Tag: roll arcus cloud

Some cloud families

Cumuliform clouds add energy to any photo. Even photos in black and white benefit from them largely, whether it is for a normal or an HDR photo.

The stratiform clouds add to the tranquillity and the stability of a photo.

Clouds including a stratiform and cumuliform components (stratocumulus) produce an effect that is more energizing than the simple stratus, while avoiding the explosion of energy of the cumuliform clouds.

The cold front

The approach of a cold front enhances the possibility of interesting photos. If it is a fast moving cold front of moist and unstable air, the photos will probably be more spectacular, as some thunderstorms will be associated with the system. A dew point of more than 15 C indicates the presence of a lot of water vapor which can be transformed into precipitation, thus releasing a lot of energy. When these conditions are combined with a really strong contrast between the new air mass which approaches and the one which goes away, the produced meteorological phenomena will certainly be intense.

In the photos below, the meteorological system approaching the Quebec Jean-Lesage international airport also had to cross a small mountain range.

The morning fog

The morning fog offers many opportunities for interesting photos. You can choose an isolated tree and capture the combined effects of the morning sun and fog. Or you may choose a cluster of trees, for a completely different effect. Both photos below were taken in Domaine Cataraqui, Quebec City.

A morning fog resulting from a cold cloudless night will persist for hours if there is no wind. The cold morning air, motionless over a slightly hotter stretch of water, creates a fog that will finally disappear just before noon, when the atmosphere has been heated enough. If there had been an overcast sky during the night, chances are that the air over the water would have remained at a higher temperature, preventing the formation of fog.

The opportunities for more interesting photos arise when you witness the first holes in the fog layer.

We can take into account the season to estimate the speed of the diurnal reheating of the lower atmosphere. A morning fog will need more time to dissipate from late autumn to early spring: that leaves more time for the photographer to prepare. The forecasts can announce the disappearance of fog while it will not be the case if, over your sector, there is an invading layer of stratocumulus preventing the morning sun from reaching the ground.

To determine if the fog is going to dissipate as expected or will remain and possibly intensify, watch the difference between the temperature and the dew point on the hourly meteorological observations issued by weather stations near your place of residence. If the temperature and dew point spread increases, the fog is going to lift. If the difference between those two decreases, the fog is going to persist and possibly intensify.

The mist

The mist can be qualified as such when the visibility is superior to ½ mile, but do not exceed 6 miles for an observer on the ground. If the visibility is of ½ mile or less, it is called fog. This photo of the Bic National Park, near Rimouski, shows the interesting effect that the mist adds to a beautiful landscape.

Hot and unstable air in winter

When there is a warm and unstable air advection (about 0 degrees) while winter has already settled, there are good opportunities for photos. A moderately developed cumulus produces significant snow showers and this snow sticks on all the surrounding objects. All that snow would have begun to melt on contact of objects if the latter had had a temperature superior to zero degree. But, the winter being already settled, the snow persists. It gives enough time to capture some souvenirs.

The local effects

A photographer might benefit from learning about the meteorological local effects influencing the regions he intends to visit. The local effects are often simple to understand and they repeat themselves regularly, according to wind and season changes. The knowledge of these effects allows the photographer to be ready and position himself even before the phenomenon occurs. It limits the comments like: “If I had known that it would occur, I would have settled down here one hour earlier!“

The local terrain as well as large size bodies of water produce predictable meteorological phenomenon that can be used by a well prepared photographer. It can consist of persistent fog, repetitive snowstorms over a small sector, strong winds, cumuliform clouds alongside the mountain summits, etc. By being positioned at the right place, at the right time, the desired photo can be realized.

A change in the wind direction

A change in the wind direction suddenly increases the opportunities of interesting photos. It might announce the approach of a cold front, a warm front, a sea or land breeze, etc. In the photo below, a bit of fresher air suddenly began crossing the St-Lawrence seaway at the end of the day, thanks to the approach of a weak cold front. The water was still relatively warm and the moisture which was present over the surface became visible due to the cool air supply. The conditions were now ideal for a short-term thin fog, as long as the wind speed would not increase. Just in time for a photo.

Familiarization with weather radars

It can be useful to get acquainted with weather radars which, for the needs of photography, remain simple to interpret. Multiple echoes of small dimension with a steep gradient of various colors indicate precipitation resulting from cumuliform clouds. The showers associated with these clouds are often moderated or strong and will be the result of approaching towering cumulus or cumulonimbus (thunderstorms). A towering cumulus presents a dark base and a white summit to the photographer. At sunset, their vertical development can be used to emphasize the last rays of light.

Large echo areas of similar colors of low intensity indicate a relatively stable air generally producing steady light rain or drizzle. This should be understood as a possibility of increased humidity limiting the visibility through mist or fog.

Hoar frost

Hoar frost is a short-term phenomenon. It is thus necessary to capture the scene before the sun melts everything. The photo below shows some small twigs on which hoar frost has settled. It was taken at the beginning of the seventies. Although the quality of the photo is not exceptional, the meteorological phenomenon is well demonstrated.

Forest fires

Wishing to make photos of western Canada during summer 2014, I came up against a season where hundreds of forest fires were raging. The smoke was covering some parts of Alberta and British Columbia. Some fires were important enough to require the closure of the sole highway connecting Lake Louise to Jasper. I thus decided to include the effects of those fires in the holiday souvenirs.

A visibility reduced in forest fire smoke allows a photographer to obtain, without special editing, sunsets with interesting colors.

The smoke also produces an effect similar as fog, but a fog which would be impossible to obtain at the end of a summer afternoon while the sun shines and there is a 38 degrees Celsius temperature.

At dusk, the residual smoke is visible near tree tops while the setting sun strikes the mountain side. The effect is of two horizontal lines of complementary colors, blue and orange.

Metar decode and description

Significant Present Weather Codes