As the golden-ringed sun settles toward the horizon it reaches the shores of Morocco and the city of Casablanca. It's not an auspicious ending. Casablanca is a fairly cloudy city, with a climate that resembles that in the Baja. As in Mexico, the controlling influence on cloudiness in northwest Africa is a large and permanent high pressure cell - the same one which controls the weather of the Azores. Strong northerly winds circulating around this high push the cool Canary Current southward along the coast of Morocco. The by now familiar combination of cool ocean breezes and moist air trapped beneath a temperature inversion conspire to cloak the coast in low clouds and occasional fogs. The eclipse ends in much the same weather as it began.
Inland regions usually escape the marine cloudiness, especially on the rising slopes of the towering Atlas mountains. The probability of a sunny sunset increases from a dismal 30% on the Atlantic shores to a promising 50% near the end of the track ( Figure 9). Cloud seems to pile up against the mountains in the neighborhood of Ifrane, which reports fewer sunshine hours than any other Moroccan location in Table 15. Cloudiness in the interior comes from a variety of sources. The most likely is a low pressure depression related to more intense systems moving over Europe. Another is a passing low pressure disturbance which travels eastward into the Mediterranean. Sometimes the latter originate in the Atlantic, and pass through the Straits of Gibraltar. At other times they form on the east side of the Atlas Mountains and move across the northern reaches of the Sahara Desert through Algeria and Libya.
If the track is just right, these lows can draw hot oppressive dusty air from the desert, a wind known as the sahat in Morocco and the scirocco elsewhere in north Africa. The scirocco is not usually as intense over Morocco as other parts of the Mediterranean, but the dust can be a considerable problem for eclipse chasers. One description, though not over Morocco, confesses to a yellowish leaden sky "through which the sun can be seen only as pale disk, if at all." Satellites have traced Saharan dust all the way to the Caribbean. From Tangier eastward about 5 scirocco days per month are reported in May.
As the scirocco lows move eastward, winds turn northerly again and moist air is drawn inland against the Atlas Mountains. Lifted by the terrain, clouds build deeply, bringing the occasional rains and thundershowers of spring. These variable weather systems are especially favored in May. Even so, sunshine is the dominant element, with most inland areas receiving an amount comparable to northern Mexico.
One of the major problems for sunset eclipses is the apparent thickening of cloud near the horizon due to perspective effects. Skies must be fairly clear to hold promise of an open horizon, as many discovered in southern California in 1992. Haze may obscure the horizon, hiding low cloud layers until silhouetted by the declining sun, leaving only a half hour or less for movement to a more promising location. Since the terminus of the eclipse is on the Sahara side of the Atlas Mountains, the horizon view to the west will be blocked by the terrain. These are significant peaks with some summits reaching over 3500 meters along the center line. The most promising chances are likely to be found about 150 kilometers inland, perhaps somewhere along the road joining Marrakech and Meknes where the view to the setting sun is unobstructed. Another promising route is along the highway from Casablanca to Khouribga and beyond, climbing steadily upward from the coastal plain.
Chasers will have the best chance of success if they've scouted a few locations beforehand. Up-to-date weather information and a commitment to mobility will also help. Luckily the eclipse is late in the day, affording considerable time and daylight for planning and decisions.
