mumblesmetdata.net

Welcome to the Mumblesmetdata.net website. the site displays live data from the automatic weather station located in Thistleboon, and on many aspects of the weather we experience every day.

Air Pressure

High and low pressure systems cause day-to-day changes in our weather. In this article, we look at how they are defined and how they form.

What do we mean by ‘pressure’?

The Earth’s atmosphere exerts pressure on the surface. Pressure is measured in hectoPascals (hPa), also called millibars. Standard pressure at sea level is defined as 1013hPa, but we can see large areas of either high or low pressure. These areas are all relative to each other, so what defines a high will change depending on the area around it.

Weather chart

On a weather chart, lines joining places with equal sea-level pressures are called isobars. Charts showing isobars are useful because they identify features such as anticyclones (areas of high pressure) and depressions (areas of low pressure).

Ascending and descending air

Areas of high and low pressure are caused by ascending and descending air. As air warms it ascends, leading to low pressure at the surface. As air cools it descends, leading to high pressure at the surface.

In general, low pressure leads to unsettled weather conditions and high pressure leads to settled weather conditions.

Anticyclone (high pressure)

In an anticyclone (high pressure) the winds tend to be light and blow in a clockwise direction (in the northern hemisphere). Also, the air is descending, which reduces the formation of cloud and leads to light winds and settled weather conditions.

Depression (low pressure)

In a depression (low pressure), air is rising and blows in an anticlockwise direction around the low (in the northern hemisphere). As it rises and cools, water vapour condenses to form clouds and perhaps precipitation. This is why the weather in a depression is often unsettled, there are usually weather fronts associated with depressions.
<Info from Metoffice>

The Sun

The Sun, also known as Sol, is a star at the center of the solar system. It is a white star that gives off different types of energy such as infrared energy (heat), ultraviolet light, radio waves and light. It also gives off a stream of particles, which reaches Earth as “solar wind“. The source of all this energy is nuclear fusion. Nuclear fusion is the reaction in the star which turns hydrogen into helium and makes huge amounts of energy. It is a nearly perfect ball of hot plasma.

The Sun looks yellow to people on Earth, but it is really white. This happens because the air around the Earth scatters sunlight. The blue and green colors in the sunlight spread out more than the red and yellow colors. Because of this, the light that reaches our eyes is mostly red and yellow, making the Sun appear yellow. If we were in space, where there is no air to scatter the light, we would see that the Sun is actually white.

The Sun is a star like many others in our Milky Way galaxy. The Sun is a type of star called a G-type main-sequence star based on its spectral class.^[15]

The Sun is about 4.5 billion years old.

The Sun is about a hundred times as wide as the Earth. It has a mass of 1.9891×10³⁰ kg. This is 333,000 times the mass of the Earth. 1.3 million Earths can fit inside the Sun.^[16] The Sun fuses about 600 million tons of hydrogen into helium every second.

The Sun is the main source of energy for the Earth. This energy is made deep inside the Sun in a process called nuclear fusion. Four hydrogen atoms are fused together to make one helium atom. Some of the leftover matter turns into energy. This is the same way energy is released in a hydrogen bomb.

It can take between 10,000 and 170,000 years for the energy in the core of the Sun to escape.

The Moon

The Moon is Earth’s only natural satellite. It orbits at an average distance of 384,400 km (238,900 mi), about 30 times the diameter of Earth. Tidal forces between Earth and the Moon have synchronized the Moon’s orbital period (lunar month) with its rotation period (lunar day) at 29.5 Earth days, causing the same side of the Moon to always face Earth. The Moon’s gravitational pull—and, to a lesser extent, the Sun‘s—are the main drivers of Earth’s tides.

The lunar surface is covered in lunar dust and marked by mountains, impact craters, their ejecta, ray-like streaks, rilles and, mostly on the near side of the Moon, by dark maria (“seas”), which are plains of cooled lava. These maria were formed when molten lava flowed into ancient impact basins. The Moon is, except when passing through Earth’s shadow during a lunar eclipse, always illuminated by the Sun, but from Earth the visible illumination shifts during its orbit, producing the lunar phases.^[18] The Moon is the brightest celestial object in Earth’s night sky. This is mainly due to its large angular diameter, while the reflectance of the lunar surface is comparable to that of asphalt. The apparent size is nearly the same as that of the Sun, allowing it to cover the Sun completely during a total solar eclipse. From Earth about 59% of the lunar surface is visible over time due to cyclical shifts in perspective (libration), making parts of the far side of the Moon visible.

Shipping and inshore water stuff.

The Shipping Forecast is a BBC Radio broadcast (click the link to read todays shipping forecast)
of weather reports and forecasts for the seas around the British Isles. It is produced by the Met Office and broadcast by BBC Radio 4 on behalf of the Maritime and Coastguard Agency. The forecast dates back over 150 years. There are currently two or three broadcasts per day, at 00:48, 05:20, and 17:54 (weekends only) UK local time.^[1]

In the forecast, the waters around the British Isles are divided into 31 sea areas, also known as weather areas. The forecast begins by listing areas with gale warnings, followed by a general synopsis of pressure areas, then a forecast for each individual sea area covering wind speed and direction, precipitation, and visibility. Extended forecasts at 00:48 and 05:20 include information from coastal weather stations and an inshore waters forecast.

The unique and distinctive presentation style of these broadcasts has led to their attracting an audience much wider than that directly interested in maritime weather conditions. It is frequently referred to and parodied in British popular culture.

Moon related stuff.

Inshore waters stuff

The inshore coastal areas of the United Kingdom are 15 fixed stretches of coastline that are used in weather forecasting especially for wind-powered or small coastal craft. Each area is delimited by geographical features such as headlands, seaports or estuaries. When used as part of a broadcast weather forecast they are mentioned in the same order, clockwise round the mainland starting and finishing in the north west of the island of Great Britain. The Isle of Man is included in the forecasts but it is not part of the United Kingdom.

List of inshore coastal areas

[edit]

Cape Wrath – Rattray Head including Orkney
Rattray Head – Berwick on Tweed
Berwick on Tweed – Whitby
Whitby – Gibraltar Point
Gibraltar Point – North Foreland
North Foreland – Selsey Bill
Selsey Bill – Lyme Regis
Lyme Regis – Land’s End including the Isles of Scilly
Land’s End – St David’s Head including the Bristol Channel
St David’s Head – Great Orme‘s Head including St George’s Channel
Great Orme’s Head – Mull of Galloway
Isle of Man
Lough Foyle – Carlingford Lough (covers the entire coastline of Northern Ireland)
Mull of Galloway – Mull of Kintyre including the Firth of Clyde and the North Channel
Mull of Kintyre – Ardnamurchan Point
Ardnamurchan Point – Cape Wrath including the Outer Hebrides
Shetland Isles

The BBC’s coastal forecast splits some of these into shorter lengths of coast. The points at which they are split are Duncansby Head, Fife Ness, Harwich, Thames Estuary, Beachy Head, The Solent, St Albans Head, Start Point, Hartland Point, Holyhead, Morecambe Bay, Firth of Clyde. Additionally, there is a forecast for the Channel Islands.

Follow this link to view the current inshore waters information…..https://www.metoffice.gov.uk/weather/specialist-forecasts/coast-and-sea/inshore-waters-forecast

Tide related stuff

Tide Times for Mumbles.

19 May 2025

Time	Type	Height
04:49	low	2.69m
11:12	high	7.58m
17:05	low	2.96m
23:42	high	7.66m

20 May 2025

Time	Type	Height
05:58	low	2.86m
12:16	high	7.37m
18:25	low	3.12m

21 May 2025

Time	Type	Height
00:54	high	7.58m
07:15	low	2.81m
13:31	high	7.4m
19:47	low	2.98m

View full 7 day tide times.

Tides. An explanation.

Tides are the cyclical rise and fall of sea levels, primarily the gravitational pull of the Moon and Sun on Earth’s oceans. This gravitational force creates bulges of water on opposite sides of the Earth, resulting in high tides. The Earth’s rotation then carries coastal areas through these bulges, causing the cycle of high and low tides.

Here’s a more detailed explanation:

- Gravitational Influence:
  The Moon’s gravitational pull is the primary driver of tides. The Sun’s gravity also plays a role, especially when it aligns with the Moon during spring tides.

Bulges:
The Moon’s gravitational force causes a bulge of water on the side of Earth closest to the Moon (creating high tide) and a corresponding bulge on the opposite side.

Earth’s Rotation:
As the Earth rotates, coastal areas pass through these bulges, resulting in high tides when they are in a bulge and low tides when they are in between the bulges.

Tidal Cycle:
Most locations experience two high tides and two low tides each lunar day, which is about 24 hours and 50 minutes long.

Spring and Neap Tides:
When the Moon and Sun align (during new and full moons), their gravitational pulls combine to create stronger spring tides with higher high tides and lower low tides. When the Moon and Sun are at right angles to each other (around the first and third quarter moons), their gravitational pulls partially cancel each other out, resulting in weaker neap tides with less variation between high and low tides.

Cloud related stuff

This area of the site will provide you with a relatively easy way to identify clouds you see on a day to day basis.

A good starting point is to estimate the height of the lowest cloud, then go to the picture below, look for that particular height and see what clouds could be visible. Click on the green circle nearest to the cloud you think it could be. The link will then take you to the World Meteorological Cloud Atlas, which will show you real examples of the cloud and more info on it.

click click click click click click click click click click

Visual phenomena stuff
Aurora

The most well known and seldom seen visual phenomena in the UK, is the Aurora borealis, also known as the Northern Lights, it is a natural light display in the night sky caused by solar activity.

Click here to see current conditions and more info.

What causes it
The sun releases electrically charged particles, called solar wind, which travel towards Earth. Earth’s magnetic field captures some of these particles and directs them towards the poles. The particles collide with atoms and molecules in the upper atmosphere, which heats them up and produces light.
The are a host of other visual phenomena which can be experienced. Click her to explore a Wikipaedia page, which goes into more detail.
https://en.wikipedia.org/wiki/Atmospheric_optics

Lightning

What causes lightning?

As warm air rises it cools and condenses forming small droplets of water. If there is enough instability in the air, the updraft of warm air is rapid and the water vapour will quickly form a cumulonimbus cloud. Typically, these cumulonimbus clouds can form in under an hour.

As the warm air continues to rise, the water droplets combine to create larger droplets which freeze to form ice crystals. As a result of circulating air in the clouds, water freezes on the surface of the droplet or crystal. Eventually, the droplets become too heavy to be supported by the updraughts of air and they fall as hail.

As hail moves within the cloud, it picks up a negative charge by rubbing against smaller positively charged ice crystals. A negative charge forms at the base of the cloud where the hail collects, while the lighter ice crystals remain near the top of the cloud and create a positive charge.

The negative charge is attracted to the Earth’s surface and other clouds and objects. When the attraction becomes too strong, the positive and negative charges come together, or discharge, to balance the difference in a flash of lightning (sometimes known as a lightning strike or lightning bolt). The rapid expansion and heating of air caused by lightning produces the accompanying loud clap of thunder.

Where do thunderstorms form?

Thunderstorms are common occurrences on Earth. It is estimated that a lightning strike hits somewhere on the Earth’s surface approximately 44 times every second, a total of nearly 1.4 billion lightning strikes every year.

Owing to the fact thunderstorms are created by intense heating of the Earth’s surface, they are most common in areas of the globe where the weather is hot and humid. Landmasses, therefore, experience more storms than the oceans and thunderstorms are also more frequent in tropical areas than the higher latitudes.

In the UK thunderstorms are most common over the East Midlands and the southeast.

Info supplied from the Met Office.

Click here for thunderstorms in the UK.

Thunder storms can be very exciting to watch, they can also cause severe damage and can be a serious threat to life. Luckily, this country does not suffer thunderstorms on a regular basis. Click …here… for live , UK thunderstorm locations.
The following link will take you to The Tornado and Storm Research Organisation …click here… which will give you some more facts about thunderstorms in the UK.

Rainbows

A rainbow is an optical phenomenon caused by refraction, internal reflection and dispersion of light in water droplets resulting in a continuous spectrum of light appearing in the sky. The rainbow takes the form of a multicoloured circular arc. Rainbows caused by sunlight always appear in the section of sky directly opposite the Sun. Rainbows can be caused by many forms of airborne water. These include not only rain, but also mist, spray, and airborne dew.

Rainbows can be full circles. However, the observer normally sees only an arc formed by illuminated droplets above the ground, and centered on a line from the Sun to the observer’s eye.

In a primary rainbow, the arc shows red on the outer part and violet on the inner side. This rainbow is caused by light being refracted when entering a droplet of water, then reflected inside on the back of the droplet and refracted again when leaving it.

In a double rainbow, a second arc is seen outside the primary arc, and has the order of its colours reversed, with red on the inner side of the arc. This is caused by the light being reflected twice on the inside of the droplet before leaving it.

This area of the site will give you access to various broadcast stations, which transmit weather forecast and other weather related information.

Weather from the BBC for Mumbles,
Met office weather forecast
Windy.com
Time and Date