Weather forecast for the solar eclipse on 12 August, issued at 16:00 on Monday 10 August

Forecast issued at 16:00 on Monday 10 August.
The forecast period extends 50 hours ahead.

A low-pressure system is expected to approach southern Iceland on Wednesday. The latest weather model runs indicate that it will be located just south of Reykjanes on Wednesday afternoon, with its associated fronts crossing most of the country. The low is then expected to move eastwards along the south coast. Rainfall will mainly affect southern Iceland, while less rain is expected in Breiðafjörður and the Westfjords until the evening, when the fronts appear likely to move across the area. These areas will therefore probably have the best chance of breaks developing in the cloud cover around the time of the solar eclipse. It is also expected to remain dry across northern Iceland for most of the day.

Most models now place the low in a similar location, increasing confidence in its forecast position. However, there is still some uncertainty about the extent of the fronts and how far north they will reach along Faxaflói Bay. This will significantly affect whether, and how clearly, the eclipse will be visible.

The Icelandic Met Office’s high-resolution models now extend far enough to cover 18:00 on Wednesday. They provide forecasts for three cloud layers: high, medium and low cloud. High cloud has little effect on viewing the eclipse, as sunlight can pass through it relatively easily. Medium-level cloud is less transparent, although it may still be possible to view the eclipse. If low cloud covers an area, however, there is little chance of seeing the Sun or the eclipse.

The total cloud-cover forecast indicates that skies will be almost completely overcast across Iceland at 18:00, as shown in the green panel. However, the low-cloud forecast shows some breaks in western Iceland and the Westfjords. The medium- and high-cloud forecasts show gaps in similar areas, although not in exactly the same locations. The upper image shows the latest run of the IG high-resolution model, while the lower image shows the DINI high-resolution model. The models do not fully agree, so the location of any breaks in the cloud cover remains uncertain.

Cloud-cover forecasts are generally among the most difficult forecast products to produce, as the underlying physics is highly complex. Small gaps in the forecast cloud cover should therefore be treated with caution. The forecasts primarily indicate that breaks may develop somewhere within the area, but their exact location cannot be determined.

The forecast for Iceland on Wednesday is as follows:

Easterly and northeasterly winds of 3–10 m/s. Cloudy in many areas with intermittent rain, but somewhat stronger winds along the south coast. Rain easing in western Iceland during the evening. Temperatures of 8–18°C, coolest along the north and east coasts.

Weather outlook along the path of totality

Capital region

Light easterly or northeasterly winds, overcast with rain. Little chance of breaks developing in the cloud cover around the time of the solar eclipse.

Reykjanes Peninsula

Similar conditions to the capital region, with northeasterly winds and rain. Little chance of breaks developing in the cloud cover.

Snæfellsnes

The current forecast indicates easterly winds and mostly dry conditions until noon. Intermittent rain is expected in the afternoon, first in the south and then in the north towards evening. Rain will ease during the evening. Skies will probably be cloudy, but there is some chance of breaks developing in the low- and medium-level cloud, particularly in the north, into the early evening.

Westfjords

Light northeasterly winds and mostly dry conditions. Skies are likely to be brighter in the Westfjords, with a reasonably good chance of breaks developing in the cloud cover, particularly in the north. The clouds are currently expected to consist mainly of medium- and high-level cloud, with less low cloud.