Keith (Southend) wrote:



Thankyou Graham, I always read your posts closely as I have for a long
time felt SST's hold much of the key.
A couple of things, I keep looking at the SST's but don't really see
much of an El Nino: Yet? Maybe I'm expecting reds across most of the
equatorial eastern Pacific! Although it is stated as a 'mild' El Nino.

The SST anomalies have a similar pattern to 1997 but, as you say, much
weaker than that year. As well as the ribbon of warmer than normal water
along the Equator, widening and getting more intense in the east, the
waters around Indonesia and Australia are cooler than normal.

https://www.fnmoc.navy.mil/products/...sstanomaly.gif

I'm using the data at http://www.osdpd.noaa.gov/PSB/EPS/SST/climo.html. I
packed up using the other site years ago - I think because there were
occasions of dodgy data which did not show up on the NOAA site. Also, the
NOAA anomalies in the Arctic are a bit more realistic. And they have
archive going back to 1996.

Secondly, the cool pool to the south of NFL is pretty small and fairly
recent, as the last couple of months the SST anomalies have been high
across most of the Atlantic at our latitudes and average to cool nearer
the equator, which made me think this was the reason for the quiet
hurricane season, until the change over the last couple of weeks, hence
Gordon, Helene and the like. Also interesting how they are taking a
completely different path to last years, must be some other differing
circulation(s) in the atmosphere. I was also thinking that we would have
a wet autumn due to those high SST's. Of course autumns not really
started yet.

Yes, the cold pool is pretty weak but I'm not sure how important the
magnitude of the anomaly is. I suspect the contrast between the anomalies
north and south of the Banks is more important.

One effect of El Nino seems to be to displace hurricanes eastward. In El
Nino years, the US and Central America get hits from Pacific hurricanes
rather than from the Atlantic. See
http://iri.columbia.edu/climate/ENSO...tic/track.html
for a comparison of El Nino and El Viejo years.

The problem with both sites is the short period for the "normals". Changes
in anomalies we see are sometimes a result of changes in the normals from
month to month rather than changes in actual temperature.

I only mentioned these things for comment really, as no way would I want
to question your thoughts, infact that ounce of a hard winter was what
woke me up grin


I question my thoughts all the time so don't worry about it. I still think
we're in for a mild winter but not for the same reason as earlier in the
year. El Nino appears to increase the strength of upper westerlies over the
East Pacific and Atlantic and this weakens Atlantic Hurricanes - through
increased shear - and forces them eastwards. I suspect that the effect on
the UK would also be for increased westerlies.

You can go back to sleep now.

--
Graham Davis
Bracknell