Regione autonoma Valle d'Aosta - Bollettino meteorologico

Meteo

Current conditions [ Expanded ] [ Collapsed ]

Latest weather observations, satellite imagery, mapped last 3 hours temperature and last 24 hours rainfall

Map display of recent weather data for observing locations

Satellite imagery
This image is obtained by the infrared channel of the MSG (Meteosat Second Generation) satellite, in geostationary orbit at 36000 km of altitude. The infrared channel can be used even in night-time, since the presence of clouds and of other meteorological structures is detected by a indirect measure of their surface temperature.

Immagine satellite

Temperature last three hours
The map shows the average temperature of the last three hours, figured out from a network of 40 thermometric stations. The spatial distribution is based only on altitude. That means that differences between two stations located at the same altitude due, for instance, to a different aspect, are not taken into account.

Temperature ultime 3 ore

Precipitations last 24 hours
This map shows the precipitations of the last 24 hours measured from 30 rain gauges able to melt snow. The spatial distribution is based on a simple real time data interpolation.

Precipitazione ultime 24 ore

Satellite imagery Satellite imagery Temperature last three hours Temperature last three hours Precipitations last 24 hours Precipitations last 24 hours

Weather bulletin

(Issued at 16/09/2014 11:28:06)

Synoptic situation [ Expanded ] [ Collapsed ]

Sea level pressure recorded today at 7.00 am. in Aosta : 1017 hPa.
Sea level and 5500 m situation
Colour contours indicate the geopotential height at 500 hPa, while the blue isoline indicates the sea level pressure (slp). The geopotential height at a given value of pressure indicates the altitude above the sea level with this value of pressure. The geopotential height at 500 hPa is given in decametres: if you multiply by ten you get the altitude, usually between 5200 and 5700 m. Low values – grey to green to blue colours – indicate low pressures systems aloft girdling cold air, while high values – yellow to orange colours – indicate high pressures systems aloft, girdling relatively warm air.

Colour contours indicate the geopotential height at 500 hPa, while the blue isoline indicates the sea level pressure (slp). The geopotential height at a given value of pressure indicates the altitude above the sea level with this value of pressure. The geopotential height at 500 hPa is given in decametres: if you multiply by ten you get the altitude, usually between 5200 and 5700 m. Low values – grey to green to blue colours – indicate low pressures systems aloft girdling cold air, while high values – yellow to orange colours – indicate high pressures systems aloft, girdling relatively warm air.

Situation at 1500 m
The isolines indicate the geopotential height of the 850 hPa surface in decametres – usually around 1400-1500 m – while the colours indicate the temperature at this altitude in the free atmosphere. It is important to notice that the real value of temperature around 1500 m, in the Aosta Valley or in any region with a complex orography, might be very different from that of the free atmosphere, especially in the bottom of the valleys, where the thermal excursion is usually higher, being colder in wintertime and in the dark hours, and warmer in summertime and when the sun shines. The temperature of the free atmosphere is nevertheless very important, showing the true nature of the air masses.

The isolines indicate the geopotential height of the 850 hPa surface in decametres – usually around 1400-1500 m – while the colours indicate the temperature at this altitude in the free atmosphere. It is important to notice that the real value of temperature around 1500 m, in the Aosta Valley or in any region with a complex orography, might be very different from that of the free atmosphere, especially in the bottom of the valleys, where the thermal excursion is usually higher, being colder in wintertime and in the dark hours, and warmer in summertime and when the sun shines. The temperature of the free atmosphere is nevertheless very important, showing the true nature of the air masses.

Situation at 3000 m
This image represents the situation at 700 hPa – around 3000 m – and can therefore be considered representative of the Aosta Valley mountains. The relative humidity is shown by the colours and the wind by the arrows. Grey, yellow and orange colours indicate a progressive nearing to the saturation, favouring the presence of clouds at about 3000 m. The wind vectors are shown only if the wind speed exceeds 10 m/s (about 36 km/h).

This image represents the situation at 700 hPa – around 3000 m – and can therefore be considered representative of the Aosta Valley mountains. The relative humidity is shown by the colours and the wind by the arrows. Grey, yellow and orange colours indicate a progressive nearing to the saturation, favouring the presence of clouds at about 3000 m. The wind vectors are shown only if the wind speed exceeds 10 m/s (about 36 km/h).


Z (dam) and T (°C) at 850 hPa today 12Z Sea level and 5500 m situation Z (dam) and T (°C) at 850 hPa today 12Z Situation at 1500 m RH (%) and Wind at 700 hPa today 12Z Situation at 3000 m

Weather forecast

Tuesday 16/09/2014

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morning
Today
Wednesday 17/09/2014

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morning
Tomorrow
Thursday 18/09/2014

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morning
Day after tomorrow
afternoon
Today
afternoon
Tomorrow
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Mostly sunny sky with stratiform clouds withdrawing more and more near the landslides of the mountains, and growing again over the course of the day likely with chance of showers from the afternoon.

Mostly sunny sky likely with local showers; some fleeting sunny spells may occur, especially during the central hours.

Partly sunny with even wide cloud banks, with chance of local showers.

Winds: 3000 m light from SW; afternoon breezes in the valleys. Winds: 3000 m light Southerly; afternoon breezes in the valleys. Winds: 3000 m light Southerly; afternoon breezes in the valleys.
Temperatures: rising during the daylight. Temperatures: decreasing during the daylight in the valleys. Temperatures: stable or rising slightly.
Freezing level 3200 » 3600 m
Temp 1500 m 7 » 18 °
Temp 3000 m 1 » 6 °
Freezing level 3300 » 3600 m
Temp 1500 m 6 » 14 °
Temp 3000 m 2 » 4 °
Freezing level 3300 » 3800 m
Atmospheric pressure: stable.
Atmospheric pressure: stable.
Atmospheric pressure: rising.
Communications no warning. Communications no warning.
  • General outlook

    Reliability attendibilità attendibilità attendibilità

    Friday 19/09/2014

    4th day

    Saturday 20/09/2014

    5th day

    Sunday 21/09/2014

    6th day

    Monday 22/09/2014

    7th day

    Still unsettled weather conditions on Friday, and then sunnier likely.


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