This log will detail unusual events.
2005
3 December: It is now 2.5 weeks since we had any significant wind. High night-time humidities (~80-82%) with clear skies have engendered morning haze over last few days and very heavy dews. More cloud today.
8 December: It is now about 4 weeks that we have been stuck in anticyclonic conditions. This is pushing all the normal successions of Mediterranean depressions northwards towards the Black Sea and Turkey. The result is that we are not receiving any of the usual "wet season" rain. In this time, we have received less than 8 mm of rain, instead of the normal 50 mm or more. Many of the country's dams are nearly empty. If this weather system does not move away and fast, we may not receive enough rain to supply our needs for 2006, recalling the drought period at the end of the 1990's. If this happens, rationing will again become inevitable, as the Government, in its infinite wisdom, abandoned the increased desalination programme as soon as we had one winter of normal rain.
12 December; Funny weather today. We are still in the strong anticyclone system, but the night temperatures were slightly higher than they have been and the humidity considerably lower. The morning had intermittent low-lying stratus which the sun had difficulty in breaking up and it took until mid afternoon for the sky to become ~50% clear. The wind is still confined to a few gentle gusts around mid-day.
15 December. Barometer has dropped over 10 hPa. Signs that a Med depression is trying to push the high-pressure out of the way, instead of being diverted to the N. Some cumulus seen above the stratus, but no rain of any consequence (none registered). More persistent light winds which have veered about 180 deg. By evening, it looks as if the high pressure may come back, in which case there may not be any significant change for a few days. Keep an eye on the pressure; if it rises again, we will not expect any rain or wind - if it drops further, winter may arrive - at last! As I write this, we are 30 minutes short of the full moon.
27 December. The lowest air temperature recorded this winter, so far, was 1.9°C, just before dawn of 26 December. Ground frost occurred, and on the previous night (just), but there was none today. The barometric pressure has been steadily rising over the last three days from about 1008 hPa to 1026 hPa. The heavy cloud cover today is unusual with a rising barometer and a high pressure and I speculate that it may foretell that the pressure will collapse suddenly, in which case I would expect heavy precipitation.
28 December. I guessed wrongly! Today is typical anticyclonic weather, clear skies, little wind. The pressure has dropped quite sharply from a record high of 1027.3 hPa in the morning by about 3 hPa, but is rising again. It may take a lot to kick this one out of the way!
2006
24-27 February. We have had a lot of very fine dust
blown over from the Sahara desert. The predominant altitude wind has been S to
SSW but the low altitude wind has been fairly weak, allowing the dust to remain
suspended. Visibility here dropped to about 75 m on 25 February, but it has been
slowly clearing since then and is currently about 3-4 km.
This weather phenomenon is quite common, perhaps twice per year on average. It
sometimes signals the end of an anticyclone, followed by a depression with heavy
rain, sometimes thunderstorms, which leaves a layer of sticky yellow dust on
everything. However, this time, the barometer has remained fairly high and
constant for 72 hours, but the wind has dropped. I can't see rain coming in the
immediate, although the cloud cover is intermittently increasing. It a result of
the Khamsin, derived from an Arabic word meaning 50 because it can happen over
50 days from late winter to early Spring.
13 March. Another Khamsin day (see above) with estimated visibility of ~500-750 m at ground level. RH is low (30-36% for most of the day) and temperatures slightly higher than preceding days.
14 March. Dust continues. As often happens in these conditions, a thunderstorm started at about 1500 h, but not enough rain to be registered (ground barely wetted) or to lay the dust. Another short, sharp shower about 1630 h, registering 0.5 mm rain. Not enough to settle all the dust, but visibility is up to ~2 km from about 600 - 1,000 m this morning.
15 March. About 3 mm of rain, overnight, has settled the dust and visibility exceeds 50 km.
29 March. Portrait of a solar eclipse. A partial (~95%) eclipse took place here today, with a maximum at ~1355 h. This is what happened to the weather:
 |
The black line is
approximately at maximum obscuration of the sun. Top panel: The wind (red line) started to become gustier as it approached maximum with a maximum average (blue line) coincident with minimum temperature (see below) Middle panel: the wind direction became consistently SSW during the whole eclipse. Bottom panel: The temperature (green line) dropped about 7°C from the start to just after maximum. It rose again to about normal levels, forming a curve resembling a sine curve from 180° to about 340°. This is not surprising. The dew point (magenta curve) remained substantially constant, so the relative humidity (blue curve) took a shape substantially opposed to the temperature, which is normal. |
December has mirrored last December's weather, although more extreme. The 27th has had the highest wind gust, average and wind run since monitoring started. The 29th has a second high barometric pressure and the first air frost of the season (-1ºC). Very dry month (1.0 mm total precipitation, of which 0.2 mm was a heavy dew), which is beginning to be worrying. Let's hope the rains come in earnest in January 2007.