Jump to content
  • entries
    12
  • comments
    16
  • views
    34,835

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


OKpowdah

4,125 views

 Share

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)

blogentry-128-0-38506200-1364238043_thum

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.

blogentry-128-0-01190100-1364238040_thum

The phase I would be keying in on for hurricane season based on average "residence time" is 60 degrees.

blogentry-128-0-14371700-1364238041_thum

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)

blogentry-128-0-20675800-1364238030_thum

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.

blogentry-128-0-76270900-1364238032_thum

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

 Share

4 Comments


Recommended Comments

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?

Link to comment

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

Link to comment

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.

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...