Weather data updated on: den 29 augusti 2008, 05:40 CET
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Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Humankind has attempted to predict the weather since ancient times.

Today, weather forecasts are made by collecting quantitative data about the current state of the atmosphere and using scientific understanding of atmospheric processes to project how the atmosphere will evolve.

The chaotic nature of the atmosphere, the massive computational power required to solve the equations that describe the atmosphere, and incomplete understanding of atmospheric processes mean that forecasts become less accurate as the range of the forecast increases.


The forecast from my station's console is based on the barometic reading and trend, wind speed and direction, rainfall, temperature, humidity, latitude & longitude and time of the year. The symbol indicates the predicted weather for the next 12 hours. The text predicts the weather up to 48 hours in advance.


The forecast from DMI is based on their computer model called DMI-HIRLAM.
 
Automatic forecast from the console



Mostly cloudy and cooler. Precipitation possible within 12 hrs., possibly heavy at times. Windy.
 

 
Forecast from DMI










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A barometer is commonly used for weather prediction, as high air pressure in a region indicates fair weather while low pressure indicates that storms are more likely.

Simultaneous barometric readings from across a network of weather stations allow maps of air pressure to be produced. Isobars drawn on such a map links sites with the same pressure and give, in effect, a contour maps of areas of high and low pressure.

Localized high atmospheric pressure acts as a barrier to approaching weather systems, diverting their course. Low atmospheric pressure, on the other hand, represents the path of least resistance for a weather system, making it more likely that low pressure will be associated with increased storm activities.

If the barometer is falling then bad weather or some form of precipitation will fall, however if the barometer is rising then there will be nice weather or no precipitation.
 
Barometric pressure 1009 hPa
Currently changing 0 hPa/1h   +0 hPa/3h   -2 hPa/12h
Today's average 1009 hPa
Air density 1,2110 kg/m³

Today's highest

1009 hPa at 00:50
Today's lowest 1008 hPa at 02:20

augusti's highest

1020 hPa on 2008-08-01 at 00:10
augusti's lowest 984 hPa on 2008-08-04 at 19:20

2008's highest

1044 hPa on 2008-02-16 at 09:30
2008's lowest 966 hPa on 2008-03-01 at 08:20

Highest ever*

1046,6 hPa on 2006-01-23 at 11:00
Lowest ever* 965,1 hPa on 2007-03-18 at 22:00

24h graph
14day graph







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Temperature measurement using modern scientific thermometers and temperature scales goes back at least as far as the early 18th century, when Gabriel Fahrenheit adapted a thermometer (switching to mercury) and a scale both developed by Ole Christensen Røemer. Fahrenheit's scale is still in use, alongside the Celsius scale and the Kelvin scale.

The world's average surface air temperature is 15 °C

Vostok, Antarctica holds the lowest temperature record of -88 °C on 13 Sep 1922

The highest measured temperature on Earth is 57.8 °C in the desert of El Azizia, Libya on 21 Jul 1983
 
Temperature 15,0 °C (changing -0,2 °C per hour)
Wind chill 15,0 °C
Thermal stress moderate thermal stress (17)
Today's average 15,7 °C
augusti's average 17,16 °C

Today's highest

15,5 °C at 00:20
Today's lowest 14,8 °C at 05:00

augusti's highest

28,9 °C on 2008-08-01 at 17:10
augusti's lowest 9,0 °C on 2008-08-25 at 04:20

2008's highest

28,9 °C on 2008-08-01 at 17:10
2008's lowest -8,7 °C on 2008-03-23 at 06:10

Last frost in spring 2008

2008-04-18 with -1,1 °C
First frost in autumn 2008  - - - with -- °C

Highest ever*

31,1 °C on 2006-07-06 at 13:10
Lowest ever* -17,7 °C on 2006-03-07 at 07:30

24h graph
14day graph







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Absolute humidity refers to the mass of water in a particular volume of air. Absolute humidity is expressed as the number of kilograms of water vapor per cubic meter of air. Imagine a cube of air that is one meter wide, one meter high, and one meter deep. If we could "squeeze" all the water out of that cube of air into a container, we could weigh the container and see how many kilograms of water it contains. The amount of vapor in that cube of air is the absolute humidity of that cubic meter of air.

Relative humidity is defined as the ratio of the partial pressure of water vapor in a gaseous mixture of air and water vapor to the saturated vapor pressure of water at a given temperature. That is, a ratio of how much energy has been used to free water from liquid to vapor form to how much energy is left. Relative humidity is expressed as a percentage

Associated with relative humidity is dew point (if the dew point is below freezing, it is referred to as the frost point). Dew point is the temperature at which water vapor saturates from an air mass into liquid or solid usually forming rain, snow, frost, or dew. Dew point normally occurs when a mass of air has a relative humidity of 100%. This happens in the atmosphere as a result of cooling through a number of different processes.
 
Relative humidity 83 %
Today's average 79 %
Absolute humidity 10,66 g/m³
Dewpoint 12,1 °C
Today's average DP 12,0 °C

Today's highest DP

13,4 °C at 23:30
Today's lowest DP 10,5 °C at 15:50

augusti's highest DP

17,8 °C on 2008-08-07 at 11:20
augusti's lowest DP 6,8 °C on 2008-08-01 at 12:20

2008's highest DP

19,0 °C on 2008-07-27 at 19:40
2008's lowest DP -13,3 °C on 2008-03-22 at 18:10

24h graph
14day graph
24h graph
14day graph







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Wind is the rough horizontal movement of air (as opposed to an air current) caused by uneven heating of the Earth's surface. It occurs at all scales, from local breezes generated by heating of land surfaces and lasting tens of minutes to global winds resulting from solar heating of the Earth. The two major influences on the atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet (Coriolis effect).

Given a difference in barometric pressure between two air masses, a wind will arise between the two which tends to flow from the area of high pressure to the area of low pressure until the two air masses are at the same pressure, although these flows will be modified by the Coriolis effect in the extratropics.

The all-time surface wind record is 103.3m/s. The place was Mt. Washington on 12 April 1934.
 
Windspeed (gusts) 3,1 m/s
Average (10min) 0,4 m/s
Direction West Northwest (dominant: W)

Today's highest

6,3 m/s at 00:00

augusti's highest

15,2 m/s on 2008-08-13 at 16:20

2008's highest

22,4 m/s on 2008-01-26 at 14:00

Highest ever*

27,3 m/s on 2007-01-14 at 12:10

24h graph (average wind)
14day graph (average wind)
24h graph (gusts)
14day graph (gusts)
24h graph (wind direction)
14day graph (wind direction)







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Precipitation (also known as hydrometeor) is any product of the condensation of atmospheric water vapor that is deposited on the earth's surface. It occurs when the atmosphere (being a large gaseous solution) becomes saturated with water vapor and the water condenses and falls out of solution (i.e., precipitates).

Precipitation that reaches the surface of the earth can occur in many different forms, including rain, freezing rain, snow, sleet, and hail. Virga is precipitation that begins falling to the earth but dries up before it reaches the surface.

Precipitation is a major component of the hydrologic cycle, and is responsible for depositing most of the fresh water on the planet. Approximately 505,000 km³ of water falls as precipitation each year, 398,000 km³ of it over the oceans.

The world's place with the highest annual precipitation is Lloro, Colombia with approx. 13000mm/year. (Yes, 13-thousand!!)

The place with lowest precipitation is the desert of Arica, Chile with only 0.7mm/year.
 
Rain today 0,0 mm
Rain last hour 0,0 mm
Rain last 3 hours 0,0 mm
Rain last 24 hours 2,0 mm
Rain in augusti 176,5 mm
Rain in 2008 609,1 mm

Rain the last month

127,5 mm
augusti, last year 93,0 mm

Days with rain in 2008

118 days (we are now on day 242)
Last rain was 12 hours, 9 minutes ago

Most rain/day ever*

73,2 mm on 2007-06-22
Most rain/hour ever* 33,3 mm on 2006-08-21
24h graph
14day graph
24h graph (Rain rate)
14day graph (Rain Rate, max/day)
Rain the past 12 months
Rain rate the past 12 months







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See how it really looks like outside my window in Vilshärad

Webcam, viewing west
 







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The moon & sun dates are based on the coordinates of 56° 41' 29" North  -  12° 41' 35" East

Twilight: astronomical morning 03:30
Twilight: nautical morning 04:33
Twilight: civil morning 05:25
Sun rises 06:06 (tomorrow: 06:08  2008-08-30)
Sun in zenith 13:10 (the day is 14:05 hours long)
Sun sets 20:12 (tomorrow: 20:09  2008-08-30)
Twilight: civil evening 20:52
Twilight: nautical evening 21:44
Twilight: astronomical evening 22:46

Moon rises

04:00
Moon in transit 12:00
Moon sets 19:35

Moon's age

27 days, 18 hours, 11 minutes
Moon's phase ß 4%
Next new moon 21:59  2008-08-30
Next full moon 11:14  2008-09-15








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Perhaps not the most interesting section. ;)

24h graph
14day graph
24h graph
14day graph






* = With "ever" means since the beginning of data recording, i.e. November 2004.

Sources of facts:
Wikipedia
NOAA Global measured extremes
Mount Washington Observatory
DMI-HIRLAM