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Old 29-11-2010, 07:00 PM
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AstroTourist (Terry)
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Join Date: Jul 2007
Location: Brisbane
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Weather observations Nov 2010 for the eclipse in 2012

I was in the path of the 2012 total solar eclipse for a few days either side of 14 November this year (10th to 17th). Observations of the weather from about sunrise at 0535, until eclipse time of 0638 were mildly encouraging. These observations were from the coastal areas (on 4 days) and from the coast to just west of the ranges (on 3 days).
For observations over the 7 mornings, visibility at eclipse time was broadly as follows:
1 day generally clear skies but with patchy cloud in some areas (probability of seeing eclipse say 85%)
4 days mostly visible through thin clouds but some areas in cloud (say 65%)
1 day much of the area cloudy but some areas with breaks (say 40%)
1 day only a few lucky ones would have seen the eclipse (say 10%)
Average say about 50 - 60%
Chance of seeing the eclipse would have been improved by some judicious relocation.

Some weather patterns that were observed:

The weather was certainly more humid than the same time last year. Last year in the eclipse path, I experienced about 8 out of 10 days as good days. Last year there were several days of clear sunny weather. This year there were none. When it was clearer this year, there was usually thin high cloud present that would have reduced the view of the corona a little.

The weather along the coast often started at pre dawn with cloud generally off shore and quite thick but typically no higher than about 8 degrees (sun at eclipse will be at 14 degrees), and little cloud overhead. The cloud generally broke up after dawn with the cloud moving towards shore. A low bank of cloud often remained and the sun was above this bank usually by between about 0600 and 0630. Cloud cover generally increased across the sky after eclipse time as the day started to warm.

There were often local weather disturbances. On two mornings there was quite thick local cloud over the capeGrafton headland such that Cairns and the southern areas of the Cairns northern beaches would have been seriously affected. On the next two mornings the Cairns area was clearer and there was thick cloud (and rain) in the Port Douglas area. On a later morning, cloud returned to the CapeGrafton area.

On perhaps half of the mornings there was some cloud up against the coastal ranges at dawn, but typically well away from the area of the sun when viewing from a beach location. This did not appear to change greatly up until eclipse time. On three mornings I drove from the coast at sunrise over the ranges (on each of the three separate routes). What I observed when there was cloud up against the coastal ranges, was that in the Atherton area (which is generally quite high at about 800m elevation) the cloud appeared to extend further to the west (beyond Atherton); whereas around Mareeba and further north (which is generally lower elevation at around 400m) as the wind descended from the coastal ranges, the cloud appeared to dissipate more quickly. On the morning I that traveled on the Mulligan highway west of Mount Molloy, the cloud had dissipated reasonably quickly such that the eclipse would have been seen at Mount Carbine through thin cloud.

These observations are from the east coastal areas. On checking the cloud images for these days, on some days the inland and west coast would have fared better, but there are of course difficulties in escaping very far to the west. One sobering thing is that a colleague of mine who was in the path area for the three days after I left said that it was generally cloudy and rain at times over the whole coastal area for the three days.

Currently we have a La Niņa weather pattern established and this year has been the wettest we have experienced in Queensland for many years. There is a reasonable chance that the pattern will have reversed and El Niņo will be back by 2012.

I am not suggesting that we can read too much into these observations. This is just one sample (as were my observations last year). And if there is a reversal of La Niņa/ El Niņo, this year may not be very relevant.
Regards,
Terry
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