I noticed last year that from April to about October there was very
little difference in the air pressures in cyclonic and anticyclonic
air masses in the North Atlantic.

The phenomena does not seem to be regarded as a significant event,
though temperature statistics brought about by the cause of such
events are used to compile an advisory for the state of the NAO for
the mid-winter months.

I'm not sure why that method is chosen or what good it is to notify
anyone for just that time frame. Significant anticyclonic activity
takes place nearly every day of the year at some point on the 60
degree latitude on the North Atlantic.

More interesting in my opinion (for what that's worth) is that in
periods when the situation is negative here, the likelihood is for
misty weather and these of course can be forecast from the phases of
the moon.

And if one was sufficiently interested, one might put together the
next step in that line of thought; that misty weather here is
concurrent with tropical cyclonic activity.

Which brings me to another phenomenon, higher than usual volcanic
activity when there is this "negativity" in the North Atlantic:

New Activity/Unrest: | Kliuchevskoi, Russia | Nevado del Huila,
Columbia | Piton de la Fournaise, Reunion Island | Telica, Nicaragua |
White Island, New Zealand

Ongoing Activity: | Karangetang, Indonesia | Karymsky, Russia |
Kilauea, USA | Manam, Papua New Guinea | Popocatépetl, México |
Rabaul, Papua New Guinea | Sakura-jima, Japan | Santa María, Guatemala
| Shiveluch, Russia | Soufrière Hills, Montserrat | St. Helens, USA |
Suwanose-jima, Japan | Ubinas, Perú

http://www.volcano.si.edu/reports/us...k=feb_14-20_07

*******
Increased summit activity at Kliuchevskoi on 15 February led KVERT to
raise the Concern Color Code from Yellow to Orange. Ash explosions and
incandescence at the summit were observed. Strombolian explosions
expelled bombs about 300 m above the crater.

Based on video data and observations, gas-and-steam plumes with small
amounts of ash rose to altitudes of 5.3 km (17,400 ft) a.s.l. and
drifted SW. A thermal anomaly at the summit was seen on satellite
imagery.

INGEOMINAS reported increased seismic activity and two explosions from
Nevado del Huila on 19 February. An ash plume rose to an altitude of
approximately 6 km (19,700 ft) a.s.l. During aerial observations on 20
February, ash deposits were seen on the W sector of a summit glacier
and dispersed to the NW.

Fumarolic plumes originating from several points along a fissure rose
to 7 km (23,000 ft) a.s.l. Small mudflows from a glacier traveled down
a gorge. Based on news reports, small avalanches prompted officials to
order evacuations from towns bordering rivers.

OVPDLF reported that on 18 February a small "seismic crisis" at Piton
de la Fournaise began at 16:11 and lasted only a few minutes. About 20
minutes later, based on seismic interpretation, an eruption at the
summit began and ended the next day at 01:55. A crack across Dolomieu
crater was seen during an aerial observation on 18 February.

The Washington VAAC reported that continuous emissions of ash from
Telica were visible on a web-camera on 15 February. A resultant plume
rose to an altitude of 1.5 km (5,000 ft) a.s.l. Based on satellite
imagery, the plume drifted SW and a hot-spot was present at the
summit.

Recent visits to White Island's Crater Lake, including one on 13
February, have confirmed a continual rise in lake temperature since
August 2006 from a normal range of 48-50°C. In January 2007, the
temperature reached over 60°C.

The last temperature measurement was 74°C, the highest ever recorded
in the lake. The increased heat flow caused accelerated evaporation,
and the lake level has dropped over 6 m. Steam plumes have been
observed over the island. A deformation survey of the crater floor
showed no significant changes from recent months.

*******
Having said that, there isn't all that much of a negative oscillation
in the N. Atlantic going by the forecasts he
http://www.westwind.ch/?link=ukmb,ht...racknell+13 2
Pressures in the 970's isn't all that high and further west there is
deeper stuff to come.

But there seems to be the remains of negative spell on the European
mainland. (A Scandi (not very) High of 1017 and a not very low Low of
1015 sandwiched in between another high over North Africa.)

But of course one would have to look at last weeks data for the air
pressures. I seem to have lost that link. It is available at
WetterZentrale somewhere -or if you care to make the pilgrimage to the
wilds of Exemoor you can search Her Majesties own archives.

RantThey will do a search for you but that attracts a fee and I
already paid at the office, BSTRDS!/rant

I know I should have been paying more attention. (A small personal
flaw that you all know and love, no doubt.)