This sudden stratospheric warming event (SSWE) in the N hem polar stratosphere associated with the splitting of our polar vortex could provide the impetus for the MJO remaining strong for at least the next 2 weeks or so. When you get a SSWE, the downward branch of the Brewer Dobson Circulation in the extratropical/polar stratosphere accelerates downward, compresses and warms the air. By virtue of mass continuity, the upward branch over the tropics also has accelerate upward. When parcels accelerate upward they cool via expansion because the density of the atmosphere decreases monotonically with height, which leads to more intense adiabatic cooling all the way to the tropopause. This cooling of the equatorial tropopause is often capable of destabilizing the troposphere enough to instigate intense convection in/around the equator (usually first in the N Hem then the S Hem) which lasts for a week or two even after the SSWE has ended. You can actually see that happening in real-time.
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Here's a near-equatorial (10S-10N) time-height temperature anomaly cross-section. Notice how the lower stratosphere and equatorial tropopause cool significantly over the coming week or so w/ temperature anomalies just above 100 hPa approaching 5C below average
after the stratospheric warming event in the Northern hemisphere got underway!
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Tread
extremely carefully the next few weeks, NWP models do not handle these troposphere-stratosphere coupling interactions well at well, much less how these interactions are capable of triggering convection in the tropics, which will later feed right back onto the mid-latitude circulation. We're gonna essentially be going blind for a little while after day 7 ish (even relative to what we normally see), best advice is to just use large-scale principles and physical linkages between various phenomena instead of dry humping/regurgitating NWP. You really couldn't draw up a more fickle/uncertain pattern than what we're about to see thru early March.
