El Niño Snows in DC However Not Pittsburgh


Snow on sweetgum seed balls, 17 Dec 2020 (picture by Kate St. John)

27 November 2023

Final week a pal remarked on the wide range of winter forecasts being touted for Pittsburgh from “Swamped With Snow” to “No Skis in Our Forecast.” How may the predictions be so totally different? I feel it’s the Beltway impact.

Proper now the world is in an El Niño yr of heat sea floor temperatures within the central and jap Pacific on the equator and alongside the coasts of Ecuador and Peru.

Sea floor temperatures throughout 1997 El Niño (map from Wikimedia Commons)

In accordance with Wikipedia, this warming causes a shift within the atmospheric circulation with rainfall turning into diminished over Indonesia, India and northern Australia, whereas rainfall and tropical cyclone formation will increase over the tropical Pacific Ocean. El Niño severely impacts South American climate and ripples out to North America as properly. The U.S. seasonal outlook, Dec 2023 to Feb 2024, reveals greater temperatures within the north and wetter climate within the south this winter.

Seasonal temperature and precipitation outlooks for the U.S., Dec 2023-Feb 2024 (maps from NOAA)

After all this impacts snowfall. El Niño’s winter historical past in 1959-2023 reveals extra snow in some locations (blue colour) and so much much less in others (brown colour). Apparently, Pittsburgh is within the Much less Snow class whereas Washington, DC has Extra Snow than standard.

Snowfall throughout all El Niño winters (January-March) in comparison with the 1991-2020 common (after the long-term pattern has been eliminated). Blue colours present extra snow than common; brown reveals much less snow than common. NOAA Local weather.gov map, based mostly on ERA5 knowledge from 1959-2023 analyzed by Michelle L’Heureux.

Information organizations have an enormous presence within the DC Beltway space and write tales for the area. Some climate tales originate there and cross the Appalachians however when the information will get to Pittsburgh it may not apply to us. The standard instance is when 2 ft of snow are forecast for D.C. and hardly any falls right here. I consider this because the (DC) Beltway information impact.

So once we hear dire predictions for Pittsburgh’s winter this yr I plan to attend slightly then fear. My guess is that we’re prone to have rain.

Raindrops on twig (picture by Kate St. John)

I certain hope the temperature doesn’t hover close to freezing when it rains. Fingers crossed that we’ll be high-quality.

Glaze ice in Pittsburgh (picture by Kate St. John)

Learn extra about snow and El Niño at NOAA’s S(no)w ache, S(no)w acquire: How does El Niño have an effect on snowfall over North America?

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