Current Evolution of the QBO and Implications on the Atlantic Hurricane Season
To start, here's the equatorial zonal wind anomalies so far this spring. Can see the -QBO holding on by its thumbs, with the westerlies starting to descend and near 30mb (first days with a + anomaly since July 2011 WOW)
The current profile fits the 330 degree phase of my "index" pretty well. Descending westerlies above 30mb, easterlies centered around 70mb, and neutral right around 30mb.
The phase I would be keying in on for hurricane season based on average "residence time" is 60 degrees.
Here's the tropopause pressure correlation for phase 60. It's a pretty weak signal, with on average zero correlation in the MDR and negative in the central Atlantic. This may support more disturbances in the central Atlantic more recurvatures of any TCs that do form.
(Negative = a higher tropopause height, Positive = a lower tropopause height)
Here's the same map for phase 90. Notice the equator to off-equator dipole tightens and intensifies, and the Gulf and NW Caribbean is under a very low correlation (high tropopause height) and that band extends across the Atlantic between 15N and 30N.
That dipole that I mention is tightest and most intense around phase 120.
So if the QBO reaches phase 90 during the season (essentially a full-blown +QBO), this suggests an increased TC threat in the NW Caribbean and Gulf. Of course this is one factor, and probably still relatively insignificant, but something that's interesting to discuss anyway
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