Where, Oh Where, Is The Bermuda High?

[Larry_Cosgrove]

You may have noticed that it has been a while since we have seen what could be termed a "classic" Bermuda High. That is the anticyclone which often sets up near the British island commonwealth duirng the summer months. Last year saw complete domination by the Sonoran and Great Smokies heat ridges, leading to intense heat but only periodic rises in relative humidity. And this year there has been some tendency for a subtropical high across the Southeast, which has not been strong enough to hold off intrusions of cP values from QC and ON into the Northeast.

If the numerical models and variants are correct, however, we could soon see a resurgence of our "old friend" over the western Atlantic Ocean, If you have noticed, the deep mean easterlies have been returning, and surging northward, from Africa into the Greater Antilles (evidence the tropical wave nearing FL at the time of this writing). The GGEM and GFS schemes show 500MB height rises around Day 10 over the Gulf Stream, culminating in what looks to be a very impressive positive height anomaly in the Bermuda position during the extended period.

Should this scenario verify, we could see a rather humid regime take over the eastern third of the U.S. after July 8. Diurnal thunderstorms may be an issue, as a typical Bermudan ridge will be accompanied by mesoscale disturbances (cold pools and vorticity maxima aloft) rotating around its western and northern extent. And if you like extreme heat without the high humidity, consider that both the Canadian and American model families show a conjoined Sonoran and Great Smokies ridge complex back in place by July 13.

Best Regards,
Larry Cosgrove