Some clouds, warm and fog/mist explained
Good morning Augusta.
This morning it is clear, then partly cloudy. High of 79F. Winds from the SW
at 5 to 10 mph.
Tonight it will be Clear. Low of 59F. Winds less than 5 mph.
The readings from my own instruments are:
The humidity is 83% with a Dew Point of 57.7ºF and a wind chill of 62.8ºF.
The temperature is 62.8ºF.
We have Southeast winds between 0.0 mph and 1.0 mph.
Our Barometric pressure is 30.18 HPA 1021.6 and rising with a weather
graphic indicating sun.
The UV rating is 2 out of 16, sunset will be at 7:39 PM with Moon Rise at
5:544 p.m. and the moon phase is waxing gibbous.
For the pilots out there, Raw Metar readings are:
METAR KAUG 181153Z AUTO 00000KT 10SM CLR 14/13 A3028 RMK AO2 SLP253
T01390128 10144 20111 52003
Visibility is 10.0 miles/16.1 kilometers with slowly encroaching clouds.
We've had no rain here in the past 24 hours.
Since we are slipping towards September at an ever-increasing rate, Fog,
especially for those of us who are in New England and are near water will be
dealing with fog.
I hope the following explanation about Fog and Mist will be informative.
Downloaded and copied directly from:
http://www.weatheronline.co.uk/reports/wxfacts/Fog-and-Mist.htm
The foregoing is a U.K. web site and it is a good one.
"It was on the ninth of November [...] He was walking home about eleven
o'clock from Lord Henry's, where he had been dining, and was wrapped in
heavy furs, as the night was cold and foggy."
The beginning of chapter twelve of Oscar Wilde's "The Picture of Dorian
Grey" describes many things about fog and how we feel in it. First, fog is
very common in fall and winter. Also fog is often forming during night-time
and the calm and cold weather together with reduced visibility and the damp,
close air is evocing a feeling of loneliness and fear.
Meteorologically speaking fog is nothing but a very low stratus (latin:
layer) cloud. In fact this cloud often even touches ground. Fog is made of
tiny liquid water droplets, lightweighted enough to remain suspended in the
air. Their average diameter is varying between 0.01mm and 0.1mm and causing
any light present to be reflected off in different directions. This is the
cause of the whitish vale that we all know. The term fog is used when
visibility reduces to less than 1km and the relative humidity exceeds 95%.
Whereas mist is reported when visibility exceeds 1km. Obscuration by dry
particles is defined as haze , which must not be mixed up with the popular,
but somewhat vague term 'hazy skies' describing high thin clouds (often
cirrus) obscuring the sun. Another form of fog is sea, lake or river smoke.
The main criteria for fog formation is water-saturated air. When air is
saturated, the water vapor turns into liquid water droplets in a process
called condensation. The two ways air can become saturated are cooling the
air to its dewpoint temperature or evaporating moisture into the air and
increasing its water vapor content.
The five most important factors for forecasting fog formation are
1) long nights during colder months;
2) clear skies and light winds;
3) moist air;
4) a low-level temperature inversion and the
5) sufficient supply of condensation nuclei.
the most common cause of fog is cooling by radiation, when 1) the ground
surface radiates heat and cools; 2) the layer of airnext to the surface is
cooled by contact with the surface. 3) As fog forms itradiates heat
(condensation heat) and thus becomes cooler. Eventually 4 ) gentle movement
of air increases mixing and the fog will gradually become thicker reducing
visibilities to zero.. Fog usually clears soon after dawn as the sun heats
up the air again, allowing it to hold more moisture. The fog is "burned
off".
Types of fog are:
Radiation or ground fog - in mountain areas and cold pools often seen as
valley fog. Radiation fog might be rather shallow over damp and wet ground
after a rainy night and is sometimes called precipitation fog. Radiation fog
might also form as a low stratus cloud forming just underneath an inversion,
gradually expanding and descending towards the ground surface.
Advection fog - is also called sea fog, when warm air flows over relatively
cold sea surface, but is just as common over land. Advection fog is often
associated with the passage of cold and warm fronts and thus is also known
as frontal fog.
Sea smoke or river smoke. Mainly caused by evaporation. This type of fog is
rather shallow and lies generally below 10m in height from the surface and
is locally restricted to places with large temperature differences with the
air colder than the water.
This morning it is clear, then partly cloudy. High of 79F. Winds from the SW
at 5 to 10 mph.
Tonight it will be Clear. Low of 59F. Winds less than 5 mph.
The readings from my own instruments are:
The humidity is 83% with a Dew Point of 57.7ºF and a wind chill of 62.8ºF.
The temperature is 62.8ºF.
We have Southeast winds between 0.0 mph and 1.0 mph.
Our Barometric pressure is 30.18 HPA 1021.6 and rising with a weather
graphic indicating sun.
The UV rating is 2 out of 16, sunset will be at 7:39 PM with Moon Rise at
5:544 p.m. and the moon phase is waxing gibbous.
For the pilots out there, Raw Metar readings are:
METAR KAUG 181153Z AUTO 00000KT 10SM CLR 14/13 A3028 RMK AO2 SLP253
T01390128 10144 20111 52003
Visibility is 10.0 miles/16.1 kilometers with slowly encroaching clouds.
We've had no rain here in the past 24 hours.
Since we are slipping towards September at an ever-increasing rate, Fog,
especially for those of us who are in New England and are near water will be
dealing with fog.
I hope the following explanation about Fog and Mist will be informative.
Downloaded and copied directly from:
http://www.weatheronline.co.uk/reports/wxfacts/Fog-and-Mist.htm
The foregoing is a U.K. web site and it is a good one.
"It was on the ninth of November [...] He was walking home about eleven
o'clock from Lord Henry's, where he had been dining, and was wrapped in
heavy furs, as the night was cold and foggy."
The beginning of chapter twelve of Oscar Wilde's "The Picture of Dorian
Grey" describes many things about fog and how we feel in it. First, fog is
very common in fall and winter. Also fog is often forming during night-time
and the calm and cold weather together with reduced visibility and the damp,
close air is evocing a feeling of loneliness and fear.
Meteorologically speaking fog is nothing but a very low stratus (latin:
layer) cloud. In fact this cloud often even touches ground. Fog is made of
tiny liquid water droplets, lightweighted enough to remain suspended in the
air. Their average diameter is varying between 0.01mm and 0.1mm and causing
any light present to be reflected off in different directions. This is the
cause of the whitish vale that we all know. The term fog is used when
visibility reduces to less than 1km and the relative humidity exceeds 95%.
Whereas mist is reported when visibility exceeds 1km. Obscuration by dry
particles is defined as haze , which must not be mixed up with the popular,
but somewhat vague term 'hazy skies' describing high thin clouds (often
cirrus) obscuring the sun. Another form of fog is sea, lake or river smoke.
The main criteria for fog formation is water-saturated air. When air is
saturated, the water vapor turns into liquid water droplets in a process
called condensation. The two ways air can become saturated are cooling the
air to its dewpoint temperature or evaporating moisture into the air and
increasing its water vapor content.
The five most important factors for forecasting fog formation are
1) long nights during colder months;
2) clear skies and light winds;
3) moist air;
4) a low-level temperature inversion and the
5) sufficient supply of condensation nuclei.
the most common cause of fog is cooling by radiation, when 1) the ground
surface radiates heat and cools; 2) the layer of airnext to the surface is
cooled by contact with the surface. 3) As fog forms itradiates heat
(condensation heat) and thus becomes cooler. Eventually 4 ) gentle movement
of air increases mixing and the fog will gradually become thicker reducing
visibilities to zero.. Fog usually clears soon after dawn as the sun heats
up the air again, allowing it to hold more moisture. The fog is "burned
off".
Types of fog are:
Radiation or ground fog - in mountain areas and cold pools often seen as
valley fog. Radiation fog might be rather shallow over damp and wet ground
after a rainy night and is sometimes called precipitation fog. Radiation fog
might also form as a low stratus cloud forming just underneath an inversion,
gradually expanding and descending towards the ground surface.
Advection fog - is also called sea fog, when warm air flows over relatively
cold sea surface, but is just as common over land. Advection fog is often
associated with the passage of cold and warm fronts and thus is also known
as frontal fog.
Sea smoke or river smoke. Mainly caused by evaporation. This type of fog is
rather shallow and lies generally below 10m in height from the surface and
is locally restricted to places with large temperature differences with the
air colder than the water.
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