Prediction for a historic Arctic temperature spike during late May.

Potential Historic Arctic Warming Scenario in the GFS Model Forecast for Late May

Robertscribbler,

19 May, 2018

For years, Arctic watchers have been concerned that if May and June ran much warmer than average following an equally severe winter, we could see substantial sea ice losses, severe Arctic fires, and related knock-on global weather effects. This May, temperatures over the Arctic Ocean have run much warmer than average. And in the GFS model forecast, we see a prediction for a historic Arctic temperature spike during late May.

(Discussion of a potentially historic Arctic warming event for late May of 2018. Information for this analysis provided by Climate Reanalyzer, Global and Regional Climate Anomalies, and DMI.)

According to GFS model analysis, temperatures for the entire Arctic region could spike to as high as 3.5 degrees Celsius above average from Saturday, May 26 through Tuesday, May 29th. So much warming, if it does occur, would shatter temperature records around the Arctic and accelerate the summer melt season by 2-4 weeks. It would also elevate Arctic fire potentials while likely increasing upstream severe weather risks to include higher potentials for droughts, heatwaves and severe rainfall events (as we have seen recently across the Eastern U.S.).

The model run indicates three ridge zones feeding much warmer than normal air into the Arctic. The zones hover over Eastern Siberia, Western North America, and Central Europe through the North Atlantic and Barents Sea — pushing wave after wave of warmth into the Arctic Ocean region.

(Three ridges transferring heat into the Arctic are feeding the potential for a major polar temperature spike over the next ten days. Image source: Climate Reanalyzer.)

Over the coming days, this three-pronged flood of warm air could push temperatures over the Arctic Ocean to 2-10 C above average temperatures while Western North America, Eastern Siberia, and the Scandinavian countries could see the mercury climb to 5 to 20 degrees Celsius above average. This translates to 70 to 80 degree (Fahrenheit) temperatures for Eastern Siberia above the Arctic Circle, mid 70s to mid 80s for near Arctic Circle Alaska, and temperatures in the 70s to 80s for Scandinavia. For the Arctic Ocean, it means above freezing temperatures for most zones. Zones that are likely to see more rapid sea ice melt as a result.

Upstream effects include the potential continuation and emergence of fixed severe weather patterns. Extreme heat will tend to intensify for Western North America, while a pattern that favors severe rainfall is likely to remain in place for the Eastern U.S. Meanwhile, South-Central Asia through the Middle East are likely to see very extreme daytime high temperatures. Fire risks will tend to rise from Alberta to the Northwest Territory into Alaska and on through Central and Western Siberia as much warmer than normal temperatures take hold and Arctic lightning storms proliferate.

(Forecast Northern Hemisphere temperature anomaly patterns hint at a hot or unstable late spring pattern for many regions as the pole inters record warm territory. Image source: Climate Reanalyzer.)

It’s worth noting that should such an event occur during late May, it would represent yet another major and historic temperature departure for an Arctic zone that has thus far seen severe winter warming and related loss of sea ice. The concern is that eventually such heating would result in ice free conditions during summer — although when is a subject of some debate.

To this point, it is also worth noting that we should take the present GFS forecast with a bit of a grain of salt. Such amazingly warm temperatures are still 6-10 days away. Forecasts beyond the 3 day are notably fickle. And this particular model has run a bit hot of late. However, it is worth noting that the model has been correct in predicting a much warmer than normal May. And that we have already experienced one historic temperature spike during early May. So a pattern that demonstrates the potential for such extreme warming has clearly taken hold.