atmospheric energy from the tropics summer could go into feeding stronger mid-latitude systems in the winter time, possibly creating snowfall anomalies for the Eastern and Southeast US?
That was a great question and one that we all are wondering about ourselves (Hmmmm…)
Our weather team started to do a little research on past hurricane seasons in the Atlantic basin. To recap current times, so far in 2022 we have seen only three named storms in the Atlantic. The last named storm was Colin that formed off the South Carolina coast back in July. That was nearly eight weeks ago to this point so compared to climatology it has been on the quiet side in the Atlantic basin. We on average would have seen five named storms by this point in the hurricane season.
For the basis of research we looked back over the past 70+ years at the number of hurricane seasons that featured three or less named storms by September 1st. We also wanted to link those years to what state of the ENSO (El-Nino Southern Oscillation) they were in. ENSO readings began around 1950 so that was why we spanned back as far as we did. The 1950’s/1960’s was also a time in which satellite technology improved to where Meteorologists could detect and observe tropical features in the MDR (Main Development Region).
The findings were somewhat interesting.
The following hurricane seasons (1950-2020) fell into the criteria that we were looking for..
1952, 1956, 1957, 1961, 1962, 1963, 1965, 1967, 1972, 1973, 1982, 1983, 1984, 1986, 1987, 1991, 1992, 1994, 2014
Of all the matching analogs…
12 of the analogs that matched were under an El Nino state, 9 of them moderate to strong Nino’s
5 of the analogs that matched were under a neural ENSO state
2 of the analogs that matched were under a La Nina state, both Weak Nina
For comparison purposes the most recent ENSO reading for 22 during a three-month period was -0.9 degrees Celsius which is classified as a moderate La Nina.
Persistent La Nina Continues…
Here’s a look at the ENSO readings over the past decade across the equatorial Pacific, globally we have been in an extended La Nina state (blue shading) since late summer 2020 and current forecasts has that continuing but slowly weakening to the point that we could enter an neutral state as soon as March of 2023.
Statistical Winter Breakdown of Matched Analogs
This table below is a listing of the ensuing winters, the ENSO state they were in and a look at snowfall amounts from the Western Carolinas during those winters. We chose climate data for Asheville, Lenoir, Charlotte and Greenville-Spartanburg to have a broad representation of the differing microclimates in the Western Carolinas.
(NOTE: Current 30-year snowfall averages for these climate sites are in parenthesis.)
Data Source: National Weather Service, Greenville-Spartanburg SC
Some of the big takeaways from this research:
- The abundance of El Nino fits with historically big winters for Western North Carolina.
- Just 1 neutral state season features abnormally low snowfall
- All but 1 neutral/La Nina state winters were a struggle to produce significant snowfall outside of the mountains.
So, can we definitively answer the question that is being asked? Unfortunately, we cannot answer confidently only for the main reason that we will enter this winter with the lowest ENSO state of the 70 years documented. If you believe the global indices the region, especially outside of the mountains may be challenged to see snowfall. If you had to nail us down on an answer I would side with lower winter storm potential.
On the other hand with a documented moderate La Nina already in place, the atmospheric conditions that are keeping the Atlantic Basin (Wind shear) held down during the heart of the hurricane season are a lot more reminiscent of the El Nino state rather than a La Nina.
We will be interested to see how the next month of the hurricane season evolves and how it may try to provide some hints for the winter.