The GFS and it’s ensembles are forecasting a dramatic reduction in westerly zonal winds over the North Pole during the second week of November.
October has seen very strong zonal winds to date, which goes hand in hand with the below-average temperatures the Pole has experienced this last month.
The zonal winds in the stratosphere strengthen as the temperature over the North Pole drops.
But just look what’s in store for late November through the rest of the winter months.
The westerly Zonal winds look set to have reduced quite dramatically by the second week of November, which could indicate the start of some high pressure building up in the northern latitudes.
The coloured lines in the below chart (turquoise and pinks) are the four individual CFS runs which take us through to the end of January.
Three out of the four runs are showing a dramatic collapse in the strength of the zonal flow beginning during the second week of November and could be picking up on a sudden stratospheric warming event, likely a result of the deep solar minimum our sun is entering.
Impacts of SSW
Following a sudden stratospheric warming (SSW), the high altitude winds reverse to flow eastward instead of their usual westward.
The eastward winds progress down through the atmosphere and weaken the jet stream, often giving easterly winds near the surface and resulting in dramatic reductions in temperature across Europe and often North America to boot.
For a strong SSW event to occur this early in season is really quite unusual.
The GFS and its ensembles are certainly something to keep an eye on.
Stay tuned for updates.
JMA January 2019
JMA’s January 2019 forecast is in and it’s setting up for some brutally cold wintry weather for North America and Europe.
January’s 500z height anomaly shows a mammoth area of high pressure (blocking) is setting up over the North Pole which extends from Greenland and Iceland all the way back to the Pole itself.
Underneath we see a deep trough of low pressure over the United States which would lead to a very wintry month.
There’s also a trough over central Europe and so we would expect to see very cold conditions with winds primarily from a north-easterly direction bringing cold air and the potential for some heavy snow into north-west Europe.
Winter is shaping up to be a doozy.
Grand Solar Minimum