Winter '14 / '15 - Weakening Polar Vortex ==> Sudden Stratospheric Warming: UPDATE 4

OBS

Expanding area at 10 mb over Siberia (red shading) where the one-week temperature change exceeds 25°C.

 

10-hPa temperature change in a week in the Northern Hemisphere

The contour interval is 5 °C. The pink and light blue shadings indicate warming and cooling, respectively. The red shading denotes warming for values higher than 25 °C.

 

Imagery courtesy Tokyo Climate Center, Climate Prediction Division

 

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PROGS

The 12z / 29-DEC-14 ECMWF suggests the 'split-vortices' SSW portion of the current event will peak between 03 / 06-JAN-15 followed by displacement. on D+10.

Deep-layer easterlies depicted on 03-JAN.
Short-lived daughter vortices appear briefly at the 475K level on 06-JAN.

Displacement

 

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SSW TYPES