On 25 Oct 2006 16:03:22 -0700, "Richard Dixon"
wrote:

Dear All,

Does anybody know the most rapid recorded pressure rise during the
passage of an extratropical system? I just tried googling with little
success, I'm sure we've talked about it before on here.

"Lothar" in France had rises of 27mb/3hr - but this appears to be
surpassed by the "Greenhouse Low" - an extraordinary low that hit
Iceland in 1991 with sustained winds of 57m/s recorded and pressure
rises of 30.4mb/3hrs. I'd doubt the validity of those gusts!!

Anyhow - does anybody know of 3-hour pressure rises bigger than these?

No... but the biggest UK and british Isles pressure rise in 3 hours
was during the Great Storm of October 1987, was it not? I quote from
the Met Office website's analysis
http://www.meto.gov.uk/education/sec...ents/1987.html

"The greatest rise over three hours occurred at the Portland Royal
Naval Air Station in Dorset, where, between 0300 and 0600 UTC, the
rise was 25.5 mb. This was, by some margin, the greatest change in
pressure - either upwards or downwards - ever recorded in three hours
anywhere in the British Isles. At many places in southern England, the
pressure rose more than 20 mb in three hours. The return period for
such an occurrence is, again, roughly once in 200 years."

--
Dave