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Current Evolution of the QBO and Implications on the Atlantic Hurricane Season

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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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Thank you.  I had wondered about QBO phase and TC activity ever since Gray used that as a predictive tool with success better than climatology in the early 1990s.


It apparently doesn't work as well as a predictor for overall numbers the last decade and a half.



Anybody have analogs of March QBO phase or trends and US landfalls?

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Dr. Gray only examined the QBO as measured by the one-dimensional index. There are some issues with that as I've demonstrated in one of my past posts.


This takes into account the downward propagating nature of the QBO. As such, I'm able to determine the more favorable stages of the QBO for tropical cyclone activity.


I haven't examined any relationship between the QBO and landfalls. Could be interesting. Right now I'm working on a link to favored phases of the MJO

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Please try to look up the correlation, if any, between the March QBO phase and landfalls based upon similar past evolutions. I would be highly interested. Keep up the great research, as always.

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