"Richard Dixon" wrote:

Thought I'd point out how similar the T+240 charts are for the GFS and
the ECMWF at 06Z / 00Z respectively, regarding Hurricane Bill.

Both have Bill flirting dangerously with the eastern seaboard of
Canada before weakening and then explosively developing in the
westerlies in the mid-atlantic as it recurves out to sea. ECMWF 945mb,
GFS 960mb.

Naughty Richard!

The treatment of recurving TCs is notoriously difficult (as you
well know...), and the outcome can vary from deep
depressions heading north across Quebec and Baffin Island
triggering long-lasting blocking in the northern Atlantic,
to curious creatures sliding sluggishly into Portugal or
Biscay. Even these days, models fail to handle them with
any sort of consistency even at 72h range (c.f. Gordon,
September 2006).

Philip