"Philip Eden" philipATweatherHYPHENukDOTcom wrote in message
...

"Alex Stephens Jr" wrote in message Alex, have
you devised a local 30-year average, or are you comparing
with 1994-2003? If the latter, you should be aware that the 1994-2003
mean for December is roughly 0.2 to 0.5 degC *lower* than the
1971-2000 mean. So your positive anomaly will be that much bigger.
My figures also take account of the fact that the long-term mean for
1st-25th is 0.1-0.2 degC higher than that for the whole month.

Philip Eden

Philip Eden

I only use an estimate for the 1971-2000 mean for December at this site.
It's calulated from various data sets and I believe the figure to be very
accurate.
The LTA figure I have arrived at of 3.1ºC, is indeed 0.3ºC higher than the
2.8ºC average of my own records (1994-2003) for December.
If we therefor say the LTA for December 1st to the 26th is 3.3ºC, the
anomally is still around +1.8ºC to this point of the month.
If you would like to see the monthly values and method I use to calculate
the LTA mean here, I have no problem posting them.

I have no reason to dispute your figure for central Scotland Philip, but it
seems that the anomally in the middle of the central lowlands is greater
still.
I don't have the figures at hand, but Drumalbin Saws is the nearest
climatological station to my own (AFAIK) and I would think it shows a
similar anomally?
A few additional reasons which may factor;
At the start of the month, whilst the very low areas of the central belt
(such as Glasgow) were shrouded in fog and had low daytime maximums, fog
quickly dispersed here and temperatures climbed 4 or 5 ºC higher than those
recorded around the city.
The 8th to 13th saw a very unusual run of SE'ly winds at this location...
Unusual because SE'ly is rather a rare direction due to shelter from the
Souther Uplands and on the same days I noted that nearby sites, such as
Glasgow, Edinburgh, Prestwick & Eskdale had a differing prevailing direction
(SSW I think). I'm unsure why this happened (I'm still learning about the
local climate) - but it may have led to a very slight fohn effect for this
location and/or may even perhaps have extended a slight heat island from the
nearest town centre (about 1 mile S-SE)?
And thirdly, and perhaps most importantly. My maximums and minimums are
calculated midnight to midnight.
So perhaps it isn't a level playing field?

But I would say if the mean temperature for the whole month remains above
4.8ºC here (the 1997 value), it will have been the warmest since 1989 -
which I estimate was exceptional in this area with a mean at around +6.4ºC.
Or an anomally around the value of +3.3ºC.

If that hasn't explained it, I hope it at least gives guidance?
;-)
Alex